thank's once again Chris.
decided it was time to learn about capacitors and found this site good:
http://www.uoguelph.ca/~antoon/gadgets/caps/caps.html( more good info on this site, e.g. about opamps:
http://www.uoguelph.ca/~antoon/gadgets/741/741.html,
resp. links to circuits on the main page:
http://www.uoguelph.ca/~antoon/circ/circuits.htm )
term 1 should be N/C, term 2 should be going to r1 and term 3 should be going to c3.
thank's for looking that deeply into the circuit. I shall try this, but I with a new preamp that I am going to build, I do not want to open the first one I had succeeded fitting into this tiny box and which is working fine.
I don't really like pots in the feedback loop unless they are very high quality, because more often then not they introduce more noise. You could use a rotary switch with resistors to set gain, use metal film and the more positions the better. I like 0.5 db increments anything more is no good
Will try to find a rotary switch with 0.5 db increments.
Metal film for what? Does this refer to the resistors, or is there a metal film rotary switch?
This preamp circuit that your looking at is very simple. It should be a a breeze to build.
Well, I already had built one, you can see it here:
http://i39.photobucket.com/albums/e190/kuuan/IMGA2584.jpghowever I used cheap materials bought in a local store in Thailand, but still I really like it's performance!
I shall build one more with better materials and incorporatring your suggestions, specially the rotary switch. ( those cheap pots I had bought sucked big time anyway, I had to buy 3 until I had gotten one which was not noisy when turning )