Hello,
my first post here.
I have changed the Opamps in my CD-Player. The Original-ones were the JRC4565. The sound was ok. They account for the filter and followed by a discret ampflifier current stage.
I tried the BurrBrown OPA2134 and the National Semiconductor LME49720 but was dissapointed by big trade offs. Conclusion: I don't understand why people like opamp swapping!!!!!!!!!!!!!!!!!!
My results compared to each other:
I guess the studio mixers have simple JRC4565 or NE5532 in it. And all the effect are best and most musical only with them, because the music was heard and mixed with them in the studio.
Ok, as a conclusion the JRC4565 should be put again in the Player.
But:
Would be there an improvement if i would try the cheap JRC/NJM 2068?
It has better distortion and slew rate than JRC4565! It is said to be an improvement over the NE5532!! But
Will be there the nice decay of the JRC4565 there?
my first post here.
I have changed the Opamps in my CD-Player. The Original-ones were the JRC4565. The sound was ok. They account for the filter and followed by a discret ampflifier current stage.
I tried the BurrBrown OPA2134 and the National Semiconductor LME49720 but was dissapointed by big trade offs. Conclusion: I don't understand why people like opamp swapping!!!!!!!!!!!!!!!!!!
My results compared to each other:
- JRC4565 - deep bass a little bit bloomy, soundstage wide and deep with nice and longest decay, sometimes at high pitched loud synthesizer or full loud passages distant feeling of distortion and a little bit nervous, but nevertheless most musical and foot tapping yes!
- OPA2134 - loudness curve, kicking bass but often no real depth and too fast unnatural cut away yes!, the worst soundstage or imaging, the decay is lost! Everything sounds swapped and cleaned, no distortion, but it sounds filtered to sound rounded, even the sometimes silvery highs don't disturb. But the last musical feeling and foot tapping is missing.
- LME49720 - neutral, people say that it has a good soundstage, the soundstage is indeed deep but only distant, there is no offset in depth no different levels of soundstage depth. And it sounds as if you have but your loudspeaker on a stage with some distant.
I guess the studio mixers have simple JRC4565 or NE5532 in it. And all the effect are best and most musical only with them, because the music was heard and mixed with them in the studio.
Ok, as a conclusion the JRC4565 should be put again in the Player.
But:
Would be there an improvement if i would try the cheap JRC/NJM 2068?
It has better distortion and slew rate than JRC4565! It is said to be an improvement over the NE5532!! But
Will be there the nice decay of the JRC4565 there?
Because it is easiest way to get the result, no matter good or bad. Pick the one you like.
The opamp swapping did improve sound on most of the unit that I tested not all.
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There is no spoon! It's just in your mind!
No way an OpAmp can influence the "decay" or act like a "loudness curve". It is physically impossible.
I don't care what you THINK you heard, that is not what happens in real world.
An OpAmp can influence noise, distortion, high-end of the spectrum. Very seldom, in bad designs, a jfet-input OpAmp will have more bass than a regular OpAmp. In decent devices that is not happening.
No way an OpAmp can influence the "decay" or act like a "loudness curve". It is physically impossible.
I don't care what you THINK you heard, that is not what happens in real world.
An OpAmp can influence noise, distortion, high-end of the spectrum. Very seldom, in bad designs, a jfet-input OpAmp will have more bass than a regular OpAmp. In decent devices that is not happening.
Later opamps such as the LM4562 and LME49720 or LME49710 are far less forgiving of poor power supply implementation and poor track layout and supply line bypassing.
Get that right and they will outshine the earlier opamps.
The OPA134 and OPA2134 etc. aren't quite as fussy, but will still benefit from the same areas being correctly implemented.
SandyK
Get that right and they will outshine the earlier opamps.
The OPA134 and OPA2134 etc. aren't quite as fussy, but will still benefit from the same areas being correctly implemented.
SandyK
I am not sure why you tried the OPA2134.
I got one of those to go along with my CMOY headphone amp.
It's not too great.
Surely there are better opamps to try.
