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General => Open Discussion => Topic started by: AntKnee on May 28, 2014, 05:34:32 AM

Title: Building an amp... Where to start?
Post by: AntKnee on May 28, 2014, 05:34:32 AM
I'm thinking about building an amp, 10 watts or less. First amp build, so maybe a kit would be a good idea. Anyone have any advice or suggestions on where to start?
Thanks
Title: Re: Building an amp... Where to start?
Post by: brucer on May 28, 2014, 06:06:38 AM
Hey Anthony.

I strongly recommend Dave Hunter's Guitar Amp Handbook as a starting point (see http://www.amazon.com/Guitar-Amplifier-Handbook-Understanding-Amplifiers/dp/087930863X (http://www.amazon.com/Guitar-Amplifier-Handbook-Understanding-Amplifiers/dp/087930863X).  He explains amp circuitry in pretty common language.  It REALLY helped me as a newbie non-electronics guy to understand what I wanted out of an amp and how to get it.  It also includes an amp project at the back of the book that I built and definitely recommend.  It's similar to a Weber Maggie DIY kit (see https://taweber.powweb.com/store/kits_weber.htm#Maggie (https://taweber.powweb.com/store/kits_weber.htm#Maggie)), so I waited for Weber to have a sale, then bought that kit, less pots, switches, jacks, capacitors, resistors, tubes and copper cap.  I later picked the omitted parts up as higher-quality stock elsewhere (except the copper cap, I went with a rectifier tube instead).  I then drilled an extra power tube hole in the chassis to build exactly as spec'd in the book.  LOVE that amp.  More info on it and demos here: http://www.tubeampnetwork.com/host-post/tan-two-stroke (http://www.tubeampnetwork.com/host-post/tan-two-stroke).  I'm not affiliated with any of these guys in any way, I just came out of the the whole learning/building process with a really positive outcome (and the confidence/courage to try building an effects pedal!).

Hope that helps, Bruce.

PS.  You might also start lurking on the "Shock Brother's DIY Amps" section of TDPRI to get more info and ideas.
Title: Re: Building an amp... Where to start?
Post by: pryde on May 28, 2014, 12:46:21 PM
The Fender F51 is likely the most popular beginner amp build out there. Dave Hunter's book mentioned above gives a thorough walk-through of this circuit as well so it would be a good choice. Its a nice sounding and easy little tweed to build up.

I recommend Boothill Amps to get a complete 5F1 kit. Dave uses high-quality chassis and parts (Classictone transformers). He also frequents the TDPRI "Shock Brothers" forum where there is tons of support.

http://www.boothillamps.com/


Title: Re: Building an amp... Where to start?
Post by: Leevibe on May 28, 2014, 01:20:51 PM
A good kit is definitely a smart place to start. If you need it to be a tube amp, learn all you can about working around lethal voltages!!! Heed all warnings about poking around a circuit with those big filter caps. They will zap you good even with the amp unplugged if they're not bled down.

If you're OK with solid state, I like the Ruby amp. It's about as simple as building an overdrive and it sounds great! A little on the dark side but very nice breakup and it can get loud enough at <1w to make the neighbors mad.

For tubes, a tweed champ would be a smart move. A 5F1 with a VVR circuit would make a killer sounding amp at any volume and you would learn a ton.

If you can get your hands on an Epi valve jr, you can rip out the PCB and use the chassis and head cab as donors.
Title: Re: Building an amp... Where to start?
Post by: mmlee on May 28, 2014, 02:20:36 PM
... VVR?
Title: Re: Building an amp... Where to start?
Post by: davent on May 28, 2014, 03:27:52 PM
VVR Variable Voltage Regulator or Power Scaling, allows you to dial down the HV to the output tube (and preamp tubes if desired) so the amp breaks up nicely at much lower volumes, take things down to bedroom level.

Ax84 is a good forum to get you rolling.

