[ppl]

This is to inform you of my finial verdict on the PPA for 3K lovers sorry it took so long.

(1st choice= OPA637)
Nice and smooth tames the overly bright top end of the CD3ks while still preserving imaging and ultra detail. and a tight almost over dampened bass.
.
(2ed Choice=OPA-627) Warmer and slightly rolled off compared to the 637 but more punchy and dynamic bass. Woody sounding mids with 3ks that sounds organic to me. i like this.

my portable rig is going to be based upon this setup with OPA-627's in the aos DAC also so as to have the total BB sound at its best from Digital conversion forward on to Diamond buffer.

(3ed Choice LT-1122 ) Slightly less dynamic bass but tube like upper midrange and treble silky clean vocals and strings are fast and articulate. Use Bw enhancing pin by jumper-ring pin 8 the Speed overcome pin to pin 7 the V+ Pin as depicted on pg 8. This increases bandwidth and slew rate and notably improves the Micro dynamics of the Device.

(4th Is the AD-8065 ) can be down right haunting on some ambient music making one believe they are hearing voices overlaid upon the sound scrape. Kryptos never sundered so deeply involving shall I say. Bass is too polite for full out rock so The 8065 was not placed more prominent on my short list. Mega micro dynamics and non bright but accurate top end make this OPA in the OPA-637 class but different in its presentation and less Bass.

(NOT RECOMMENDED Below)
AD-825 slightly degraded AD8065 the bass is also lacking making it edged out by the AD8065. the AD825 is dark with no Micro dynamics.

AD-744 Bloated upper bass result in exciting resonances in the 3k’s in that range and reproduces a hollow sound.

 

[digi01]

that is good informations.
for low-Z high sense headphones,have you tried to stock double DM buffer?

-digi

 

[gracky]

Wasn't the diamond buffer unstable with OPA637? It's a new version?

 

[SteeleBlayde]

Top choices for me in no particular order:
AD8065 - Detailed, not quite as smooth as the below. Nice with HP-1.
LT1122 - Smoooooooth .... amazing with my MS-Pros.
LT1028 - Not quite as smooth, though more punchy and dynamic, slightly better extension than the 1122. I still have to compare these to the AD8065.

I like using them all in conjunction to suit the particular headphones or music.

I still want to spend more time with these chips. Really interested in seriously sitting down with and AD744.

 

[xtreme4099]

no it works just fine ... it was some different output transistors where it wasnt working its fine now. I'll add the LT1028 to the list it has been mention by john_jcb before but must mention its great qualities of the LT's in general, smooth, great tonality, this 1028 happens to have more extension in the mids and highs than the 1122.

 

[jamont]

Quote:

Originally posted by xtreme4099 no it works just fine ... it was some different output transistors where it wasnt working its fine now. I'll add the LT1028 to the list it has been mention by john_jcb before but must mention its great qualities of the LT's in general, smooth, great tonality, this 1028 happens to have more extension in the mids and highs than the 1122.

I received my buffer about a month ago, how can I tell if it has the right transistors? I'd like to try some of these chips...

 

[xtreme4099]

dont worry it should work ... mine is older than that ...

 

[fwh1599]

I have no PPA,I have my Twinkle(OP+DB structure),I used OPA627/OPA637,AD8065 and AD8610.I think AD8065 is best for me,because I like it's lively and springiness.
I think OPA627/637 as a scholar,more information,but too sober,AD8065 as a young, great-hearted and smart.

Sorry for my poor English.

 

[ppl]

SteeleBlayde. reminder this is for CD3K not MS Pro's or HP-1 those do sound better with the LT1122. the 3K's can sound good on that chip but the OPA-627/637 is better suited to the 3K

jamout if you have 5 caps blue BC film Box then its the new version and the old version can be upgraged with the addition of the other two capacitors quite easy just solder capiacitor between the Buffer channels to create a string with the ones presently on board if you good with a soldering iron, However alteration of an exsisting product and voiding any warrenty is what DIY is all about Ah.......

The 5 cap Buffer board has showen to be stable in my applications however YMMV.

 

[Voodoochile]

Nice post, Phil, loaded with good info as usual. I just finished installing the diamond buffer in Al's PPA (*the* resident CD3K-head), and although I am listening through Grado 225s for lack of a CD3K, it sounds really very nice. He is using the 637s with 627 in ground channel. No issues whatsoever. Very nice listening.

Quote:

Originally posted by ppl ...alteration of an exsisting product and voiding any warrenty is what DIY is all about......

Spoken like a champ...

 

[jamont]

I'm guessing I have the old one, ppl could you look here
and let me know for sure? Thanks!

 

[ppl]

Jamount you got mail

 

[gracky]

PPL, may I ask you which configuration of battery board do you use for OPA637s? How much voltage is sufficient?

Thank you in advance.

 

[SteeleBlayde]

the Full 18 Cells

 

[Sean H]

Hey, great info guys, thanks! I know we're talking CD3k here but I had a question. I think I have raised this question with Stellblayde and xtreme before, I was wondering if any of you have noticed how much the opamp in the ground channel affects the sonics? I believe feedback so far has been "some" but not significant. Anybody else? I am currently toying with 637, 627 and LT1122's in my PPA, experimenting but also looking for the best combo (HD650 are my cans). I love the LT1122's so far, they are excellent but wondered what might happen if I take the 627BP I have in the ground now out and throw in a AD8610 as that amp seems like it might be quite different from the LT1122 or 627 and perhaps a balance could be struck, I don't know. 627 in the L&R spots with 8610 in ground could be interesting too. Anyone have an opinion about the ground channel opamp?