[cipher[_3_]]

These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

[Peter Wieck]

On Nov 24, 12:21*pm, cipher wrote:
These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? *Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

Well, given the silliness of a DAC and a tube, the purpose is so that
the manufacturer can say that their device (were it actually 'all
tube' would be the size of a large building and require its own power-
plant) is "tube". There is no legitimate reason in my opinion.

My guess is that at-best, the unit uses a tube at the analog output
end - nowhere in the actual conversion process.

That same crowd that purchases speaker cable catenaries, $X,XXX.XX
cables and patch cords, magic rocks and so forth will eat it right up.
Nothing counter-intuitive about separating the sheep from their wool.

Peter Wieck
Melrose Park, PA

[Trevor Wilson[_2_]]

"cipher" wrote in message
0...
These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

**There is no such thing as a "tube DAC". Given the requirements of a
typical DAC, to build one from tubes would occupy the volume of a small
house. Power consumption would likely be in the order of many tens of
kWatts.


--
Trevor Wilson
www.rageaudio.com.au

[Peter Wieck]

On Nov 24, 4:21*pm, "Trevor Wilson"
wrote:
"cipher" wrote in message

0...

These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? *Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

**There is no such thing as a "tube DAC". Given the requirements of a
typical DAC, to build one from tubes would occupy the volume of a small
house. Power consumption would likely be in the order of many tens of
kWatts.

--
Trevor Wilsonwww.rageaudio.com.au

Awwww... c'mon, guy!!

http://www.angelfire.com/biz/bizzyb/TADAC.html

http://www.audioreview.com/USBTDcrx.aspx

http://www.highendpalace.com/HEP%20CD.htm

Peter Wieck
Melrose Park, PA

[John Byrns]

In article ,
Peter Wieck wrote:

On Nov 24, 12:21*pm, cipher wrote:
These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? *Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

Well, given the silliness of a DAC and a tube, the purpose is so that
the manufacturer can say that their device (were it actually 'all
tube' would be the size of a large building and require its own power-
plant) is "tube". There is no legitimate reason in my opinion.

My guess is that at-best, the unit uses a tube at the analog output
end - nowhere in the actual conversion process.

I would agree with you there, most likely these devices use a silicon solid
state DAC followed by an analog tube based output buffer stage.

However I don't agree that a tube DAC would "would be the size of a large
building and require its own power plant". I suspect that the real problem with
building a tube DAC would be achieving the required 16 bit accuracy, and not
that a totally unreasonable number of tubes would be required, as you suggest.

I can think of at least three possible approaches to building a reasonably
living room friendly real tube DAC, perhaps with enough effort one of these
approaches could be made to provide the required accuracy.

Your comments suggest that you are thinking of not just a tube DAC, but also a
tube DSP, for it to "be the size of a large building and require its own power
plant".

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[Andy Evans]

The good thing about a "tube DAC" is that you can feed the DAC's
converted analog signal straight into the grids of the input tubes
together with the DC on the signal, which becomes part of the bias.
It's an elegant way of doing it and many including myself believe it
sounds better than transformer out or a solid state output stage.

andy

[fryzz]

One possible approach not requiring a roomful of equipment: An analog
voltage representation of a sixteen bit value can be achieved by
summing the voltages corresponding to the states of the individual
bits. This would require sixteen voltage references with .01%
error, sixteen precision analog switches, and a precision summing
junction. As John points out, achieving the required accuracy would
be the challenge here.

[LGLA]

"cipher" wrote in message 0...
These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.


One thing I have noticed about stereo stacks... everything has an output
in one way or another, even if it is the sound itself, from a speaker. And,
the output stage of a DAC would be the point, just for that tube's worth
of sound quality. Any output stage to another component, is an amplifier.

This is my FIRST post, as a reply, in this NG.

Alex
SoCalifornia

[Patrick Turner]

LGLA wrote:

"cipher" wrote in message 0...
These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

One thing I have noticed about stereo stacks... everything has an output
in one way or another, even if it is the sound itself, from a speaker. And,
the output stage of a DAC would be the point, just for that tube's worth
of sound quality. Any output stage to another component, is an amplifier.

