2. amps-preamps
  3. 133789-525

Gain into my preamp from DAC

I am using a Bryston BDA-1 DAC into a Jolida Fusion Tube preamp. The output of the DAC is 4.6V via 'fully differential balanced' (Bryston terminology) XLR and 2.3V via unbalanced RCA. I understand that this is to be expected. Both DAC outputs can be used simultaneously, however I geberally use the XLRs to the Preamp and the RCAs to a headphone amp.. 

When I compare output volume between the XLR and RCA inputs of the preamp there is no difference. I would have expected 6dB greater gain via XLR . I understand that the preamp is not balanced.

Please elucidate as to this finding. Thank in advance.


mesch

Showing 2 responses by cleeds

cleeds
6,070 posts
 
mesch
Cleeds, I am not sure that the input portion of a single ended device can't be configured to accept both signals from a balanced device when connected via XLR such that the 6 dB gain is enforced.
I think you're assuming that an XLR connection is inherently balanced and, if so, you're mistaken. If your preamplifier is not a true balanced differential preamplifier, it doesn't benefit from the gain of a balanced connection. Depending on the circuit, you may get some of the benefit of a balanced connection's  noise rejection, but you won't get the gain.

cleeds
6,070 posts
 
If your preamplifier is not balanced, then you won't get higher gain on the  XLR inputs because it's using them single-ended.
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