interface for hifi amp ?

[nadojaz]

Hello,

I look for a diy preamp for doing an interface between my hifi poweramp (qed a240, 2x40W) and my guitar. Or another basic solution, of course.

Thank you.

[indianajo]

If you are in the western hemisphere, look at tubelab.com kits. A used 10 to 32 V DC wall transformer makes a good power supply instead of batteries. See the end of this thread for converting a DC wall transformer to a quiet split DC power supply.www.diyaudio.com/forums/analog-line-level/164102-improving-disco-mixer-mid-fi-performance.html Watch out for very light wall supplies, they may be switchers and howl into an amp circuit. Don't use 741 dual dip op amps like tubelab specifies, use MC4558 or TL082, or splurge on some more power supply bypass capacitors (.1 uf disks) and a feedback resistor bypass cap (22 pf) and use MC33078 or RC4560. The latter has more current out to drive longer cables. Or pick up a used RA88a mixer like I did for $15 and fiddle with the gains (feedback resistor) to get what you want. Gets you a nice steel box, too, in come cases. Warning, behringer stuff is alleged to contain SMD's which ordinary mortals can't modify. Some cheap mixers also have non replaceable slide pots without a new pcb, I don't know which ones. My Peavey mixer has nice repairable construction. Mono Peavey mixers from the seventies go very cheap on CL, as do all brands of mono mixers. I have an Ampeg mono mixer I got for $40 25 years ago.