2. amps-preamps
  3. 1395356030

Connecting Preamp to AVR

I just picked up an old (1982ish) Harman Kardon HK725 Preamp for $60. After some messing around I seem to have gotten it to work.
I connected my Thorens TD145 to the phono input and then the tape output into one of the analog inputs on my HK AVR7550HD. This seems to work fine. However, with this approach none of the functions on the preamp have any effect. The preamp has volume, balance, and a range of filters on volume, tone, etc. There is an "output" connector (RCA) on the back that seems to be a pre-out, but it doesn't sound right when connected to the analog in on my AVR. It is a variable volate connection rather than line out like Tape.

Does anyone have any suggestions for if and how I might use the pre-out from the preamp (and therefore the various controls on the preamp) with my AVR?

Thanks.
kmaclac
zd542
5,339 posts
 
I see 3 options for you. The first is to use the tape out. You have already tried it and know it works. That would be better than the 2nd option, which is to use the pre outs. If you fool around with the volume controls on both units, you can probably make it listenable; although it should still sound much better going through the tape loop because you are bypassing much of the preamp circuitry of the 725. 3rd, you can just get an entry level phono stage. Even the cheapest one you can find should be the best sounding option.
arnettpartners
312 posts
 
I had an hk725 years ago and actually had all controls bipassed by a tech except for volume and balance. The improvement was huge and made it into an excellent pre. Can't you use tape out and use the controlls on hk7550hd to adjust for balance, tone etc? The hk7550hd has a ton of adjustments, but maybe not the filtering you need for tt.
zd542
5,339 posts
 
"Can't you use tape out and use the controlls on hk7550hd to adjust for balance, tone etc? The hk7550hd has a ton of adjustments, but maybe not the filtering you need for tt."

Have another look at the OP. He did try the tape loop and the results were OK. I still think an affordable phono stage would be a better option, though. If you go to Audio Advisor's web site, they have phono pre's starting at $100.
arnettpartners
312 posts
 
Zd542, I understand, and you are probably right that a new phono pre would sound better. But his issue with using tape out is that then he cannot use the controls of the hk725--I think. The source inputs of the avr7550hd are independently programable so that he could adjust bass-treble,balance etc with the avr. I'm not sure what he could do about infrasonic filtering if he needed it.

If it were I, I'd just have fun playing with it and then if I were not happy in a month, I'd follow your suggestion.
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