overdrive circuit

[drlowlow]

I am working on revisions on this circuit and would be interested to hear feedback from people with much more experiance then me. This is the first circuit of this type I have designed and think it is a pretty good theory if I can get the values correct. Alot of the circuit is generic stuff, besides the drive control which has direct control over two stages of amplification. The allignment pot is set up to adjustable (but hidden from normal use) so that the input to 3rd stage amplification will be close to the input to the second. The procedure would be to set the gain pot to the highest setting prior to overdrive which would be viewed at TP2. After the drive is set put the second channel of the O'scope on TP1 and use the minus function on the scope until you get a flat line or close. That way both stages should go into overdrive at the same point on the gain control (even though the second stage will have a non linear increase through the progressive movement of the gain control. Of course this concept for me is but accademic at the moment. Let me know what you think.

[Smitty]

Learn to Lurk

You've got the right idea. You can learn one succesful approach to overdrive tone at this other forum:

http://maximoaudio.com/forum/index.php

Lot's of fanatics over there. Good crowd.

I learned how things sounded by sucking on solder fumes. There is really no other way. Slap that thing togther an listen to it. You will want to do a couple things:

1) Decouple stage one and two from three and four in the power supply by adding another node. Anything north of 1K and 10uF will likely work.

2) You may find you like the sound of a direct coupled cathode follower so you can lose the master volume and direct couple stage three to four.

3) Experiment with where you want to put the tone stack.

Have fun!

Smitty

[Chris / CMW amps]

If the last stage is a cathodefollower you gotto change the place of the mv and rewire that section, just check some post '76 Marshall 2204 and 2203 schematics.

[drlowlow]

All points well taken, i will direct couple the output of stage three to the cathode follower, and move the 1 meg mv pot right prior to the bypass switch. Thanks for the help.