Notes on Audio Op-Amps
I don't know what your voltages are like, but that should give you something to look at.
I got one of those to go along with my CMOY headphone amp.
It's not too great.
Surely there are better opamps to try.
Notes on Audio Op-Amps
I don't know what your voltages are like, but that should give you something to look at.
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The JRC/NJM4565 is pretty unique in being rated to deliver 20 volts pk/pk into 400 ohms although I doubt that aspect of it's performance is called for here. In other respects it's very average.
What is the CD player these are fitted too ?
What is the CD player these are fitted too ?
It is the small Kenwood DP-1001. It has the Philips TDA1547 (or DAC7) as the DAC. It is from 1994 and was then a good CD-Player. The opamps have even as default a good power supply! And they are followed by an unloading discret current stage.
With good power supply i mean not only big elkos and transformer but there are small caps at the opamps even as a default!!!!! Even at 1994 Kenwood still built some good Hifi-ware.
The Kenwood DP-1001 was part of the small but good Kenwood HD 1000 (or 1001) Serie. It is still famous in Japan.
@ SoNic_real_one
YES, you are absolutley right! Even the "cheap" opamps like the NJM4565 have sufficent quality characteristics.
I had this discussion already at the diy-loudspeaker-forum of Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories "Diskussionsforum".
There is an electric-engineer I respect and he told me the same as you.
But i counter a little bit and say the datas given in the sheets are very statically measured.
I asked, Could it be that when a dynamic and frequence-full signal like music it behaves a little bit different?
The electric-engineer said it could at last the transient-distortion that you can hardly measure!!!!
At next I want only test the also cheap NJM2068 for some lower distortion. (for me that was the only weakness of the original NJM4565 at loud passages)
Otherwise the Original NJM4565 is put in again.
The Kenwood DP-1001 was part of the small but good Kenwood HD 1000 (or 1001) Serie. It is still famous in Japan.
@ SoNic_real_one
YES, you are absolutley right! Even the "cheap" opamps like the NJM4565 have sufficent quality characteristics.
I had this discussion already at the diy-loudspeaker-forum of Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories "Diskussionsforum".
There is an electric-engineer I respect and he told me the same as you.
But i counter a little bit and say the datas given in the sheets are very statically measured.
I asked, Could it be that when a dynamic and frequence-full signal like music it behaves a little bit different?
The electric-engineer said it could at last the transient-distortion that you can hardly measure!!!!
At next I want only test the also cheap NJM2068 for some lower distortion. (for me that was the only weakness of the original NJM4565 at loud passages)
Otherwise the Original NJM4565 is put in again.
Yes, i have had the OPA2134 now for 6 month in the CD-Player? I was aware of changing after 1-2 month but now there is no further improvement.
Here we go. OpAmp break-in... What to break in, the silicon crystal lattice???
The only real issue with swapping OpAmps is the power supply and decopling. If those are not done decent, can hamper the performance.
The only real issue with swapping OpAmps is the power supply and decopling. If those are not done decent, can hamper the performance.
The mistake is assigning some sound quality to the opamp, when the surrounding layout and parts can also have a effect. When you take a nice stable garden variety opamp and replace it with a wide bandwidth high performance opamp, you *must* test with a signal generator and scope to see how it performs. If you've got overshoot or some instability, maybe very HF oscillation, you have to adjust the circuit accordingly. Opamps are not plug and play, layout matters and all bypass caps were not created equal.
So, you have this covered and provided supply layout and decoupling are reasonably good, the new opamps simply don't sound all that good. Not very surprising as the OPA2134 is usually an opamp i upgrade, not one i upgrade to. At least you don't appear to be deaf 🙂 Plenty more opamps to try and quite possibly some will fit your system and taste better.
@Mooly
The Opamps make the active filter:
There are as default already caps in the feedback loop!!!!!!!!!!
At the first Opamps there is a 120p cap and at the second a 1000p cap!!!!!!!!!!!
The cutoff frequenz is something over 22kHz i guess.
And near the Opamps are 0,1uF caps to have fast power supply.
