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benadrian wrote:japmn wrote:So I'm having 2 problems with this Bassman preamp.
1. It is way too loud. I can only basically turn it up just enough for it to be making sound and then it is way too loud after that. It also is basically a fuzz if I don't turn the guitar volume down to about 2. It's a cool as hell fuzz, so if that is the way it is, so be it. It does sound great when it is clean though.
Ideas?
2. Should this design with these transistors have an excessive amount of hiss? Because it does.
Ideas?
1. You can try taking the 25uf caps out of the circuit. That should reduce the gain of the gain stages. Make sure you still have 4.5 volts at the drain. If that's still too loud/distorted, then you can try replacing the 1.5k resistors on the source pins of the JFETS with 10K, and then rebiasing to 4.5 again.
2. Yes. these pedal circuits are known to be pretty hissy.

Nate Dort wrote:Fuzz pedal design:
ImDADA wrote: Die Richtung ist die Chefetage.



Evanc521 wrote:I have a Phat Cat in the bridge of my Epi Dot, how do you like it in the neck? I'm considering switching the 57' classic out with one.

Rodabod wrote:benadrian wrote:japmn wrote:So I'm having 2 problems with this Bassman preamp.
1. It is way too loud. I can only basically turn it up just enough for it to be making sound and then it is way too loud after that. It also is basically a fuzz if I don't turn the guitar volume down to about 2. It's a cool as hell fuzz, so if that is the way it is, so be it. It does sound great when it is clean though.
Ideas?
2. Should this design with these transistors have an excessive amount of hiss? Because it does.
Ideas?
1. You can try taking the 25uf caps out of the circuit. That should reduce the gain of the gain stages. Make sure you still have 4.5 volts at the drain. If that's still too loud/distorted, then you can try replacing the 1.5k resistors on the source pins of the JFETS with 10K, and then rebiasing to 4.5 again.
2. Yes. these pedal circuits are known to be pretty hissy.
Further to 1, you can try taking those drain bypass caps out, but it increases negative-feedback which you may not want; it'll reduce the amount of asymmetrical distortion you're getting. You also lose the fact that the LF is kept in check (less gain and less distortion at LF). What I think you want to try is balancing out the gain at each stage to achieve "good" sounding distortion. In very simple terms, you want several gain stages all clipping slightly, rather than one stage getting overdriven hard and shitting the bed (ie. fuzz), that is, unless you want that.
2. You can use a quiet transistor for the front end of this, and balance the gain as described before to achieve useable s/n ratio. It's mainly down to gain staging, and how you go about choosing what gain where. Experiment.




japmn wrote:Here is a quasi-finished version of the Bassman Fuzz Drive thing.





japmn wrote:Building a Tube Sound into a box with a little booster circuit I cooked up. The Booster is based on an LPB-1, but with some parts excluded/switchable. It makes it a pretty dirty booster, but I like it that way. I whipped it up on a Vero strip and it's about the size of a computer key. I'm installing a 3PDT toggle to switch the order of the booster and the Drive. It will be a cool little box, I think. Here is the booster Vero layout. It's almost free to build.
Niftyness!

benadrian wrote:japmn wrote:Building a Tube Sound into a box with a little booster circuit I cooked up. The Booster is based on an LPB-1, but with some parts excluded/switchable. It makes it a pretty dirty booster, but I like it that way. I whipped it up on a Vero strip and it's about the size of a computer key. I'm installing a 3PDT toggle to switch the order of the booster and the Drive. It will be a cool little box, I think. Here is the booster Vero layout. It's almost free to build.
Niftyness!
That vero looks really wrong. Maybe I'm missing something. it looks like the input is going through a .1uf cap to ground. Also, it looks like the output signal before the put (the blue wire) connects to the .1uf cap directly to the power supply, which is essentially an AC short. Also, in an LPB1/2, there should be a 390 ohm resistor on the source/emitter, not a 390k. Do you have a schematic dawn up for this circuit?



benadrian wrote:Okay, then that Vero program sucksSeriously, that would throw of almost any builder unless there was a big ass disclaimer on the layout!
Looks like the switch is in the wrong place though, I'f I'm reading it right. it appears to be on the output side of the gain stage.


japmn wrote:benadrian wrote:Looks like the switch is in the wrong place though, I'f I'm reading it right. it appears to be on the output side of the gain stage.
A little MsPaint clears it up I think.

benadrian wrote:japmn wrote:benadrian wrote:Looks like the switch is in the wrong place though, I'f I'm reading it right. it appears to be on the output side of the gain stage.
A little MsPaint clears it up I think.
Much Better!
I think the switch is still in the wrong place. The blue line that goes to A-F should go to A-E if you want to match the schematic.

japmn wrote:Much Better!
I think the switch is still in the wrong place. The blue line that goes to A-F should go to A-E if you want to match the schematic.


japmn wrote:Do you know of a good program for drawing up Vero layouts, cause this one sucks ass. Maybe I'll just make a template in Flash or something.
The little booster sounds kinda cool, the switchable resistor acts like a little dirty boost.

benadrian wrote:japmn wrote:Do you know of a good program for drawing up Vero layouts, cause this one sucks ass. Maybe I'll just make a template in Flash or something.
The little booster sounds kinda cool, the switchable resistor acts like a little dirty boost.
I've never made a vero drawing in software. I've just used graph paper.
Your buffer reminds me of this one.
http://www.muzique.com/tech/bipolar-j.htm
Awesome!

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