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Is that a choke? Cool for a cheap amp...

That was exactly what I thought.  I don't think I've ever seen a budget amp with a choke, let alone one that is as big as its output transformer.

What's the volume like?  And what's your impression of the power tube sound?  Knocking a 6L6 to 5/2W is not something I've heard of before, and I'm curious how they did it and if it worked out.

I was cleaning out the old hobby drawer and I came across an ancient green madbean PCB that I had no idea I had. It's a Gruntbox v.1 [(c) 2009 madbeanpedals(!!!)].  Any chance of getting the build docs for this?  I haven't fully traced it but the first part is identical to the current Mudbunny w/just a small change to the power section.  Anyway, any info would be appreciated. 

I almost hate to say this, but I've had better luck lately buying enclosures from Tayda than from Small Bear.  The powdercoated 125s and Bs I got from SBE were probably the worst I've ever seen.  Massive flakes coming off of the coats during routine drilling, and obvious paint defects on the surface.  I sometimes get Tayda enclosures with minor defects (bubbling in the paint or a small scratch), they can flake a bit during drilling, and generally aren't the quality of say a Hammond.  They also tend to scratch easily because the finish is soft.  But unless you're going to spend 2-3X the money, it's not like you're going to do better from the other usual suspects.

Generally speaking, I think Tayda's bad reputation is mostly undeserved, and we put the other sellers on a pedestal.  It's a bit silly.

I'm not entirely sure I follow your plan or understand your setup or your concern.  You are connecting your pedalboard into the house mains, and you're going to tap that with the IEC connector, put the new mixer wall wart supply on that outlet, and then plug the wart out into the mixer, correct?  Seems a bit complicated and I don't totally follow why you can't plug into the outlet for your board supply with your new, smaller transformer, but so long as the new wall wart is the correct voltage and current rating and it's plugged into the mains and its polarity and end barrel type is correct, then it will work.

It's encouraging that they seem to be taking their Canadian business more seriously lately.  My experience has been much the same as yours, broadly positive.  The only complaint I have is that I still I have no idea how their free shipping is supposed to work.  Every time I make an order it's over a hundred bucks, and every time I'm somehow uneligible for free shipping. 

I guess it's a small gripe given the convenience and selection they offer, but there's something infuriating about being promised something and then not getting it!

Love the enclosure.  The rounded corners and the embellished cutout in the back are a classy touch and the overall rounded shape gives it a sweet sixities vibe.  You really did a fantastic job on that.  Great design and building.

Was there any particular inspiration for the way you shaped it, or is that just the way it happened to come out because of the mismatch between the small size of the project and the relatively large size of the materials having been made for big amps?

A thing of beauty!  Congrats!

Perhaps I'm far too cynical, but I think that the music industry is being very deliberate in which artists get prime airtime and mass-media broadcasting.

Rock stars, almost by definition (Keith Richards, Liam Gallagher, Keith Moon, the list goes on) are very hard to control. They are charismatic, have loyal fans, and tend to speak their mind about whatever they damn well please. They write songs about doing drugs (Champagne Supernova) and slave rape (Brown Sugar), and get away with it. Even if, after they become troublesome to PR, the record industry tries to bury them, the fans keep them alive and in the public eye for quite awhile.

Pop stars, on the other hand, are micromanaged and airbrushed to within an inch of their lives. All their lyrics are carefully crafted, anodyne, to appeal to as broad a base as possible while offending as few as possible. Any passion is of the usual love story kind, whether unrequited love, or whatever. But never the Hey Joe type, she-done-me-wrong-so-I-sorted-her type, as that could be problematic. And if they do become an issue, then they can be safely dropped and replaced with the next airbrushed hopeful with nary a beat dropped. Any fans of their unobjectionable music is unlikely to be particularly loyal to the artist, as much as they are to the general sound (oh what a lovely love song!)

And the easiest way to control that lack of PR problem is to make sure that, as step one of the filtering process for who gets airtime, is to remove as many rebellious symbols as possible. And rock and roll is
with it's electric guitars is punk as hell, middle fingers flying.

