Philips CD951 • A DAC7 (TDA1547) vs TDA1541A R1 vs SM5872 story

[Markuzz]

Originally Posted by Malefoda

Fixed!
Stupid at iron... I've seen a small cap at 2107... 2.2µF not for supply, changed it for a 470/35 back to 2.2 it works just fine! Will change this to film.
Now I'll have an ear but with cheap non polar lytics at dc blocking (and MKS to bypass them, won't be worst...).

Thank for support Mark

No worries mate

I'll be doing some mods in the coming days..... keep you posted.

[Malefoda]

How is your analog stage right now?

[Markuzz]

Originally Posted by Malefoda

How is your analog stage right now?

The analog stage is currently standard, thus the 5532 opamps in the CD951. 5534 in the Marantz if I am correct. I am a little in doubt wether to go for the lampizator stage or upgraded opamps.

Obviously the lampizator can be used in both players enabeling a really good comparison of the sound and quality of the player. However I have no experience with tube buffer amps and need a very detailed description in order to make a good one.

Upgrading to (for instance) Burr Brown 2904's is another option, companied with nice parralleling caps etc. Low cost, simple and often with interesting results.

Any recommendations from your side?

Cheers, Mark.

[Kurt von Kubik]

Regarding op-amps, I really do not like any of them, but when experimenting with them, I´ve always ended up with 5534 and 5532 which often are the originals.
They have very low noise and very good current delivery, all the rest is pretty ordinary, but told to be sufficient, and most important to me, they are bipolar.
They are through their lifetime modified and developed further, so you might find newer ones sounding different. Btw. they are used in almost all pro audio gear and also Accuphase use them in their high end players @ only 8V.

Carefull decoupling is a sport that can provide substantial improvements. Try polyphenylene sulfid capacitors from i.e. Evox or Wima. They are exellent for that purpose, and also deliver very good sound quality, when used for feedback caps also.
The Evox is called SMR and comes in 5mm packages and up.

[Malefoda]

My first player, the CD-53 is waiting for its Discrete Output Stage back, as seen on Ray's website http://www.raylectronics.nl/ it's just more neutral, more fluid than any opamp I've tried in this one. I also want to avoid opamps and also want to have the best decoupling work and these PPS are recommended very often, thanks for the Evox tip.

The CD951 will also get one, the problem being the internal opamp doing the I/V thing and the buffer for the switched capacitors. I may use the DOS after the DAC opamps, as it's balanced voltage output or not by reuising the former PCB traces of the output ones to use better opamps. Maybe LME49720HA, maybe other solutions if possible as I've found 2 cases wich seams to load the switched capacitors network without buffer.
Right now the LM4562 does a good neutral job but I can't tell much as the output caps are still OEM. If I were to keep the opamp circuit I would change tiny regulators and even smaller caps after.

And the CD-40 (wich is a CD-50 without a daughter board that's it?) is planned to be fitted with AD8620 or another fast IC like AD8066. I don't know what cheap option is avalaible for an non-opamp output.

But I agree with you, such "I have to choose" game is complicated, how to know if the work done and still to be done is the same? Some enjoy modding just for modding, I like it but just to choose, when done it's over for me! I'm scared my heavily modded CD-53 is "better" than other right now because it's recloked 2 times and has no opamp but only DOS and top output caps combo... and what about price? I've not planned to loose money in trying, at least get my money back on modded players and why not make money... that's all but uncertain...

[Markuzz]

Originally Posted by Kurt von Kubik

Regarding op-amps, I really do not like any of them, but when experimenting with them, I´ve always ended up with 5534 and 5532 which often are the originals.
They have very low noise and very good current delivery, all the rest is pretty ordinary, but told to be sufficient, and most important to me, they are bipolar.
They are through their lifetime modified and developed further, so you might find newer ones sounding different. Btw. they are used in almost all pro audio gear and also Accuphase use them in their high end players @ only 8V.

Carefull decoupling is a sport that can provide substantial improvements. Try polyphenylene sulfid capacitors from i.e. Evox or Wima. They are exellent for that purpose, and also deliver very good sound quality, when used for feedback caps also.
The Evox is called SMR and comes in 5mm packages and up.

Hi Kurt,

What do you recommend for an analogue stage?

Cheers,

Mark.

[Markuzz]

Originally Posted by Malefoda

My first player, the CD-53 is waiting for its Discrete Output Stage back, as seen on Ray's website http://www.raylectronics.nl/ it's just more neutral, more fluid than any opamp I've tried in this one. I also want to avoid opamps and also want to have the best decoupling work and these PPS are recommended very often, thanks for the Evox tip.

The CD951 will also get one, the problem being the internal opamp doing the I/V thing and the buffer for the switched capacitors. I may use the DOS after the DAC opamps, as it's balanced voltage output or not by reuising the former PCB traces of the output ones to use better opamps. Maybe LME49720HA, maybe other solutions if possible as I've found 2 cases wich seams to load the switched capacitors network without buffer.
Right now the LM4562 does a good neutral job but I can't tell much as the output caps are still OEM. If I were to keep the opamp circuit I would change tiny regulators and even smaller caps after.

And the CD-40 (wich is a CD-50 without a daughter board that's it?) is planned to be fitted with AD8620 or another fast IC like AD8066. I don't know what cheap option is avalaible for an non-opamp output.

But I agree with you, such "I have to choose" game is complicated, how to know if the work done and still to be done is the same? Some enjoy modding just for modding, I like it but just to choose, when done it's over for me! I'm scared my heavily modded CD-53 is "better" than other right now because it's recloked 2 times and has no opamp but only DOS and top output caps combo... and what about price? I've not planned to loose money in trying, at least get my money back on modded players and why not make money... that's all but uncertain...

What about the Discrete Output Stage back, as seen on Ray's site for the CD50? I mean, why do you plan it for the 53 and not the 50?

[Malefoda]

That won't work with the CD50, it's an unbalanced DAC output and the DOS is meant for balanced.
It will anyway work fine with our CD951, evein if right now I don't know if filter has to be recalculated and parts values changed. In worst case I'll keep the DAC internal opamp and get rid of external analog stage in the CD951.
You also may get a DOS PCB from Ray if you plan to do it, check this link to its post about it:
Marantz CD63 & CD67 mods list
I'll report soon, maybe in few days if filter is ok as in the CD53 =) (my CD53 ones are out waiting for BlackGates )

[Kurt von Kubik]

Originally Posted by Markuzz

Hi Kurt,

What do you recommend for an analogue stage?

Cheers,

Mark.

If one have the option of choosing one self, I´d recommend a discrete design.
And to me that means NFB design, DC coupling, carefull filtration, low output impedance, high current capabillity, very low noise supplies and so on.
But this is hardly obtainable these days, almost only very expensive high end products feature this kind of design.
But next to that, I´d go for bipolar op-amps, and be very carefull about choise of surrounding components and supplies.

[Malefoda]

I have the CD651 SM in paper, the CD950's one in pdf if needed.

So we have a dicrete circuit for the TDA1547 and have to find one for the TDA1541. I remember Simon used a (Nelson?) Pass I/V stage or something in his CD650?