Mod your Beresford 7520

[Themis]

In any case, in all the years of copying data from PC to harddisk I can't remember a single file that was incorrectly copied. The same goes for anything I printed via the USB port.

File transfer uses another USB class protocol, with error recovery. USB for audio is different.
You can see the different types here : http://www.usb.org/developers/devclass_docs

[RoboCopper]

I am the last person who should start this thread but I thought it would be useful to pull together some comments from other threads. (Stan, Mods and anyone else-please correct anything I have got wrong)
Stan has provided a very high quality dac which is designed for easy modding especially with regard to the op-amps which are socketed. The stock NE5532P works fine but to put it in context are 62 pence each at Digi-key.
The replacement op-amps that I have seen mentioned to date are:
LM 4562 (recommended by Stan)
OPA2132
OPA2134
THS4032
LME4970HA (circular unit, might involve cutting legs)

The 4562 costs less than £10 for a pair from ebay. Trailer has noticed an improvement with this one as have I-fitted it today.
So lets see some more suggestions and feedback. Dont forget to detail cost and where the parts are available from.

Hi,
If I upgrade those opamps can you hear improvement in sound only via headphones, or via amplifier connected to line out fixed or variable output?

Any input and help from anyone?

[leo]

Theres 2 x dual op-amps, one is for the fixed and variable out, the other is for the headphone amp

[ReachtheSky]

Robo,
Both located behind the vol pot.
When viewed from the front; One on the left is for fixed and variable out.
One on the right is for headphone amp.
Granville

[RoboCopper]

Robo,
Both located behind the vol pot.
When viewed from the front; One on the left is for fixed and variable out.
One on the right is for headphone amp.
Granville

BIG thanks to LEO and Granville....

As I listen to Hifi on speakers (I do not use headphones) if I want to play upgrades with my 7520, I can only swap the one of the left in order to improve the sound?
That is really interesting point of design of DACs.

Any suggestions of OPAMPS for OPEN, FORWARD MIDRANGE with TIGHT BASS and FAST sound?

Big thanks for answers and lighting fast replies

[StanleyB]

any suggestions of opamps for open, forward midrange with tight bass and fast sound?

lm4562na, lt1364

[Maximum]

AD826 work well too for me and some others.

Did you try those LT1364 then Stan? On paper they seem to have similar features to the AD826, for instance the very high slew rate and good cable driver capabilities.

[StanleyB]

Did you try those LT1364 then Stan? On paper they seem to have similar features to the AD826, for instance the very high slew rate and good cable driver capabilities.

I did. I couldn't tell much difference between the LT1364 and the LM4562NA in the line output stage. It appeared to produce less sibilance though, but I have to double check that. I was trying out a potentially new mod at the same time, so I have to remove the mod and try my listening tests again. The LT1364 low current ability of 5mA made it however pretty useless in the headphone stage.

[RoboCopper]

Thank you Stan, big thanks

[ReachtheSky]

Robbo,
If your speakers and amps are quite revealing then I would choose some of the faster opamp chips about.
My own preferences are:
THS4032 (with Tirna cap mod)
LT1364
AD826
Have fun,
Granville