2. amps-preamps
  3. 153702-525

Looking to Try a Passive Preamp

I am looking to try a passive preamp in a system using a Audio Mirror Tubadour III DAC having an output impedance of 1.5K - 2K ohms  and a BEL 1001MK5 amplifier having an input impedance of 22K ohms. I am interested in this approach due to having a problem with EMI and RFI interference with my tube based active  preamp which may become a subject of another thread herein.

I own a Schiit Audio SYS passive. My concern is, given it's input impedance of 10K ohms and it's output impedance of 5K ohms may make it not the best fit. I understand that the input impedance of the SYS and Bel amp are added to give the total impedance that is 'seen' by the DAC, the combined 32K+ impedance due to SYS/amp/2pairs interconnects and that should be OK.  I am concerned about the output impedance of the SYS which to my limited understanding seems too high. Am I correct on any of this? 

If I am correct in my concern with the SYS I am interested in finding another passive pre having input/output impedance better suited to my system. Suggestions sought.

Thanks in advance for any help. Mike
 
mesch

Showing 1 response by dbxrecord

dbxrecord
29 posts
 
According to the DAC manufacturer, there are alternatives to the low output 5977 tubes , and they recommend 6N1P, 6DJ8, ECC88, 6922 and 6H23P which can provide higher output.
They considered the 5977 the best sounding, but did not state what equipment they used for that subjective opinion. Perhaps try a set of the other tubes to see if if they solve your issue. 
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