Impedance matching/balanced connection


Hello,

I’ve recently acquired a DAC that features fully balanced output, and have been looking to upgrade my cables for awhile now…

 

The thing is, my (tube) preamp has an output impedance of 325ohm single ended, and 650ohm balanced. My (ss) amp has in input impedance of 50kohm single ended and only 10kohm balanced.

Is there enough of a differential there for me to go balanced without having to worry about frequency rolloff? Or should I just order both single ended and balanced cable and let my ears be the arbiter here?

 

any thoughts would be greatly appreciated.

rfnoise

Would I be correct in assuming that the balanced output impedance  at 20hz would be double that figure?

Its two outputs, each having that 1.3K value at 20Hz. I've not found input impedance info on your amp, but if its less than 13KOhms single-ended, it could be a problem.

@atmasphere 

Thanks for the heads up regarding capacitor-coupled output. Helped me refine my results using the search function here. I probably should have mentioned my specific gear in my first post. ARC LS25 mkii & Legacy Audio High Current Amplifier (rebranded CODA Stage 3).

I was able to turn up this quote from @almarg 

 

I took a look at the schematic for the LS25 MkII at arcdb.ws, and based on some quick calculations it appears that its unbalanced output impedance at 20 Hz is in the vicinity of 1.3K or so.

Would I be correct in assuming that the balanced output impedance  at 20hz would be double that figure? If so, that seems a little higher than ideal…

From a strictly mathematical point of view you should have no problems. The only gotcha I can think of off hand is most tube preamps employ an output coupling capacitor (ours are direct-coupled to get around this problem) and so the capacitor can cause the output impedance to be considerably higher at 20Hz (often the output impedance is measured at 1KHz, which really doesn't tell the whole story).

In simpler terms, I would certainly try it!