An universal guitar preamp

[iakirov]

Hey great preamp, I'll give it a try as a part of a combo amp, I hope to do it soon, I'll tell you about it then.
Thanx for it!

[wadehavens]

Hi there! I've been working on building a guitar amp out of a chip I pulled out of a car stereo when I came across this thread. I listened to the sample mp3's and I was very impressed, so I decided to build this preamp.

I must say, this is the most awesome sounding DIY project I've built yet. This preamp can sound like almost anything you want it to. It's somewhat difficult to dial in specific tones, and you can get lost very easily, but once you learn the controls it's not very hard at all start enjoying the lovely sounds this baby can make.

There is one thing that I find puzzling though.
There aren't any directions on how to hook up the switch, so I had to spend some time looking at the schematic to figure it out. I'm pretty sure I have everything hooked up right, however, there's not much of a difference between any of the switch settings. I'm thinking that either I have the caps on the switch hooked up wrong, or the switch is not needed at all. I have to note that I'm connecting it to a chip amplifier and that may have something to do with it since it was meant to be a DI box. Any help with this would be greatly appreciated!
This is an absolute must build for EVERYONE. You will be amazed! Thanks for this!!

[off1]

This one looks great!!

I only have a question. If I set the drive knob all the way down, will I get a really clean sound?  Coz I'm planning to use it sometimes with my external effects and I don't want any distortion from the preamp when that happens.


Congrats for such a complete preamp!

[wadehavens]

This one looks great!!

I only have a question. If I set the drive knob all the way down, will I get a really clean sound?  Coz I'm planning to use it sometimes with my external effects and I don't want any distortion from the preamp when that happens.


Congrats for such a complete preamp!

If you want a really clean channel this preamp is not for you. It does get clean, but never completly clean. It always has a small amount of distortion. At least thats my experience with the one I built. However, if you build this from scratch (using the schematic and not the current layout) you can include a switch to bypass the distortion section and it should clean up very nicely. If I were to build it again, that's what I would do.

Wade

[off1]

Thanx Wade! that really clarified my concern.

Here's another question. I've always avoided using FET's in my projects coz I've heard it's like tossing a coin; they are very unreliable, sometimes they work but sometimes they don't.   What is your experience with these?


THANX AGAIN

[wadehavens]

Well, I'm not an expert by any means, but almost everything I've built has at least one FET somewhere, and I've never had any reliability problems. The only thing I've noticed is that some projects including the J201 sometimes have the pinouts wrong depending on the FETS manufacturer. As a mater of fact, I didn't even use J201's in this project since I couldn't get any localy. Instead I used a pair of 2SK55's that I found in an old cable box, and those pinouts were 180 degrees off. I'm not sure if these made any significant difference, but I love the way mine sounds. It is a little noisy though. But I expect that from a very high gain preamp. 

If nothing else, this preamp is proof that you 'can' get just about any distorted sound out of a solid state project.

[off1]

Thank you man!!!