Little help with odd noise

[whomeno]

ok
Here is what I did. I built a tiny giant from vero. works good. Then built a jcm 800 superlead preamp. woks good.
I put it all into a 1590xx . input to jcm preamp then from preamp to tiny giant. with tiny giant vol. dimed and the preamp vol dimed and both bass gain and treble gain at 3 it all works great.
If I that the gains above 3 it starts to go in and out (wavy) and sounds like speaker is farting.
What can I do to correct this?
I bolted the TDA7240 to the enclouser, so heat should not be a problem.


tiny giant vero






jcm 800

[PRR]

Is there a power supply filter between the power amp and the preamp? The power amp pulls big chunks of current and its supply will vary. When this gets into the preamp supply, it is kinda-like when speaker sound gets back in the microphone: feedback. It may be a squeal or a howl or even a putt-putt depending on the sneakage. 100r and 1,000uFd may be a good trial network.

[whomeno]

PRR,
this is how I wired it up. From the power jack to a on/ off switch. from the on/off switch I ran 1 line to amp and 1 line to the preamp.
How would I wire the power supply filter into this.
Thanks

[whomeno]

So I went and built just the amp section. I'm getting the same noise from the amp going to replace the 470uf with a 1000uf to see what happens

[whomeno]

ok replaced the 470uf with a 1000uf in the amp and still got the noise. when the amp volume is at 10 and the pre amp is at 10 with the bass & treble gain set at 5 no noise. If I add more gain on bass or treble I get a deep  eeeeewwwwwww sound.
anyone have any ideas on what I could try next

[PRR]

[whomeno]

PRR,
put filter in place, that took care of the bass gain can run it wide open.
on the treble I get just a little noise at the end of guitar chord when treble gain is wide open.
I seen you had a question mark by the resister, which way would I go larger or smaller on the resistance?
Thanks for the help

[whomeno]

PRR,
Thanks for the help I got it. I upped the 1000uf to a 2200uf now now noise at all.
With the jcm 800 super lead pre amp into the tiny giant amp is an awesome setup.
Thanks for the advice