Tube boost + overdrive running off a 9 volt battery

[Jdansti]

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Looks like there's some extra info in your photobucket link. Try copying the "direct link" from photobucket.

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Ok. Thanks for that tip. I got there in the end. It is a nightmare trying to upload photos using an iphone. My advice... Don't

[Jdansti]

Cool retro look!

Not to be negative, but I have some concern with the mains power wiring technique. Maybe it's "technically" ok, but it could possibly be hazard. I'll let the EEs comment on that. Otherwise, it's a really nice looking build!

[sgmb]

I'd be worried if you weren't concerned. I don't plan on sticking my fingers in it though. I think it's as dangerous as any of my other amplifiers. I wouldn't stick my fingers in them either:)

[sgmb]

Damn!..I deleted a whole lot of extraneous pictures from photobucket and I seem to have accidentally deleted some of the ones I posted. I don't know how I did that.

[Jdansti]

Do you use the iphone photobucket app?  It seems to work well for me.

[duck_arse]

Ekco and Eko, just to confuse us. that is a beatiful looking cabinet, the stripes are v. nice. pitty we can't see the wiring mess.

[dill pickle]

So im another relatively novice tinkerer trying to make a valvecaster... Im running at 12v 1A walwort and using jjECC82 tube.  The tube glows, and the signal is going through; the gain and volume pots seem to work, and the tone control is doing something, but the output volume is really low, essentially no boost at all.  Ive looked at a few schems. and rechecked my wiring over and over, finding nothing.  Any ideas out there as to what may be happening?  Thanks
Dylan

[sgmb]

Do you use the iphone photobucket app?  It seems to work well for me.

I didn't know about the iphone app. I too the convoluted approach. The deletion was just due to me being a dumb ass.

Ekco and Eko, just to confuse us. that is a beatiful looking cabinet, the stripes are v. nice. pitty we can't see the wiring mess.

The wiring is actually fairly tidy...not brilliant but fairly tidy. Jdansti was referring to my setup where the power cord is strain relieved and attached to a tag strip which connects the power switch.

So im another relatively novice tinkerer trying to make a valvecaster... Im running at 12v 1A walwort and using jjECC82 tube.  The tube glows, and the signal is going through; the gain and volume pots seem to work, and the tone control is doing something, but the output volume is really low, essentially no boost at all.  Ive looked at a few schems. and rechecked my wiring over and over, finding nothing.  Any ideas out there as to what may be happening?  Thanks
Dylan

This has come up a few times through the thread but I don't remember what the solution was. I'm sure it's there somewhere. One thing that has been mentioned is that the JJ tubes don't work particularly well in the valvecaster circuit. I don't know why and I haven't tried them, I'm just going by memory.

[vigilante397]

So im another relatively novice tinkerer trying to make a valvecaster... Im running at 12v 1A walwort and using jjECC82 tube.  The tube glows, and the signal is going through; the gain and volume pots seem to work, and the tone control is doing something, but the output volume is really low, essentially no boost at all.  Ive looked at a few schems. and rechecked my wiring over and over, finding nothing.  Any ideas out there as to what may be happening?  Thanks
Dylan

Now that I think about it I always used GE tubes for my valvecasters and JJ for my twincasters. Not entirely sure why, but that's what I did. I didn't have any trouble with the JJ's in the twin, so I can't imagine it would be a problem in a valvecaster. Has the tube been tested to ensure it's a good tube?

[dill pickle]

Hey thanks for the response, im just getting back from a canoeing trip and back to the bench!  I have two brand new jj 12au7s from tube depot, and i tried both, same results.  I also have an old GE 12ax7 that i tried just to see what it would do, having read that they work, but dont sound good.  It was the same result, signal getting through but no amplification at all.  Ive searched the thread but didnt really find anything that helped.  Im about to take everything apart and start over, hoping to catch my mistake that way.  Is there a schematic that people like more?  Seems like there is some discrepancy between ones ive seen.

[Trippy Demon]

After the awesome read of this entire thread since January up till now I've been tinkering with some of the schematics here and decided that I really needed a valve drive before my tube top.

These were the schematics I started out with:


I had some 12A*7 tubes to work with and after careful, thirsty consideration and testing on the breadboard:


I came to this schematic:


Further design needed to be made for inside and out:



And at this stage I've just etched, and drilled the pcb:


The reason for the two different switches is that I have some DPDT swithes lying around, so I aim to use them here and there with millennium bypass switching.
As I could find a cheap 24V adapter at conrad's there was no need to keep the voltage at 9v.
I tried different tubes with different voltages but the 18/12 volt version sounds the best with 12AX7 and 12AY7 tubes.
I've tried all kinds of tonestacks but the simplicity of the original design seemed to end up winning every time.
So I ended up with a double tube drive where the 12AY7 simply drives and next to that a 12AX7 drives with a simple tone pot.

That's all for now, I'll keep you posted on further results!

[Trippy Demon]

Oh, and for the tubes I've tested from left to right: Sovtek 12AX7, Electro Harmonics 12AY7, JJ ECC83 S and two RCA 12AU7's



The Sovtek and Electro Harmonics I use in the 24V Twin Valvecaster.
The JJ tube doesn't give out enough drive power, so with the information of other builders it seems JJ's are not really suited for Valvecasting...
The RCA tubes work well on 12volt with this schematic:



The RCA tubes are cleartops so they look better in a build like this where they will be exposed.
If the first build works out I'll try to do this 12V version as well.

[toplak666]

That's a hell of a post Demon. Looking forward to the finished build.

[sgmb]

Agreed. One hell of a post. My hat is off to you sir