Good build doc/explanation of their P1 amp which is your basic 2 tube single ended Champ derivative.

http://www.ax84.com/static/p1/AX84_SE_Builders_Guide.pdf
http://www.ax84.com/p1/P1_Theory_Document.zip

Lots of info and helpful people at these. Have to register to be get a peak.
Wattkins.com http://www.wattkins.com/forum
Sewatt.com  http://www.sewatt.com/forum
Title: Re: Building an amp... Where to start?
Post by: miter53 on May 28, 2014, 04:05:23 PM
+1 on Boot Hill Amps. Good components and reasonable prices.
Title: Re: Building an amp... Where to start?
Post by: thesameage on May 28, 2014, 04:31:13 PM
Another, even bigger dipping your toe in the water, option is to build some kind of tube pre like a valvetizer and run that into a larger SS amp like the Tiny Giant.
Title: Re: Building an amp... Where to start?
Post by: Blues Healer on May 28, 2014, 06:57:35 PM
I agree that Dave Hunter's book is a great place to start!
The way he breaks down circuits is the clearest explanation I've read.

For kits, I'd recommend MojoTone, Weber, and Mission Amps 5E3.

And yes, a tweed Champ is about the best place to start: the simplest circuit, and great tone. It's just a little low powered, but probably the best place to get your feet wet, and see if you want to pursue a bigger build.

I have a Mission Amps 5E3 (Tweed Deluxe), that with a good Weber speaker in it, sounds better right now than my original '56 Deluxe. Bruce @ Mission Amps has sold quite a few of these, and offers good support and lots of documentation -- with lots of pictures to clarify things.
Title: Re: Building an amp... Where to start?
Post by: das234 on June 07, 2014, 02:57:13 AM
Those of you who have built the 5F1, how's the head room on that?  Can you get a nice clean tone before it breaks  up?
Title: Re: Building an amp... Where to start?
Post by: Leevibe on June 07, 2014, 03:43:11 AM
I haven't built the champ, but I'm pretty sure headroom is not its thing. On my 5E3 there's the littlest bit of cleans, low on the dial, but they are beautiful.
Title: Re: Building an amp... Where to start?
Post by: midwayfair on June 07, 2014, 03:51:25 AM
Quote from: das234 on June 07, 2014, 02:57:13 AM
Those of you who have built the 5F1, how's the head room on that?  Can you get a nice clean tone before it breaks  up?

I haven't built one (yet :)), but I've played a couple: Like almost every tweed circuit, it gets to about 4 on the dial before it starts to distort and doesn't get much louder after that, and perhaps 3 before there's noticeable distortion on a hard chord (keep in mind that early Fenders are also 30% audio tapers! So 3 is more like 5 on a modern 10% taper). It's not super loud at that point; louder than an acoustic, but certainly reasonable. The 5E1 has a bit more range on the dial, but the total volume isn't appreciably different. BUT it can take a larger INPUT signal before it distorts because it doesn't have a cathode bypass. So the 5E1 is better for hotter pickups for headroom. But you're not going to be overdriving the first tube by much if at all regardless without a boost.

I'm still in the process of buying parts for my build. I ran across this power transformer, which is a "big iron" for a champ: http://store.triodestore.com/40-18031.html. Those transformers have gotten good reviews across a lot of sites. Anyway, that transformer will put out a few more Watts when running a 6V6, but you can also wire it to run a 6L6 instead and get a lot more headroom. I'm really on the fence about getting it, because I look at it and say, "Hey, those all sound like good things for my playing!" Buuuuut ... then I remember the whole purpose of the project. The champ is made for two things: A practice amp (clean at really low volumes), and an "ow what are you doing to me" amp at somewhat low volumes. You can't expect a single 6V6 to do much beyond that.

Oh, and based on plugging a couple different types of champs into 12" speakers, and confirmed by Morgan and others: A 12" speaker is awesome with a champ circuit, especially for a little perceived headroom (i.e., pure volume before you get distortion).
Title: Re: Building an amp... Where to start?
Post by: Leevibe on June 07, 2014, 04:07:58 AM
Quote from: midwayfair on June 07, 2014, 03:51:25 AM
Quote from: das234 on June 07, 2014, 02:57:13 AM
Those of you who have built the 5F1, how's the head room on that?  Can you get a nice clean tone before it breaks  up?

