Mod your Beresford 7520

[rhmjmango]

Help! Is anyone having this issue? I took out my 7562s and put in the 4032s (new Tirna version). Variable out to my amp sounds fine. But the headphone amp sounds noisy/crappy/distorted thru the first 1/6 rotation (lower volume). I have the 50ohm Sennheiser 595s.

The HPA sounds fine if I... 1) remove the variable out 4032 and leave empty, 2) replace the variable out 4032 w/ the 4562, or3) use a 4562 back on the HPA with a 4032 on the variable out. Both 4032s sound the same (i.e. either works fine alone in the HPA, but as soon as two of them are onboard, the HPA sounds like crap).

Anyone else??? This is a bummer.

I experienced the same problem. The 4032 give distortion in mainly the left channel of my headphone when placed in the headphone socket.

[leo]

If the 4562 drives your headphones ok it maybe worth just having the 4032 in the fixed position only for now .

[drumlins4ever]

Phew ,
This thread has got so long its getting hard to find some specific info,
Is the same opamp shared for both headphone and fixed out duties?
And which one is it ?

[Dougr33]

True that! I searched back to where Stan said that the one over the volume control is the headphone, and the one over the headphone jack is the "output"... but he didn't say if both fixed and variable. But I noticed that if there's no opamp in the "output" socket, my variable output is much lower (yes, it makes music without anything at all... assuming that the DAC's analogue out has enough voltage to drive my amp).

[leo]

You need a sticky keep all the tweaks and bits in

[drumlins4ever]

You need a sticky keep all the tweaks and bits in

good idea Leo, if only i'd thought of it ages ago

[HighFidelityGuy]

Hmm, I assumed that the same op-amp was used for the fixed and line output and that the other op-amp was only for the headphone output. Perhaps that isn't the case. I guess it would make some sense that the headphone op-amp was also used for the variable output as both of these use the volume pot.

Perhaps this means that the variable output also has a different impedance or something than the fixed output, which would maybe explain why they both have different characteristics.

I guess we need some clarification on this from Stan.

[trailer]

Hmm, I assumed that the same op-amp was used for the fixed and line output and that the other op-amp was only for the headphone output. Perhaps that isn't the case. I guess it would make some sense that the headphone op-amp was also used for the variable output as both of these use the volume pot.

Perhaps this means that the variable output also has a different impedance or something than the fixed output, which would maybe explain why they both have different characteristics.

I guess we need some clarification on this from Stan.

http://theartofsound.net/forum/showt...?t=2160&page=6

Posts 55 and 56.

[Dougr33]

"ones for the fixed and the others for the 'phones?" Answer: (from those posts)

Doesn't really answer the question. When I took the op amp out of the 'fixed' socket, the volume (of my variable output to my power amp) went way down. I think the phones and variable out are different chips. Would love to know.

[trailer]

When I took the op amp out of the 'fixed' socket, the volume went way down.

What volume?