Denon DVD2900 tweaks

[clm811]

Another mod I did was to reduce the resistor value for IV conversion.

Please elaborate- which resistor did you change, and to what final value?
Thanks.

[ctong]

Originally posted by clm811


Please elaborate- which resistor did you change, and to what final value?
Thanks.

It is the resistor connecting the inverting input and the output of the IV opamp. I think the original value was 550 ohm and the current values is around 450 ohm.

[clm811]

Unless your system is on the bright side, I wouldn't recommend the opa2132/34 family. Save your pennies and replace the 2 op275's with 4 opa627's and don't look back.

Mrdon:

How do the 627's compare in this output buffer position to other opamps(specify) you've tried?

Also, the power supply rails in the 2900 are +/- 9v; however, the recommended voltage for the OPA627 is higher; isn't this a problem? see:
http://www.tangentsoft.net/audio/opamps.html

are class-A "pulldown" resistors different values for the different OPAMPS you've tried?

Thanks,
-chas

[clm811]

O.K.

Got OPA627's and using Brown Dog adapters replaced stock OP275's.

Greater clarity, detail and microdynamics; however, after only a few hours break-in the sound is somewhat bright and more forward in the midband than OP275.

I'll wait until after a few days' break-in to judge the final effect.

-chas

[singleended40]

Hi,

Have you tried Audio Consulting AD825? What is the sound like? Thanks.

[clm811]

The OPA627's have been run-in for a few days and sound much nicer now. Soundstage is wider than before, and there is additional image "height"! I am hearing a more "engaging" sound from my system and can finally appreciate the additional resolution of my DVD-A's (AIX, Classic). Piano has better attack/decay and violin and horns have more natural "bite" and overtones. The SACD's sound nicer too. My toes are tapping! I do find the mids to be a tad bit more forward than I prefer, as my speakers are quite flat through the midband and treble.

Have you tried Audio Consulting AD825? What is the sound like? Thanks.

Not yet; However, I'm going to try the similar AD826 . I will report back once these are "run-in" for a while, and compare the sound with the OPA627's. I've heard these have a more laid-back midrange, which may better suit my speakers.

[singleended40]

I have ordered the Burson Discrete op amps to replace the NE5534 op amps in my Promitheus DAC. Let see if the Burson can do any better than OP627s and AD825s.

[clm811]

Good news- I FINALLY got a working pair of replacement OP627's to fit to my line stage & finally have the parts to finish tweaking my dream system this year.
I just want to thank my friends here who sent me emails of support (and agree: I didn't want to " get into the middle of a p1$$1ng match " on the forum if I could avoid it either).
Thanks to Don and Mark for reporting here on these great-sounding op amps in the first place. These and the AD826's Matt sent me beat the OP275 and OP2134 amps by mile. I'm still deciding on which I prefer, as I really like the AD826's and they're reasonably priced.
Tweak posts should restart afresh and Moderator: I promise to post strictly about DIY audio matters in the future, and I hope others will too.
And thanks especially to Danny who kindly sent me said opamps; They are the real thing and arrived properly packed
(see pic). I am truly grateful!

It's a comfort to know there are other gentlemen here who are pleasant and stay focused on the REAL purpose of this forum: helping to better sound!

In this spirit of Holiday giving I'm willing to GIVE AWAY my extra mod parts that I won't be needing to any of you gentle members (Cont'l U.S. please) who are interested. Just Email me for a list of what items I have available.

Merry Christmas/ Happy New Year and God bless all!
(yes, even the Grinch ).

-chas

[jtsaudio]

Chas,

Please email me the list.

and Happy New Year too!

-JT

[clm811]

Here's the list of items:
8 Pin DIP opamps:
*JRC4556AD...(2pcs)
*AD846AN.....(2pcs)
*AD827JN.....(2PCS)
*AD711JN.....(2PCS)
*AD712JN.....(2PCS)
*NE5534AP....(2PCS)
*NE530N..... (2PCS)
*OPA2132P... (2PCS)
*OPA627BCHINA(2PCS)

8-lead TO-99 Can:
*LH0002CH Buffer (2PCS)

Capacitors:
*Elna SilmicII 2.2uf/50v(2pcs)
*Elna SilmicII 220uf/16v(2pcs)
*NipponChemcon220uf/16v (1pc)
*PanasonicHF 330uf/25v (2pcs)
*TRANSCAP PS .01/50V (4PCS)
*WIMA FKP1 3900/1000V (2PCS)
*WIMA FKP1 .01/630V (3PCS)

Other Items:
*Gold-plated RCA Socket(4pcs)
*Gold 8pin DIP Headers (4pcs)
*Single-Dual 8pin DIP adptr PCB's,China(2pcs)
(As-Is: one has solder bridge as received)

Just email me re: which item you want (you may
reimburse me the actual postage later if you choose).
(Again, offering within Continental US only please)

Happy New Year!
-chas

p.s. First-responses/first gets!