Marantz CD63 & CD67 mods list

[Fidelity Audio]

Originally posted by RCruz


Hi Brent

I can hear the hiss if I turn the volume up without any CD playing.

Should a 470uF BG STD after each spower remedy this small issue ?

Regards

Ricardo

Hi Ricardo

With the opamps the hiss will not be coming from the SPowers (+ your SPowers are fitted with the 100n feedback cap to eliminate any noise on a discrete). I wouls check elsewhere for pick up.

Brent

[avr300]

Remember, Ricardo, you're running the CDP without the muting transistors (right?). I think what you're hearing it's digital garbage from the DAC.

[SimontY]

Originally posted by avr300
Remember, Ricardo, you're running the CDP without the muting transistors (right?). I think what you're hearing it's digital garbage from the DAC.

Tis a good point! There's plenty of noise to hear on mine and even on Brent's mighty machine - if you get the volume CRANKED. I find I never much hear it when I shouldn't though, and I sit VERY close to my speakers in this room.

Simon

ps. I'm eating some delicious rhubarb with clotted cream vanilla ice cream and hearing Clapton sound as fresh and sparkly as I've heard him

[RCruz]

Originally posted by rowemeister


Hi Ricardo

With the opamps the hiss will not be coming from the SPowers (+ your SPowers are fitted with the 100n feedback cap to eliminate any noise on a discrete). I wouls check elsewhere for pick up.

Thank you Brent...

Originally posted by avr300
Remember, Ricardo, you're running the CDP without the muting transistors (right?). I think what you're hearing it's digital garbage from the DAC.

I hope this does not get worse with the discrete outputs

Originally posted by SimontY


Tis a good point! There's plenty of noise to hear on mine and even on Brent's mighty machine - if you get the volume CRANKED. I find I never much hear it when I shouldn't though, and I sit VERY close to my speakers in this room.

Simon

ps. I'm eating some delicious rhubarb with clotted cream vanilla ice cream and hearing Clapton sound as fresh and sparkly as I've heard him

I Agree with you... after some 2004 wine I only hear the music... Nevertheless I am glad I reported it.... I am sure there will be a solution soon.

It surely would be better to be able to Crank it up and hear no noise.....

Ricardo

[SimontY]

Originally posted by RCruz
It surely would be better to be able to Crank it up and hear no noise.....

Indeed it would, but is that actually technically possible? And to be honest, most CDs have lots of background noise that when modified enough is very, very audible in the quiet sections.

Some modern CDs have very little but that's because they use nasty digital noise filters (they'll cut all output below, say, -40dB, I think it's called a noise gate). Can't be good for the music.

Simon

[martin clark]

BUt it's also down to the DAC architecture. Bitstream devices are noise-generators; it varies with precise implementation, but essentially over 50% of the energy the things put out is wideband noise above the audiospectrum. It's a direct result of the way the things work, and 'noisehaping'...

Dealing with that kind of crud properly (ie without intermod issues) is very, very hard, and the only reason you see spectacular S:N figures on some datasheets is down to 20 or 30Khz 6+ pole lowpass filters in the measurements...Take a look at the datasheet of many bitstream dacs and get a lurch upwards in the noisefloor above the audioband. The NPC dac in eth 63 is pretty poor for this, it must be said. A better solution is to use several bit levels, hence the so-called 'hybrid / multibit' bistream dacs around these days. Still not great, though.

One reason I think some like the old multi-bit devices is because they are genuninely quite, out-of band; even the old TDA1541 manages a creditable -110dB S:N ratio here...

[SimontY]

Martin,

Would you say the architecture of the NPC DAC is why the CD63 sounds a bit "ragged" or "enthusiastic"?

Compare this to, say, an SACD player, or a player based on a TDA1541, both of which can sound very "relaxed" or "easygoing" by comparison, if dynamically less engaging (less attack and sense of timing).

It takes many clean, separate power rails to make the CD63 not sound messy, but mine finally sounds extremely clean. I wonder how this observation is relevant to the nature of the DAC chip used.

Thanks,
Simon

[martin clark]

I'm not sure one can make any such generalisation; it's all down to the fine details of implementation - and what moves you when you listen> which is why we're all here, chasing after some illusory personal take.

Funnily enough one of the reasons I stopped playing with the CD63 was because it ended sounding very boring once sufficiently worked-over; it's actually not particularly dynamic IMO, and funnily enough my current squeeze is based on a 1541S1 and I haven't heard anything I'd swap it for on that front. Weird stuff, this audio lark...

[RCruz]

Well... after all I believe the noise is unavoidable.

Does the discrete output make things easier ?

Ricardo

[Fidelity Audio]

Hi Ricardo

The discrete makes everything better full stop, it will not make the hissing any better or worse to be honest though, don't worry.

You should fit relay muting to the output so that no noises are present during stop or pause mode (even between tracks it will mute).

There is a simple muting cct on page 6 (or is it page 8) of my cd upgrade pdf. http://www.audioupgrades.co.uk/system.shtml

Brent