About tube DACs?

[AlliumPorrum]

Originally Posted by Julf

Low output impedance is not what everyone wants. Some like low, some like mid, some like high. Maybe your preference is served by an nCore, but others may not think highly of such an amp, and prefer a tube amp.

I also really do like nCores very much! I think that they are simply one of the best, maybe even THE best power amps that I have ever heard, regardless of the price. Very "tube-like" and "live-like" in their presentation, but with ability to drive pretty much any speaker. They are going to be my choice for my active setup. So the it is going to be DEQX -> tube DAC -> nCore -> Maggie driver -> :=)

Also, how do you know that your nCores are not colored?

A combination of measurement data and double-blind ABX listening.

On what do you compare it for in your double-blind ABX listening??

[Julf]

Originally Posted by AlliumPorrum

On what do you compare it for in your double-blind ABX listening??

My previous main amp - Creek Destiny. The hard part ABXing amps is getting the loudness matched closely enough - I did a blind listening test a while ago, where even die-hard audiophiles preferred a lower-resolution audio sample if it was even 1 dB louder than the other samples...

[AlliumPorrum]

Originally Posted by Julf

I am sure you also can see how somebody who thinks the opposite to you, and thinks your taste is for the colouring most tube stages tend to introduce (and unless you do both proper measurements and true double-blind ABX there is no way to know), would think that DSP is a good way to introduce that colouring in a controllable way...

Well I can surely understand if somebody thinks so, but I also think that he/she has understood it wrong ;=)

As it was previously mentioned, all active analog components add something to the signal. Every transistor, every diode, every tube makes its own coloration to the signal. So the question is not IF tube or transistor adds some coloration to the signal, it's about WHAT KIND OF coloration was added.

Another quite common misunderstanding is that tube devices are bad, because they have more measurable distortion than the solid state ones. Well, of course low distortion is always good, no doubt about it. But, the amount of distortion is *only one* (easily measurable) parameter. As wikipedia states:

"The tube sound is often subjectively described as having a "warmth" and "richness", but the source of this is by no means agreed on. It may be due to the non-linear clipping that occurs with tube amps, or due to the higher levels of second-order harmonic distortion, common in single-ended designs resulting from the characteristics of the tube interacting with the inductance of the output transformer". Source: Tube sound - Wikipedia, the free encyclopedia.

Judging a device by just the amount of it's measured distortion is like judging a car for it's ability go from 0 to 100. In audio devices, just like in cars, you can measure tens or even hundreds different kinds of variables, and you can measure them in many many different ways. Which one of all these measurements tells you if the device sounds good or not? Well, I don't have a clue, and I think that no one has. Because of that, I only trust my ears, and comparison to the live instruments. And in my experience and for my ears, less transistors and more tubes sounds usually better, for some reason.

So, my point for this (too...) long story is: there is no any DSP that could remove the coloration (for example transistor's crossover distortion, and much much more) that solid state device already added to the signal, and replace it with the tubey ones.

[stephensank]

Originally Posted by DougL

I have a recommendation:
The K&K Audio RAKK DAC.
I have the Version 1 with the Passive (Transformer) output and love it.

They also have a tube output that looks interesting.

K & K Audio - Lundahl Transformers, audio DIY kits and more

On a technical note, any tube DAC that use a 12AX7 as a cathode follower uses it to color the sound. I think that tubes can be used that way, but are also very linear if used correctly. I am a big fan of tubes when used correctly. Tubes are one solution. Certainly not the only solution.

Doug

I have a great deal of experience with this & several other versions of this K&K dac setup. It does not sound as good, IMO, as the redone Monarchy, and is prone to reliability problems. I think the sound is limited by the choice of Llundahl for i/v transformer, as they don't actually know how to make a truly excellent transformer, and by, in the tube out version, the choice of purely current source HV supply regulation & it's usual lack of any post-reg energy storage/filtering, strangling dynamics. The depletion-mode power mosfets used in the regs make a habit of failing, and the reg circuit overall leaves a lot to be desired. And the choice of the particular tube type is very odd & very limiting as to choices of better brands/vintages.

The dac Gyuri links is basically a variation on the Monarchy, and makes the same FATAL mistake of letting the SRPP circuit be the final output drive, making for a dac that sounds different/better/worse from one preamp to the next. It'll only sound its best by a magic coincidence of feeding a preamp with exactly the right input impedance, and cables in between that don't disturb that.

[kevinh]

Originally Posted by AlliumPorrum

I also really do like nCores very much! I think that they are simply one of the best, maybe even THE best power amps that I have ever heard, regardless of the price. Very "tube-like" and "live-like" in their presentation, but with ability to drive pretty much any speaker. They are going to be my choice for my active setup. So the it is going to be DEQX -> tube DAC -> nCore -> Maggie driver -> :=)

On what do you compare it for in your double-blind ABX listening??

