Valvecaster + LPB-1...thoughts?

[awgearhart]

I'm getting ready to build the standard Valvecaster but am slightly unsatisfied with the low gain seen in video demos. I see a lot of opinions about how a boost in front sounds great, others think it sounds bad. I'm looking at the simple LPB-1 boost from TonePad: http://www.tonepad.com/getFile.asp?id=68

Does anyone have a video/audio demo running a boost in front of the Valvecaster? I'm thinking I may have both circuits in the same enclosure, LPB in front, and having independent selection of either the boost or VC. Worst case scenario (if I don't like the sound of the boost in front), I have two pedals in one.

Just wanted an opportunity to hear it before I actually start building. Or any non-opinionated descriptions of the effect of the boost with the VC.

Thanks!

[italianguy63]

I did a "double" VC with 2 valves... it had TONS of gain with the 2 stages... I was never able to get the tone-stack to work, so I have to rework my design.  Otherwise, it had tons of boost.  From mild to very wooley!  MC

Here:

I am going to redo it and scrap the Tone control piece all together, also the "more boost" switch was not as effective as I would have hoped.  I would also remove it, and just use 1 fixed resistor on each valve....

[mozz]

I think it depends on what kind of amp you are running the VC into. I think it's a very strong driver though I have used it to drive other pedals and not the other way around. I'm also going to say I don't like the cathode pot and use a fixed value. I also run the plate at 20ish volts with a 12au7 12at7 12av7. I don't like 12ax7 starved plate.

[awgearhart]

I like the idea of the tone control, I wouldn't want to get rid of that. But that double VC looks pretty tight.

Mozz, I'm running into a Mesa Boogie Road King II (Rectifier Series). This pedal is more of a "fun project" than anything else. In fact, I already have a BKB Tube Driver as is.

I'm just looking for a way to provide a little bit more drive than what I hear in videos. If running into the Mesa means no need for anything extra, I'm all game. I also want it to be simple. Ideally running at 9 volts.

[awgearhart]

Even a simple mod to use a 12ax7 instead would be cool. I saw a post about changing R2 and R4 to 100k and it's supposed to work (resistor numbering based on original/standard schematic)

[italianguy63]

I like the idea of the tone control, I wouldn't want to get rid of that. But that double VC looks pretty tight.

Mozz, I'm running into a Mesa Boogie Road King II (Rectifier Series). This pedal is more of a "fun project" than anything else. In fact, I already have a BKB Tube Driver as is.

I'm just looking for a way to provide a little bit more drive than what I hear in videos. If running into the Mesa means no need for anything extra, I'm all game. I also want it to be simple. Ideally running at 9 volts.

If you screw with this and are able to get the tone-stack to be effective, I would appreciate the info!  I would rather have it too.

Also, this design is boosted to 12V and that helps a lot (with overhead and enough power for the valves).  The Mosfet design is slick and puts out a good amount of power.  MC

[awgearhart]

I've also heard about the "ValveMASTER" but it's hard to find any diagrams and/or sound clips of a demo. Don't know if this is supposed to have more overdrive/sound "better." Any thoughts on the Valve Master?

The two diagrams I've found are these:

[awgearhart]

I'm thinking of doing the ValveMaster from Renegadrian with a DPDT diode clipping mod (Si or Ge options) before the Volume pot, and maybe a DPDT cap mod at the input for variable input capacitance. I've heard people like just a 22nF rather than the 47nF...thinking of 22nF when off, and option for either 44nF (close to 47) or 90nF (close to 100).

Not going to do the boost in the same pedal... for now I guess.

[vigilante397]

The Valvemaster is a pretty good starting point. It uses the gain like an actual gain control instead of a bias control like the valvecaster. Swapping the input cap is a pretty good idea as well, since the stock Valvecaster tends to be pretty dark sounding. You may also look at swapping C2 and C4 as they have a big affect on the tone.

As for using a 12AX7, swapping the plate resistors still won't do much good. You really need to run it at a higher voltage. The BKB Tube Driver has a plate voltage of about 30V, which is about what I consider to be the minimum for a "starved" 12AX7. The Valvecaster uses a 12AU7 because it still sounds like a tube with 9V on the plates.

[awgearhart]

Just curious, what would different values for either C2 or C4 change in terms of tone?

Does increasing add bass, decrease lower bass type thing?

[vigilante397]

Just curious, what would different values for either C2 or C4 change in terms of tone?

Does increasing add bass, decrease lower bass type thing?

Yup, you nailed it.