2. amps-preamps
  3. 1222489027

cd plays without preamp

OK so I just get my new Cambridge Audio 640 cd player shipped, I hook it up to replace my old unit and turn on CD player listening to great music and realize I forgot to turn on my preamp , only the amp was on. meanwhile I was adjusting the volume and tone controls and they were working ALL with the preamp off. Can someone explain this to me. The equipment besides the CD is ST-70 triode/ pentode amp by Bob Latino, Dynaco Pat5 bifet preamp,(which will be replaced in a few days shipping with a Cary) and a pair of Klipsch (Crite) Cornwalls. The Cambridge by the way is a very nice sounding CD player for the modest system
rcme53
musicnoise
377 posts
 
Rcme53 - from what you describe, it appears that the volume control is only acting as a rheostat to attenuate the incoming signal and that the preamp provides for only unity gain, if any active gain at all. I suppose that the tone control could also be passive. While completely passive preamps are not unheard of, generally if one goes to the trouble to include a power supply there are some active components that do more than provide for source selection.
kijanki's avatar
kijanki
4,428 posts
 
Rcme53 - I was able to find that your Dynaco Pat5 has:

Magnetic Phono (LO) to Audio Out: 57 dB at 1 KHz.
Magnetic Phono (HI) to Audio Out: 63 dB at 1 KHz.
Magnetic Phono (LO) to Tape Out/E.P.L. Out: 37 dB at 1 KHz.
Magnetic Phono (HI) to Tape Out/E.P.L. Out: 43 dB at 1 KHz.
High Level to Audio Out: 20 dB.
High Level to Tape Out/E.P.L. Out: unity.

Is it possible that you used Tape-Out (gain=1) instead of Audio-Out (gain=20dB)?
rcme53 OP
15 posts
 
Kijanki, actually I used the Spare, not the tape out for the CD, as it obviously didn't have a CD option back then. When I have some time, I'll try to hook it back up, but right now with a new Cary preamp, I can't bring myself to disconnect right now, thanks for your help. Rich
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