About tube DACs? - Page 4 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st January 2013, 05:47 PM   #31
diyAudio Member
 
Join Date: Jul 2011
Hey, now I found one interesting option: Audio Note Kits - L3.1 DAC Kit

Does anyone here have experience on these? Not a cheap option anyway since balanced 3.1 costs way over 2k$, but how about the sound quality...?
  Reply With Quote
Old 21st January 2013, 06:05 PM   #32
Julf is offline Julf  Europe
diyAudio Member
 
Join Date: Oct 2011
Location: Amsterdam, The Netherlands
Quote:
Originally Posted by kad View Post
As a side note, the reason I believe 32-bit DAC signal processing sounds better than 24-bit or 16-bit is the 'staircase' effect above the SNR floor.
There is no "staircase effect" as the DAC will have a reconstitution filter (sinc function).

Quote:
It follows that even a 16-bit Analog to Digital Converter (ADC) used to quantify any analog waveform, such as used in the recording industry to produce mere "CD Quality" will have gross amplitude quantization steps (65,536) of them. These are known as .wav files. A CD .wav file can be compressed without any bit-loss via the lossless FLAC codec. Usually the standard specifies 44.1KHz sampling rate.

Then comes "DVD-Audio" quality, mostly 16-bit quantization @ 48KHz sampling rate. But also allows 24-bit quantization @ 192KHz sampling rate.

Then comes "SACD" quality which is a single bit quantization (the prior bit defines the next level) but is sampled at 64x44.1KHz. Currently this is the ultimate in terms of Audio Quality.
Eh?

FLAC allows 24@192, and that is definitely higher resolution than the 2.8224 MHz x 1 bit (64 x 44.1 kHz, but only 1 bit) DSD encoding used on SACD.

Quote:
It utilizes 32-bit DSP (Digital Signal Processing).
Only 32 bit? For DSP you do need to use a much higher bit depth to avoid rounding and accumulation errors (precisely the cumulative errors you pointed out with the analog signal). That's why most DSP's are 48, 64 or even more bits - but the output is still only 24 or 16.

Quote:
All my digital audio media accumulated over the years, now truly sounds better! Sweeter. More definition. Things I never heard before, such as the pluck of a string, or the slightest brush of a snare, now become clearly audible. It is like rediscovering a whole new library of music!

Really!
Enjoy the cool-aid!
  Reply With Quote
Old 21st January 2013, 06:33 PM   #33
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Dither has a role to play too, but let us not introduce too many facts into the discussion.

I'm not quite sure what this thread is now about. 'Valve after DAC chip' DACs are quite common, aren't they? When properly designed they may sound as good as a conventional circuit; valves don't have to insert noticeable distortion, although some people seem to prefer it when they do. So what does the OP actually want that is not provided by existing designs?
  Reply With Quote
Old 21st January 2013, 07:38 PM   #34
diyAudio Member
 
Join Date: Jul 2011
Quote:
Originally Posted by DF96 View Post
I'm not quite sure what this thread is now about. 'Valve after DAC chip' DACs are quite common, aren't they? When properly designed they may sound as good as a conventional circuit; valves don't have to insert noticeable distortion, although some people seem to prefer it when they do. So what does the OP actually want that is not provided by existing designs?
Nothing.

Once again, this thread is NOT about:
- some strange "discreet" DAC designs, or any DAC *designs* at all
- tube vs. solid state comparisons
- technical issues, measurements or SNRīs

What I would like this thread to be is:
- experiences and recommendations on high quality DIY tube kits
- comments on tube DIY kits against high end commercial ones

Thanks!
  Reply With Quote
Old 21st January 2013, 08:10 PM   #35
cotdt is offline cotdt  United States
diyAudio Member
 
Join Date: Oct 2005
Send a message via AIM to cotdt
You might be interested in taking a look at the Lampizator page. He is both DIY and commerical, and his tube output stage is well regarded.
  Reply With Quote
Old 21st January 2013, 08:51 PM   #36
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Lampizator's designs and views are certainly not universally "well regarded". It is a while since I last looked at his website, but "best avoided" would be my verdict.
  Reply With Quote
Old 22nd January 2013, 12:04 AM   #37
kad is offline kad  Canada
Banned
 
Join Date: Jan 2013
Quote:
Originally Posted by AlliumPorrum View Post
Nothing.

Once again, this thread is NOT about:
- some strange "discreet" DAC designs, or any DAC *designs* at all
- tube vs. solid state comparisons
- technical issues, measurements or SNRīs

What I would like this thread to be is:
- experiences and recommendations on high quality DIY tube kits
- comments on tube DIY kits against high end commercial ones

Thanks!
Since you are the OP, I shall respect your wishes. Please forgive the next few replies (I feel compelled to correct some disinformation); after which I'll only focus onto your wishes which also happens to correspond to mine.

Cheers!

