madbeanpedals::forum

Projects => General Questions => Requests => Topic started by: madbean on July 04, 2010, 05:55:27 PM

Title: Sub-mini tube amps
Post by: madbean on July 04, 2010, 05:55:27 PM
Any interest in this kind of project? I've been considering one for myself for a while...even have the tubes and enclosure. I've just never gotten around to designing anything.
Title: Re: Sub-mini tube amps
Post by: Boom on July 05, 2010, 10:11:52 AM
Yes please !

If no one else is interested, i'll promise i'll order enough to justify a startup !
Title: Re: Sub-mini tube amps
Post by: pauloman80 on July 05, 2010, 11:32:11 AM
Heck yes!  Count me in.
Title: Re: Sub-mini tube amps
Post by: PeterMorton on July 05, 2010, 02:50:02 PM
Like the ZVEX nano or  EH .22 caliber? Yes!
Title: Re: Sub-mini tube amps
Post by: Haberdasher on July 05, 2010, 03:59:34 PM
Yeah, I'd like to learn more about this too.  Sounds very cool!
Title: Re: Sub-mini tube amps
Post by: madbean on July 05, 2010, 05:54:05 PM
It would be an original design...most likely british-voiced, to start. I'm thinking something like a 12v input internally multiplied up to 70 or so volts, like most of the frequencycentral stuff. There are some safety issues to consider, though, since the higher voltages can definitely hurt you.
Title: Re: Sub-mini tube amps
Post by: lincolnic on July 05, 2010, 11:31:21 PM
When you say "British", does that mean Marshall or Vox?
Title: Re: Sub-mini tube amps
Post by: madbean on July 06, 2010, 12:27:26 AM
Yeah, I mean something "Vox" like.
Title: Re: Sub-mini tube amps
Post by: Haberdasher on July 06, 2010, 11:32:07 AM
There are some safety issues to consider, though, since the higher voltages can definitely hurt you.

Right, there's always a danger of someone getting zapped.  You should probably make a video outlining safety measures, and definitely illustrate a method for discharging caps.
Title: Re: Sub-mini tube amps
Post by: Boom on July 06, 2010, 11:46:57 AM
Have anyone ordering a board for such a project confirm reading a disclaimer before finalizing an order....
Title: Re: Sub-mini tube amps
Post by: lincolnic on July 06, 2010, 10:24:11 PM
Yeah, I mean something "Vox" like.

In that case, I'm definitely interested.
Title: Re: Sub-mini tube amps
Post by: madbean on July 07, 2010, 06:41:33 AM
Cool. I'll start wrapping my brain around this one. Could be a super project!
Title: Re: Sub-mini tube amps
Post by: Haberdasher on July 08, 2010, 02:52:41 PM
Brian- just out of curiosity do you think this amp would use 6021w subminiatures?
Title: Re: Sub-mini tube amps
Post by: gtr2 on July 10, 2010, 05:42:30 AM
mmm yummy
Title: Re: Sub-mini tube amps
Post by: madbean on July 10, 2010, 06:51:04 AM
Brian- just out of curiosity do you think this amp would use 6021w subminiatures?

Sure, why not!
Title: Re: Sub-mini tube amps
Post by: dcribbs1412 on July 16, 2010, 01:58:37 PM
I'm in
would be great to use 12a_7's
kind like this one?


[attachment deleted by admin]
Title: Re: Sub-mini tube amps
Post by: crashguitar on July 24, 2010, 12:46:01 PM
Since this was posted, I've gotten curious. If it was Vox-like, would one of these be able to do a clean sound, or do they really just do the overdriven thing?
Title: Re: Sub-mini tube amps
Post by: Mr. G. on July 29, 2010, 08:13:00 AM
I would definitely be interested in a project like this!
Title: Re: Sub-mini tube amps
Post by: Haberdasher on August 05, 2010, 05:39:02 PM
Since this was posted, I've gotten curious. If it was Vox-like, would one of these be able to do a clean sound, or do they really just do the overdriven thing?

Good question...
Title: Re: Sub-mini tube amps
Post by: madbean on August 05, 2010, 05:58:34 PM
Well, I guess that comes down to the design process. Can't really say much yet until I've had time to dig into it. But, my goal would be to offer up something that has a range of tones. Maybe something  like the Top Boost.
Title: Re: Sub-mini tube amps
Post by: pauloman80 on August 07, 2010, 02:34:17 PM
Well, I guess that comes down to the design process. Can't really say much yet until I've had time to dig into it. But, my goal would be to offer up something that has a range of tones. Maybe something  like the Top Boost.

Two thumbs' up to that!
Title: Re: Sub-mini tube amps
Post by: Haberdasher on August 07, 2010, 03:22:32 PM
Well, I guess that comes down to the design process. Can't really say much yet until I've had time to dig into it. But, my goal would be to offer up something that has a range of tones. Maybe something  like the Top Boost.

Two thumbs' up to that!

x2  :)
Title: Re: Sub-mini tube amps
Post by: gtr2 on August 08, 2010, 11:11:32 AM
x3
Title: Re: Sub-mini tube amps
Post by: free2rock on November 05, 2010, 05:47:10 AM
Sounds great :-)
Title: Re: Sub-mini tube amps
Post by: juansolo on December 06, 2010, 06:01:26 AM
A submini twincaster would be high up on my want-list (and help me use up my submini stash) :)
Title: Re: Sub-mini tube amps
Post by: culturejam on December 06, 2010, 07:36:30 AM
I still can't believe that nobody has put together a project with the Zvex Nano schematic and info at FreeStompBoxes.  ???
Title: Re: Sub-mini tube amps
Post by: camsna on December 07, 2010, 10:49:46 PM
+1. I'd LOVE to take on such a thing!
Title: Re: Sub-mini tube amps
Post by: dbharris on December 08, 2010, 03:02:23 PM
I would really love to do a sub-mini tube amp as a warm up to a kit amp project...
Title: Re: Sub-mini tube amps
Post by: madbean on December 08, 2010, 03:36:33 PM
Okay, I'll put this on the table for the first of the year. Sounds like quite a few people are into it!
Title: Re: Sub-mini tube amps
Post by: gtrplaya101 on December 09, 2010, 10:17:29 AM
Sounds awesome! look forward to seeing this in the future!
Title: Re: Sub-mini tube amps
Post by: madbean on December 09, 2010, 11:39:53 AM
Yeah, I'm definitely into this project. I'll start looking at some amp designs to get an idea of what I want. If it goes well, I expect to do two or three different ones.
Title: Re: Sub-mini tube amps
Post by: culturejam on December 09, 2010, 07:19:29 PM
Shit yeah! I'd be in for at least one or two of those. If you could find a way to do something like Rick's submini FireFly, that would be boner-ific!  ;D
Title: Re: Sub-mini tube amps
Post by: Jordo on December 09, 2010, 08:28:35 PM
I'm in!
Title: Re: Sub-mini tube amps
Post by: maysink on December 09, 2010, 08:34:45 PM
2 or 3 completely different ones or one board which can magically transform into one of three configs?
Title: Re: Sub-mini tube amps
Post by: madbean on December 10, 2010, 07:14:29 AM
2 or 3 different designs, I think. Vox, Fender, Marshall...or maybe something else.
Title: Re: Sub-mini tube amps
Post by: thetrend77 on December 10, 2010, 09:29:59 AM
Matchless ;)
Title: Re: Sub-mini tube amps
Post by: night-B on December 11, 2010, 04:19:22 AM
Two thumbs up for this project!
I'm very interested by sub-minis but I've never built an amp, only pedals.
I won't be afraid to build my first amp if this is a wonderfull pcb + pdf from Madbean  ;D
Title: Re: Sub-mini tube amps
Post by: gtr2 on December 18, 2010, 09:03:41 AM
I'm really interested in this project.   ;D
Title: Re: Sub-mini tube amps
Post by: willc on December 18, 2010, 10:39:31 PM
This would be great.  I have a few subminis lying around waiting to be put to use.
Title: Re: Sub-mini tube amps
Post by: ilikeguitars01 on December 19, 2010, 04:10:53 AM
Sounds cool
Title: Re: Sub-mini tube amps
Post by: princeton on December 19, 2010, 04:12:44 PM
Very interested! Thumbs up.
Title: Re: Sub-mini tube amps
Post by: raulduke on December 23, 2010, 10:47:15 AM
+1 on very interested   ;D!
Title: Re: Sub-mini tube amps
Post by: stevewire on December 23, 2010, 12:51:12 PM
Sounds pretty cool.  I would be interested in doing a project like that.
Title: Re: Sub-mini tube amps
Post by: CRBMoA on December 23, 2010, 03:01:22 PM
I will send you a list of the sub mini tubes I currently have. That way, if you get stuck, you can choose what I already have.  :-*
Title: Re: Sub-mini tube amps
Post by: jkokura on December 23, 2010, 03:34:03 PM
Haha...

