You think tube overdrive is impossible with your Twin or Bandmaster amp? Think again...

Wag

Member
Messages
455
The Twin Reverb and the Bandmaster. Their reputation is infamous. As clean as the day is long. No one knows this better than me. I own both amps.

So, a few weeks ago Im browsing some DIY pedal websites and I run across the schematic for the "Valvecaster", a tube-based, clean boost/overdrive pedal. It uses a low voltage (12vdc) "starved plate" circuit designed around a 12AU7.

Seriously!?!?

I immediately fired up the soldering iron and started building!

And here is my first completed Valvecaster:



Wow!

Y'all know that the Twin and the Bandmaster take pedals well anyway, but this pedal was MADE for these amps. It gives them that overdriven tube tone that so many of the other Fender amps are famous for. I hooked the VC up along with an Aqua Puss clone and an NPN Boost (both great DIY builds in their own right) and I was just blown away by the tone I was getting from this setup.

I say this is my "first" valvecaster because I do intend to build several more. This design has been around for many years now and there are a number of modified versions floating around. One in particular was dubbed the "Subcaster" and uses 2 sub-miniature 6111 tubes instead of the 12AU7. Im anxious to get that one started.

Im really surprised this pedal hasnt gained more popularity outside the DIY community. A search of the guitar forums I frequent will pop up a few old threads but it really hasnt gotten the attention it deserves. Even if you dont play thru a super clean amp, this is an awesome pedal, worthy of some real estate on any pedal board. The build is very simple as DIY pedals go. About $50 in parts and a few hours of your time.

So, all you Twin and Bandmaster owners get building! Trust me, you want (need) this pedal!
 

Wag

Member
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455
Thx Kas.

Yea, last time I went "enclosure shopping" I spotted the translucent boxes. Had to try one out. Ive read where plastic boxes can create noise issues with some pedals, but Ive had no problems in this case. What I did discover though, is that you want to keep the time you spend working on/in these boxes to a minimum. Ive been in and out of this box dozens of times as I tweaked, modded and rebuilt various parts of the circuit and it starts taking a toll on the plastic. Scuff marks, flux splatters, soldering iron scars, etc. Need to treat them with kid gloves best you can.

No, I dont have any clips and tbh doubt that I could record any on a cell phone that would do it justice either. But keep in mind this circuit can be, and usually is, tweaked to suit that persons particular tastes. The original thread at diystompboxes is a monster and runs in excess of 180 pages covering every kind of tweak and mod imaginable. And then, like most tube circuits, its only going to sound as good as the tube you put in it and there are literally dozens of different tubes that WILL WORK in this pedal and every one of them sounds different then the next.

Link to original thread...
http://www.diystompboxes.com/smfforum/index.php?topic=63479.0

Link to a "summary" pdf file...
http://www.aronnelson.com/DIYFiles/up/12AU7-6111_Valve_Caster_Summary_Rev002.pdf
 
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stahlhart

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2,449
Kim Mitchell, with Max Webster, along with a second guitarist they had added for the tour, were both using silverface Twins when I saw them open for Rush back in '81. They were running them far from clean. I was too far from the stage to note whether it was the amps wide open (or modded), or if they had anything in front of them. But the pedal choices back then were obviously not what they are today.

Edit: yup.

 
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stahlhart

Member
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2,449
I also recall that there is a 1980 or 1981 issue of Guitar Player that had plans for building something a lot like this, and I believe it was also 12AU7-based. I've got that magazine stashed away here somewhere.
 

BobK

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2,256
Kim Mitchell, with Max Webster, along with a second guitarist they had added for the tour, were both using silverface Twins when I saw them open for Rush back in '81. They were running them far from clean. I was too far from the stage to note whether it was the amps wide open (or modded), or if they had anything in front of them. But the pedal choices back then were obviously not what they are today.
Kim Mitchell knows tone.
 