I haven't built one (yet :)), but I've played a couple: Like almost every tweed circuit, it gets to about 4 on the dial before it starts to distort and doesn't get much louder after that, and perhaps 3 before there's noticeable distortion on a hard chord (keep in mind that early Fenders are also 30% audio tapers! So 3 is more like 5 on a modern 10% taper). It's not super loud at that point; louder than an acoustic, but certainly reasonable. The 5E1 has a bit more range on the dial, but the total volume isn't appreciably different. BUT it can take a larger INPUT signal before it distorts because it doesn't have a cathode bypass. So the 5E1 is better for hotter pickups for headroom. But you're not going to be overdriving the first tube by much if at all regardless without a boost.

I'm still in the process of buying parts for my build. I ran across this power transformer, which is a "big iron" for a champ: http://store.triodestore.com/40-18031.html. Those transformers have gotten good reviews across a lot of sites. Anyway, that transformer will put out a few more Watts when running a 6V6, but you can also wire it to run a 6L6 instead and get a lot more headroom. I'm really on the fence about getting it, because I look at it and say, "Hey, those all sound like good things for my playing!" Buuuuut ... then I remember the whole purpose of the project. The champ is made for two things: A practice amp (clean at really low volumes), and an "ow what are you doing to me" amp at somewhat low volumes. You can't expect a single 6V6 to do much beyond that.

Oh, and based on plugging a couple different types of champs into 12" speakers, and confirmed by Morgan and others: A 12" speaker is awesome with a champ circuit, especially for a little perceived headroom (i.e., pure volume before you get distortion).

I used the classic tones in my build. They're nice. Great price too.
Title: Re: Building an amp... Where to start?
Post by: das234 on June 08, 2014, 01:37:49 AM
Quote from: midwayfair on June 07, 2014, 03:51:25 AM
Quote from: das234 on June 07, 2014, 02:57:13 AM
Those of you who have built the 5F1, how's the head room on that?  Can you get a nice clean tone before it breaks  up?

I haven't built one (yet :)), but I've played a couple: Like almost every tweed circuit, it gets to about 4 on the dial before it starts to distort and doesn't get much louder after that, and perhaps 3 before there's noticeable distortion on a hard chord (keep in mind that early Fenders are also 30% audio tapers! So 3 is more like 5 on a modern 10% taper). It's not super loud at that point; louder than an acoustic, but certainly reasonable. The 5E1 has a bit more range on the dial, but the total volume isn't appreciably different. BUT it can take a larger INPUT signal before it distorts because it doesn't have a cathode bypass. So the 5E1 is better for hotter pickups for headroom. But you're not going to be overdriving the first tube by much if at all regardless without a boost.

I'm still in the process of buying parts for my build. I ran across this power transformer, which is a "big iron" for a champ: http://store.triodestore.com/40-18031.html. Those transformers have gotten good reviews across a lot of sites. Anyway, that transformer will put out a few more Watts when running a 6V6, but you can also wire it to run a 6L6 instead and get a lot more headroom. I'm really on the fence about getting it, because I look at it and say, "Hey, those all sound like good things for my playing!" Buuuuut ... then I remember the whole purpose of the project. The champ is made for two things: A practice amp (clean at really low volumes), and an "ow what are you doing to me" amp at somewhat low volumes. You can't expect a single 6V6 to do much beyond that.

Oh, and based on plugging a couple different types of champs into 12" speakers, and confirmed by Morgan and others: A 12" speaker is awesome with a champ circuit, especially for a little perceived headroom (i.e., pure volume before you get distortion).