I'd rather see something using typical preamp tubes (!2ax7, ay7, at7). That way it would be a little bit easier to source the tube parts.

Jacob
Title: Re: Sub-mini tube amps
Post by: Marcelo on December 27, 2010, 11:46:07 PM
one more interested....count me in please! great idea!
m
Title: Re: Sub-mini tube amps
Post by: k.rock! on September 03, 2011, 08:52:56 AM
I think I should revive this thread :P

So...how about it Brian?  ;D

I think this along with your mini pedal series would be freakin awesome...sub mini amps and mini pedals with HUGE tone! Ah! can't wait...


-Kaleb
Title: Re: Sub-mini tube amps
Post by: jighead81 on September 03, 2011, 09:44:19 AM
+1  I'd love to do this too! 
Title: Re: Sub-mini tube amps
Post by: T_MBaker on September 03, 2011, 06:24:36 PM
Another vote of desire here
Title: Re: Sub-mini tube amps
Post by: JeffdaMaori on September 04, 2011, 01:50:45 AM
+1 definitly! ;D
Title: Re: Sub-mini tube amps
Post by: madbean on September 04, 2011, 02:12:02 AM
I'm totally open to doing a couple of these. Now, WHEN is an entirely different manner! But, I think I could work on this a bit once we get closer to the release of the baby boards. It certainly would be the bomb, as they say.
Title: Re: Sub-mini tube amps
Post by: irmcdermott on September 04, 2011, 09:46:07 AM
That's awesome! Mini amps, mini pedals.... it's a beautiful thing. It's like "Build You Own Practice Rig... That Doesn't Suck" :)
Title: Re: Sub-mini tube amps
Post by: gtr2 on September 05, 2011, 06:11:49 AM
practice rig...ha  I'd use on of those mini amps for live use, mic'd of course  ;)
Title: Re: Sub-mini tube amps
Post by: derevaun on September 06, 2011, 12:20:34 PM
Wow, awesome! I'm midway into a Murder One on perf, and have wound up fairly well stocked up on submini tubes. It'd be awesome to have a couple choices on PCB.
Title: Re: Sub-mini tube amps
Post by: bigmufffuzzwizz on September 06, 2011, 01:07:44 PM
A submini tube head would definitely become my main home practice rig.
Not anywhere loud enough for my band  :-\
Title: Re: Sub-mini tube amps
Post by: slimtriggers on September 09, 2011, 12:28:38 PM
Maybe something like the Egnater Tweaker?  I wonder if you stuck a Tonemender (http://www.runoffgroove.com/tonemender.html) circuit in for the tonestack if that would be Tweaker-esque? 

Since we're all pedal builders here, an effects loop would be nice, too 8)
Title: Re: Sub-mini tube amps
Post by: TNblueshawk on September 23, 2011, 12:38:29 PM
Count me in and I think I could drag a few people over here to count them in too.
Title: Re: Sub-mini tube amps
Post by: rasta_maleek on October 01, 2011, 03:04:42 AM
i┤m in, hello all.
I built a couple of this amps and i will say that is the best pactice amp that i have.
Tinny, handfull, and sound as loud as human scream, to practice with the singer "acapella".
If you need some info brian, just PM me to send you the proyect.
Now, i playing with some model, that is not in the forums circuits. It has gain, complete tone stack, cathode follower and single ended.

(http://i783.photobucket.com/albums/yy114/DrMalignoTech/Submini-Amplification/100_1949.jpg)

(http://i783.photobucket.com/albums/yy114/DrMalignoTech/Submini-Amplification/100_1948.jpg)

(http://i783.photobucket.com/albums/yy114/DrMalignoTech/Submini-Amplification/100_1943.jpg)

some video testings with some pedals






And this is and older unit, master, gain and multiple voicing, mashallized, fenderisíhed, and insane.



i hope you enjoy with it.

Note. this subminiamps are really pedal friendly.
cheers
Title: Re: Sub-mini tube amps
Post by: Marcelo on October 08, 2011, 10:31:45 AM
hey rasta_maleek, nice! very nice!
you shoudl share the schematics and info! maybe that would get us all going and get the project off the ground.
did i say nice...very nice?
m
Title: Re: Sub-mini tube amps
Post by: bigmufffuzzwizz on October 08, 2011, 11:58:48 AM
That looks great Rasta Maleek! Looks really compact but sounds pretty versatile by what you described. I could see this being a great beginner project for a lot of us into the tube amp world (mini one first :)).
I can't stop laughing about the artwork, I really need an F-U amp!!  :D
Title: Re: Sub-mini tube amps
Post by: FuzzMonkey on October 12, 2011, 03:07:55 AM
Sounds great!
Title: Re: Sub-mini tube amps
Post by: BRGPollen on October 17, 2011, 04:21:44 PM
I would definitely be in for something in the way of the "Nano-Amp!" Mr. Bean, please let us know?!

"B"
Title: Re: Sub-mini tube amps
Post by: DuctTapeRiot on October 17, 2011, 04:25:55 PM
Yes Please!!
Title: Re: Sub-mini tube amps
Post by: wgc on October 07, 2012, 03:06:37 PM
Hate for my first post here to be a "wake the dead thread" but would love to see a madbean project like this!
Title: Re: Sub-mini tube amps
Post by: madbean on October 07, 2012, 04:09:48 PM
I have two designs etched and partially populated. One just a couple of days ago. One is a variation on the Nano head and the other is more or less "Fender-y". So, yeah...this is still very much on the table. And, welcome to the forum!
Title: Re: Sub-mini tube amps
Post by: wgc on October 07, 2012, 07:31:36 PM
Oh yeah!!

And thanks for the welcome!  Its been awhile since I've used pedals but decided to try some DIY to go with a valve jr I fixed and then modded to be more vox sounding.

Your layouts and PDFs are top notch, and I just got 3 boards from you last week, (cupcake, cave dweller, slow loris) really nice job, esp the plated thru holes and silk screen.

Hope to post once I get them into enclosures.

Please keep up the amazing work!
Title: Re: Sub-mini tube amps
Post by: sgmezei on October 07, 2012, 08:58:58 PM
I have two designs etched and partially populated. One just a couple of days ago. One is a variation on the Nano head and the other is more or less "Fender-y". So, yeah...this is still very much on the table. And, welcome to the forum!

ahhhhhhhh yeeaaaahhhhhhh!!!!!!!
Title: Re: Sub-mini tube amps
Post by: aballen on October 21, 2012, 04:39:55 PM
I'm sooo totally interested in this one.  I actually have a couple of firefly boards waiting to be built as well.  I would love to have a sub mini tube amp, but the MurderOne and Nano-head, are a bit pricey.. when this comes out I'll probably buy a few.

