Tube CD Player???

[Dr Tinear]

Yeah, I know you say so.

But I disagree.
Belt drive is contributing the a lesser harsh sound in CDP's.
IMHO.

"dolph"

Sigh. This is what too often happens when people don't know enough about the technology to distinguish substance from snake oil.

For starters, CD is a constant linear velocity playback system, not constant angular velocity like the LP. A CD spins at about 500 RPM near inner radius (where the encoded signal starts) and slows down to about 200 RPM at the outer recorded radius on a full disc. The virtue of constant speed that a good belt-drive system brings to LP playback isn't needed or wanted in the CD system.

Next, the laser read system that extracts the EFM signal from the pits on the CD and sends it to the data separator for ECC (error-correcting code) recovery, de-interleaving and conversion to NRZ data doesn't care what mechanism spins the disc. It's simply looking for transitions from pit to land on the disc. If a disc drive maker wanted to design an idler drive system for a CD player, there's no reason he couldn't do it ... but why bother when a direct-drive spindle motor is cheap, compact and effective?

Finally, CD data is timed to a master clock that virtually eliminates jitter at the D/A converter if it's implemented properly. A buffer memory stores the data from the data separator. A stable master clock times data retrieval from the buffer and is an input to the servo system that controls spindle motor speed. This architecture ensures that any minor speed errors at the spindle motor are not translated into timing errors at an internal DAC's word clock pin or on the S/PDIF data signal to an external DAC.

To sum up, belt-drive CD transports and players may sound different from conventional transports and players, but the difference is almost certainly NOT due to the drive system. In a transport, I'd look to the clock circuitry or the S/PDIF circuit implementation as more likely causes for sonic differences, or to a listener hearing things that aren't there because he or she expects to hear a difference.

 

[niklasthedol]

Sigh. This is what too often happens when people don't know enough about the technology to distinguish substance from snake oil.

After reading this first sentence of your post, I didn't even care to read the rest.
It just left me back thinking: "So he thinks he's a smart guy."

Thanks for making my day.
I had a great laugh after this.
;-)

"dolph"

 

[robobxman]

After reading this first sentence of your post, I didn't even care to read the rest.
It just left me back thinking: "So he thinks he's a smart guy."

Thanks for making my day.
I had a great laugh after this.
;-)

"dolph"

Yeah, but he backed it up with substance. Thanks for the lesson Dr Tinear - I knew I'd learn something today.

 

[chadnliz]

Yeah, I know you say so.

But I disagree.
Belt drive is contributing the a lesser harsh sound in CDP's.
IMHO.

"dolph"

If you atill think so after all this, dont walk too far to the edge of thw earth, (its flat you know).

 

[niklasthedol]

If you atill think so after all this, dont walk too far to the edge of thw earth, (its flat you know).

If You really think so after all this; If you ever happen to get traumatized from listening to your digital gear, don't urge to get psycologist therapy (Just use your mathematic skills to analyse your subconsciousness and mental state).

"dolph"

 

[niklasthedol]

If you atill think so after all this, dont walk too far to the edge of thw earth, (its flat you know).

Oh, and by the way................
As a navigating officer in the merchant navy, I can reveal for you that Earth is not flat.

It's not really round either.

So maybe you'll need a bit more and different math and science to find your way than what you allready believe you have.

"dolph"

 

[cwall99]

I think Dr Tinear's point is that there are systems in a CDP or transport that separate the bits being delivered to the DAC from any sort of errors induced by the transport mechanism.

CDPs are designed so that with these systems in place, it doesn't matter if you have direct drive, belt drive, or hamsters in a wheel: it's impossible to hear the drive system reflected in the audio signal sent from the DAC (wherever it may be: in the CDP, on an outboard DAC, in your pre/pro, in your receiver) to the amplifier.

But, if you do believe that you can hear the transport mechanism of your CDP in the audio you hear through your speakers, I have a bridge you may be interested in. Or some speaker wire stands.

 

[niklasthedol]

I think Dr Tinear's point is that there are systems in a CDP or transport that separate the bits being delivered to the DAC from any sort of errors induced by the transport mechanism.

CDPs are designed so that with these systems in place, it doesn't matter if you have direct drive, belt drive, or hamsters in a wheel: it's impossible to hear the drive system reflected in the audio signal sent from the DAC (wherever it may be: in the CDP, on an outboard DAC, in your pre/pro, in your receiver) to the amplifier.

But, if you do believe that you can hear the transport mechanism of your CDP in the audio you hear through your speakers, I have a bridge you may be interested in. Or some speaker wire stands.

I'm aware of his, yours and others POV.
But I disagree.

This is not only about speed correction.
This is also about DD noise transplanted into components like capasitors etc.

Do this test:
Play music with your CD's cabinet open (or amplifiers cabinet or whatever is active in the listening chain) in the room next to your speakers.
Make someone knock gently on the circuit board with something rigid, like a pen or screwdriver or similar.

Detect if it's audible in what you speakers present for you.
This test will convince you that mechanical noise can be transmittet through circuit boards and components. (If you didn't already know that)

The drive of TT's, Tape decks and CDP's are equally prone to transmitting the bad noise from DD mechanisms through circuit boards and components.