So you're putting yours together off a schematic rather than building a kit, correct?  I was looking at kits since I'm not nearly as far along on the electronics knowledge road as you are but I might consider doing it from scratch if I can follow a decent road map.  There's so much good information on here.
Title: Re: Building an amp... Where to start?
Post by: Leevibe on June 08, 2014, 04:00:04 AM
I recommend a kit. There's a lot to scratch building, including drilling and/or punching the chassis and woodwork, tolex etc. a kit gives you pre-punched chassis, finished cabinet, documentation, and parts sourcing is handled. And it might be hard to build one cheaper than a kit. I think the weber kits look reasonable.
Title: Re: Building an amp... Where to start?
Post by: alanp on June 08, 2014, 04:24:20 AM
Ceriatone have good reviews, also.

I'll admit that in terms of kits, Asian ones tend to get time from me. When they're good, they're pretty good, and all of them turn up a hell of a lot faster than anything American. Mojotone are always worth considering, however :)

Weber used to get bad press for the cheapness of their parts, but I've heard that they've gotten a lot better over the years.
Title: Re: Building an amp... Where to start?
Post by: midwayfair on June 08, 2014, 04:37:50 AM
Quote from: das234 on June 08, 2014, 01:37:49 AM
Quote from: midwayfair on June 07, 2014, 03:51:25 AM
Quote from: das234 on June 07, 2014, 02:57:13 AM
Those of you who have built the 5F1, how's the head room on that?  Can you get a nice clean tone before it breaks  up?

I haven't built one (yet :)), but I've played a couple: Like almost every tweed circuit, it gets to about 4 on the dial before it starts to distort and doesn't get much louder after that, and perhaps 3 before there's noticeable distortion on a hard chord (keep in mind that early Fenders are also 30% audio tapers! So 3 is more like 5 on a modern 10% taper). It's not super loud at that point; louder than an acoustic, but certainly reasonable. The 5E1 has a bit more range on the dial, but the total volume isn't appreciably different. BUT it can take a larger INPUT signal before it distorts because it doesn't have a cathode bypass. So the 5E1 is better for hotter pickups for headroom. But you're not going to be overdriving the first tube by much if at all regardless without a boost.

I'm still in the process of buying parts for my build. I ran across this power transformer, which is a "big iron" for a champ: http://store.triodestore.com/40-18031.html. Those transformers have gotten good reviews across a lot of sites. Anyway, that transformer will put out a few more Watts when running a 6V6, but you can also wire it to run a 6L6 instead and get a lot more headroom. I'm really on the fence about getting it, because I look at it and say, "Hey, those all sound like good things for my playing!" Buuuuut ... then I remember the whole purpose of the project. The champ is made for two things: A practice amp (clean at really low volumes), and an "ow what are you doing to me" amp at somewhat low volumes. You can't expect a single 6V6 to do much beyond that.

Oh, and based on plugging a couple different types of champs into 12" speakers, and confirmed by Morgan and others: A 12" speaker is awesome with a champ circuit, especially for a little perceived headroom (i.e., pure volume before you get distortion).

So you're putting yours together off a schematic rather than building a kit, correct?  I was looking at kits since I'm not nearly as far along on the electronics knowledge road as you are but I might consider doing it from scratch if I can follow a decent road map.  There's so much good information on here.

Yeah. Though alanp is right, in some ways it's very difficult to beat the price of some of the cheaper kits. The only real major savings is on the chassis and the cabinet if you can do those yourself.

