BB OPA637 okay in these applications?

marchewd · 11th January 2007, 04:43 AM

I am going to swap out the opamps in my Music Hall CD25 player. I know the 627's work in this player (with BrownDog adapter and 2 chips), but was wondering about the 637's, as I can get a much better price on compared to the 627's. Or would a discrete opamp, like this one work out better? www.bursonaudio.com/burson_hdam_module.htm ?

Any and all help would be greatly appreciated!

Thanks,
Dan

Epicurean · 11th January 2007, 10:53 AM

I would say no. I doubt your CD-player has a high gain and the OPA637 needs a minimum voltage gain of 5 whereas the OPA627 is stable at unity gain. I have OPA637s in my headphone amp and a gain of 6 was too low so I raised it to 10 and now its working fine.

btw. that link of yours didn't work

ckng · 11th January 2007, 02:50 PM

I posted a similar question to yours in this thread earlier:-
OPA637AP in Rotel RCD-02

Tried 2 OPA637APs per channel on my Rotel RCD-02 and it didn't work too well either. There's quite a bit of noise which I think is due to oscillation.

You might want to try the LM4562s if you can get hold of them. General opinion is that it's better than the OPAs.

Regards
CK

marchewd · 12th January 2007, 07:21 AM

Thanks for the replies. What about using the 637's in either a Jolida JD-9 phono pre or Rogue Stealth phono pre?

Thanks,
Dan

musicfan_cbs · 12th January 2007, 08:08 AM

In my opinion OPA627 is a better/safer choice (although more pricey). It is a lot easier to integrate that 637 (-->>voltage gain) and from what I've heard so far yields a bit better sonic results (in both cd-players and preamp stages).
I think you should at least buy a pair of opa627 and compare the results.

11th January 2007, 04:43 AM	#1
marchewd diyAudio Member Join Date: Jan 2007	BB OPA637 okay in these applications? I am going to swap out the opamps in my Music Hall CD25 player. I know the 627's work in this player (with BrownDog adapter and 2 chips), but was wondering about the 637's, as I can get a much better price on compared to the 627's. Or would a discrete opamp, like this one work out better? www.bursonaudio.com/burson_hdam_module.htm ? Any and all help would be greatly appreciated! Thanks, Dan

12th January 2007, 07:21 AM	#4
marchewd diyAudio Member Join Date: Jan 2007	Thanks Thanks for the replies. What about using the 637's in either a Jolida JD-9 phono pre or Rogue Stealth phono pre? Thanks, Dan

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11th January 2007, 10:53 AM	#2
Epicurean diyAudio Member Join Date: Jan 2006 Location: Borga	I would say no. I doubt your CD-player has a high gain and the OPA637 needs a minimum voltage gain of 5 whereas the OPA627 is stable at unity gain. I have OPA637s in my headphone amp and a gain of 6 was too low so I raised it to 10 and now its working fine. btw. that link of yours didn't work

11th January 2007, 02:50 PM	#3
ckng diyAudio Member Join Date: Jan 2006 Location: Singapore	I posted a similar question to yours in this thread earlier:- OPA637AP in Rotel RCD-02 Tried 2 OPA637APs per channel on my Rotel RCD-02 and it didn't work too well either. There's quite a bit of noise which I think is due to oscillation. You might want to try the LM4562s if you can get hold of them. General opinion is that it's better than the OPAs. Regards CK

12th January 2007, 08:08 AM	#5
musicfan_cbs diyAudio Member Join Date: Oct 2006	In my opinion OPA627 is a better/safer choice (although more pricey). It is a lot easier to integrate that 637 (-->>voltage gain) and from what I've heard so far yields a bit better sonic results (in both cd-players and preamp stages). I think you should at least buy a pair of opa627 and compare the results.