I always thought that the single OP176 is the same as double OP275 too.
Anyway, my Audio Alchemy DDE v3.0 originally had both.
It uses the OP176 on the analog stage, biased in class A, and two OP275s as the PSU for the OP176s.
I/V is discrete.
Some years ago I removed the OP176s and put OPA627s.
Much better.
Never tested the 176 for I/V though.
Anyway, my Audio Alchemy DDE v3.0 originally had both.
It uses the OP176 on the analog stage, biased in class A, and two OP275s as the PSU for the OP176s.
I/V is discrete.
Some years ago I removed the OP176s and put OPA627s.
Much better.
Never tested the 176 for I/V though.
Bricolo said:
Hi Thorsten,
I was thinking about this carefull implementation. I've been scratching my head for a while, and can't decide what's ok or not.
The PS pins of the clock will be connected directly after the diode bridge, that's sure. There's no other choice.
But where to connect the ground??
-at the transformer's ground
-at the nearest ground from the decoder (where the clock is connected)
-other?
Dave S said:
Just to set the record straight, and in case anyone else is interested in reading it, Chris Found's article on modifying the CD723 is still available on the web via his new URL:
http://www.cfmedia.org
or you can access the pdf file directly:
http://www.cfmedia.org/mods.pdf
Nuuk said:On CD723 modder I know has found a pair of 5534's work best for him and believe me, he tried most of the options!
Comparing to what?
I find this very amusing: (from the pdf)
"First, change the op-amp (NJM4560D) to a NE5532 ( Signetics type only), this improved the sound performance over the much faster NJM that seems to get confused by out of band noise."
Of course the NE5532 is better than the NJM4560D, but the explanation is
.
You name it Carlos, this guy tried it. He is extremely methodical in this sort of work!
It's strange to me that any mention of the 5534 bings this sort of incredulation. They are opamps and quite good ones at that. !n this guys set-up they sound the best to him.
The person concerned is also a classical musician with perfect pitch hearing so I trust his judgement in these matters. He goes for accuracy rather than 'wow factor'.
Remember that this is what this game is all about - achieving the sound that we like the best - not about building hi-fi with the highest spec!
Je slaat de spijker op z'n kop!
Hi Jean-Paul,
I couldn't agree with you more.
This is something I can not understand, this is a product that may not be sold as consumer electronics.
Best regards,
Audiofanatic
BTW Jean-Paul, I now have a CD80 and I'm gona modify it and report to you later if this one is better than the VRDS transport/player
jean-paul said:
Hi Jean-Paul,
I couldn't agree with you more.
This is something I can not understand, this is a product that may not be sold as consumer electronics.
Best regards,
Audiofanatic
BTW Jean-Paul, I now have a CD80 and I'm gona modify it and report to you later if this one is better than the VRDS transport/player
good point.
Remember that this is what this game is all about - achieving the sound that we like the best - not about building hi-fi with the highest spec!
at the risk of confirming about each and every prejudice against the dutch... add (in my case):
"for as little money as possible."
and in that respect the cd723 is a sound investment.
i've done most of the tweaks on nuuk's site and i must say that they improve the cd723 to a point where it's no longer the bottleneck in my sysem. now, my loudspeakers and room are...
Nuuk said:
That's fine, OK.
Nuuk said:
Don't take me wrong on what I'm gonna say, please.
The last classical-music-only-lover I've been with happens to be owner of an hi-fi store.
He was demonstrating me (and a friend of mine) an espen$ive system with choral music and some strings.
The sound was OK.
But my friend had asked me to go with him because he was thinking in buying those speakers.
Of course I took two CDs of mine.
Stop with choral music and put something really serious for a system test.
Unbearable
, unlistenable , bass was overblown, muddled everything. I guess this guy sells plenty of systems demoing with that kind of music, that is the music he loves and it happens that it doesn't have any dynamics, any bass.
He could put a cheap Nad driving some Apogees and love the sound.