Bean, are you building in an smps to boost the voltage?
Title: Re: Sub-mini tube amps
Post by: madbean on October 21, 2012, 05:19:00 PM
No, just cascaded diodes via a charge pump, like a lot of the frequency central designs. Gets up to around 80v or so. The heaters use a resistor.
Title: Re: Sub-mini tube amps
Post by: juansolo on October 22, 2012, 03:07:28 AM
I'm sooo totally interested in this one.  I actually have a couple of firefly boards waiting to be built as well.  I would love to have a sub mini tube amp, but the MurderOne and Nano-head, are a bit pricey.. when this comes out I'll probably buy a few.

Bean, are you building in an smps to boost the voltage?

I've got one of the original Murder Ones (one of the perf ones). It's a stunning display of Rick's skill and an impressive bit of miniaturisation. It's more of a curiosity or a cool object though than anything else. Mainly as my main amp is very low wattage anyhow. Actually I use it more as a headphone amp, which it's brilliant at.
Title: Re: Sub-mini tube amps
Post by: jubal81 on October 22, 2012, 10:52:45 AM
Tube headphone amp? Yes, please!

A built-in cab sim would be way cool. I've never built a cab sim. Can anyone say if they work well?
Title: Re: Sub-mini tube amps
Post by: gtangas on February 10, 2013, 05:54:08 AM
I have two designs etched and partially populated. One just a couple of days ago. One is a variation on the Nano head and the other is more or less "Fender-y". So, yeah...this is still very much on the table. And, welcome to the forum!

Hi Brian

Any updates on this project?
Title: Re: Sub-mini tube amps
Post by: aballen on March 02, 2013, 07:28:22 PM
Yeah man how is this one going?
Title: Re: Sub-mini tube amps
Post by: gtangas on April 17, 2013, 07:40:43 AM
I have to share my sadness...  ;D ;D i want one of those mini amps!!!   I don't know why but i want one ;D ;D ;D ;D

any news on this?

Thanks
Title: Re: Sub-mini tube amps
Post by: aballen on May 01, 2013, 10:08:36 AM
I just have to keep bumping this one.  Whats up Brian?  Is this getting close, or are you just afraid someone is just going to kill themselves trying to assemble one  ;)

Title: Re: Sub-mini tube amps
Post by: thomasha on October 29, 2013, 06:01:09 PM
Well, after murder one I tried to build my own tube amp combo...
based on jcm800 amplifier, using russian submini tubes, with PP triodes and LTP PI.
I used Dmitry's power amp schematic, and made a PTP layout using nails as turrets.
The speakers are old oval computer speakers, and I used a big muff tonestack instead of the TMB.
The power supply is the max1771 SMPS, from frequency central projects, and a 12V, 2A wall wart.
I made some videos with my crappy phone cam:


Clean sound

High gain


I think removing the 470pF caps across the grid stoppers would help with a little more low end.
Thomas
Title: Re: Sub-mini tube amps
Post by: thomasha on November 03, 2013, 01:40:25 PM
Finally made some better pictures!

(https://68.media.tumblr.com/1edea64d3516e1115c1c7c90ad188eed/tumblr_ne4o83iAwb1qh9jzro1_1280.jpg)
(https://68.media.tumblr.com/895b94943ce24c77bbfc93485c1033e4/tumblr_ne4o83iAwb1qh9jzro2_1280.jpg)
(https://68.media.tumblr.com/ed6febd521489808d11ba0b571322caf/tumblr_ne4o83iAwb1qh9jzro3_1280.jpg)
(http://i.imgur.com/tidOW7ql.jpg)
cheers
Title: Re: Sub-mini tube amps
Post by: jubal81 on November 03, 2013, 01:50:23 PM
That is outstanding! I want one!
Title: Re: Sub-mini tube amps
Post by: jkokura on November 03, 2013, 02:11:19 PM
Love it! How loud does it get?

Jacob
Title: Re: Sub-mini tube amps
Post by: juansolo on November 03, 2013, 03:19:06 PM
AWESOME  8)
Title: Re: Sub-mini tube amps
Post by: billstein on November 03, 2013, 06:49:43 PM
NEEEEEEED
Title: Re: Sub-mini tube amps
Post by: Ettore_M on November 04, 2013, 02:37:52 AM
Awesome! I want to build something like this!  :D
Is this a full-tube amp? Does it have an output transformer?

Hector
Title: Re: Sub-mini tube amps
Post by: thomasha on November 04, 2013, 04:46:59 AM
Yes, it is an all-tube amp, the output transformer is a Hammond 125a, and i guess the full distorted volume has aprox. 1W

Some gut shots!

(https://68.media.tumblr.com/5225c2ef0523b878420f64313563bcff/tumblr_ne4o83iAwb1qh9jzro5_1280.jpg)
(https://68.media.tumblr.com/0ae5d4e39c977fac3e98127c4900d1d8/tumblr_ne4o83iAwb1qh9jzro4_1280.jpg)

it's a small turret board build

and Schematic!
(http://i.imgur.com/j1ThQYMl.png)
https://dl.dropboxusercontent.com/u/10420127/submini%20JCM800.pdf (https://dl.dropboxusercontent.com/u/10420127/submini%20JCM800.pdf)
Thomas
Title: Re: Sub-mini tube amps
Post by: thomasha on May 10, 2014, 04:02:37 PM
Well, another one!
now a superfly in a 1590a!
(https://68.media.tumblr.com/ca5e0145e1fa896238f0b2980182e869/tumblr_ne4n4cOdD41qh9jzro6_1280.jpg)
(https://68.media.tumblr.com/aeb7a29107fb397493463266daccd519/tumblr_ne4n4cOdD41qh9jzro5_1280.jpg)
(https://68.media.tumblr.com/f0fa14e55b3add90414340fae1b9421c/tumblr_ne4n4cOdD41qh9jzro4_1280.jpg)
(https://68.media.tumblr.com/5c5a5cef479b2390539ef02ccfe8cef9/tumblr_ne4n4cOdD41qh9jzro3_1280.jpg)
(https://68.media.tumblr.com/a7f01064b82a13cf4f6f3760872a4119/tumblr_ne4n4cOdD41qh9jzro2_1280.jpg)
Greetings
Thomas
Title: Re: Sub-mini tube amps
Post by: aballen on May 10, 2014, 04:39:59 PM
Ok is anyone making a board for this?   I have a firefly, but I would love to build something smaller
Title: Re: Sub-mini tube amps
Post by: thomasha on May 10, 2014, 08:30:11 PM
I think Frequency Central was interested in making some PCB's to sell.
this is a smaller version, and the build is a bit more difficult, to make all the components fit in such a little space.

If you're interested i can send you my layout, or the normal version.

Title: Re: Sub-mini tube amps
Post by: culturejam on May 10, 2014, 10:55:59 PM
I was working with Rick on a PCB for the Murder One, but we never finished the project. I actually wanted to split it into two boards and have the charge pump and power tube on one board and the preamp on another. I think I might have finished the power board, but I can't remember. I just thought more people would find the modular approach useful.
Title: Re: Sub-mini tube amps
Post by: Leevibe on May 11, 2014, 07:07:40 AM
Well, another one!
now a superfly in a 1590a!

Greetings
Thomas


Wow Thomas. That is a tight build man! Good job.


I was working with Rick on a PCB for the Murder One, but we never finished the project. I actually wanted to split it into two boards and have the charge pump and power tube on one board and the preamp on another. I think I might have finished the power board, but I can't remember. I just thought more people would find the modular approach useful.


I agree. I've thought about the same thing for a murder one 
Title: Re: Sub-mini tube amps
Post by: thomasha on May 11, 2014, 07:51:27 PM
Hi, here comes the sound sample!

Cheers, Thomas
Title: Re: Sub-mini tube amps
Post by: jubal81 on May 11, 2014, 09:30:25 PM
Sounds great and I get the impression it's more than enough for jamming at home. Really great job.
Title: Re: Sub-mini tube amps
Post by: thomasha on May 11, 2014, 09:36:48 PM
yes,
it is really loud to play at night. I only play full gain when the volume is at 1/4 of the pot.

