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Marantz CDA-94

Heavyweight Digital to Analogue Converter (1989-90)

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Marantz CDA-94


The CDA94 is the worlds first digital to analogue converter with multisampling, for conversion of Compact Disc, DAT digital audio tape and Broadcast Satellite signals with 16-bit 4 times oversampling accuracy, and with high precision analogue circuitry.

The high performance of the digital filter and twin 16-bit D/A converter are further accentuated by optical coupling between the digital filter and the D/A converter, by high precision analogue filter and by L/R independent amplifier circuits.


Digital converter: 16-bit, 4 x oversampling

Digital Inputs: Coaxial, Optical

Sampling Frequency: 32, 44, 48kHz

Frequency response: 2Hz to 20kHz

Dynamic range: 96dB

Signal to Noise Ratio: 101dB

Channel separation: 90dB

Total harmonic distortion: 0.0015%

Line output: 2V (unbalanced), 2V (balanced)

Dimensions: 462 x 87 x 333mm

Weight: 11kg


brochure   English -

service manual   English -

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Thanks for your reply re the failed transformer, sorry to be a year in getting back. Events here have caused a distraction, only just got around to looking at the problems again.

Indeed a 15-0-15 volt toroid did the job, fits nicely in the space of the original transformer, mounted with a nylon bolt through the centre (MUST NOT BE METAL) into the base plate.

I have not attempted changing any capacitors, I really cannot see any advantage while the existing ones are performing faultlessly, however I do know that there are subtle differences when using these hi-end, hi-spec caps in some CD player audio circuits.

My main use for the CDA-94 is as a audio distribution hub, connecting both coaxial digital devices, and optical output players to a balanced analogue buss. this is does excellently.

The unit is still working faultlessly a year or more later, leave well alone I say.


Marantz CDA-94 D-A + optical converter

Does anyone have a circuit diagram or service manual for this Converter
mine has a failed power transformer, I just need to know the raw AC voltage of the output windings.

I did some more research, some trial and error with different transformers all protected with secondary limiter resistors. The 15v-0-15v toroidal type of transformer at a current rating of 2A seems to provide stable voltages that are well within the capacitor ratings on the boards, the proof of the concept is the fact that the machine functions perfectly now with no hum, or noises audible at full volume, which is about as technical as I can get with my own test equipment. The selected transformer fits in the space of the original, with some minor modifications to the mounting, it does NOT have the original Mu-metal screen, this does not seem to cause any problems with its operation.
Magnus71 (August 2009)

Failed CDA-94 transformer

Hi Magnus71,

Mine failed recently as well - the toroidal which powers the PCB with the TDA chip.

I replaced it with a 12V unit from Farnell and seems to be working fine on my CDA-94.

Has no hums or anything of that sort - dead silent.

Please note on my unit I have replaced most of the original capacitors (film and electrolytic) with higher quality equivalents on the PCB(s) of same values where possible e.g Wima, OSCON, Elna, Panasonic FC(s).

Worth the effort and every penny spent!!!

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