The Opamps make the active filter:
There are as default already caps in the feedback loop!!!!!!!!!!
At the first Opamps there is a 120p cap and at the second a 1000p cap!!!!!!!!!!!
The cutoff frequenz is something over 22kHz i guess.
And near the Opamps are 0,1uF caps to have fast power supply.
I've checked out the schematic(very surprised to see such a modest player using the potentially great DAC7 chipset), and you are, in my opinion, quite wrong about the power supply on the unit. The output stages have a rather pitiful 220uf per rail post-regulator, which is a)not located very near even the second chip, and b)is very distant from the first stage chip. To have a PRAYER of sounding it's best, with OPA2134 IMO(which I can tell you from a very great deal of experience using OPA134-series in Meitner BiDAT's w/DAC7), you MUST have at least another pair of 470uf caps on the +/- rails as CLOSE AS POSSIBLE to EACH output stage chip's supply pins & nearest ground. The 134 series chips have tremendous dynamic range & tonal richness when supplied this way. The lower echelon chips like those JRC's & 5532's etc. can be supplied in a pitifully weak manor & get away with it, but you really have NOT heard what the DAC7 can do without trying properly-powered OPA2134's. And if you really want to get the most refinement, add to those 470uf(hopefully Nichicon if you want them to last) lytics at least 0.47uf of the best film caps you can squeeze into the available space, and also make the post-regulator filter caps for the DAC7 chips as large as can fit w/film bypasses. This is a potentially phenomenal sounding player if you are willing to do some work.
I have been building a modular synthesizer for a while, and often the circuits I work from use a TL072/82 or TL074/84, sometimes when i decide a certain part of the circuit would benefit from a better op/amp i will use on of the nice OPA or LME ones, almost invariably it will not work without some minor changes to the circuit. usually a small capacitor (18-33pf)across the + and - inputs or in parallel with the feedback resistor.
Also if the Op Amp you are replacing is a JFET input, rail to rail output, Low offset or other special characteristic, make sure the new one is the same type.
you really need an oscilloscope though, to see what is going on. even the $100 "dso nano" would be better then nothing for audio-100khz work, at least you can see if oscillations are happening.
Also if the Op Amp you are replacing is a JFET input, rail to rail output, Low offset or other special characteristic, make sure the new one is the same type.
you really need an oscilloscope though, to see what is going on. even the $100 "dso nano" would be better then nothing for audio-100khz work, at least you can see if oscillations are happening.
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@stephensank:
At first the main power supply caps are 3300 uF caps that are very big for a cd-player. (on page 10 right to the "power control" with the transistor)
The 220 uF cap you mean is only connected to the DA-Converter. (page 11 top left C91 and C92)
The big main power supply caps are very close to the last output stage.
And as i said there are further 0,01 uF caps close to the opamps.
AND I forgot to say that I have already added Wima MKS 4 caps there.
At first the main power supply caps are 3300 uF caps that are very big for a cd-player. (on page 10 right to the "power control" with the transistor)
The 220 uF cap you mean is only connected to the DA-Converter. (page 11 top left C91 and C92)
The big main power supply caps are very close to the last output stage.
And as i said there are further 0,01 uF caps close to the opamps.
AND I forgot to say that I have already added Wima MKS 4 caps there.
A further question about the supply caps connected directly to the opamps:
Is there any difference if I connect one from + to - or have there to be two, one from + to ground and another from - to ground?
And can someone recommend me an opamp that has good soundstage?
I already tried the LME49720 but the stage is only distant with no good different levels of depth.
I haven't broken in the LME49720. Does it improve over time?
Has someone compared different NJM/JRC like JRC4565 , JRC4580 or JRC2068?
Is there any difference if I connect one from + to - or have there to be two, one from + to ground and another from - to ground?
And can someone recommend me an opamp that has good soundstage?
I already tried the LME49720 but the stage is only distant with no good different levels of depth.
I haven't broken in the LME49720. Does it improve over time?
Has someone compared different NJM/JRC like JRC4565 , JRC4580 or JRC2068?
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