OPA627BP or OPA637BP for preamp?

JoeBob · 17th July 2003, 06:59 PM

Anyone have a preferance between these two for a preamp stage? I ask because many like the 637 for phono and the 627 for IV, but what about a simple preamp?

peranders · 17th July 2003, 07:53 PM

Both types are excellent as long as they work in optimal conditions but also there are at least a dozen of good other opamps, which are substantially cheaper.

Doh · 18th July 2003, 07:23 PM

I once built a headphone amplifier which used the 627, followed by a 634 buffer. Swapping the 637 for the 627 resulted in a much more rounded, natural sound to my ears. Both sound great. Just note that the 637 is not unity gain stable and needs a gain of at least 5.

JoeBob · 19th July 2003, 02:35 AM

Thanks, I already have some of both and was wondering which to use, I think I'll give the 637 a go and see how I like it.

tbla · 12th September 2003, 03:38 PM

how did it go...?

PMA · 12th September 2003, 05:39 PM

637 is stable for gain 5x and more, 627 can be used for gain 1x and more and has lower basic distortion.

analog_sa · 12th September 2003, 06:56 PM

Quote:

once built a headphone amplifier which used the 627, followed by a 634 buffer. Swapping the 637 for the 627 resulted in a much more rounded, natural sound to my ears

Impression seconded in a phono stage. What i really don't get though is why JoeBob is lazy to compare them himself. Too much work?

JoeBob · 12th September 2003, 07:48 PM

I did compare, I just wanted to see what other peoples opinions were on these parts.

I tried them and my preferance was the 637, gave better sound in my opinion. I liked it alot more, not just a small preferance. But for unity gain, I tried the 627, but in this place I liked a monolythic buffer more ( I used the EL2001).

PGW · 13th September 2003, 02:35 AM

Does anyone know how the 627/637 compare with the regular OP-27/37?

Are the 627/637 quite different internal architectures but designed to do (essentially) the same job as OP-27/37, i.e a pin-for-pin replacement in the appropriate circuit but with "improved" performance?

KevinLee · 13th September 2003, 03:14 AM

Hello,

I am just today replacing my AD826 in my pre-amp stage with (2) OPA627AP.

I will let you know how I like the new op-amp.

It is a chore to do this swap without the Brown Dog adapters.

Cheers

KevinLee

17th July 2003, 06:59 PM	#1
JoeBob diyAudio Member Join Date: Nov 2001 Location: Montreal, Canada	OPA627BP or OPA637BP for preamp? Anyone have a preferance between these two for a preamp stage? I ask because many like the 637 for phono and the 627 for IV, but what about a simple preamp?

17th July 2003, 07:53 PM	#2
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Both types are excellent as long as they work in optimal conditions but also there are at least a dozen of good other opamps, which are substantially cheaper. __________________ /Per-Anders (my first name) or P-A as my friends call me

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
For sales: TDA1541A, OPA627BP, OPA637BP, AD1865NJ, new old stock chips	gaetan8888	Swap Meet	12	29th February 2012 03:20 PM
Brand new OPA627BP and OPA637BP	hkaudioparts	Vendor's Bazaar	0	7th May 2008 02:11 PM
Fs: Opa637bp, Lm3875tf	mudihan	Swap Meet	2	5th July 2006 05:13 PM
FS/FT: OPA637BP x 2	some1x	Swap Meet	1	23rd March 2006 08:54 PM
For sale:BB OPA637AP and OPA637BP	mikrus2000	Swap Meet	0	24th January 2006 07:09 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

18th July 2003, 07:23 PM	#3
Doh diyAudio Member Join Date: Oct 2002 Location: New York	I once built a headphone amplifier which used the 627, followed by a 634 buffer. Swapping the 637 for the 627 resulted in a much more rounded, natural sound to my ears. Both sound great. Just note that the 637 is not unity gain stable and needs a gain of at least 5.

19th July 2003, 02:35 AM	#4
JoeBob diyAudio Member Join Date: Nov 2001 Location: Montreal, Canada	Thanks, I already have some of both and was wondering which to use, I think I'll give the 637 a go and see how I like it.

12th September 2003, 03:38 PM	#5
tbla diyAudio Member Join Date: Jul 2002 Location: denmark	how did it go...?

12th September 2003, 05:39 PM	#6
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	637 is stable for gain 5x and more, 627 can be used for gain 1x and more and has lower basic distortion.

12th September 2003, 07:48 PM	#8
JoeBob diyAudio Member Join Date: Nov 2001 Location: Montreal, Canada	I did compare, I just wanted to see what other peoples opinions were on these parts. I tried them and my preferance was the 637, gave better sound in my opinion. I liked it alot more, not just a small preferance. But for unity gain, I tried the 627, but in this place I liked a monolythic buffer more ( I used the EL2001).

13th September 2003, 02:35 AM	#9
PGW diyAudio Member Join Date: Jun 2003 Location: SoCo	Does anyone know how the 627/637 compare with the regular OP-27/37? Are the 627/637 quite different internal architectures but designed to do (essentially) the same job as OP-27/37, i.e a pin-for-pin replacement in the appropriate circuit but with "improved" performance?

13th September 2003, 03:14 AM	#10
KevinLee diyAudio Member Join Date: Oct 2002 Location: Winnipeg MB Canada	Hello, I am just today replacing my AD826 in my pre-amp stage with (2) OPA627AP. I will let you know how I like the new op-amp. It is a chore to do this swap without the Brown Dog adapters. Cheers KevinLee

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)