This is my FIRST post, as a reply, in this NG.

Alex
SoCalifornia

Welcome to our little group. I hope you have a wardrobe full of flame
suits to protect yourself from the barbs, sarcasms, inuendo, and
downright BS that this group generates like mushrooms springing up in
compost.

Between the lines of BS there is much to be treasured here, and if you
increase the treasure then you'll get by better than some.

If you did all the functions of a D to A converters using tubes,
methinks you'd have no room to keep a wife at your house and you'd be
horrified by the power bills. The Green Police would call to arrest you
for causing so much greenhouse gas. Rather a lot of tubes are needed.
However, their purpose would be to perform un-digitalling tasks which
can be done better with zillions of transistors in a chip.
But the tubes are very nice things to use as the fist device to handle
and filter the audio coming from the DA chip.

But soon the digital world will be rocked with DXD etc, so prepare to
say tata to CDs.
The world has always hosted a mix of the best and the worst in any
product. MP3 is the worst, but the DXD could be the best but only for
those who can afford it unless the DXD becomes a real cheap alternative
due to parallel developments in data processing speeds, memory
capacities and broadband data transfer rates.


Put it this way, in 25 years time, will anyone remember how CD players
worked? Will replacement lasers be available? Will anyone know how to
install them? And won't 44kHz x 16 bit all seem even more primitive than
vinyl?

And will we have holographic porno online streaming? and film character
/ plot choice? and a host of other gee wizz ways of creating
entertainment without actors, actresses, and orchestras?

Hu nose? I don't. And the future might arrive and I'll be too old to
enjoy it.


Patrick Turner.

[John Byrns]

In article ,
Patrick Turner wrote:

If you did all the functions of a D to A converters using tubes,
methinks you'd have no room to keep a wife at your house and you'd be
horrified by the power bills. The Green Police would call to arrest you
for causing so much greenhouse gas. Rather a lot of tubes are needed.
However, their purpose would be to perform un-digitalling tasks which
can be done better with zillions of transistors in a chip.
But the tubes are very nice things to use as the fist device to handle
and filter the audio coming from the DA chip.

Patrick, methinks that you are confusing "D to A converters" with DSPs. A tube
D to A converter wouldn't be anywhere near as complex as you imply, the problem
is how to achieve the desired 16 bit accuracy. I believe D to A converters
built from tubes, of less than 16 bit accuracy, actually existed back in the
1950s, although I am not going to look for any links right now.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[TT]

"Peter Wieck" wrote in message
...
On Nov 24, 4:21 pm, "Trevor Wilson"
wrote:
"cipher" wrote in message

0...

These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

**There is no such thing as a "tube DAC". Given the requirements of a
typical DAC, to build one from tubes would occupy the volume of a small
house. Power consumption would likely be in the order of many tens of
kWatts.

--
Trevor Wilsonwww.rageaudio.com.au

Awwww... c'mon, guy!!

http://www.angelfire.com/biz/bizzyb/TADAC.html

http://www.audioreview.com/USBTDcrx.aspx

http://www.highendpalace.com/HEP%20CD.htm

Peter Wieck
Melrose Park, PA

Trevor is dead right or even a little conservative with his estimation.
Look at the very first link you posted and read the specs as it uses a "96k
max input data speed, Crystal 8414 feeds a 192k 24-Bit Burr-Brown 1793
Advanced Segment Verification Jitter Free D/A chip" So it has a silicon
chip in it that is *not* a tube,

BTW check this link out and see how hard it is to just make a digital clock
out of tubes.

http://www.engadget.com/2006/06/26/a...in-the-making/

And you want to make a DAC chip out of them? Best of luck ;-)

Perhaps people should accurately call these things what they really are a
"tubed output stage DACs"

Cheers TT

[Peter Wieck]

On Nov 28, 5:15*pm, "TT" wrote:

Perhaps people should accurately call these things what they really are a
"tubed output stage DACs"


Your sarcasm-detector needs adjustment!