Unfortunately there is not much distortion at this volume level, even with gain maxed.

It works nice with pedals, but most of my pedals are bigger than the amp...
Title: Re: Sub-mini tube amps
Post by: Leevibe on May 11, 2014, 10:02:45 PM
Sounds great cranked! Nice breakup
Title: Re: Sub-mini tube amps
Post by: Niquel on June 28, 2014, 01:46:00 PM
Really nice amp!!
What high voltages are you using?
Regards
Title: Re: Sub-mini tube amps
Post by: jtn191 on June 28, 2014, 02:24:35 PM
Not exactly a sub-mini tube amp, I love the results of these designs using 12au7 as a push-pull output stage:
http://diyguitarfreak.wordpress.com/2010/09/15/the-miniamp-2-0/



JTM1 http://ampgarage.com/forum/viewtopic.php?t=24671 (login to see schems)

Title: Sub-mini tube amps
Post by: Hangingmonkey on June 28, 2014, 04:47:57 PM
Wow, that looks really cute. I want to build one.

Edit, I'm referring to thomasha's mini jcm amp
Title: Re: Sub-mini tube amps
Post by: thomasha on July 05, 2014, 06:19:06 PM
Really nice amp!!
What high voltages are you using?
Regards
The Max1771 SMPS delivers 240 v from a 12v 1A supply.

The board and schematic are here:
https://dl.dropboxusercontent.com/u/10420127/Superfly%20Project.pdf (https://dl.dropboxusercontent.com/u/10420127/Superfly%20Project.pdf)

Hope you enjoy!
Title: Re: Sub-mini tube amps
Post by: Niquel on July 06, 2014, 09:41:31 AM
Really nice amp!!
What high voltages are you using?
Regards
The Max1771 SMPS delivers 240 v from a 12v 1A supply.

The board and schematic are here:
https://dl.dropboxusercontent.com/u/10420127/Superfly%20Project.pdf (https://dl.dropboxusercontent.com/u/10420127/Superfly%20Project.pdf)

Hope you enjoy!
Thanks Thomas,
What I find more intersting is the submini-combo.
I built some subminiamps, using the same schematics from Dimitry but the self-split output stage version, all of them with 6n16b and 6n17b, although I am glad with their sound, now I have bought some 6n21b to try for the preamp.
I mailed him (very kind guy) and he recommended me using any 8~10kOhm  O.T. but with this impedance, and feeding output tubes with the same SMPS than you at 220V, I was running 6n16b out of specs, so I had to lower plate voltages.
I suppose that you can use higher voltages due to the larger impedance of your O.T. Isn't it?
By the way, now I am triying to build a similar boost converter but with a cheaper UC3845 instead of the expensive MAX Ic.

Cheers
Title: Re: Sub-mini tube amps
Post by: thomasha on July 08, 2014, 09:28:53 AM
Hi,
I have seen some cheaper boost converters too based on MC34063, but I still have some Max1771 for new builds. The last one I build was based on FrequencyCentral's Obsession amp:
(https://68.media.tumblr.com/a5eee29067a2400ee44de98c8b40b247/tumblr_ne4mztGzcJ1qh9jzro1_540.jpg)
(https://68.media.tumblr.com/ca25f98ac4eec7f80f5bc78d5b3db2c4/tumblr_ne4mztGzcJ1qh9jzro3_1280.jpg)

For the JCM combo I choose the output transformer based on information from other projects, like the superfly, and I adjusted the SMPS voltage for less noise and better tone. Recently I changed the mosfet for a better one with less internal resistance,and put some 10uF 400V low ESR capacitors and reduced that value to 200 V. 

I made a document for Magnus, if you're interested it's here:
https://www.dropbox.com/s/4hcgkkefek6znqg/submini%20JCM800.pdf (https://www.dropbox.com/s/4hcgkkefek6znqg/submini%20JCM800.pdf)
It still needs some tweaking to reduce a bit of hiss at max. setting and to control gain, I always play with the gain at half, more than that and It's too much for that small speakers, they sound too distorted and have some fuzziness. With a bigger speaker it's ok.

Finished a 1590b layout, take a look:
(http://i.imgur.com/mHV4jhkl.png)
it only has 73.4x44mm, but I'm still thinking if mounted jack's are a good approach for this build...layout was still NOT TESTED, so feel free to ask for it if You want, but there will be noise.

Cheers


 
Title: Re: Sub-mini tube amps
Post by: Niquel on July 14, 2014, 06:19:07 AM
Thank you Thomas for all the info. I am still surprised of the primary impedance of your O.T.
I will post some pictures of my submini-amp which is enclosed in a bigger 1590DD box. I got it sounding well until I mounted  inside the box and stopped sounding so I need to do some debugging (probably a broken cable).
My idea is to build a small cabinet with a 6" 12W Jensen speaker as well, but it will take more time as I cannot fill my home with sawdust. I will keep this updated.
Cheers
Title: Re: Sub-mini tube amps
Post by: thomasha on July 14, 2014, 07:43:36 AM
Very Nice Niquel!
I also build a not so small cabinet with the 6" Jensen, I made it big enough for a 8" speaker if I change my mind in the future.

As I said, I have no idea of the ideal impedance of these tubes, I just took the information available and made some experimentation.
Recently I tried a 4 ohms speaker on the 8 ohms tap, so it would result in 11k approximately, but there was a perceptible volume drop, so I'm guessing that 22.5k is better than 11k.

Are you using the hammond 125A? Could you experiment with some other impedance configurations and see what happens? Mine transformer has only the 22.5k tap.
Good luck with your build!
Title: Re: Sub-mini tube amps
Post by: Niquel on July 14, 2014, 12:52:04 PM
Hi again,
The transformer I use is a 'custom made' model by a local 'trannymaker' it has 8k75 at primary and 4-8 at secondary, 2,5W.
At the moment I am using a 2x12 Celestion Vintage30 cabinet at 8 Ohms and I can say there is very low hum and enough power to annoy my neighbours. 8)
The idea is to build the amp as an aluminium head, with everything inside the box to keep it enough portable to bring it in the guitar cover.
I built its power stage prototype, the schematic is from Dimitry's web page, in a can box of I don't know what, but it is funny because the brand says SOVIET... I forgot to switch it off for two nights and their days and it was still cool enough. When I'll finish the current version I hope I'll be able to make enough holes on its box surface to keep it cool enough as well  ;)...Then there'll be the nightmare of finding a good painting.
Cheers,
Miquel
Title: Re: Sub-mini tube amps
Post by: thomasha on July 14, 2014, 01:45:48 PM
Well,
if you plug the 8 ohm speaker in the 4 ohm tap you will have 17k5, you could give it a try if you want.
I'm gonna try the 4 ohm speaker again and see if it really get's louder.

it's nice that yours stays cool, because mine, with 4 tubes, and specially the 6n17b, is really hot, even the guitar plug is hot after a hour playing.
But I blame the layout, the combo is very small, made of wood, and the tubes are upside down, inside of it, so not great for convection, maybe I need to add a fan.
The head is the best Idea, heat goes up and not into te chassis, and a metal one is even better to maintain things cool.

Does your boost converter uses the mosfet grounded? Because the Max1771 SMPS has a 0R1 resistance between the mosfet and ground, so it needs a special heat sink. In the 555 version the mosfet goes directly to ground, so it can be bolt directly to the enclosure. The mosfet in mine is also really hot, so I put a small heatsink on it, but it's outside the main chassis. To the 1590b version I still need to change that...

Cheers!
Title: Re: Sub-mini tube amps
Post by: madbean on July 14, 2014, 07:01:49 PM
it's only taken...four years to finally get around to this? We getting close.