My real problem was that I'm deviating from anything I can use a predrilled chassis for. I don't know any 3-knob single ended classic amps! I probably would have ended up with a kit otherwise.
Title: Re: Building an amp... Where to start?
Post by: Leevibe on June 08, 2014, 05:25:54 AM
A VVR would give you the third knob and they're useful, I would think even on a 5w SE amp. I came up with a layout for one that uses a turret strip if you want it. I've used it successfully in 3 amps.
Title: Re: Building an amp... Where to start?
Post by: upthepunxxx on June 08, 2014, 07:26:56 AM
Thanks for starting this thread. This is great. I've been really wanting to build a low watt tube amp and didn't know where to start. I'm gonna check out these books and forums and links. Hope everyone is having a good weekend :)
Title: Re: Building an amp... Where to start?
Post by: jtn191 on June 09, 2014, 01:35:51 AM
I like the 5e3 circuit. The higher wattage gives a little more headroom and low end. Mine's setup with 6l6s and it's actually pretty clean at low volumes. It's one of those simple, timeless classics that has just enough controls and parts to work really well.
Title: Re: Building an amp... Where to start?
Post by: sonarchotic on June 09, 2014, 02:12:04 AM
Quote from: jtn191 on June 09, 2014, 01:35:51 AM
I like the 5e3 circuit. The higher wattage gives a little more headroom and low end. Mine's setup with 6l6s and it's actually pretty clean at low volumes. It's one of those simple, timeless classics that has just enough controls and parts to work really well.
A 5e3 is my next build. I'm planning on building it stock but there are a ton of variations detailed over at the Watts forum. Have you tried any of them?
Title: Re: Building an amp... Where to start?
Post by: jtn191 on June 09, 2014, 03:28:52 AM
I built mine on a Tubedepot pcb and built it pretty close to stock. It would not be too hard to build on turretboard...wiring the heaters is the biggest deal. I sourced my own parts and went with "mojo" happy sozo coupling caps. Orange drops are another popular favorite.
-I upped the first two power filter caps to 30uF. This tightens bass and reduces sag. Stiffens it up. Kind of a trade off, thinking about putting parallel caps on a switch...if that's even safe
-I used all Metal film resistors except carbon comp resistors for the plate resistors before the phase inverter, according to RG Keen's advice on CC resistors and their "magic".
-I used a higher wattage output transformer designed for a Tremolux. The effects of this are debatable and I'm curious to what degree there are any. I heard somebody would do that to run two 4x12s...maybe more iron means more bass!

The only changes I'd make now are to the filter caps and pre-tone control coupling caps/cathode bypass. A lot of people like to cut bass by lowering those values in this amp. It is very pronounced with single coils and even less friendly with humbuckers.
Title: Re: Building an amp... Where to start?
Post by: alanp on June 09, 2014, 04:42:16 AM
I love the sound of tweed amps (I have a Low Power Tweed Twin combo, and a 5E3 head (in marshall style chassis), and purely from the experience of wiring up the Twin, I'd strongly hesitate to do another.

The Tweed caketins are VERY claustrophobic to work in.

That said, I'd like to build either a JTM45/100 (shake the walls down...) or a Ceriatone Overdrive Special.
Title: Re: Building an amp... Where to start?
Post by: sonarchotic on June 09, 2014, 06:48:08 PM
Quote from: jtn191 on June 09, 2014, 03:28:52 AM
I built mine on a Tubedepot pcb and built it pretty close to stock. It would not be too hard to build on turretboard...wiring the heaters is the biggest deal. I sourced my own parts and went with "mojo" happy sozo coupling caps. Orange drops are another popular favorite.
-I upped the first two power filter caps to 30uF. This tightens bass and reduces sag. Stiffens it up. Kind of a trade off, thinking about putting parallel caps on a switch...if that's even safe
-I used all Metal film resistors except carbon comp resistors for the plate resistors before the phase inverter, according to RG Keen's advice on CC resistors and their "magic".
-I used a higher wattage output transformer designed for a Tremolux. The effects of this are debatable and I'm curious to what degree there are any. I heard somebody would do that to run two 4x12s...maybe more iron means more bass!

The only changes I'd make now are to the filter caps and pre-tone control coupling caps/cathode bypass. A lot of people like to cut bass by lowering those values in this amp. It is very pronounced with single coils and even less friendly with humbuckers.
Thanks for the input! I think I'll still build it stock just to see how I like it and take it from there. I'll keep the filter and coupling cap mods in mind though.
Title: Re: Building an amp... Where to start?
Post by: miter53 on June 09, 2014, 08:05:41 PM
I used the kit from Triode Electronics for my 5E3, and it worked out well. Good price and good components. I did use the bigger transformer that allow 6L6s to be used.