BASS FUZZCASTER (How to turn the Valvecaster into a sweet bass fuzz!)

[Bill Mountain]

I was toying with a Valvecaster on higher than 9 volts and I ended up with this design on my breadboard.  I plan to experiment with it some more but I thought I'd post what changes I made that help get a killer bass fuzz tone.

The voltage for the anodes on Bass Fuzzcaster is 60 volts.  You could probably go as low as 20 volts depending on how hot your pickups are but any lower and the LED's won't conduct.  You might be asking yourself, "isn't this basically just a Valvecaster with LED clippers?"  Damn straight it is and it sounds awesome!

[blown240]

So what does the LED clipper actually do?  Also, couldnt you still run a 12v wall wort, and then a 12v to 120 transformer inside to get your higher voltage?

[Bill Mountain]

So what does the LED clipper actually do?  Also, couldnt you still run a 12v wall wort, and then a 12v to 120 transformer inside to get your higher voltage?

The LED's give it a compressed "fuzzier" tone.  It's less touch sensitive and basically full distortion at most gain settings.  I cut a lot of lows in the beginning of the circuit to prevent the nasty side effects of too much low end in the tube gain stages and the LED's compression and bassier tone help make that less noticeable.

You could run higher volts but with the LED's cropping the signal you'll reach a point of diminishing returns.  I used 60 volts because that's the max on my bench top power supply.  If I played really hard the LED's got bright enough to land a plane!  With less and less voltage there was less and less gain to clip the LED's hard.  Also on their own, the tubes produced a nice midrangy tone which didn't require any tone shaping to control the high end.

[Renegadrian]

How does it sound like on the breadboard!? the input cap is looooooow in value, would it sound like a treble booster?! I know a standard valvy enphatizes the bass frequencies more, but hell 2.2n is more a treble booster!!! or that 2.2 compensates the sound and you have a good range!?
I'd have a 1µ - 2.2µ at the input...you're saying that would be good without the clippers?!
And you stayed with the cathode ground gain...and no cathode caps...

[Bill Mountain]

How does it sound like on the breadboard!? the input cap is looooooow in value, would it sound like a treble booster?! I know a standard valvy enphatizes the bass frequencies more, but hell 2.2n is more a treble booster!!! or that 2.2 compensates the sound and you have a good range!?
I'd have a 1µ - 2.2µ at the input...you're saying that would be good without the clippers?!
And you stayed with the cathode ground gain...and no cathode caps...

I started with a standard Valvecaster and kept lowing the input cap to remove unwanted "farty" tones.  The 2.2nf on the input only rolls off at about 70 Hz (like playing bass through a guitar amp).  Then I wanted to compress the signal some so I added the LED's.  If I was designing this from the ground up, I would use a stock Fender gain stage but I started with the Valvecaster so I used some of it's signature design elements.  I didn't use any cathode bypass caps because I don't need a whole lot of gain.  That's why I put the divider in between the stages.  The 12 AX7 produces plenty of gain at 60v so I threw some of it away to keep the 2nd stage from being hit too hard.  I play a down-tuned high output bass so I need to control excess volume when I can.

Most effects can't handle my bass so I need to control the lows as much as possible.  Extreme low end is not as important as most people think.

I'm working on a higher voltage transistor fuzz to hopefully get the same sort of tones I got with the Bass Fuzzcaster.  I would prefer to have to figure out how to provide 20 to 30 volts for a transistor than have to build a tube power supply.

[Renegadrian]

right, thx for your explaination!