Tda1547 + Sm5803 + Hef4750 Studer

[cdfr]

Hi,

Trying to see if improvements can be made to a Studer D730. For instance I am wondering if clock signal could be improved.

Would anybody have the Studer D730 Service Manual?

The set of chips in the D730 are:
Xtal 11.2896 + Philips HEF4750UD (wondeing if this chips helps regarding jitter).
Digital filter: NPC SM5803APT
DAC: TDA1547
Analogue section: 7x 5532 and output trasformers.

cd

[mb]

I've found the TDA1547 very responsive to improvements in power supply. Almost every improvement to supply (eg. good film bypass cap, Ocson for digital supply cap, etc) is rewarded with improvement in sound. So my experience is that op2134 and lm6172 work well with the dac. Even with improved power supply for the opamps, the ne5532 just doesn't deliver the transparency available from the 1547 output.

[Guido Tent]

Originally posted by cdfr
Hi,

Trying to see if improvements can be made to a Studer D730. For instance I am wondering if clock signal could be improved.

Would anybody have the Studer D730 Service Manual?

The set of chips in the D730 are:
Xtal 11.2896 + Philips HEF4750UD (wondeing if this chips helps regarding jitter).
Digital filter: NPC SM5803APT
DAC: TDA1547
Analogue section: 7x 5532 and output trasformers.

cd

Hi

The 4750 is a sampling phase comparator, which potentially works very good, but finally the jitter depends on the oscillator structure and power supply.

The 1547 reacts very positively on a real low jitter clock at the inputs pin 5 an pin 28.

Studer generally makes well designed equipment, not always most audiophile though

best regards

[cdfr]

Indeed in general Studer products are well build. You can sse here if you are curious the Power/DAC/Analog board.

It seems that there are two paths possible to follow:
1) OP amp changes 5532 to AD825 or BB2134 or 2132. Probably best to add sockets to make trials.

2) Replacing crystal by higher quality low jitter clock. Would you have a recommendation or a schematic?

and third path would be caps upgrade, I am assuming though those would have less effect than first 2.

Thanks,

cd

[Guido Tent]

Originally posted by cdfr
Indeed in general Studer products are well build. You can sse here if you are curious the Power/DAC/Analog board.

It seems that there are two paths possible to follow:
1) OP amp changes 5532 to AD825 or BB2134 or 2132. Probably best to add sockets to make trials.

2) Replacing crystal by higher quality low jitter clock. Would you have a recommendation or a schematic?

and third path would be caps upgrade, I am assuming though those would have less effect than first 2.

Thanks,

cd

Hi

I assume this player can also run at external wordclock (Hence the 4750). If you want to upgrade the clock, it is best to have schematics avalable as you may want to chose to exclude the external wordclock operation (simple upgrade).

There's 2 decent DIY clock solutions on the market that I am aware of, the Kwak clock and my own (TentLabs).

cheers

[cdfr]

Thanks Guido.
Indeed it has a world clock input, but I don't understand how if unused it would affect the internal clock signal? Is the clock poluted by EMI?

I have not posted a reply in while because I am searching for the service manual (it has the schematics). I have not been able to find one at a reasonnable price yet.
Studer sells one but the pages must be gold platted for the price


cd

[Alien8]

Hi Cdfr

conserning analogue stages, have you thought about bypassing the on-chip I/V opamps ?
My understanding is that they resemble NE5532 types.

My idea is this (TDA1547 in CD950 philips) : see pdf.
First page 'resembles' the situation in my player now. (which I used to simulate)
Second page is my attempt to produce something simpler and hopefully audibly a lot better.
PSU changes are not included there.
Don't mind the current sources for the inputs, these are guessed on the basis of some measurements.

the only problem are the on-chip opamps which are internally connected to the outputs of the dac itself (cfr. datasheet)

Oh, and PSU upgrades indeed do matter a lot, as does guido's clock.

Any thoughts ?

A8

edit : first page included here (schema2.pdf)

[Alien8]

new schematic
(schema.pdf)

[Gasho]

I have a Studer D731 which is a same player like D730 in rack-mount version. Yours is desktop.

This players are made to play silver discs in most natural way.

It have almost no jitter becouse of special system that adapt clock to one recorded on every disc (every cd is not the same in racorded clock)

Power supplyes in Studer are tuned for most natural sound.

I like to tweak players, and I belive that even the best "audiophile" machines can be tweaked to work better, but this Studer remain untouched by my hand becouse it yust plays natural music.

Even audiophile power chords don´t work on this playe. It work best with standard computer (3X2,5 square mm) IEC cable.

Regards.

P.S. Studer need very well balanced audio system becouse it don´t have some strong caracter of it´s own, and every disbalance in system will be heard like bright or warm sound.

[analog_sa]

Originally posted by Gasho

This players are made to play silver discs in most natural way.

Hmmm. Perceptions do vary. I used to have a D732 which soundwise was amazingly unremarkable. So much so i didn't even consider modding it. It already had green LEDs shining over the cd anyway