[alexone]

Hi, Bryston!

(or anyone who knows...)

The SP2 has balanced and unbalanced outputs. And for biamping purposes with a 3B SST² and a 4B SST i need to use the rca & xlr outputs at the same time.
Would it be possible to connect both amps to the SP2 by choosing the same gain (both amps 23 or both amps 29 db) even if each amp has a different cable connection (one amp would be rca the other one would be xlr connected).

many thanks,

al.

[mv038856]

You can connect both amps to your SP-2 using and Y-splitter cable - then both amps should have the same gain setting. When you want to connect one amp via XLR and the other via RCA, I would expect that the amp using RCA should have an input sensitivity of 2 V and the one connected via XLR should be set to 4V.

You can try if I am correct - you will notice if one speaker is louder/quieter, for test purposes you might want to run your speakers full range.

[alexone]

Hi, Marcus!

thanks for your input. i always thought that a y-cable would degrade sound quality in some way?!

al.

[GeorgeAb]

I have not read the manual for the SP2, but likely the XLR have a higher gain than the RCA, often 6dB difference. If the gain is 6dB difference than RCA could use 29dB amp setting and XLR for 23dB amp setting and all should be good. Not sure what the input impedence is of the Bryston amplifiers, but likely 47K to 100K ohms. By using a y splitter would half the input imedence to 23K to 50K. Likely the SP2 would have a low enough output impedence to drive 23K load effortlessly. The SP2 may have minimum input impedence load in specs. So I would take a look at the SP2 and amp manuals to make the decision on method to proceed. 

Manual is here: https://www.hifiengine.com/manual_library/bryston/sp2.shtml

From the manual:
output 8V rms (16V rms balanced) in DSP mode.
Output impedenace is 110 ohms.

[mv038856]

I would expect the output stages of an SP-2 to easily drive two input stages of two Bryston amps from a single output. For the preamp it would be the same as two bridged 9B SST modules. There Bryston offers a Y cable to make sure both modules get an identical signal. One of the modules needs a 180 degree phase switch, but looking at the preamp to power amp connection it would be the same as driving two amps for bi-amping. I am not sure if Bryston would recommend to add some resistors in the Y-cable though. Maybe James can elaborate…

[alexone]

...maybe James knows it or anyone else from the Bryston Team ??

thanks,

al.

[James Tanner]

A Mike question for sure - mpickett@bryston.com

james