Title: Re: Sub-mini tube amps
Post by: culturejam on July 14, 2014, 09:17:35 PM
Finally!!!  ;D

I'm as giddy as a school girl.
Title: Re: Sub-mini tube amps
Post by: cooder on July 14, 2014, 10:31:20 PM
Lookin' snazzy....!!! 8)
Title: Re: Sub-mini tube amps
Post by: thomasha on July 15, 2014, 05:27:11 AM
That's a nice Board!
Title: Re: Sub-mini tube amps
Post by: Niquel on July 15, 2014, 11:08:28 AM
Madbean:My boards look much more shabby!

Thomasha: I haven't used any heat sink that's what surprised me, I have to see what happens with the max1771 smps...but I have enough room inside the case if I need any.
I repaired many 'big' combos with tubes downward mounted and almost all of them had marks of heat in their pcb's if these were above tubes, there's a model I remember, a Crate Vintage Club that had this heating issue in their pots, but I have to admit that your whole amp looks very nice, I would try a fan, as you mentioned.
Cheers,
Miquel
Title: Re: Sub-mini tube amps
Post by: thomasha on July 15, 2014, 12:55:09 PM
The first month after my build I played with the amp without the heat sink and I was experiencing a change in tone after playing some time. With the multimeter I saw that when the amp was really hot the high voltage dropped from 220 to 190 V. With the heat sink the amp became more stable, and there is a lower voltage drop.

I'm waiting to see a little more from your boards! They look amazing!
Cheers
Thomas
Title: Re: Sub-mini tube amps
Post by: Niquel on July 16, 2014, 01:06:52 PM
Hi all,

I've been working a little on the 3 submini tubes and max1771 smps head, now it sounds quite good but I have the same issue than you, Thomas: hiss at max. gain and max. volume. I like its tone specially for ac-dc, led-zepp rocks.
I need more holes on its top to cool it (about 50║C after 30') and have to do some tests recording to find changes in tone due to heating, but I┤d like to keep its psu without heat sink, if possible. I'll test it with the 4Ohms output as well to listen its changes.
The 2x6n16b, with a NE555, will stay as it is, I know it can cope with its temperature and it has been my test rig for months without issues.
There are some pictures of the 2x6n16b and 2x6n16b+6n17b model.
Cheers,
Miquel
Title: Re: Sub-mini tube amps
Post by: thomasha on July 18, 2014, 06:05:15 AM
Nice builds, make some gut shots from the second one, if possible,
I would like to see how you managed to squeeze everything inside the box.
And a sound sample.
The hiss doesn't bother me, as I newer play mine at full volume, normally only at something between 1/4 and 1/2 of the total volume.
I also bought some 6112 to compare with the 6n17b. I read somewhere that the russian subminiature are cleaner sounding when compared to the american, to make my Superfly crunch I had to use 220k anode resistors with a cold and a hot biased stage.
I'm waiting for some components to start my new board and test it.
Cheers
 
Title: Re: Sub-mini tube amps
Post by: Niquel on July 21, 2014, 11:53:38 AM
Hi Thomas,
Sorry, I can not take any pictures right now, but I hope I will have some time one of these day, I'd like to profit when I open the amp to fix the hiss issue, make some more holes and take some temperature readings.
At the moment, I can show you the preamp section I have used, is from a JCM800 series, but I don't know which one.
The power stage is the same schematic as on previous post.
The layout is the same idea as the other amp, but it has two PCB's for pots: gain, vol, sweep and tone stack at the other. All linked by screened cables.   
I like the sweep pot, as it moves all the bands, it is quite useful to change the whole amp tone for different styles.
I also would appreciate suggestions for paintings. I already have some synthetic solvent based painting in spray but last time I used it, it did not last so long, so I am thinking in some primer.
...Whel, that's all for now.
Cheers,
Miquel
Title: Re: Sub-mini tube amps
Post by: thomasha on July 22, 2014, 07:05:35 AM
Hi,
reusing a marshall schematic was a good idea, it looks very nice also.

Never tried that sweep pot, maybe on the next build...

To your painting I would say:
a lot of fine sanding (600 to 1200), than paint it 3 times with the primer and wait until it's dry,
after that 3 to 5 times of the spray painting. You can use a hair dryer to make the painting/waiting steps faster,
but be careful to not overheat it, otherwise it will produce small bubbles.
Cheers,
Thomas
Title: Re: Sub-mini tube amps
Post by: m-Kresol on July 22, 2014, 12:02:14 PM
it's only taken...four years to finally get around to this? We getting close.

Woohoo! Since I only started 3/4 of a year ago it hasn't been to long for me but I can't wait to get rid of my solid state Fender amp I've got since I started playing years ago... definitely looks most awesome to me. Looking forward to this!
Title: Re: Sub-mini tube amps
Post by: thomasha on August 04, 2014, 10:25:35 AM
Hi you all,
After some reading I started calculating the best configuration for the 6N16B output stage.

A friend from another forum, Matec, ploted the load lines for the 6N16B tube using the Paint KIT V2 from here:http://www.dmitrynizh.com/tubeparams_image.htm (http://www.dmitrynizh.com/tubeparams_image.htm)

For 150V and 180V a 22k transformer was used, while for 200V a 34k, and for 230V a 44k transformer.
As the images show, the 180V 22k configuration runs the tube with a 0.8W dissipation to output 0.75W.
In this configuration a lot of heat is produced, and the tube's life is reduced. Matec suggested to use de 44k configuration, that has an output of almost 1W with a 0.7W plate dissipation.
To bias the amp at 9.1VDC the 1.2k cathode resistor will now be 2.2k, as 2*2.1mA*2.2k=9.24V.

To achieve this, i'm going to use the 4 ohms tap of my 22.5k transformer with a 8 ohms speaker, and change the SMPS trimpot to output 230V.
With the increase in voltage and impedance there is a decrease in plate dissipation, current consumption and an increase in output volume.
If you guys are using the russian subminiature tubes like I do, this small change will make the amplifier louder and cooler!

The same graph also shows the power stage sensibility as 9.1V or 6.4V rms, this will be usefull to make a better PI.

I also read some articles about layout in SMPS:
http://ecee.colorado.edu/~ecen5797/course_material/layout.pdf (http://ecee.colorado.edu/~ecen5797/course_material/layout.pdf)
http://cds.linear.com/docs/en/application-note/an136f.pdf (http://cds.linear.com/docs/en/application-note/an136f.pdf)
And changed the SMPS to a separate ground, and reduced critical areas:
(http://i.imgur.com/qNAKAE3l.png)

Before building this amp I will recalculate each stage to the best configuration!
Cheers
Thomas
Title: Re: Sub-mini tube amps
Post by: Niquel on August 18, 2014, 12:37:30 PM
Hi all you,
Nice piece of work, Thomasha.
I have been working on the submini head on its ground scheme to remove hums and other noises and finally achieved a quiet amp.
As shown on picture at previous post #100, I have replaced the 1K5 R8 (cathode resistor in output stage) for a 2K2, reducing power dissipation from 0,99W to 0,7W, as I have now B+1=210V and Vk=7,72V. I have an impedance ratio of 8750:8 in my O.T. and tested with the 8750:4 and an 8ohm speaker too, to double its Zpri. but readings didn't changed much.
It would be nice to test it with a hammond 125A transformer with other impedances to see if it really increases output power with higher impedances.
Find below some gutshots and the 6" jensen speaker cabinet.
Cheers.