Well if you are going to use the Deqx then you might want to look at the option of the Jensen transformer version for the D/A conversion and perhaps a tube buffer depending on what you need to drive the amp.

[Julf]

Originally Posted by AlliumPorrum

As it was previously mentioned, all active analog components add something to the signal. Every transistor, every diode, every tube makes its own coloration to the signal. So the question is not IF tube or transistor adds some coloration to the signal, it's about WHAT KIND OF coloration was added.

No, the question is if the minuscule addition is audible or not.

And, actually, no, you are wrong.

While, on an individual level, "every transistor, every diode", and even every resistor has some minuscule contribution to the signal, the feedback loop in a typical amplifier circuit actually corrects and nulls out that contribution.

As wikipedia states:

"The tube sound is often subjectively described as having a "warmth" and "richness", but the source of this is by no means agreed on. It may be due to the non-linear clipping that occurs with tube amps, or due to the higher levels of second-order harmonic distortion, common in single-ended designs resulting from the characteristics of the tube interacting with the inductance of the output transformer". Source: Tube sound - Wikipedia, the free encyclopedia.

Thanks - I think you just argued my case. The reason a lot of people like tube sound is "due to the non-linear clipping that occurs with tube amps, or due to the higher levels of second-order harmonic distortion, common in single-ended designs resulting from the characteristics of the tube interacting with the inductance of the output transformer". As in tubes causing a "pleasing" (rather than "accurate") sound.

Judging a device by just the amount of it's measured distortion is like judging a car for it's ability go from 0 to 100.

Yes. To me that is one of the most important criteria for a car.

In audio devices, just like in cars, you can measure tens or even hundreds different kinds of variables, and you can measure them in many many different ways.

Agree. Can you tell me one of the hundreds of criteria where tubes measure better than semiconductors?

in my experience and for my ears, less transistors and more tubes sounds usually better, for some reason.

"less transistors" and "more tubes" are two separate and independent variables.

So, my point for this (too...) long story is: there is no any DSP that could remove the coloration (for example transistor's crossover distortion, and much much more) that solid state device already added to the signal, and replace it with the tubey ones.

Crossover distortion is not an issue in class-A operation (the way transistors work in most linear circuits - class A/B power amps being the only major exception) or class D...

[AlliumPorrum]

And hey, one more addition about the previous "The tube sound is often subjectively described as having a "warmth" and "richness"";

Is see that clearly as an positive description. In my opinion, well made tube devices really don't add any additional "warmth" and "richness" to the sound. I see it so that solid state devices often add some "coldness" and "dulness" to the sound, and lose the natural warmth of acoustic instruments.

But, hey, that's just me :=)

[cotdt]

Originally Posted by AlliumPorrum

And hey, one more addition about the previous "The tube sound is often subjectively described as having a "warmth" and "richness"";

Is see that clearly as an positive description. In my opinion, well made tube devices really don't add any additional "warmth" and "richness" to the sound. I see it so that solid state devices often add some "coldness" and "dulness" to the sound, and lose the natural warmth of acoustic instruments.

But, hey, that's just me :=)

When the microphone is placed inside the acoustic instrument body, or 1" inch away from the mouth, of course it will sound different from natural listening positions.

Close-mic'ed, the sound waves don't get a chance to fully propagate, or to pick up harmonics in the air, before entering the microphone. There is no soundstaging information. A colder tone is to be expected. People often say that tube amps sound more like real life instruments and vocals, and there is actually soundstage. You may draw your own conclusions why this is so, but I do prefer tubes for its increased realism and musical involvement.

[stephensank]

Originally Posted by Julf

No, the question is if the minuscule addition is audible or not.

And, actually, no, you are wrong.

While, on an individual level, "every transistor, every diode", and even every resistor has some minuscule contribution to the signal, the feedback loop in a typical amplifier circuit actually corrects and nulls out that contribution.
D...

Sir, you VERY clearly have an immovable prejudice against vacuum tubes, and it is YOU who are wrong. Feedback does NOT correct colorations in actual practice, a more often feedback corrects most, but then adds distortion of it's own, due to the time delay involved. As for the deviced themselves, bipolar transistors are LESS linear than tubes when doing voltage gain. Tubes are less linear at current gain, but far more linear at voltage gain. If you ask tubes to ONLY due voltage gain, it absolutely can sound less colored than transistors in equivalent circuits, and I have verified this many, many times in practice.
To me, it's not about whether tubes or transistors, but where and how well each is used. It seems very likely that you have been prejudiced by hearing tube gear that was not well designed and/or well made, or have simply refused to accept what you have heard with your ears because of what you have read or have seen on a distortion analyser.
But, seriously, dude, you are VERY obviously prejudiced against tubes.

[qusp]

seems to me like people might be jumping straight from tubes to expecting that we are recommending opamps? personally I quite like them used well, but for IV I would usually use discrete Fet based Class A, solid state trans-conductance amp, such things are just natural sounding, to say they somehow suck the life out of the music is quite hilarious