Jolida JD9 Opamps

I've been following all the info about different opamps available for this unit and after awhile it all becomes a bit confusing. I've had my JD9 for a year now and I'm quite pleased with it but would also like to improve it if possible. I'm not handy with a soldering iron so changing the opamps would seem to be the route for me. I'm using a Denon DL-304 LOMC with very low output (.18mv) so I would like to keep the noise floor as low as possible. Could someone give me guidance as to which opamps would be best to use in my setup? Or should I just leave it be and enjoy it as is?
Regards, Sam
I own a JD-9, and after upgrading the opamps to 637s, it improved greatly. You can roll the tubes to regulate the warmth level.

Given the opamps are easily swapped and make it better in just about every way, leaving it stock didn't seem to make much sense.

I've got several pairs of tubes I roll from time to time. Does anyone what the difference is between the 627s and the 637s?
Regards, Sam
I had my JD9 open about a year ago but I forget now: how many socketed op amps are there to replace?

I tried the 627s and found the 637s to be slightly more extended at both ends of the frequency spectrum, which was to my taste. Tonally they were very similar in my system.


There are six opamps total in mine, although I've heard other versions of the JD9 may have a different arrangement.

Armstrod, where can I buy 637 opamps?
I got mine as samples directly from TI, but here's one place to buy them at retail:

There are many others; just Google "OPA637BP".

There is a cheaper version of the 627/637 family you may wish to try. It is the 827. Very close to the 627/637 in specs, a bit better noise and a bit better distortion, and cheaper.

It is only available as surface mount mount though, so you have to use a Brown Dog adapter or similar if you need an 8 pin DIP. BTW, its about $7.50 in singles. If you want to buy one pre-mounted, Brown Dog has the 827 for $22 mounted.

The 627/637 DIP has gone up to between $25 and $35, depending on grade.