Title: Re: Sub-mini tube amps
Post by: thomasha on August 19, 2014, 05:56:45 AM
Hello,
great build! Good to hear that you solved the noise issues!
I'm still waiting for my parts to test the new layout.
How is it sounding to you with the new cathode resistor and higher/lower impedance?
Cheers
Title: Re: Sub-mini tube amps
Post by: Niquel on August 19, 2014, 08:43:12 AM
Hi again, Thomas and others, and thanks.
I would say it had more "character" before, but it was just noticeable when I turned up the volume pot. The thing is that, for practising at home, I have enough volume with gain at some point, depending on what I am going to play, and volume control between minimum and first quarter. The first stage draws so much, that you can play with the volume pot all the way down but then, tone stack is useless.
I hope one of this days will get a mic. and time to record some sound samples, painting the box and covering the cabinet with tolex. I don't know where I can get some corners for a so small cab.
Your design is very interesting, although I would prefer a separate SMPS from main board, just because if PSU starts smoking you just have to replace it and if you have ground noises you can find a solution moving a single (or maybe more) cable(s) as I did. But obviously, if everything goes right you'll have a design much more compact.
Good luck and tell us your findings ;).
Cheers.
Title: Re: Sub-mini tube amps
Post by: mishagolin on September 08, 2014, 11:51:35 AM
it's only taken...four years to finally get around to this? We getting close.

Brian, Could you give a brief overview of the amps you've created?

I know you were designing them with charge pump power supplies but what about the other design aspects

Are these mainly 6111, 6112, 6021 tube styles?
Push-Pull or single ended?
Hammond 125 output tranny for push pull? Hammond 1750 for single ended?
Will they have a headphone output option (bypass the power amp section)?

I'm really looking for a small headphone amp i can build that is a preamp section off of a tube guitar amp. I can try to mock it up myself but my etching abilities suck. I was considering buying your PCB and then just populating the preamp section and pushing that straight to an output without the tube power amp or output tranny.

Misha
Title: Re: Sub-mini tube amps
Post by: mishagolin on October 02, 2014, 09:19:39 PM
Well, after murder one I tried to build my own tube amp combo...
based on jcm800 amplifier, using russian submini tubes, with PP triodes and LTP PI.
I used Dmitry's power amp schematic, and made a PTP layout using nails as turrets.
The speakers are old oval computer speakers, and I used a big muff tonestack instead of the TMB.
The power supply is the max1771 SMPS, from frequency central projects, and a 12V, 2A wall wart.
I made some videos with my crappy phone cam:

Beautiful work Thomas. I was thinking of taking this route. Do you think the sound would be greatly improved if you switched the last tube from the 6n16b dual triode to two power pentodes? I'd imagine since the EL34 is a pentode that something like the 5902 would sound closer to the real thing, just quieter.

i think any beam power amplifier might give you a better power amp section.
Title: Re: Sub-mini tube amps
Post by: thomasha on October 08, 2014, 12:13:37 PM
Hi,
I also believe that the pentode would be an improvement, and using the 5902 is exactly what Dana made here:
http://ampgarage.com/forum/viewtopic.php?t=6159&start=0&postdays=0&postorder=asc&highlight=submini (http://ampgarage.com/forum/viewtopic.php?t=6159&start=0&postdays=0&postorder=asc&highlight=submini)

edit: Nice would be use low voltage subminiatures, like the 5672 and a low voltage triode, with max. 100V, to make a small and low dc amp. These 1W amps are quite too loud to play at home....
cheers
Thomas
Title: Re: Sub-mini tube amps
Post by: thomasha on October 23, 2014, 07:36:55 PM
Well,
finally started the build, found a lot of noise in the preamp,
but PI and power are nice and quiet, now I will build it inside a 1590b to verify if the proximity with the grounded enclosure reduces the noises.
(http://i.imgur.com/RwHzVBO.jpg)

Cheers, Thomas
Title: Re: Sub-mini tube amps
Post by: mishagolin on December 08, 2014, 07:09:43 AM
thomas, a beautiful build you've got there.

i had read about Dana's sub mini plexi. thats how i found out about his submini power pentode.

still really excited to see and hear some of these builds
Title: Re: Sub-mini tube amps
Post by: thomasha on December 10, 2014, 10:44:36 AM
Hi,
unfortunately I had some problem during the build, and with the amplifier in the enclosure there is a lot of noise and blocking distortion.

Recently I found some new sub-miniature tube amp ideas:

http://lucythesoloist.blog33.fc2.com/blog-category-50.html (http://lucythesoloist.blog33.fc2.com/blog-category-50.html)

http://lucythesoloist.blog33.fc2.com/blog-category-58.html (http://lucythesoloist.blog33.fc2.com/blog-category-58.html)

http://lucythesoloist.blog33.fc2.com/blog-category-55.html (http://lucythesoloist.blog33.fc2.com/blog-category-55.html)

http://lucythesoloist.blog33.fc2.com/blog-category-64.html (http://lucythesoloist.blog33.fc2.com/blog-category-64.html)

Time to learn japanese!

I still have the heat issue, the 1590b is getting really hot, and with temperature the SMPS voltage is also dropping.
The fan could be an improvement, or relocating the fet to the exterior, drilling some holes in the chassis...change to a bigger box.

Well, I'm still working on it.

I'm hoping to see what Madbean has done with all that sub-miniature tube layouts he posted.

Thomas

PS. Just another video from my first small combo, I'm thinking of making one more!

Title: Re: Sub-mini tube amps
Post by: thomasha on December 27, 2014, 06:04:54 PM
Hi you all!
let's start with the vacation builds!
I finished a small (3" speaker) subminiature amplifier, based on frequency central's vibratone.

It's just a murder one with a tremolo at the first cathode.

I tried to build a antique radio style cab, similar to a gibson.

I also tried a power transformer as output. It's a 220v to 6v transformer, but I rearranged the laminations to create a small gap. It still sounds nice though.

Well here are the pictures: there will be a video soon!
(http://i.imgur.com/ekunc1yl.jpg)
(http://i.imgur.com/h7dLB5cl.jpg)
(http://i.imgur.com/MK20CSel.jpg)
(http://i.imgur.com/QnFtgh4l.jpg)
(http://i.imgur.com/dNBCFlol.jpg)

Cheers,
Thomas
 
Title: Re: Sub-mini tube amps
Post by: copachino on December 27, 2014, 06:26:01 PM
i love it, so nice
Title: Re: Sub-mini tube amps
Post by: Leevibe on December 27, 2014, 11:08:48 PM
Looks and sounds awesome! I'm jealous. :)
Title: Re: Sub-mini tube amps
Post by: thomasha on March 11, 2015, 07:47:33 PM
Hi,
this time another video, but with a comparison between the small PC speakers and a Celestion greenback 12".

It's the same amplifier that was introduced before, it's kind of noise, and there is still a lot of gain in this amp.
The output stage is very sensitive but I use the guitar volume to tame the highs.



Made one for the Vibratone too!


And the preamp tubes amplifier:


Next one will be the superfly!
Cheers
Thomas
Title: Re: Sub-mini tube amps
Post by: HamSandwich on July 03, 2016, 09:40:54 AM
A O RIVER!
Title: Re: Sub-mini tube amps
Post by: Scruffie on October 03, 2016, 05:50:27 AM
So I took Tomasha's ball and ran with it, a full sub-mini JCM800 to fit a 1590BB with everything but the jacks board mounted. The layout was tighter than I thought it was going to be so i'm not holding out too much hope of it working without a couple of noise or oscillation issues but you never know! So if anyone wants to try it...
Title: Re: Sub-mini tube amps
Post by: Leevibe on October 03, 2016, 01:40:39 PM
So I took Tomasha's ball and ran with it, a full sub-mini JCM800 to fit a 1590BB with everything but the jacks board mounted. The layout was tighter than I thought it was going to be so i'm not holding out too much hope of it working without a couple of noise or oscillation issues but you never know! So if anyone wants to try it...

Holy smokes!! :o :o :o
Title: Re: Sub-mini tube amps
Post by: pickdropper on October 03, 2016, 04:52:28 PM
I don't know when I'd have time to build it, but I kind of want to.
Title: Re: Sub-mini tube amps
Post by: selfdestroyer on October 03, 2016, 05:18:53 PM
I don't know when I'd have time to build it, but I kind of want to.

