Opamp swapping in a Music Hall 25.2 Integrated
Mar 19, 2006 at 4:49 AM Thread Starter Post #1 of 15

HiGHFLYiN9

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Just recently picked up a Music Hall 25.2 integrated amp for a small speaker setup, and lo and behold, it has socketed opamps, so I'm on my way to some easy rolling.

It has a pair of OPA2134PA, I'd like to swap them out for some OPA627s, are they direct swapable or am I in need of some brown dog adapters?

It also has what looked like 'NE5532P' which is the same size as the OPA2134PAs, anyone know who makes this and what would be a good swap for it?

Finally it has a larger chip, a PGA2311P, any recommended swaps for this one?

TIA.
 
Mar 19, 2006 at 5:00 AM Post #2 of 15

n_maher

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As far as I can tell you'll need the browndogs. The 2134 is a dual opamp, the 637 a single. So check and make sure you've got the physical room to make the single chips fit.

Also, based on what I can find the NE5532P is also an opamp but I'm not sure what exactly it's doing in your case. Also, the PGA2311P is listed as a volume control so I don't think you want to be rolling that one.

HTH,

Nate
 
Mar 19, 2006 at 5:51 AM Post #3 of 15

HiGHFLYiN9

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Thanks Nate, I should have just sent you a PM in the first place
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The sockets have a few caps above and below them, so the adapter could only come out horizontally or go straight up. I'll open up the case tomorrow and take some pics.

I wonder what that Texas Instruments opamp leads to?
 
Mar 19, 2006 at 7:11 AM Post #5 of 15

Teerawit

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The NE5532 is one of your "standard" opamps so you can definitely roll it. However it is a pretty good opamp in itself...maybe roll in an AD825 or dual OPA627s?
 
Mar 19, 2006 at 12:37 PM Post #6 of 15

Garbz

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OPA2604s is also a worthy contender. Just a question did you give this a good long chance yet? As in had a good listen for a month or so before you played with it? I made this mistake with my phono stage. Built it. Sounded good with OPA134s. So I put in OPA637s a few days later. Liked it a little more but a month later I put the 134s back in and have loved it so much more since.

I guess it comes down to a psychology thing but I think too many people write off the OPA134 before having a good listen. It's wonderful in Class-A and I'll never swap it out in my electrocompaniet integrated regardless of how it will sound after simply because I like it as it is.
 
Mar 22, 2006 at 11:57 AM Post #7 of 15

FritzS

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Quote:

Originally Posted by HiGHFLYiN9
It has a pair of OPA2134PA, I'd like to swap them out for some OPA627s, are they direct swapable or am I in need of some brown dog adapters?
It also has what looked like 'NE5532P' which is the same size as the OPA2134PAs, ........



You can test OP275 - I use them in my Philips CD 650
OP275 are dual OP's
Philips has original NE5532P they sounds good, the OPA2134PA sounds better - like "musically" - for me, now I use OP275, they are much more detailled, analytic - more about you will see at:
http://www.stockhammer.at/hifi/cd650.php

http://www.stockhammer.at/hifi/

PS: If you use OP275 you should bypass the +-V inputs with 100 nF caps!!!

Happy hearing
580smile.gif
 
Oct 16, 2006 at 4:57 PM Post #8 of 15

Mike53

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A bit late posting, on this subject, but I just discovered this group.

I recently purchased the Music Hall 25.2 amp, CD player and tuner. Prior to buying this equipment I contacted the guys at Underwood HiFi modifications. Underwood had upgrades for the Music Hall CD 25.2, as well as the Maven, Mambo and Maverick, but none for the A25.2. I spoke with Walter and he told me that, at the present (8/06), the components in the A25.2 were the best available - there was no way to upgrade the amp. (Check Teerawit's post.)

Just curious: What kind of speakers are you guys driving with your A25.2s?
 
Jul 19, 2007 at 6:55 PM Post #9 of 15

Mike53

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Just in case anyone is still reading this thread: Underwood HiFi (www.underwoodhifi.com) is now doing upgrades on the Music Hall A25.2 amp.
The amp uses the same opamps as the cd player (OPA627). They also do a "Minimod" on the amp using OPA-8066 opamps (less expensive). Not as great as the 627 but much better than the stock op.

If you want to do it yourself the parts are available from the Parts Connexion
(www.partsconnex.com).
 
Jul 20, 2007 at 9:08 AM Post #10 of 15

majkel

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The easiest upgrade would be OPA2107 - it's the same technology as OPA627/637, a bit different sound (darker but also a bit more lively), surely better than OPA2134, 2227, AD823, OP275. OPA275 is quite OK any way, AD8066 very nice but you need a Brown Dog adapter.
 
Jun 16, 2008 at 3:06 AM Post #11 of 15

Sparky14

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Bumping this old thread back up.....anybody done this OPAMP upgrade to the A25.2? Is it worthwhile?

I did the OPA627 upgrade to my Onix XCD-88 (same as MH CD25) and was pleased with the results....but not sure if I'd get comparable results with the A25.2 OPAMP upgrade.
 
Jun 16, 2008 at 6:34 AM Post #12 of 15

adamus

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another vote for the 2107, i have used it a fair bit and its my favourtie, best bang for buck.
 
Oct 28, 2008 at 1:51 AM Post #13 of 15

Sparky14

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Just bumping this for any future A25.2 owners....

I did put the OPA627 opamps into the A25.2, and it was a worthwhile investment. Nice sound improvement.
 
Oct 28, 2008 at 4:05 AM Post #14 of 15

bundee1

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How's the bass now? That was the reviewers biggest complaint and my biggest reason not to buy it.
 
Oct 29, 2008 at 3:59 AM Post #15 of 15

Sparky14

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Mine is driving the Onix Reference 1 speakers, which for a monitor already have great bass.

I tried the A25.2 and the NAD C325BEE, the NAD was quite a bit boomier and not as sharp as the MH.

The OPA627 upgrade (in both my CD and Amp) has really gotten rid of treble harshness, which are very apparent through the Ref 1's Vifa tweeter.

As for the bass, I cannot complain a bit. Not quite sure how to describe it, but it is very fast....not boomy at all and the bass notes don't hang around.
 

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