Mod your Beresford 7520

[Dougr33]

What volume?

repaired my post above... the volume of the variable output to my directly connected power amp was much lower with no opamp in the socket, so I "think" it's not the same as the headphone opamp. But I really don't know crap about this!

[trailer]

Neither am I to be honest(!). But I'm sure I remember seeing that the two chips should be "variable (ie variable line out AND headphone)" and "fixed (fixed line out)".

Over to Stan!

[Dougr33]

Who has two 4032s installed, and can you listen to your headphones at lower volume without obvious noise/distortion??

[HighFidelityGuy]

I have two 4032's installed and everything sounds fine through the headphones. No crackles or distortions. I can't turn the volume up very high but I have got quite low impedance phones (32 ohm I think), so that's what you'd expect, I think.

It's only when I connect my power amps directly to the variable output that odd things happen.

[Dougr33]

I have two 4032's installed and everything sounds fine through the headphones. No crackles or distortions. I can't turn the volume up very high but I have got quite low impedance phones (32 ohm I think), so that's what you'd expect, I think.

It's only when I connect my power amps directly to the variable output that odd things happen.

which is how I use mine. Well, we'll see who else replies. Maybe it's only when using the variable out (the whole reason I went this route). Well, I'm less a headphone listener, so the 4562 on that socket (if indeed it's separate from the variable) would be fine... but it would show, to me at least, that it'd be nice if Tirna had tried their "upgrade to Beresford 7520" on a actual Beresford 7520.

[ReachtheSky]

When I emailed Stan directly about the two opamps he indicated that the variable out (preamp) and line out use the same opamp.

[technobear]

It might aid you folks understanding to remember that these are DUAL op-amps

[StanleyB]

. but it would show, to me at least, that it'd be nice if Tirna had tried their "upgrade to Beresford 7520" on a actual Beresford 7520.

and also stop some people blowing up their TC-7520. On at least two cases the pins on the modded PCB from them has shorted against the top case of the DAC. At least one perosn has also put the modded PCB in the wrong way round.
Those DAC were then history.
I am NOT recommending the Tirna modded PCB as a result of those blown up DACs. Neither am I offering any technical advise or encouragement to those who are prepared to risk blowing their DAC up that way.

[Clive]

Who has two 4032s installed, and can you listen to your headphones at lower volume without obvious noise/distortion??

I recall a posting somewhere from Stan where he said he changed a few resistors around the opamp board. Maybe this is related to the distortion some are getting.

re some of the other comments/requests:
We can't expect Stan to spend time on advising, he's in business to sell the DACs he developed. Given the low cost of the 4032 chip and board we can't really expect Tirna to source a 7520 to test the upgrade either. They are simply responding to a specific market demand which makes them a little money but I very much doubt it would justify say 10 hours work on testing and guarantees for the upgrade.

[trailer]

re some of the other comments/requests:
We can't expect Stan to spend time on advising, he's in business to sell the DACs he developed. Given the low cost of the 4032 chip and board we can't really expect Tirna to source a 7520 to test the upgrade either. They are simply responding to a specific market demand which makes them a little money but I very much doubt it would justify say 10 hours work on testing and guarantees for the upgrade.

Well put.