Maybe, though, I really am being too cynical.

I like this!  Bring on the conspiracy theories!  alanp for truth!  Show me Taylor Swift's birth certificate!

Just a Hamptone derivative. There should be a thread around somewhere and I think the CB is still public on OshPark:
https://docs.google.com/document/d/16242mJW2ZmwldvevZ6Yy1l5WBadvsuWd13oR7KGU258/edit

Wow, Jon, thank you!  That is pretty much exactly what I've been looking for for the past few weeks.  Great doc.  Much appreciated!

The distributor provided the schematic!

Interesting setup. The second triode and EL84 look exactly the same as a Valve Jr. (down to the values). Front half is its own thing, as far as I can tell. Not sure about that tone stack setup. It almost looks like a Bassman / Marshall TMB at first, but then I see how Treble is setup differently.

I think it should be easy to implement half a dozen minor mods to this thing without a lot of trouble. Biggest issue is that there just isn't much room to add a lot of hardware. Squeezing another tube in there is going to be tricky, so I might just leave that one alone. But man, adding an EF86 up front would be sweeeeet.

I'll try a few things and put together a quick guide on what I did.

Side note: I put a set of JJs in there tonight. Doesn't per se sound *better*, but it definitely has more breakup now and longer sustain.

It's pretty cool of them to send the schematic.  Seems like a lot of companies are refuseniks on that account.  Anyway, thanks for posting it.

As you said, it's a pretty standard design (I mean that in a good way - very modable).  As far as I can see, the tone stack is basically your standard passive Baxandall with a bright cap and a couple cap changes off the treble control.  They removed the cap on the wiper and added an extra cap to ground.  How do you find it?  IMO, at low volume amps generally need a really heavy-handed approach to tone control in order to compensate for the whole Fletcher-Munson effect thing.  But it doesn't look like they've done too much here.

I've had the idea to use something like an ECF82 which has both a pentode and triode in it to do like a variation of a Matchless Clubman preamp. Could be a cool application for a little amp like that.

I'm pretty sure on the AX84 forums I saw where someone posted something similar to what I described actually. Triode -> pentode -> power pentode.

Wow, talk about timing.  I just bumped into something like this the other day on Merlin Blencowe's page.  He offers a set of PCB boards for amp prototyping, and just released a board for the ECL86--almost precisely what you're talking about, a triode/SC pentode combo tube.  If you're interested in checking it out, here's the link:

http://www.valvewizard.co.uk/ecl86pcb.html

Did you ever use it to goose a mic pre?

No, I usually chain mic pres for that. My FET pre distorts really well. I've also chained the channels of the 1176.

What's the FET pre?  I'd be interested to hear more about that.

I think it might be possible to add an additional preamp tube for more gain. But failing that, I think there could be easy mods for negative feedback and probably a pentode/triode switch. And of course, there will be some easy mods for increaseing or decreasing gain via resistors and tightening bass via cap swaps.

Looking forward to this.

One of the things that caught my eye was that the power transformer label says it can put out 2.5A on the filament winding.  That's surprisingly generous.  If memory serves, an EL84 requires 0.75A, and 12AX7s are 0.3A a piece, I think, so it should be able to power several more tubes.  That's cool.  If you don't like the amp, it's gonna be really modable.

That comp looks awesome.  I like how you used a rotary switch instead of that fussy 4 button panel that model uses.

Did you ever use it to goose a mic pre?  I've read that both the 1176 and the LA2A are good for getting an extra bit of gain for quiet sources or to drive other equipment.  I might have a use for that if it works.

Not that I'm trying to talk myself into finally building something like this or anything...  No, no, no...

Also, country music. Currently wildly popular and lots of guitar. Personally, I like classic country music and find much of modern country music sterile or cliched, but it's a steady market for acoustic guitars and Telecasters at least. That may not help Gibson as much.

That's a really great point.  I never thought of that, even though in retrospect it seems obvious.  I guess we're all prisoners to our own interests.  Country music is really popular where I live, though I wholeheartedly agree with your "sterile or cliched" take on its modern variety.

Maybe country music will save the instrument.