Mod your Beresford 7520

[Covenant]

You can get them from RS for £4 each or so. It's the interface boards that seem to be harder to find.

The picture on RS shows an op-amp without 'legs'. Is this what the interface board provides?

[trailer]

Luckily I can get the chips for free. The boards can be bought from http://myworld.ebay.co.uk/tirna_electronics/

Excellent. Thanks

[Getgaff]

Stan's 7520 is only my second DAC having previously owned the 7510 Mk6/3 with MOD21.

Tweaking does appeal to me (wolf in sheep's clothing and all that) despite my complete and utter ignorance of all things electrical, so I largely rely on the expertise and experience of others.

For a measly £8.99, I swapped out the original 7520 opamps with the recommended LM4562NA at the weekend. While I can't (yet) claim to hear the same improvements as others (limited perhaps by my modest system/listening time/etc), I did notice a distinct improvement with bass control and timing.

Following on from other comments here on AoS, I've now ordered from the same Ebay seller a pair of LME49720HA opamps to try out. And shortly after ordering them I received the following email,

"Hi Gareth

Many thanks for the purchase – I’m sure you’ll be impressed with these opamps.
Everyone and his dog appears to be buying LM4562/LME498720 to upgrade their Beresfords! Even Stan himself bought some today
Of course I can form them – I’ll try and do you some special ‘low profile’ versions although there is a limit as I need to be careful not to short any of the legs against the metal casing.
I’ll get them posted off tomorrow.
Please let me know that you have received them safely, and others know how good they are, by leaving feedback.

Cheers
Simon"

One question though, and with reference to my aforementioned ignorance, will the LME49720HA metal caps short if they come into contact with the DAC lid?

[drumlins4ever]

Luckily I can get the chips for free. The boards can be bought from http://myworld.ebay.co.uk/tirna_electronics/

Thanks for the link but which type board would i use ?

Great thread by the way

[StanleyB]

You need the 8 pin SOIC to DIL boards.

[rhmjmango]

You need the 8 pin SOIC to DIL boards.

Is this the board i need to use the THS4032.
http://cgi.ebay.co.uk/Surface-Mount-...3A1|240%3A1318

Some more questions
- Is it oke to change both standard opamps with the THS4032 or just one?

- I noticed that there are different types of the THS4032 that can be purchased. Do i need the THS4032CD or the THS4032ID? Seen on the site of Farnell.

- Has there any soldering to be done to mount the THS4032 on the board?

[HighFidelityGuy]

Hi,

This is my first post here. I was recommended this forum by Stan when I was looking for info on swapping the case of my 7520 for a silver one. That's something I may look into later. For now I'm interested in trying a few opamp's and also running my 7520 from a battery.

As the current theme is opamps I'll stick to that subject for now.

The THS4032 is also available from Farnell for £4.63. There are two models, the CD and the ID. The THS4032CD is the standard model with the THS4032ID being tolerant of a wider ambient temperature range and not really worth the extra cost.

I think this is the adapter that is required LINK. It looks like Farnell sell a similar product but it's over 4 times the price.

I have a couple of questions about this combination:

Should the adapter board be plugged into the existing IC socket or should the existing socket be removed and the new socket soldered in place?
Also, the THS4032 data sheet mentions that it should be heatsinked via it's underbelly to the ground plane. As the adapter board won't really allow this, are we likely to run into overheating problems?

Thanks.

[sponge]

Just a quick update following the THS4032 installation.
The paranoia factor got the better of me regarding decoupling caps. This was mentioned in the previous thread by Leo. So I decided to fit an additional 0.1uF ceramic across pins 4 and 8 of the opamp. It's not easy and I found the best way was to form the cap leads slightly and solder it directly to the chip pins lying the caps body on top of the chip.

However, the difference is well worth the effort - The sound is "cleaner", sharper and more dynamic.

If anyone is considering this opamp upgrade, I recommend fitting the decoupling caps from the start, believe me, you won't regret it.

For info, I got the THS4032's from Farnell at 4.63 GBP + VAT and the BrownDog adapers I already had from cimarrontechnology.com p/n 970601 at $2.39 + postage. Ceramic caps from pretty well anywhere - Dirt cheap.

Ken

[sponge]

Should the adapter board be plugged into the existing IC socket or should the existing socket be removed and the new socket soldered in place?
Also, the THS4032 data sheet mentions that it should be heatsinked via it's underbelly to the ground plane. As the adapter board won't really allow this, are we likely to run into overheating problems?

Thanks.

The adapter board plugs directly into the existing socket.

I have had the THS4032's running for quite a while now - they run warm but not hot - I would say overheating wont be a problem. Of course, if the chip is unstable, it will tend to get hotter.

Ken

[trailer]

Well I've gone from the standard op-amps. Had the LM4562NA's in for a week or so now. Like I have said they were a big improvement over the standards.

Next step was to try out a pair of LME49720's and I've stuck them in this morning.

First impressions. The sound is a bit "leaner" and more "airier" than with the 4562's. I'll let them run in some more.