opa 2134 vs 2 opa627

[Htguy]

hI,
I am just looking for thoughts on my upgrade of my system going from ad712 opamps to either opa2134 or 2 opa627. Is there a big difference in sound quality through these two?
(I already have 4 of each so cost is not a big deal, although finding the right adapter might be.

Thanks for your thoughts.

God bless...

Mark

[BrianL]

Assuming that the AD712 and OPA2134 are both DIP
packages, the OPA2134 should drop in without an adaptor.
That makes it quick.

I hear that both benefit from biasing the output stages
more heavily into class A.

[Zombie]

adaptor? look for Brown Dog

[David Nessim]

Hi Mark,

The two are very different designs. The OP 627 is an updated op 27. That was a very good low noise design. It was good also in IC based RIAA amps. The 2134 is a more modern design, with beefier output and much higher speed. I use it in place of NE 5532's, it is always better. What was the original chip in which instrument? What was the job of the chip you want to replace?

David

[motherone]

The GBW and Slew Rate of the 627 is higher than that of the 2134 (GBW of 16mhz versus 8, and a Slew Rate of 55 V/us versus 10). Furthermore, the noise performance of the 627 is about 50% better than the 2134.

I would say that if you want a quick drop in replacement to try out the Burr Brown/TI sound, pop in the 2134. If you would like to see what BB's best chips have to offer, get a browndog single-to-dual opamp adapter.

In my personal opinion, the 2134 is pretty mediocre, while the 627 sounds really nice. I can't spew audiophile words over it, just that the 627 sounds a lot better to my ears and there's really no comparison. This seems to be inline with most folks opinions on those two opamps. (And even against the "better" version fo the 134/2134, the 132/2132)

The brown dog adapters can be purchased here:

http://www.cimarrontechnology.com/in...ATS&Category=5

I'm sending the link because it's not fun to google for, and doing site searches on most forums won't yield the site

Good luck and welcome to the wonderful world of op-amp rolling!

[David Nessim]

Hi.

I have just had a good look through the 627 datasheet. I was reffering to the OP 27 when I said the 2134 is better. The 2134 is not as bad as someone said here, it just likes good bypassing, etc, to work well.
The 627 could well be a better sounding device. But you will need an adapter if you replace a 5532 or any dual opamp. I am interested how your experiment works out, I may get some of these 627's myself..

David.

[Htguy]

Hi Everyone,

Thanks for all the great advice and opinions. Today I installed an 8pin dip adapter into my Parasound preamp so I can swap opamps out easily and quickly. I tested the opa2134 vs the ad712 that were stock. (Opa2134 is not broken in at all, so it will most likely get better w/time) The base is much better from the 2134, but it does not seem to be as powerful on the output side, but could just be the break-in needed.

I plan to get the brown dog adapters and try the opa 627's soon. I will update this page in a week or two when they're in.

God bless...

Mark

[BrianL]

IC op-amps do not "break in".

[motherone]

Originally posted by David Nessim
Hi.

I have just had a good look through the 627 datasheet. I was reffering to the OP 27 when I said the 2134 is better. The 2134 is not as bad as someone said here, it just likes good bypassing, etc, to work well.
The 627 could well be a better sounding device. But you will need an adapter if you replace a 5532 or any dual opamp. I am interested how your experiment works out, I may get some of these 627's myself..

David.

I love the 627 and the 637. They're great sounding chips. I also like the AD8610/8620. The easiest way to go dual with the 627/637 is to buy a dual SMD opamp to single DIP adapter from browndog, and solder down the two SMD 627/637's. This keeps the traces shorter than doing a dual-DIP to single-DIP swap.

I'm still waiting to try my AD8065/8066 chips as well. They're supposedly far better than the 8610/8620.. I'm just lazy and haven't given them a critical listen yet.

I have to say that one of the OP amps I'm surprised by at the quality is the AD746. It's an older Analog Devices one. It's comparable to the 627, but it's slightly slower, faster slew rate, and a little higher noise. Still pretty good sounding though, with a beefy PSU.

Brian: I also agree -- With the exception of mechanical devices, I don't think parts really "break-in" .. if anything, their specs drift to worse than when they were brand new. I've always thought that it was more of your brain getting used to the changes in the sound. But I'm gonna drop out of that convo, since it'll stir up a firestorm

[jackinnj]

Originally posted by motherone

Brian: I also agree -- With the exception of mechanical devices, I don't think parts really "break-in" .. if anything, their specs drift to worse than when they were brand new. I've always thought that it was more of your brain getting used to the changes in the sound. But I'm gonna drop out of that convo, since it'll stir up a firestorm

Parts do "break-in" -- and I was a skeptic -- every chipamp I have built I test on a scope -- the very first turn-on you get some nasty oscillations for perhaps a second or so -- all subsequent turn-ons are fine -- I don't know whether it's the chip itself, the electrolytics etc.

Certain resistors absorb moisture and drift through time -- they will have different values depending upon the amount of time they are in use AND the relative humidity --

i don't think that opamps get better or worse with age.