Rolling Op-amps

[Little Nellie]

Just wondering if anyone try rolling the op amps used in some of the McIntosh?

LN

 

[Number 9]

I did in the output stage of my 7005 CDP. Easy to do because the output ICs were socketed.

Using a pair of OPA 2134's now vs. the stock NECs.

I once asked the same question, and it seemed no one would dare to try. Surprising, given how many people are willing to roll tubes. A lot of op-amps are from the same "family", and just as long as you have a schematic handy, ensure that the voltages are correct, and are familiar with op-amps ... why not I say.

 

[ron-c]

If you are working on an older unit I would be surprised if the OP amp is the main issue. To test this theory I just went through a C29 from 1980 and changed all of the caps to new high end parts. The sonic change was very satisfying and I will write this up soon.


Thanks,
Ron-C

 

[Number 9]

Some op-amps sound better than others Ron.

Those old 5534 and 5532s which were ubiquitous back in the 1980s and used in Mac gear, can be replaced by newer, lower distortion and better sounding op-amps, that are almost plug-and-play swaps.

 

[ron-c]

I am sure the newer op amps do perform better. On the older gear the caps are all on their way to becoming resistors though so how good will a older unit perform with a clean up, new caps and a whole bunch of solders joints reworked? I contend much better.

Thanks,
Ron-C

 

[EchoWars]

Use the OPA2132P rather than the OPA2134. The 2134 is the 'budget' IC.

 

[ron-c]

Echo,

Is that a plug and play upgrade?

Thanks,
Ron-C

 

[Little Nellie]

more changes???

Hello Ron, please give more detail about the cap changes for newer equipment. I re-cap all of my really old pre-amps... C22, MX110 etc and what a difference they made. I also re-res them with tested NOS carbon comp also. I am surprise to hear that the unit made in the 80s are now needing an overhaul. Sounds like I need to take a closer look at the 33 and 34s I am running also.

BTW, what kind of caps you are using? I see there are lots of caps in the 33 and 34. Unlike the 22, there are not as many and the bill for those yellow caps were not that cheap...

One thing for sure, this hobby is keep me out of visiting all the local bars...:yes:

LN

 

[EchoWars]

Echo,

Is that a plug and play upgrade?

Thanks,
Ron-C

The OPA2132 and OPA2134 both use a standard dual opamp pinout.

1. Output A
2. - In A
3. + In A
4. V-
5. + In B
6. - In B
7. Out B
8. V+

 

[ron-c]

Thanks Echo,

It looks like Mc used a lot of the mono NE-5534AN 8 pin op amps, one per channel. The modern FET replacement would then be the NOPA132P I believe. Which seem to be on back order from Mouser right now of course.
The old 5534AN has good specs and the newer NOPA132P has outstanding specs. I not sure how much of the improvement will be buried in rest of the unit though.
What have you noticed making this kind of swap in the older gear?

Thanks,
Ron-C

 

[Little Nellie]

I see OPA132U, UA, UG4, UAE4 etc listed in Mouser.. wonder what is the difference between them... Anyone have an idea?

LN

 

[ron-c]

Check the spec sheet section for details on the variations.

thanks,
Ron-C

 

[applesauce]

Before you go out and start yanking NE5532's and 4's, you might want to visit Doug Self's web page www.dself.dsl.pipex.com/ampins/webbop/5532.htm and get a few facts on these devices. They exhibit amongst the lowest ever measured distortion of -any- audio opamp, present or past. There has been a myth (or whatever you want to call it) floating around pro audio circles for decades suggesting that these opamps possess all sorts of nasty and irritating high frequency distortion. The only problem with this myth is that it is pure unadulterated BS! Personally, I think your wasting your time swapping out these particular devices.

 

[ron-c]

Yes, these do spec better than any sources we had 20 years ago or today.

Thanks,
Ron-C

 

[Number 9]

I'm using the OPA2132 in lieu of NE5534s. The 2134 is the equivalent for a dual.

I found a big improvement in sound. I also tried an OPA2604, which some rave about, a little bit of an improvement, but not as open sounding as the 2132. I also tried LM6172s.

The one I still aim to try is the OPA627AP ... which many rave about, but is pretty expensive for an op-amp ... about $22 if you shop around.

 

[applesauce]

You would think that Texas Instruments would use their own Burr-Brown (OPA) series of opamps for the output stage of thier top-of-the-line D/A converter. What a surprise it is to find NE5534's shown in the app note output stage! Benchmark DAC1 also uses NE5534 in the output stage. Alan Burdick and I always get a good laugh at those who "hear" the distortion of these opamps. It's your money and time. If you want to waste it rolling out NE553x's, then go for it!

 

[Lefty]

You would think that Texas Instruments would use their own Burr-Brown (OPA) series of opamps for the output stage of thier top-of-the-line D/A converter. What a surprise it is to find NE5534's shown in the app note output stage! Benchmark DAC1 also uses NE5534 in the output stage. Alan Burdick and I always get a good laugh at those who "hear" the distortion of these opamps. It's your money and time. If you want to waste it rolling out NE553x's, then go for it!

I've long stopped being amazed at what some people hear from their system's components and parts. I try to just enjoy the music :thmbsp:

Lefty

 

[EchoWars]

I'm using the OPA2132 in lieu of NE5534s. The 2134 is the equivalent for a dual.

I found a big improvement in sound. I also tried an OPA2604, which some rave about, a little bit of an improvement, but not as open sounding as the 2132. I also tried LM6172s.

Both the OPA2132 and the OPA2134 are dual opamps. The singles are OPA132 and OPA134, respectively.

The OPA2604 is good, but needs high voltage rails (+/-22V or so) to bring out its best characteristics. Problem is, once you design for a OPA2604 with high supply rails, you can't swap opamps any more, as most have a 36V maximum (+/-18V). At lower voltages it does very nicely as a unity-gain buffer.

The 5534 has an oddball layout compared to most 8-pin DIP single opamps. Care must be taken when replacing it with any other single opamp...familiarization with the circuit is required for proper operation, as the 5534 uses external compensation and most single opamps do not.

 

[Number 9]

The voltage rail on my 7005 is 15V, which is within the range of the 604, but it may also explain why it did not live up to expectations. I still may try an opa627 one day.