Took the words out of my mouth. lol

Cody
Title: Re: Sub-mini tube amps
Post by: sturgeo on October 04, 2016, 02:26:11 AM
I've had one of these: http://www.ampmaker.com/store/190-0-190V-5W-power-transformer.html (http://www.ampmaker.com/store/190-0-190V-5W-power-transformer.html) lying around since I finished my JTM45 build with the intention of making a low watt Plexi or JCM similar to the Marshall offerings, its a pity ampgarage has been compromised as that was a valuable resource.
That Mini Amp 2.0 is exactly what I'm after  :)
Title: Re: Sub-mini tube amps
Post by: Scruffie on October 04, 2016, 07:32:58 AM
Haha, thanks guys, hopefully i'll have built it up by the end of the year and can post how it works out at least.

I'm also going to do a layout for a Selmer Treble 'n' Bass 50 (the Syd Barrett amp) bass side preamp in to a self split power amp with 12A'7 tubes like I did with my mini AC30 clone if that might be less daunting, hoping with its lowish gain fuller frequency preamp and the lower power amp distortion from self split that it'll make for a low wattage stoner rock kinda amp.

I've had one of these: http://www.ampmaker.com/store/190-0-190V-5W-power-transformer.html (http://www.ampmaker.com/store/190-0-190V-5W-power-transformer.html) lying around since I finished my JTM45 build with the intention of making a low watt Plexi or JCM similar to the Marshall offerings, its a pity ampgarage has been compromised as that was a valuable resource.
That Mini Amp 2.0 is exactly what I'm after  :)
Wait, are you talking about the amp I just posted or is there an amp in this thread called the Mini Amp 2.0? The one i've posted is set up to run off a 2A 12V Power supply, has the tube heaters in series and a SMPS on board so it's not ideal for that transformer really.
Title: Re: Sub-mini tube amps
Post by: sturgeo on October 04, 2016, 07:53:25 AM
Wait, are you talking about the amp I just posted or is there an amp in this thread called the Mini Amp 2.0? The one i've posted is set up to run off a 2A 12V Power supply, has the tube heaters in series and a SMPS on board so it's not ideal for that transformer really.

Sorry should've made it clearer, this one: https://diyguitarfreak.wordpress.com/2010/09/15/the-miniamp-2-0/
Title: Re: Sub-mini tube amps
Post by: Scruffie on October 04, 2016, 08:19:51 AM
Aha! Looks very cool, enclosures a bit big for my liking though :P
Title: Re: Sub-mini tube amps
Post by: thomasha on October 04, 2016, 11:21:12 AM
Hey guys,
nice to see that this thread is still alive!

I'm working on a second subminiature combo, now I'm tolexing a 12x17x8cm box for it. The schematic is the same as the 3 tubes version.

Unfortunatelly my board for the jcm version was too noisy, hopefully this one works better.

Just in case, I would add a small metal chassis around the SMPS circuit part, like you see in the univibe, just big enough to cover that part (or the mosfet and the inductor), you could use it also as a heatsink for the mosfet, just remember to use some electrical isolation on the mosfet, so you can ground the small cage.

I think I forgot to post this, so here it comes>
(http://i.imgur.com/eGvX7mSl.jpg)
(http://i.imgur.com/GG0QqCPl.jpg)
(http://i.imgur.com/uFgtXevl.jpg)
(http://i.imgur.com/Cl01qmOl.jpg)
(http://i.imgur.com/7MSP1dPl.jpg)
(http://i.imgur.com/SAbu9gql.jpg)

Made a PDF available here, if someone is interested
https://dl.dropboxusercontent.com/u/10420127/RussianJTM.pdf (https://dl.dropboxusercontent.com/u/10420127/RussianJTM.pdf)
Title: Re: Sub-mini tube amps
Post by: joesatch on October 04, 2016, 12:28:08 PM
a byo lunchbox amp ala tiny terror would be great, the smaller the better!
Title: Re: Sub-mini tube amps
Post by: jubal81 on October 04, 2016, 01:18:56 PM
Now that is a genius little head, Thomasha! Love it!


I've been doing some SMPS sub mini work lately and I've gone to an SMD shielded inductor. There's still a bit of EMI coming off, but it's greatly reduced. Bonus is that it's only 12mmX12mmX10MM.


http://www.mouser.com/Search/ProductDetail.aspx?R=SRR1210-101Mvirtualkey65210000virtualkey652-SRR1210-101M
Title: Re: Sub-mini tube amps
Post by: thomasha on October 06, 2016, 11:06:20 AM
Nice Jubal81,

found a similar one from bourns on a local store, will give it a try.

It's the 47uH version with 3.1A and 0.085 ohms. With the 47uH it should give me more current availability if Rsense is also changed to 0.025 ohms.
Title: Re: Sub-mini tube amps
Post by: Scruffie on October 06, 2016, 12:41:28 PM
The one thing i've yet to have issues with is any RFI noise injected from the SMPS, Nick does state that the efficiency drops with shielded inductors too, I think good layout is more important than specialist parts (others than those stated in the original) unless you do actually have a problem.

I'd think a lot of the noise issues you had with the mini JCM800 are from cramming 4 high gain stages in to a 1590B, although I don't know if going up to a 1590BB will have negated that too much as I did have to go with some long traces and miss out some proper tube layout techniques to do it all single sided and board mounted, but i'm holding out hope for good luck perhaps with just a bit of tweaking.
Title: Re: Sub-mini tube amps
Post by: thomasha on October 15, 2016, 04:44:14 AM
I will give it a try and see how it turns out.

for now finished my small cab, this time with tolex.
(http://i.imgur.com/HyCbWzol.jpg)

A small orange amp would also be a nice donor amp for this builds, since it already has the tolex and grill cloath.
It's a shame that the small marshalls are made of plastic...
Title: Re: Sub-mini tube amps
Post by: HamSandwich on October 15, 2016, 09:29:55 AM
That's amazing!
Title: Re: Sub-mini tube amps
Post by: thomasha on December 10, 2016, 01:38:28 PM
Some updates...
(http://i.imgur.com/HyCbWzol.jpg)
(http://i.imgur.com/4IXD1vUl.jpg)
(http://i.imgur.com/4P83FC0l.jpg)
(http://i.imgur.com/elOkfkGl.jpg)
(http://i.imgur.com/HLVoUjQl.jpg)
still fighting some noise
Title: Re: Sub-mini tube amps
Post by: nzCdog on December 10, 2016, 01:59:08 PM
Beautiful work 8)
Title: Re: Sub-mini tube amps
Post by: ozzy666 on December 11, 2016, 08:27:27 AM
Awesome!!!
Title: Re: Sub-mini tube amps
Post by: thomasha on December 15, 2016, 02:21:25 PM
(http://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/Photo%2014-12-2016%2021%2017%2006_zps8jw02odl.jpg)

Title: Re: Sub-mini tube amps
Post by: m-Kresol on December 16, 2016, 04:38:51 AM
you're crazy, you know that? In a good way of course.
Title: Re: Sub-mini tube amps
Post by: Niquel on December 28, 2016, 06:42:05 AM
Impressing Thomasha, as usual.
What kind of tubes did you use this time?
Cheers.
Title: Re: Sub-mini tube amps
Post by: Niquel on December 30, 2016, 06:22:27 AM
I saw the answer in the other forum, tubes are 6111 and 6112. Very nice amp!
Cheers.
Title: Re: Sub-mini tube amps
Post by: thomasha on February 07, 2017, 02:20:10 PM
Well some new information about the amp.

I tested 4 different inductors in the max1771 SMPS, and the best result so far was with this one:
https://www.conrad.de/de/induktivitaet-geschirmt-radial-bedrahtet-1111-rastermass-5-mm-47-h-3-a-wuerth-elektronik-we-tis-7447471470-1-st-1087682.html (https://www.conrad.de/de/induktivitaet-geschirmt-radial-bedrahtet-1111-rastermass-5-mm-47-h-3-a-wuerth-elektronik-we-tis-7447471470-1-st-1087682.html)
with 47uH, 3A and shielded, 0.074 ohms.

