Line out mod?

[dave-tx]

I was thinking of replacing the balanced outputs with a line-out for recording purposes.  Would there be anything wrong with routing the output of the selector switch (S2B) back up to the I/O area using shielded twisted-pair (one pair per channel)?

Other than a volume/balance issue that I'm debugging (very similar to that in a couple of threads from April 2013), this thing sounds amazing...As in, completely captivating.  And it looks stunning as well.  Next step is the BeeQuiet.

Happy Holidays,
David

 

[Grainger49]

A record out is best when isolated by a cathode follower or any other buffer stage.  The impedances of the recording device when on and off are often very different.  This can affect the input to the 300B in the BeePree.

I would advise against it.

 

[dave-tx]

Thanks, Grainger...I might try play around with a jfet source follower of some sort, but nothing that couldn't be removed in case it behaved poorly.

From the schematics I've browsed online, it appears that most pre-amps stick a buffer in the signal path before the amp stages, is that the reason they can get away with a simply a resistor between the inputs and the line out?  Avoiding that buffer was one of the main design goals in the BeePre, if I recall correctly.

 

[Paul Birkeland]

If you have the BeeQuiet, you can setup the BeePre pretty easily to be a unity gain buffer without performing any modifications.

 

[dave-tx]

If you have the BeeQuiet, you can setup the BeePre pretty easily to be a unity gain buffer without performing any modifications.

I'm assuming by this you mean with both fine and coarse set to 0dB?  Or does the BeeQuiet provide enough resistance that it would be okay to tap an output off S2B?

Thanks,
David

 

[Paul Birkeland]

The BeeQuiet has roughly 4dB of pre-attenuation.  If you go down to -4.5dB on the fine attenuator, and -0dB on the coarse, you'll have roughly a unity gain buffer.