Marantz CDA94

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#2
What a classic... Excellent CD player!

It uses two 1541. I modified one 6 months ago with great results – haven’t heard anything better for less than 5 - $6000. Haven't got diagram though, but could help you with advice...

Cheers,
Extreme_Boky
 
#3
Hi Boky. IT is a DAC, not the Cd player. I opened it, but i found only one TDA1541A..is possible.? Wich kind of work u did on it? CAn u help me?
Click to expand...

I was referring to CD94, sorry.

I am not familiar with your DAC. However, here's the list of modifications I did to Marantz CD94 CD player:
Replaced power supply + local decoupling capacitors with my favourites - 2200uF / 35V FK and 0.1uF / 50 NX Black Gates.
Installed IEC power connector at the back (silver and then gold plated pins.)
Replaced RCA connectors with high quality types.
Removed back-to-back output signal coupling caps with AURI cap 4.7uF / 200V types.
Used silver ribbon cables everywhere... got rid of connectors.
Used WIMA green-cap polypropylene caps for analogue filtering.
Replaced the xtal with 11.2MHz LC clock with dedicated power supply (with 10 X 470uF / 16V KF Black Gates + two 0.1uF / 50V NX types). Removed the original cap supplied with the clock (4700uF / 25V, I think...)
Replaced 6 dual ICs with AD8066, AD826 and OP275 in analogue stage.
Replaced two focus / tracking ICs with NE5532AN.
Removed in-series-resistors from the power supply rails and installed ferrite beads.
(I spent a lot of time getting the CD cradle to run smoothly!)

I loved doing this mod, the result was outstanding. This CD player was an excellent sounding CD player even before modifications.

Cheers,

Extreme_Boky
 
#6
Hi,

According to the old brochure, the CDA94 has only one TDA dac,
only the CD94mk2 CD player has two. Not much else info given:

32/33/48 kHz samplefreq accepted at inputs. 3 separate powersupplies, each with it's own transformer, 3 dig inputs, 3 outputs as you probably have seen already.

DAC is one TDA 1541A S1, filter the 7220B and my guess is a philips dig input receiver before that (?). 11kg weight...😱

Same brochure has CD12 set, CD94mk2, CD80, CD60....
Those were the days..😀
 
#7
oops...

Hello;

YES, guido is absolutely right, there is only ONE TDA 1541, and it is device no. Q521 on the DAC board. After looking twice I recognized there is a fault in the original schematic (wrong number in the parts index list) :xeye: . Sorry.... it is long ago since I had such a device on the bench... rather "old-school" design, but quite well-done...
@maurizio, YES, I do have a schematic, but I do not have a scanner at the moment, if you specify what information you need I will sort that out.

regards;

audiomatic
 
#8
about schematics

Thanks all for the help.

I will like to have schematics to improve that CDA94. I was thinking to change the decoupling caps on TDA1541A, with Audyn Cap Plus caps; and to replace the TDA1541A with the Silwer Crown version.


Thanks,

Maurizio.
 
#9
Changing the mains lead for a much thicker one will have far more effect of the sound quality that changing the DAC to an S1. And cost nearly nothing.

Changing the transformer for something like a 300VA is often very different too.

Strapping just one Black Gate across the +5V main reservoir cap will make a big improvement. I originally used a 1000@16, or thereabouts. Now I have an outboard supply dedicated for the +5, with a split feed, one for the 7220B and Xtal, and the other for the rest of the machine. This PSU at the moment uses a very large Tx and 10,000 mic of Elna Stargets, but I normally use 20,000 mic of Nichicon Muse KZ. There is a discrete regultor and then 5 x 100@25 black gates and 2 x 470@16 OsCons.

A decent Xtal reclocking module will make a big difference. Clean treble, big tight bass, good imagery and focus. The effect varies somewhat with different companies products. I use our own simple design. We found it better than the others we tried that cost very much more. But probably anything is better than the original Philips. Ours has it's own discrete regulator fed from the main outboard +5 supply.

I have an outboard supply for the anaolgue stage too. 30,000 microfarads on this.

Best is to get rid of the DC blocking caps completely, but that means making your own DC cancelling modification.

Putting some sockets where the 4 output chips go (or 6 with the CD12) will allow you to try many different chips as they all sound different. I currently use AD847 for the I/V converter and AD797 for the 2nd one. I've tried very many over the 10 years of tweeking this type of player. We also use BUF04 in the 2nd posn and AD847. I liked the BB OP132 but they discontinued them.

It takes a long time to get rid of the connectors and hard wire the insides of these players. It can be quicker to just make outboard supplies and wire straight to the right places.

Oh, and changing all the caps around the DAC for better PolyProp ones is one of the first things you should do. Though this can be difficult to achieve due to their size. I've used Black Gate 0.1 mic NX HiQ. They sounded OK but warm and a little fuzzy. The polyprops were cleaner sounding. Naim used the polyester multilayer caps in their CD3.
 
#10
Hi Ian,

I get AURI caps from soundlabsgroup here in Sydney. The web site for AURIcaps: http://www.audience-av.com/passive.htm. They are better than WIMA polypropylene MKP4 and MKP10, and better than any Black Gates I tried for signal coupling. Price around A$30 - A$40 each (4.7uF/200V).

I get silver ribbons from a friend who makes Hi-End cables. They are probably sourced from jewellers' shops. I also get coper solid core silver-and then- gold-plated cables which are excellent for power cables. Silver ribbons are 4mm X 0.3mm, or 6mm X 0.5mm for high current internal wirings. They are annealed - the "raw" silver sounds a bit harsh.

I can tell that you are quite into mods... It usually takes some time (10 years?) to get to the point where you know what to use where and how much of it to obtain desirable results.

My experience with Black Gates 0.1 / 50V NX is a bit different from yours because I use them together with the ferrite beads. Used alone they produce the sound you described. I use two ferrite beads one after the other on a single solid core pure silver wire. One bead is for "up to around" 10MHz - low frequencies, and the other (second bead) is for frequencies up to around 300MHz - high frequencies. There are usually coper links that feed the power supply current to IC - I remove those and install the ferrite beads followed with 0.1uF / 50V NX. I also remove all other local decoupling capacitors and use 0.1uF NX on its own. This mod helps me in obtaining holographic soundstage, very wide and very high as well. Definition improves as well. The frequency spectrum gets better defined and the quiet gets quitter (dark gets darker).

Regards,
Extreme_Boky
 
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