Tube boost + overdrive running off a 9 volt battery

[Renegadrian]

...the C2655Y would be just awesome in some sort of fuzz like a Rat...

[trad3mark]

hmmm...

slight, minor issue with my VC. It's working great, and i really love it, but, there's a slight issue with volume.
With ALL my other pedals, be them build or bought, when volume's at 9 o clock, it's more or less the same volume as clean/when it's switched off. Not with the VC. It needs to be at least at 9 o clock, and even when it's at max volume (and max everything actually) it's still not as loud as if i just use my SHO on max on clean. SO, because output is coming from lug 2 of the volume (which is a 100k pot) could i just swap the 100k pot for something like a 50k pot to get more volume? Or is there something easy i can do to increase the volume? I reckon it's roughly a half or a third of what it should be.

cheers,
tm

[frequencycentral]

Swapping the volume pot for a 500K will give you slightly more volume...........hmmm, I was going to say your build may still have an issue somewhere, but yours is a ECC81 tube, so has less gain than ECC82 anyway. It might also be worth your while tinkering with the values of the two plate resistors, as what works for a ECC82 may need tweaking to work with a ECC81.

[trad3mark]

going for a pot of HIGHER value gives more volume?!  how come it's not a lower resistance one?

[frequencycentral]

Because with a higher pot value you're putting more resistance between the signal and ground. Think about it, if you short the signal to ground you have zero resistance and therefore zero signal.

[trad3mark]

oh.... ok. I have a 470k pot. I'll try that. Cheers FC.

[doitle]

Just got a package from the mailman. 9 12AT7s. Initially put one in the valvecaster to make sure I wasn't just sold glass ornaments and it did work I didn't really hear much of a difference except for strangely... it was quieter than with the 12AU7... Similar to what we were discussing in the Promiscuous Girlfriend thread with the 6112 being quieter than the 6111 even though the 12 has more gain. Later today maybe I'll convince my room mate to record some clips of the valvecaster with the 12AU7 and the 12AT7 for comparison.

[biggy boy]

Later today maybe I'll convince my room mate to record some clips of the valvecaster with the 12AU7 and the 12AT7 for comparison.

That would be great to hear !!

[Renegadrian]

Mike, it seems that the greater the gain value of a tube, the more voltage they need to work good...
I made some little experiments with the 12**7 I got (AU, AT and AX) - AU work quite good at low voltages, AT require a little extra push and I still haven't managed to make an AX sound decent with my voltage multiplier (50V)

[azrael]

How would I make a Valvecaster, the 12Au7 version, into a clean boost? I'm not looking for overdrive.

[Renegadrian]

I believe Rick made some experiments to get unity gain or something - actually the Valvy gives a clean boost with the gain pot turned all the way down, so you may expect the same result by swapping that pot for a fixed res., say 47k <--> 100k

[CynicalMan]

How would I make a Valvecaster, the 12Au7 version, into a clean boost? I'm not looking for overdrive.

Someone (I forget who) mentioned this way back near the beginning of the message:

The nicest clean sound I've found so far, is with the following mods:
R2 = 100k
R3 = 47k
C1 = 0.1uf
Remove C4 and VR2

[Ripthorn]

Of course, more voltage will give you more clean headroom, so if you really want a good clean boost, I would look at boosting your 9V to something higher (several times higher using a charge pump, perhaps).

[trad3mark]

sorry to come back to my earlier problem of volume.

I put in a 470k pot for volume, and it made SOME difference, but it still needs to be at least 12 o'clock to match the off volume. Any ideas of what i could change in the circuit to boost the volume? Still running on 12V by the way.

[Ripthorn]

There's not much you can do to boost volume without either increasing gain or voltage.  You could do a 1M pot at the end for volume, though if I were you, I would get myself a TC1044 charge pump, put the 12V in, add a few caps and diodes and get yourself 25 or 34V on the plate.  It will make a world of difference.

[ACS]

I run a 12AT7 in mine and don't have a problem with volume - bear in mind that every pedal is different, and '12 o'clock' on one won't be the same on the next.  But you should definitely be getting way above unity if you crank the volume pot right around.  If not, then you have a problem.  From memory, mine gets unity gain at about 12 o'clock-ish as well, so it sounds right to me.

[doitle]

Just tried running the LPBass-1 into my valvecaster here... It sounds awesome! Now I REALLY want to get these things packaged up so I can show them off! Also for the people asking if the filaments glow brightly, get yourself a GE 12AT7 and run it off 12V... The thing is like a lightbulb!

I can't wait to get these bundled up as real pedals and start on my next project!

[KMARLOW]

Hi first post here and I have to say this is a great site.
I had enough parts laying around to build the Matsumin Valve Caster this weekend and it sounds great. Right now I'm swapping out some parts so i have a couple of questons.

1. Is C3 supposed to be an electrolytic cap. It looks like some of the layouts use different values and not electrolytic.

2. On the below quote I'm confused as to what VR2 is.

"The nicest clean sound I've found so far, is with the following mods:
R2 = 100k
R3 = 47k
C1 = 0.1uf
Remove C4 and VR2"
Thanks 

[Renegadrian]

Hi there and welcome!
Right, here's the answers...
As for that cap, you can use either, so polarized or unpolarized are quite the same - I used both and got no differences...
VR2 (variable resistor) is actually the TONE pot - So you have to build the toneless version (and if I read the previous pages you know that many fellas including myself think it's better without...)
Hope it helps!

[doitle]

I was thinking of removing the tone pot from my valvecaster because it doesn't do much when you turn it anyhow. Maybe when I get back down to school I will remove it.