DAC Shopping, help!

[grenert]

Yes, there appears to be only one power supply. There is one transformer which goes to a bridge rectifier and then to + and - 5V and 12V linear regulator ICs. Since the 12V supplies are only used in the analog section as far as I can tell, there is some separation of the two. However, I recall reading that linear regulators are not so good at rejecting noise, so one side could still "pollute" the other.

[Filburt]

If you're getting excessive noise on the rails for the op-amps, you can cut the traces to pins 4 and 8 (-/+ rails) and solder in something like a 10-100 ohm resistor in series with a wire to supply power, then give it fairly beefy bypassing to keep the impedance down (I've used 330uF + 0.1uF to ground, 2.2-10uF across the rails to good effect thus far, including checking on a scope and spec analyser). I've found this to be pretty much mandatory for getting optimal results (or, in some configurations, just being able to make the thing work) with fussy chips like the AD797 or THS4031 on a breadboard when using something other than a battery for power. If using a battery, it can sometimes be helpful to put in a small resistor in series and have good bypassing in order to try to damp inductance from the battery or its leads, if that is causing problems for you.

[Jon L]

I

Theta dacs from the gen V tor the pro basic lll

I am also looking at the Levinson 36 dac but it is $1900

Anyone heard the theta?

I would take Theta Gen V (or Va) way over Levinson 36. Theta really had some magic going with their Gen V DAC's with outstanding output stages. It was very detailed, very dynamic, with SOTA bass, and very fun to listen to, unlike DAC's that try to sound way too "smooth" and boring like Levinson 36 (or even 36S).

AudiogoN ForSale: Perpetual Technology P-1A, P-3A with

Unmodded P-3A is good, but it doesn't take off until at least Modwright mods, and even better yet Empirical Turbo mods, especially with their own PS.