Mod your Beresford 7520

[HighFidelityGuy]

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

Ok, so both line outputs use the op-amp on the left. Thanks.

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

As far as I understand it; one channel of the op-amp is for the left channel, the other for the right, giving you stereo.

I'm going to do some testing tonight with a scope on the line outputs with different combinations of op-amps to try and narrow down the cause of my problems.

[StanleyB]

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.

Would you fit a replacement part in your car if the part manufacturer has not tested it on the car in question?

[Clive]

Would you fit a replacement part in your car if the part manufacturer has not tested it on the car in question?

Depends on the part Stan. Something seriously mechanically internal or electronics that interact with the CAN-bus I would want testing. Whereas a wheel or tyre of suitable spec should be interchangeable without testing.

Opamps are closer to the wheel & tyre analogy although there are risks that they aren't 100% suitable for the parameters you set for the 5532. It's a small risk though that's unlikely to result in damage, excepting errors in doing the opamp install.

[StanleyB]

It's a small risk though that's unlikely to result in damage, excepting errors in doing the opamp install.

You should see my email inbox. Homer lives...

[Dougr33]

Would you fit a replacement part in your car if the part manufacturer has not tested it on the car in question?

Okay, hope not to offend, but:
1. agree with Stan on this, but because the exact title of the Tirna ebay item was "THS4032CD Dual Op Amp Beresford DAC Upgrade 8 PIN DIL "
I strongly feel that if you're selling an "Upgrade" to anything, you should have tested it in the box. I'm not very happy that I was sent two that didn't fit the case, and now two that can only be used one at a time

2. No offense Stanley, but I think you're being a little coy about this. You're the one who told us this was your Favorite Opamp, and gosh, aren't we lucky Opamps are so easy to swap in your box. How about a little help on how to implement the 4032. Why would it do what it's doing in my box?

Thanks!

[sponge]

Why would it do what it's doing in my box?

Looking back through previous posts should make it clear that the THS4032 is a very capable op-amp WHEN IT IS IMPLEMENTED CORRECTLY. It is a very high speed device which requires some care where it is fitted. The stock NE5532 on the other hand is much less fussy, being a very slow (relatively) chip. Heaving out one device and sticking in another is therefore prone to bringing up problems, as things like length of pcb track can cause instability.
The 7520 HA board has been designed around the 5532 NOT the 4032, so a certain risk must be involved in this kind of upgrade.

The THS4032 is a very fine sounding chip, but not wanting to start swapping out other components to make it stable, I personally will stick with an op-amp I know sounds (almost) as good - ie. the LM4562.

Ken

[drumlins4ever]

My own favorite is the opa2132pa.

Got the revised mod from Tirna and was disappointed. Still too much height and would not fit in my dac properly.

[StanleyB]

2. No offense Stanley, but I think you're being a little coy about this. You're the one who told us this was your Favorite Opamp, and gosh, aren't we lucky Opamps are so easy to swap in your box. How about a little help on how to implement the 4032. Why would it do what it's doing in my box?

I have nothing against the THS4032. My concern is with the PCB adapter, which is blowing up people's DAC at worst, or only the fuse if they are lucky!
The only sure fire way to fit the mod is to desolder the DIL adapter socket I fitted for the NE5532, and then solder in the SOIC to DIL adapter PCB with the THS4032 on it. Anyone in the UK who can't do that part of the job but would like it done should email me for the details of a fellow engineer who has offered to do the mod for them. The top PCB is removable, so that's all he'll need.

[Dougr33]

Well, maybe I misunderstood.. I assumed that if you thought the 4032 was best, it was a drop in for the socket you provided (to making opamp 'rolling' easier). I'd like to see if anyone is having issues with 2 Tirnas in the board. I'm not against the 4562 in for the HPA, and not even sure if I like the 4032 better in the variable out. But I'm not quite up for soldering if not certain the 4032s better all around..

I'm curious...what's the effect of the pin 4/8 decoupling cap still on your board in combo with the one Tirna puts on (because the board cap would be too far away due to pin/adaptor/adaptor length)?

[Clive]

I have nothing against the THS4032. My concern is with the PCB adapter, which is blowing up people's DAC at worst, or only the fuse if they are lucky!
The only sure fire way to fit the mod is to desolder the DIL adapter socket I fitted for the NE5532, and then solder in the SOIC to DIL adapter PCB with the THS4032 on it. Anyone in the UK who can't do that part of the job but would like it done should email me for the details of a fellow engineer who has offered to do the mod for them. The top PCB is removable, so that's all he'll need.

Now I understand your concern. I take back my comment about low risk. I have 4032 from Tirna ready to install. Time to get my IC desoldering tool out to desolder the IC socket.