[dvb]

I am using a tubed phono pre (George Wright's WPP100C) through my B60R.  This all sounds very good, but I have been wondering if there would be an advantage to going the "passive pre" approach, as a means of interfering as little as possible in the signal coming from the phono pre.

I have considered using a passive pre (say, the "little wonder") into the amp portion of the B60.  However, the thread below from "Audio Asylum" indicated I might be able to get the advantages of a passive pre, just using the B60.  I was particularly curious about the answers to the questions posed by Paul Lam (maker of the Little Wonder)

Output impedence of the WPP100C is a bit on the high side, 1Kohm, but input on the B60 is 50Kohm, which seems to be an adequate difference.

Thanks in advance for replies.




http://db.audioasylum.com/scripts/t.pl?f=amp&m=6686

[James Tanner]

Dear dvb;

   Thanks for your question about turning the B-60 into a 'passive pre'.  The Bryston B-60 uses a high-impedance input buffer to isolate the source from the lower-impedance volume and balance controls. (This is one of the reasons for the very low noise floor of the B-60).  This means you never really get all the way to 'passive', even by taking the signal from the tape-outs and going into an external attenuator. It does mean, however, that you can use a lower-impedance attenuator, like 5K or 10K, to keep noise low, and if you want to use the input part of the B-60's preamp section to drive another amp, you can use longer cables without losing HF energy.

CWR

[dvb]

nt