Why do you think the best TT's are belt driven when it takes more effort (and money) to get a belt drive run W/F less.

So much for Dr. Tinear or anyone else who, blindly, are disciples of dead-end superstring hypotheses.

"dolph"

 

[Dr Tinear]

Give it up, guys. It appears that Dolph is unwilling to consider the facts of CD player design because they conflict with the dogma that he's bought into. It's much easier to fall back on faith and the unsupported opinions of "authorities" in the subjective review press than to take the time and effort to learn about technology. This diversion on belt-drive CD transports is going nowhere, so let's drop it and get back to the original topic of CD players with tubed output stages.

In reading this thread, I saw several insightful comments including one that recommended following a current-output DAC with a resistor to do the I/V conversion and a tube buffer to gain the converted signal up and provide a suitably low output impedance. This idea is good, but misses one critical piece of the puzzle. The signal spectrum at the DAC's output includes the baseband signal (DC to half the sampling frequency) plus images of the baseband signal centered on multiples of the sampling frequency. If the DAC oversamples, the image energy is at multiples of the oversampling frequency (176.4 kHz for the old Philips 16-bit chip sets and others that ran at 4x). This energy needs to be filtered out before the signal leaves the CD player's chassis, otherwise it can overdrive wideband line stages or amps downstream and cause audible distortion. A CD player with an op amp output stage would typically do the filtering in that stage. A CD player with a tube output stage could either put an op amp or passive filter ahead of the tube buffer or design the buffer to roll off outside the audio band.

 

[bliss53]

I have a cayin cdp with a tube output that I like. I also have a mac mini with a wavelength usb dac that comes darn close to matching the cayin. The cayin is made in the same factory as the primaluna.

 

[Bigerik]

Enough with the attitude and cheap shots, guys. This is an interesting thread and I really have no desire to shut it down.

 

[chadnliz]

Keep it open but its a waste of time A BELT DOESNT CHANGE A CDP'S SOUND!

 

[robobxman]

Keep it open but its a waste of time A BELT DOESNT CHANGE A CDP'S SOUND!

Hmmm...I don't think that's going to help keep this thread alive.

 

[niklasthedol]

Give it up, guys. It appears that Dolph is unwilling to consider the facts of CD player design because they conflict with the dogma that he's bought into. It's much easier to fall back on faith and the unsupported opinions of "authorities" in the subjective review press than to take the time and effort to learn about technology. This diversion on belt-drive CD transports is going nowhere, so let's drop it and get back to the original topic of CD players with tubed output stages.

In stead of claiming I am stupid - In Your Opinion - couldn't you just admit your ignorance of the fact of microphony.
Microphony in circuits and components is a very well known pitfall for unexperienced Technical Engineers and technicians.

"dolph"

 

[robobxman]

Not letting it go - too bad.
Implicating the moderators - priceless.

 

[RayW]

"So he thinks he's a smart guy."

He is.

Give it up, guys...and get back to the original topic of CD players with tubed output stages.

Amen. Good point on the post DAC filtering. Without oversampling you'd have to have a pretty steep filter to go from 20kHz to 24kHz and get it down to an acceptable level.

Microphony in circuits and components is a very well known pitfall for unexperienced Technical Engineers and technicians.

You are claiming that microphony will be more pronounced with a belt driven CDP motor because the motor in a direct drive will induce noise in the circuit boards? Unless your belt driven CDP has an outboard motor, it will still be mounted in the same chassis as the circuitry required for the digital extraction, DAC, etc. It will induce the same noise into the circuit boards, it will just be isolated from the spinning disc by the belt. How does the microphony go down unless you mount the motor on a seperate base/chassis?

And I wonder why a post, like the one I reply to here, at all is accepted by moderators.

Could that post be more peronal?
Could that post be more "All Attidtude, No Audio"?

If you feel a post is in violation of the rules, there is a red triangle at the top right of each post. Click on it and a message will be sent to the mods. Calling them out in public is a quick way to a long vacation.

Ray

 

[cwall99]

Do this test:
Play music with your CD's cabinet open (or amplifiers cabinet or whatever is active in the listening chain) in the room next to your speakers.
Make someone knock gently on the circuit board with something rigid, like a pen or screwdriver or similar.

Detect if it's audible in what you speakers present for you.
This test will convince you that mechanical noise can be transmittet through circuit boards and components. (If you didn't already know that)

Well, it was good to have the afternoon off so I could try this. I opened up the Oppo and tapped lightly on the side of the mother board with a plastic ballpoint pen tube. My wife and I took turns tapping and listening (for all you fans of Chip and Dan Heath) over a number of different songs.

Volume was set at -15 dB.

Not an iota of noise. Tried it a number of times, and nary a peep, knock, blip, or sound other than the music being played.

Equipment used: Pioneer Elite VSX-82TXS, Oppo DV-980H. Was listening to David Bowie's The Rise and Fall of Ziggy Stardust and the Spiders from Mars on SACD.

I only opened the Oppo as we're only talking about CDPs here, and I didn't want to void the warranty on my receiver.

 

[Bigerik]

Enough!
Closing this one for now.