Wag

Member
Messages
455
I also recall that there is a 1980 or 1981 issue of Guitar Player that had plans for building something a lot like this, and I believe it was also 12AU7-based. I've got that magazine stashed away here somewhere.
As a matter of fact I ran across a tube pedal schematic last night that said it was from guitar player mag. And yes, was a 12AU7. There are quite a few tube pedals out there but every one I found used high voltages to run the tube and that wasnt something I wanted in my pedal chain. At least, not in a pedal that *I* built. Would just be a matter of time before my sloppy work came back and bit me! lol
It was the fact that the valvecaster was originally designed to run on a 9 volt battery that sold me on it!

And I guess I can only speak for my Twin really, but Ive never had mine past 5. The volume becomes obscenely loud at that point but not a lick of distortion...lol

But tbh, of the two amps I like the BM/VC combo best. Perhaps it is because the bandmaster has nos tung-sol 5881's in it? :cool:
 
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Tone_Terrific

Supporting Member
Messages
31,082
What makes this different from any other od pedal?
IF you are driving the first stage of your amp into clipping any strong boost will do that.
It generally does not sound great.
If you are generating the distortion tone from the pedal it will work into any amp, Fender or whatever.
Starved plate pedals have been around since the '80s, at least. (Butler, Markley, Ibanez, etc)
Not that they cannot be used effectively, but their functionality is not unique i.e. they generate distortion.
 

InAbsentia

Supporting Member
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1,520
I always wanted to one of these, but haven't really built anything before. Maybe one day I'll try it, or get someone to build me one.
 

Wag

Member
Messages
455
Bandmasters get fairly dirty when you crank them up, as the OT is fairly small for a 2x6L6 amp.
While this is true, most of the times that I (and many other folks too, I bet) play, playing at "cranked" volume isnt prudent. Seems that the quest for "bedroom tone" is as popular as it ever was.


What makes this different from any other od pedal?
What makes vinyl different from digital?

IF you are driving the first stage of your amp into clipping any strong boost will do that.
It generally does not sound great.
If you are generating the distortion tone from the pedal it will work into any amp, Fender or whatever.
Starved plate pedals have been around since the '80s, at least. (Butler, Markley, Ibanez, etc)
Not that they cannot be used effectively, but their functionality is not unique i.e. they generate distortion.
I wouldnt expect this, or any other pedal, to appeal to all people. No one would. Pedals are a very personal choice and no one will be upset that this particular pedal doesnt interest you. Really.
But this wasnt a very productive post. I cant see that it added anything useful to this thread. No point in trying to discourage others from trying it out, is there? Its actually been a fairly popular design among the DIY crowd.

Thanks just the same for your participation.
 

Tone_Terrific

Supporting Member
Messages
31,082
But this wasnt a very productive post. I cant see that it added anything useful to this thread. No point in trying to discourage others from trying it out, is there? Its actually been a fairly popular design among the DIY crowd.
I think you misunderstood what I was saying or what is happening with your amp, maybe both.:dunno
 

Fulldrive-1

Member
Messages
5,234
My first guitar amp was a Bandmaster head and a self-built 4x10 cabinet. It was sort of a mini-half stack. The amp was clean but I ran a fuzz face into it (this was 1975 and there were no OD pedals yet). It worked OK for the time.
 

gght

Member
Messages
198
To anyone building the Guitar Player magazine tube overdrive:

There was a mistake in the design that slipped through the editors. A month or two later they published a short "update". It won't work if built from the original article. Don't ask how I know, and yes I am that old.
 

Wag

Member
Messages
455
I think you misunderstood what I was saying or what is happening with your amp, maybe both.:dunno
I see....

I thought you said that any strong booster will do the same thing and regardless it sounds bad, even if its not a fender amp and its an old design once used by some has-beens and that there is nothing special about this pedal.

I will try to be more careful in the future...
 
Messages
6,593
I got a Butler starved-tube pedal with 3-band EQ last Fall for my rehearsal board. It's a good sounding low drive pedal.
 


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