PS: Beer And Food and Music is good.

~~~~~~~~~~~
Think much, speak little, write less.
{French Proverb}


This world is comedy to those that think, a tragedy to those that feel.
~ Horace Walpole

I would propose that life is very much like a game and that a comparison between the two is very enlightening. In any game, you need to be fit, possess certain skills and have a good knowledge of the rules in order to participate. In life, we need to have a good knowledge of the rules that apply and to use this knowledge continuously in order to assess and make decisions in every situation that we face. The more intensely we play the game of life, the better our knowledge and application of the rules, the better the results we will achieve, much like a football player who is skilled, trains hard and knows the rules.

During the course of our lives we progress from being dependent on our parents for food and shelter and emotional support, to being independent as we become young adults. We learn to make decisions for ourselves, and as we see the results of our decisions we get feedback and the resultant experience adds wisdom to subsequent decisions.

The next stage is to develop relationships with others, or interdependence, and it is through these relationships that significant personal growth can occur. Many of us however have a low sense of self-esteem which holds us back in relating to others.

How then do we make significant progress in our lives, as evidenced by personal growth or an increase in wisdom? We look at the results we have and are achieving in our lives. If our results are unsatisfactory, we reassess our beliefs and make adjustments to our actions. Additional important feedback is our emotions (fear, anger, unhappiness, disappointment etc.) which acts as warning signs and which leads us to evaluate either our rules or beliefs, or our actions. Our target is to lead a joy-filled, intense yet balanced life, leading to good life results and continually increasing wisdom.

Author's Bio:

Tony Orbin is a chemical engineer with a passion for the field of self-improvement. He is in the process of starting to give courses in this field. Tony can be contacted on aorbin@iafrica.com.
  Reply With Quote
Old 22nd January 2013, 02:19 AM   #38
diyAudio Member
 
Join Date: Oct 2006
Quote:
Originally Posted by AlliumPorrum View Post
Hey, now I found one interesting option: Audio Note Kits - L3.1 DAC Kit

Does anyone here have experience on these? Not a cheap option anyway since balanced 3.1 costs way over 2k$, but how about the sound quality...?
I have a good deal of experience on a very, very similar, earlier AudioNote dac, with the same AD1865 dac chip & i/v transformers, but a different tube selection. I was not terribly impressed, even after upgrading many of the unit's shortcomings. I think they have taken a step down from that earlier unit on this one, in choosing the oddball 5687 tube for output. There is no good reason to use this tube versus a conventionally-pinned-out 12a*7 or 6DJ8 type, and I have always found it extremely close to impossible to find 5687's that both sound good & are not badly microphonic. All of the good, vintage ones seem universally microphonic. I have also found AN's circuit boards to be of fairly poor quality, with very thin aluminum cladding & poor quality plate-through holes. The transformers they use for i/v, despite what they tout about them, seem to be the limiting factor on sound quality, at least with their AD1865 based units. They don't seem to be nearly as good as they should be, or have ill-chosen primary impedance for the dac chip and/or ill-chosen pri:sec ratio.

My suggestion would be a Monarchy 24 dac, with a fair amount of upgrading/alteration. Very reasonable average used cost, and not too hard to make into a seriously superb sounding dac. Main thing they did wrong is to not factor in that the SRPP circuit used after the passive i/v resistor only sounds it's best at one specific load impedance, with the distortion rising sharply more than one percent above or below that value. So, the key is to either feed it to a preamp with a known input impedance that calculates, with the unit's internal 220k output load resistor, to the right(42k by my running measurements) ideal load impedance for the circuit, or add a very high quality buffer stage, with it's own input Z calculated to total 42k with the 220k unit's load. I prefer the latter approach. Sounds really spectacular. The failure to account for the SRPP's specific load demands is no doubt why the 24 has gotten mixed reviews, from glowing to tepid, as the stock unit will sound very, very different according to each preamp's input Z.
  Reply With Quote
Old 22nd January 2013, 02:24 AM   #39
kad is offline kad  Canada
Banned
 
Join Date: Jan 2013
Dear All:

Please forgive my multi-posts here, but I'm hitting the limit on the number of quotes within a single post reply. Thus I shall organize them by paragraphs.

Quote:
Originally Posted by Julf View Post
Quote:
Originally Posted by kad View Post
As a side note, the reason I believe 32-bit DAC signal processing sounds better than 24-bit or 16-bit is the 'staircase' effect above the SNR floor.
There is no "staircase effect" as the DAC will have a reconstitution filter (sinc function).
Oh yes there is a staircase distortion. The DAC output low pass filter is designed to have a time constant following the Nyquist-Shannon sampling theorem.

Which basically states if one samples at 44.1KHz (44,100 samples per second) then the highest sinusoidal waveform that can be faithfully quantified and then later reproduced is 22.05KHz.

This only relates to the sampling interval. Then comes in the amplitude of the sampled signal, in the case of a 16-bit ADC/DAC means 2^16 or 65,536 levels of amplitude that can be captured.

What you call the reconstitution filter (analog low pass) must then be able to pass from 0Hz-dc to 22.05KHz ideally without altering the signal in any way, but must reject any distortion component above 22.05HKz by at least 95 dB, which is practically impossible to achieve using analog methods.

You can get a simple low or high pass filter using R/C constant (via a capacitor and resistor) of the first order @ 6dB/octave type. Second order filter @ 12dB/octave. Third order filter @ 18dB/octave. The problem is phase shift. The more filters sequences, the more phase distortion of the signal. What 'tube' audiophiles would call 'pace' or 'coherance' or 'sound stage'... While some others, more eclectics, use the proper terminology 'phase'.

Here is an excerpt on the subject:
Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
Further details can be revealed by actually reading the PDF.

Much more detailed info here:
Fundamentals of Sampled Data Systems - Analog to Digital Conversion
(Of use only if one reads it, alas)

Oh do you remember the first high-power amplifier brand? Phase Linear (of Bob Carver's fame)?

And there are less anti-aliasing glitches with a smoother waveform rather than a gross one. So oversampling the 16-bit quantization at 32-bits depth produces substantial and tangible results. Towards perfection.

Have you even actually auditioned what I am talking about? I suspect not.

Bottom line: your 'reconstitution filter' is what affects the sound quality, or 'coloration' for some? And the exact same principles would occur whether using solid-state or vacuum tube technology (as far as the low pass filter is concerned).

PS: It would be nice towards the diyAudio members community, if you would post some independent verifiable substantiation to support your claims and beliefs. Just say'n.

