Buffalo III Simple Output Stage Help?

[davecandialex]

Hi DAC People: I have a TPA Buffalo III kit that I will be putting together soon. I have a long term plan to add a high quality I/V to it based on all the threads here, but in the interim I would like to get it up and running with something fairly simple.

Unlike many of the implementations here, I am going to use it as 6 or 8 channels with single ended output. It will be replacing the DACs in my DCX2496.

Any thoughts or experiences on this would be appreciated.

[twest820]

Why not use the circuit from ESS's eval board?

[davecandialex]

Yes classic opamp I/V is a possibility, there is also the similar IVY from TPA.
I saw another opamp design that uses resistor for IV with opamps for gain and diff to single. Anybody tried that? I think the resistor would need to be 40 Ohms.
ES9018 USB DAC - Hi-Resolution System*

How do these stack up to just voltage out?

Thanks

[twest820]

That's what ESS would call voltage out, though with such a low impedance it's quite likely performance is below the voltage mode spec---based on ESS's design collateral a minimum load of 5k is probably a better choice. In ESS's current out implementation's the load's more like 30k, though it's not always obvious. You'll need the differential input impedance specs in relevant op amp's datasheets and to work back through the schematic to figure out the load.

THD+N and DNR specifications for both voltage and current mode are given in the ES9018 datsheet. Unfortunately the voltage mode measurement conditions are not stated and I never got an answer back when I asked.