So Nuuk, I guess this is really a matter of taste, audio is subjective and the fact that he likes more the NE5534 doesn't tell me much.
As I'm not in the mood to discuss this, because it's always very polemic and some people take things personally, each one to it's own.
Just wanna tell you all that my NOS Dacs have much more out-of-band noise than the 723 but there's no reason that I should change the op-amps I love for some "slower" ones.
BTW I know the NEs very well.
Opamp
Hi Dave,
Also my experience. The OPA627 is one of the best as a line amp or in a phono amp though bettered by a discrete FET inputstage.
There seems to be some "misunderstanding" regarding the connections of my clock to the CD-player in question and the formation of ground loops. Only one groundlead is connected from the clock PCB to the PCB in the CD player.
Dave S said:Carlos,
I agree, in the usual noninv op-amp config I always find OPA627 is better, that's why I was surprised that OP176 worked well in I/V.
I would welcome other's feedback on this, I have been known to be wrong in the past (frequently
Hi Dave,
Also my experience. The OPA627 is one of the best as a line amp or in a phono amp though bettered by a discrete FET inputstage.
There seems to be some "misunderstanding" regarding the connections of my clock to the CD-player in question and the formation of ground loops. Only one groundlead is connected from the clock PCB to the PCB in the CD player.
Re: Opamp
Hi Elso,
If you're reffering to my post:
Sure, it only needs one ground connection. But my question was more "where to connect the clock's ground?". Near the decoder's ground, or near the transformer's center tap?
Elso Kwak said:There seems to be some "misunderstanding" regarding the connections of my clock to the CD-player in question and the formation of ground loops. Only one groundlead is connected from the clock PCB to the PCB in the CD player.
Hi Elso,
If you're reffering to my post:
Sure, it only needs one ground connection. But my question was more "where to connect the clock's ground?". Near the decoder's ground, or near the transformer's center tap?
I would recommend connecting the clock ground at the point of lowest impedance i.e the PSU star point. Otherwise you may provoke ground bounce.
I did say I'm frequently wrong:
I went back to OPA627 for I/V in the Arcam. The OP176 was a bit too aggressive for my tastes and in my system.
I also felt the same about the OP275 in the CD723 and replaced it with RC4227 - I'm not saying this dual OP27 device is great, but even though it has less resolution than the OP275 it also lacks the aggression of the 275.
Horses for courses.
Konnichiwa,
If you do, the ground level of you clock will be shifted compared to the IC to which it is applied depending upon the ground(signal) routing for that IC. The problem, if you use the local PSU you are between a rock and a hard place and either way you add notable levels of jitter.
If this makes the result sound better we have perhaps another indicator that "low jitter" as such is not inherently a desiriable design goal, outside akademia.
If low jitter is desired we need to handle the clocks PSU noise current locally and return the ground to the ground of the IC fed the clock. This suggest a clock of the style implemented by Guido Tent for such applications.
If you use a seperate "master clock" with a complex PSU arrangement and you want low jitter, you MUST use a low leakage galvanically seperate PSU for the clock. Of course, low jitter may not "sound good" to some (just as flat frequency response with extended HF does not not neccesarily sound good to everyone).
Sayonara
Dave S said:
If you do, the ground level of you clock will be shifted compared to the IC to which it is applied depending upon the ground(signal) routing for that IC. The problem, if you use the local PSU you are between a rock and a hard place and either way you add notable levels of jitter.
If this makes the result sound better we have perhaps another indicator that "low jitter" as such is not inherently a desiriable design goal, outside akademia.
If low jitter is desired we need to handle the clocks PSU noise current locally and return the ground to the ground of the IC fed the clock. This suggest a clock of the style implemented by Guido Tent for such applications.
If you use a seperate "master clock" with a complex PSU arrangement and you want low jitter, you MUST use a low leakage galvanically seperate PSU for the clock. Of course, low jitter may not "sound good" to some (just as flat frequency response with extended HF does not not neccesarily sound good to everyone).
Sayonara
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.