avr300 said:
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
Re: Re: Re: Re: Re: Discrete output
I hope this does not get worse with the discrete outputs
It surely would be better to be able to Crank it up and hear no noise.....
Ricardo
Thank you Brent...rowemeister said:
avr300 said:
I hope this does not get worse with the discrete outputs
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.SimontY said:
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
It surely would be better to be able to Crank it up and hear no noise.....
Ricardo
Re: Re: Re: Re: Re: Re: Discrete output
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
RCruz said:
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
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...
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...
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
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
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...
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...
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
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
Thank you Brentrowemeister said:
I will build this muting circuit and report the changes.
Another question.... I have been studying Ray´s discrete output and comparing with yours, I see there are some differences (yours have two aditional diodes and less one transistor)...
Can you please explain the differences ?
Regards
Ricardo
Re: Re: Discrete Output Stage
I am now starting to build the discrete output following your indications.
Lee is providing the PCB and the parts so that is already sorted for me.
During all the time since I started modding my CD53, I always tried to understand the correlation between all the CDP components and after a lot of study, I am now able to follow this thread without major doubts.
All my mods where done after I fully understood what I was going to do so I always new what to expect.
Untill now, I did not modify any basic design of the CDP (My mods consist on several psu´s, loads of new better caps, some spowers and brent´s clocks)
Now, with this discrete output, the problem is I do not understand the schematic (I am not an electronic wizz... and I do not know enough about solid state amplification).
I have been reading a lot but I really need a push in the right direction.
Would you please explain the basics of your design...?
The only thing I know is it´s a class A type of amp but.....
Regards
Ricardo
Hi Ray6h5c said:
That's a decent player for a D.O.S.! Great to hear that it works so well. But, fair is fair, some credit must go to Remco Stoutjesdijk for setting up the initial circuit. I just shaped it into what it is now, and designed the passive filter. I'm not Einstein, i'm a lazy guy
I am now starting to build the discrete output following your indications.
Lee is providing the PCB and the parts so that is already sorted for me.
During all the time since I started modding my CD53, I always tried to understand the correlation between all the CDP components and after a lot of study, I am now able to follow this thread without major doubts.
All my mods where done after I fully understood what I was going to do so I always new what to expect.
Untill now, I did not modify any basic design of the CDP (My mods consist on several psu´s, loads of new better caps, some spowers and brent´s clocks)
Now, with this discrete output, the problem is I do not understand the schematic (I am not an electronic wizz... and I do not know enough about solid state amplification).
I have been reading a lot but I really need a push in the right direction.
Would you please explain the basics of your design...?
The only thing I know is it´s a class A type of amp but.....
Regards
Ricardo
The input stage is a long tailed pair, two transistors in a differential setup with a current source in the 'tail'. This circuit sums the two signals from the DAC, fed to the circuit through the passive filters on the input (actually it subtracts them, but the input signals are inverted w.r.t. each other).
The second stage of the circuit is nothing more than an emitter-follower that buffers the output of the first stage, so it is not loaded too much. That's basically it!
Regards,
Ray
The second stage of the circuit is nothing more than an emitter-follower that buffers the output of the first stage, so it is not loaded too much. That's basically it!
Regards,
Ray
Indeed, T5 is the output transistor in class-A (T1 and T2 are operating in class-A also btw.). T3 and T4 form the mentioned current source.
There is no global feedback (from the output directly back to the input), but the circuit used current feedback in the form of the emitter resistors of T1 and T2, R7 and R8. They set the gain of the circuit.
Ray
There is no global feedback (from the output directly back to the input), but the circuit used current feedback in the form of the emitter resistors of T1 and T2, R7 and R8. They set the gain of the circuit.
Ray
Now I understand where the current source is.... This current is than transformed in voltage variation by the output transistor right ?6h5c said:
How is the bias set in the output transistor ? Is this affected by the psu voltage ?
Can the gain be altered so the output of the CDP is not so high?
Ricardo
Yep, the current is modulated by the audio-signal that is fed to the two transistors and 'transformed' into a voltage swing by the 4k7 collector resistors.
The bias of the output transistor is set by the 1k8 resistor and the voltage at it's base. So it also depends on the voltage-drop across the 4k7 resistor. And yes, it is highly affected by the supply voltage. That's the drawback of this circuit....
But it keeps everything nice and simple, without coupling caps.
Gain: see previous post.
Ray
The bias of the output transistor is set by the 1k8 resistor and the voltage at it's base. So it also depends on the voltage-drop across the 4k7 resistor. And yes, it is highly affected by the supply voltage
. That's the drawback of this circuit....But it keeps everything nice and simple, without coupling caps.
Gain: see previous post.
Ray
Hi guys!
Hope you're well!
So I just wanna give my POV about sound & noise, fisrt I wanna know where and what is our CDP's noise, when you fuly turn the amp with no sound or such?
My aim was to get a good CDP for cheap, I was longing for a Naim CD5i but seems my CD53 can face it now.
And with the first mods things got much better but as drawback sometime some side were down, e.g. bass were gone at some points of the mods.
Right now I'm a bit shy with going on for I really enjoy the music now, singing and involving my body in the listening times. That was not the case at all the mods.
Maybe you've gone that far that your matched amps, preamps and speakers that you are still anoyed with some flaws?
I'm not, rember I listen with my Quad 11L, and they annoy me as they have a so tiny bass.
(In fact at the OEM player they got some, very round, very artificial but there, I can even here them with my Grado SR80... and now they seems more strong but at their real frenquency that my 11L show them far away, sometimes lower in freq. and these wich were there in my headphones... are simply gone! Dead silent! I think they are not that ball of **** in low ferq but in very low and just being what they are).
So, what's that noise story, I enjoy my player, just wanna understand, I just think this is a matter of overall system setup.
E.g. for lost bass is Kena "Wide Awake Man", when the corus and title then have a big beat deap bass, feel it very low and powerfull if not loud on the Quad, get just nothing at my Grados!
Matthieu upset by the TV and news (my wife is chinese... OMG...)
edit: sorry for my poor english and my lazyness to read and correct it...
Hope you're well!
So I just wanna give my POV about sound & noise, fisrt I wanna know where and what is our CDP's noise, when you fuly turn the amp with no sound or such?
My aim was to get a good CDP for cheap, I was longing for a Naim CD5i but seems my CD53 can face it now.
And with the first mods things got much better but as drawback sometime some side were down, e.g. bass were gone at some points of the mods.
Right now I'm a bit shy with going on for I really enjoy the music now, singing and involving my body in the listening times. That was not the case at all the mods.
Maybe you've gone that far that your matched amps, preamps and speakers that you are still anoyed with some flaws?
I'm not, rember I listen with my Quad 11L, and they annoy me as they have a so tiny bass.
(In fact at the OEM player they got some, very round, very artificial but there, I can even here them with my Grado SR80... and now they seems more strong but at their real frenquency that my 11L show them far away, sometimes lower in freq. and these wich were there in my headphones... are simply gone! Dead silent! I think they are not that ball of **** in low ferq but in very low and just being what they are).
So, what's that noise story, I enjoy my player, just wanna understand, I just think this is a matter of overall system setup.
E.g. for lost bass is Kena "Wide Awake Man", when the corus and title then have a big beat deap bass, feel it very low and powerfull if not loud on the Quad, get just nothing at my Grados!
Matthieu upset by the TV and news (my wife is chinese... OMG...)
edit: sorry for my poor english and my lazyness to read and correct it...