Compared to the others the noise is barely audible.

I changed the bias of the amp and reduced the signal going to the output stage, so it's running colder, and without the fuzz I was experiencing in the first builds.

After that, I made a video>



Now I'm working on a 3 board version U chaped, the vertical sides to the circuit, jack and potentiometers and the horizontal part to hold the tubes in place. Would help if eagle were 3D, so far I'm drawing it as an open book.




Title: Re: Sub-mini tube amps
Post by: bluescage on February 08, 2017, 03:26:34 AM
Wonderful! Love it!
Title: Re: Sub-mini tube amps
Post by: Scruffie on March 09, 2017, 05:27:56 PM
So I took Tomasha's ball and ran with it, a full sub-mini JCM800 to fit a 1590BB with everything but the jacks board mounted. The layout was tighter than I thought it was going to be so i'm not holding out too much hope of it working without a couple of noise or oscillation issues but you never know! So if anyone wants to try it...
Got round to building this today, the amp portion works but there's some oscillation issue I think interfering with the SMPS so it's stuck at 300V, I tried a verified standalone PCB to check it wasn't the SMPS layout and the same thing happened as soon as it was hooked up to the amp.
Title: Re: Sub-mini tube amps
Post by: Niquel on March 19, 2017, 12:57:49 PM
Quote
Got round to building this today, the amp portion works but there's some oscillation issue I think interfering with the SMPS so it's stuck at 300V, I tried a verified standalone PCB to check it wasn't the SMPS layout and the same thing happened as soon as it was hooked up to the amp.
...Then it is the amp section layout?
The image showed 250V caps, so bear it in mind.
One simplistic suggestion, grounding the pots through their metal chassis. The presence circuit is ok?
Title: Re: Sub-mini tube amps
Post by: Scruffie on March 19, 2017, 01:31:50 PM
I'm well aware the caps are only rated for 250V as that's what I rated them for ;)

I gave up on it, the tubes aren't rated to run that high and after the first one blew it just wasn't worth carrying on, it was a long shot trying to get all that board mounted in a tiny enclosure and not have issues.

Everything 'worked' including the presence circuit but the amp had ultrasonic oscillation which is a layout issue and not worth fighting.

Instead i've gone for a single 6n17b JCM800 inspired preamp with a switchable cathode bypass cap instead of a tone control in to a self split power amp in a 1590B, wont be quite as high gain or sound quite the same but i'm sure for my purposes it'll be fine.
Title: Re: Sub-mini tube amps
Post by: thomasha on March 19, 2017, 05:20:21 PM
Hi,
it's sad that it didn't worked, I had similar problems with my version, and that's why I reduced to 3 tubes, there was too much gain.
The thing with the SMPS is also an issue with this builds. I found a layout that works for me, but the inductor is also very important. In my last build I tested some inductors and some of them just squealed like hell.
Title: Re: Sub-mini tube amps
Post by: Niquel on March 20, 2017, 01:11:34 PM
It's a pitty you couldn't fix that, the board looked so nice.
I never dared to squeeze things like you guys do. :o
IMHO, a 3 gain stages is too much if you try to push the power section, I prefer just one or two gain stages and some kind of transistor overdrive before.
Cheers.
Title: Re: Sub-mini tube amps
Post by: Scruffie on March 20, 2017, 01:40:23 PM
Yeah it's a shame but, what ya gonna do, at least I tried and know now.

I think with a double sided board it would definitely be possible but it would be much more preferable to have an experienced tube layout-er tackle such a job rather than keep making prototypes.

It did help me see that for something where the distortion sound is the main attraction it was probably too loud for late night playing as opposed to the self split type amps which are usually just right.

I've still not had any inductor issues, I tried a couple of different ones and it made no difference whatsoever but you are also playing in much smaller enclosures with more gain than I am.

IMHO, a 3 gain stages is too much if you try to push the power section, I prefer just one or two gain stages and some kind of transistor overdrive before.
It sounds like you might prefer the new board I mentioned in my post above, if it works out i'll post up the layout for that too.
Title: Re: Sub-mini tube amps
Post by: thomasha on June 23, 2017, 01:38:12 PM
Just needed to show this! It wasn't me, but could give it a try.
(https://image.jimcdn.com/app/cms/image/transf/dimension=960x10000:format=jpg/path/sb134c1a1e5df3621/image/i45983e49f0496042/version/1495294667/image.jpg)

Really cool! check out the build log!
https://marinesnow-jp.jimdo.com/%E7%9C%9F%E7%A9%BA%E7%AE%A1%E3%83%9F%E3%83%8B%E3%82%AE%E3%82%BF%E3%83%BC%E3%82%A2%E3%83%B3%E3%83%97/submini-6021-guitar-amp/ (https://marinesnow-jp.jimdo.com/%E7%9C%9F%E7%A9%BA%E7%AE%A1%E3%83%9F%E3%83%8B%E3%82%AE%E3%82%BF%E3%83%BC%E3%82%A2%E3%83%B3%E3%83%97/submini-6021-guitar-amp/)
Title: Re: Sub-mini tube amps
Post by: nzCdog on June 23, 2017, 05:28:37 PM
Just needed to show this! It wasn't me, but could give it a try.
Really cool! check out the build log!
https://marinesnow-jp.jimdo.com/%E7%9C%9F%E7%A9%BA%E7%AE%A1%E3%83%9F%E3%83%8B%E3%82%AE%E3%82%BF%E3%83%BC%E3%82%A2%E3%83%B3%E3%83%97/submini-6021-guitar-amp/ (https://marinesnow-jp.jimdo.com/%E7%9C%9F%E7%A9%BA%E7%AE%A1%E3%83%9F%E3%83%8B%E3%82%AE%E3%82%BF%E3%83%BC%E3%82%A2%E3%83%B3%E3%83%97/submini-6021-guitar-amp/)

Wow that's impressive
Title: Re: Sub-mini tube amps
Post by: somnif on June 23, 2017, 05:35:51 PM
(https://image.jimcdn.com/app/cms/image/transf/dimension=352x1024:format=jpg/path/sb134c1a1e5df3621/image/ibdac7668c0385950/version/1485352385/image.jpg)

Who needs space anyway?  :o
Title: Re: Sub-mini tube amps
Post by: thomasha on July 09, 2017, 06:16:53 AM
Hi, after that tiny one I had to build something.
As I wasn't hapy with the distortion that I could achieve with my superfly, I went back to a SE design.
With the extra triode stage there was enough gain on tap, and I could reduce the output volume, which allows me to play at a higher volume settings, pushing the output stage harder.

I also made a new faceplate and cage to protect the tubes.
How it was>
(https://68.media.tumblr.com/ca5e0145e1fa896238f0b2980182e869/tumblr_ostm94NIMB1qh9jzro5_1280.jpg)

How it looks now>
(https://68.media.tumblr.com/276c5634b4692b89109a8ace7a844a8f/tumblr_ostm94NIMB1qh9jzro1_1280.jpg)
(https://68.media.tumblr.com/9a256f856838746e5839fc071902c442/tumblr_ostm94NIMB1qh9jzro3_1280.jpg)
(https://68.media.tumblr.com/981e8ddb60b4698e73b1da1d37e693f0/tumblr_ostm94NIMB1qh9jzro4_1280.jpg)
Some extra Info>
(https://i.imgur.com/oy5dwiel.png)
(https://i.imgur.com/9kmmoXal.png)
(https://i.imgur.com/A4G8t4wl.png)
it requires some serious offboard wiring, a 2 sided PCB would make it much easier.

cheers,
Thomas
Title: Re: Sub-mini tube amps
Post by: selfdestroyer on September 08, 2017, 11:26:01 AM
I think that's my favorite one you've done Thomas. Looks great.

Cody