[mdelrossi]

I put together the power supply and I'm getting 15.29v on -15v side and 14.97v on the +15v side is this ok or should I check or change something?
It sounds great as is, with the opa2134 more depth and bass.
Then I put in the LM4562 into the U3 socket.
More air a bit less mid bass (coloration?) more detail though not harsh.
Do these op-amps need burn in time and would I benefit if I put LM4562 in the other sockets?
Oh one more question, if they benefit from burn-in will putting my cd player on the inputs and set to replay hasten the process?
Thanks again for these great kits    and  all of your help.
mdr

[PatOMalley]

burn-in. I have seen the character of the AD825's change over a short time. They were crisp on the top and open thru the mids at first. they got mild after that and now they are very layered, dynamic, extended, best yet. ... and quiet. This is a 40 hour time span and I think they may improve a bit more. If you can have them burn-in in a CDP ahead you won't have to go through the audio-nervosa of the change.

[shep]

The LM4562's in my CDP have taken about 100hrs to burn in. Well I'm not sure if there's more to come. They relax, open up and sound more musical. The basic characteristics don't change but I no longer wince at their relentless presentation of detail. Also I noticed the sound stage is less in the face now.

[hagtech]

Power supply rails do not have to match or track.  You can mix +12V with -15V if you wanted to.  Mostly, it helps that they power up at the same time, minimizing any turn-on thump.

Each opamp will sound a little different.  They do not have a big break-in characteristic like cables or capacitors.  It is more subtle.  Don't expect too much.

I haven't yet played with the new national LM4562.  It looks like a fine design on paper, though.

jh

[PatOMalley]

the change between the 2604 and the 2228's were subtle but the AD 825's make a dig difference to me.
The detail and layering is far above the 2228. I feel like I've hit this spot where I shouldn't touch anything. No changes!  ... that wont last.

[mdelrossi]

Thanks for the info.
I guess I'll leave well enough alone for a while aa . Next caps are in order.
I'll report back on the way the LM4562 changes/ sounds.
mdr