Marshall Guvnor Oscilattion problem PLEASE HELP (SOLVED)

[thermionix]

Mmm...maybe 5 pins if your Xacto skills are up to it.

[Atodovax]

Sorry i just got back my phone!! I couldnt reply before!! .. is the mosfet booster conpletely clean? Because i am looking for a booster/ overdrive to crank my amp and get the gilmour sound like when he used the power booster. Haha i have never used mosfets before but i reqlly love jfets . Specially on the bsiab.. the sound and how they clean up is superb!!

[GibsonGM]

Sorry i just got back my phone!! I couldnt reply before!! .. is the mosfet booster conpletely clean? Because i am looking for a booster/ overdrive to crank my amp and get the gilmour sound like when he used the power booster. Haha i have never used mosfets before but i reqlly love jfets . Specially on the bsiab.. the sound and how they clean up is superb!!

        Antonis

Yes, it is very clean!  I use one to simply make my amp's tone louder for solos. 

Now - you have to remember, if you push a higher signal into something that doesn't have the headroom left for IT to stay clean, it will distort more, so you will want to try it and experiment.   When I do this, I do get a little bit more distortion, but it is the 12AX7 in my amp distorting due to the increase in signal level, not the mosfet boosting it.  So it is much more touch-sensitive.

And, any booster (opamp, jfet, BJT...) can be made to output a clean signal, although you may have to add more gain sections (each non-distorting so at a lower level) to do so, or increase the supply voltage (to 18v, say).  But I like the basic AMZ booster at 9v.   You also can use that as a building block for more advanced preamp designs. 

http://www.muzique.com/schem/mosfet.htm

[Atodovax]

Thank you very much !! Im going to check it out. I was looking for something like that to build a preamp actually and then a power amp to build a small practise amp and i want it to be clean. Do you know of any basic power amp to build so i can use that booster as a preamp to it and power them both from 18volt?? Haha sorry for do many questioons!

[GibsonGM]

Well, A - what I would do is to explore some of the chip power amps.   There are a lot of designs around the TDA 2030, as well as others.   That would make the power amp part very simple, for a practice amp.  Maybe one day you'll want to build something like an entire tube amp, but for now a chip-based circuit is probably the way to go!!   The internet is full of projects using them, and the chips themselves are easy to find (on Ebay, too...).

For a preamp, you'd want more than just a boost, I think.  Something with tone controls, maybe overdrive/distortion that you can switch in...

A preamp really is just a stompbox, like we build here!  You would simply have to adjust the output level to match your power amp without distorting (that is easy).

Here:  www.runoffgroove.com  Check out "sounds" first, get an idea of what is out there for easy "preamps"  (well, stompboxes, but....)

[antonis]

Hmmm...

From a Guv'nor oscillation we passed through MosFet boosters & 12AX7 stages to TDA2030 power amps..

(keep going guys..)

[Atodovax]

Sorry. Thats my fault!! Im so full of questions.. hahah i actually posted another thread about germanium transistors for an ood maestro fuzztone fz1a xD