~~~~~~~~~~
If you shut your door to all errors, truth will be shut out.
~ Rabindranath Tagore, 1861-1941, Bengali Poet and Writer

Education is the key to unlock the golden door of freedom.
~ George Washington Carver, 1864-1943, American Botanist

Excellence in any department can be attained only by the labor of a lifetime; it is not to be purchased at a lesser price.
~ Samuel Johnson, 1709-1784, English Author and Critic
  Reply With Quote
Old 22nd January 2013, 03:52 AM   #40
kad is offline kad  Canada
Banned
 
Join Date: Jan 2013
Continued from above.

(Apologies, I forgot to include a link to the PDF, so here it is.)

Quote:
Originally Posted by Julf View Post
Quote:
Originally Posted by kad View Post
It follows that even a 16-bit Analog to Digital Converter (ADC) used to quantify any analog waveform, such as used in the recording industry to produce mere "CD Quality" will have gross amplitude quantization steps (65,536) of them. These are known as .wav files. A CD .wav file can be compressed without any bit-loss via the lossless FLAC codec. Usually the standard specifies 44.1KHz sampling rate.

Then comes "DVD-Audio" quality, mostly 16-bit quantization @ 48KHz sampling rate. But also allows 24-bit quantization @ 192KHz sampling rate.

Then comes "SACD" quality which is a single bit quantization (the prior bit defines the next level) but is sampled at 64x44.1KHz. Currently this is the ultimate in terms of Audio Quality.
Eh?

FLAC allows 24 @ 192, and that is definitely higher resolution than the 2.8224 MHz x 1 bit (64 x 44.1 kHz, but only 1 bit) DSD encoding used on SACD.
How so? Since the 'master' recording usually is in DSD format? And require conversion from DSD to PCM for most?
SA-CD.net - FAQ
Click the image to open in full size.

Are you saying that a FLAC encoded @ 24 bits / 192Khz is definitely superior to SACD? Oh really?

Click the image to open in full size.


Then please tell us where to find a DSD compatible DAC, high-end or low-end, tube or otherwise for under $2K? With a true 32-bit DAC and 32-bit Signal Processing?

While I might propose a potential solution?
Pioneer DSD SC-67

Click the image to open in full size.


~~~~~~~~~~
Americans drink to get drunk, whereas in France, getting drunk is just a consequence of sampling too much wine you really like.
~ Ted Breaux, New Orleans Absinthe distiller

The mark of an immature man is that he wants to die nobly for a cause, while the mark of the mature man is that he wants to live humbly for one.
~ W. Stekel

There seems to be some perverse human characteristic that likes to make easy things difficult.
~ Warren Buffet
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Another Tube I/V converter/preamp for balanced DACs with SE output:build thread pauldune Tubes / Valves 4 31st May 2013 02:50 PM
DACs Jerseydevildog Digital Source 1 25th November 2007 06:24 PM
DACs? MashBill Pass Labs 3 28th February 2007 09:43 AM
Parallel different DACs roibm Digital Source 1 4th November 2004 10:54 AM
Audio DACs, Instrumentation DACs. Brian Guralnick Digital Source 10 3rd November 2002 04:56 PM


New To Site? Need Help?

All times are GMT. The time now is 02:16 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2