Peter Wieck
Melrose Park, PA

[TT]

"Peter Wieck" wrote in message
...
On Nov 28, 5:15 pm, "TT" wrote:

Perhaps people should accurately call these things what they really are a
"tubed output stage DACs"


Your sarcasm-detector needs adjustment!

Peter Wieck
Melrose Park, PA

Perhaps. Your posts are usually very sensible (unless replying to Arny or
Jute) and if you were using sarcasm then I did miss it ;-)

Obvious both Trevor and I took the points literally.

Cheers TT

[TT]

"flipper" wrote in message
...
On Sat, 29 Nov 2008 07:15:02 +0900, "TT"
wrote:


"Peter Wieck" wrote in message
...
On Nov 24, 4:21 pm, "Trevor Wilson"
wrote:
"cipher" wrote in message

0...

These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and
ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

**There is no such thing as a "tube DAC". Given the requirements of a
typical DAC, to build one from tubes would occupy the volume of a small
house. Power consumption would likely be in the order of many tens of
kWatts.

--
Trevor Wilsonwww.rageaudio.com.au

Awwww... c'mon, guy!!

http://www.angelfire.com/biz/bizzyb/TADAC.html

http://www.audioreview.com/USBTDcrx.aspx

http://www.highendpalace.com/HEP%20CD.htm

Peter Wieck
Melrose Park, PA

Trevor is dead right or even a little conservative with his estimation.
Look at the very first link you posted and read the specs as it uses a
"96k
max input data speed, Crystal 8414 feeds a 192k 24-Bit Burr-Brown 1793
Advanced Segment Verification Jitter Free D/A chip" So it has a silicon
chip in it that is *not* a tube,

BTW check this link out and see how hard it is to just make a digital
clock
out of tubes.

http://www.engadget.com/2006/06/26/a...in-the-making/

And you want to make a DAC chip out of them? Best of luck ;-)

You're making the same mistake Trevor did in confusing a DSP with a
DAC.

We are discussing DACs - Digital Analog Converters right? Things that
convert 1s and 0s to sine waves?

The basic principle of a "DAC" is rather simple,

Yes it is for a silicon chip ;-)

and a whole lot
simpler than the tube clock you mention,

I beg to differ. A tube DAC would be as Trevor described it.

but it's moot as there's no
'audio' value to doing digital circuits with tubes.

Correct but people still do.

Perhaps people should accurately call these things what they really are a
"tubed output stage DACs"

If it makes you feel good but there's nothing particularly 'wrong'
with calling it a Tube DAC either.

Yes there is when no part of the DAC circuit is controlled by tubes!

Just as there's nothing
particularly 'wrong' with "tube record player" instead of "tubed
output mechanical audio reproduction device."

Record players *DO NOT* require tubes or any other amplification circuitry
to work. The signal from the machine can be passed to any device you so
wish or in the case of a gramophone no other device is even required. That
is a bad example you used!

It's just that the means of getting from pit marked plastic to 'audio'
is a heck of a lot more complex than a wiggling needle but,, once
audio, the active device is, in both cases, tubes.

You have failed to convince me ;-) There is no such thing as a Tube DAC for
16 bit audio. There are, however a lot of tubed output stage DACs available
as the DAC is still a silicon chip.


Cheers TT

[keithr]

John Byrns wrote:
In article ,
Patrick Turner wrote:

If you did all the functions of a D to A converters using tubes,
methinks you'd have no room to keep a wife at your house and you'd be
horrified by the power bills. The Green Police would call to arrest you
for causing so much greenhouse gas. Rather a lot of tubes are needed.
However, their purpose would be to perform un-digitalling tasks which
can be done better with zillions of transistors in a chip.
But the tubes are very nice things to use as the fist device to handle
and filter the audio coming from the DA chip.

Patrick, methinks that you are confusing "D to A converters" with DSPs. A tube
D to A converter wouldn't be anywhere near as complex as you imply, the problem
is how to achieve the desired 16 bit accuracy. I believe D to A converters
built from tubes, of less than 16 bit accuracy, actually existed back in the
1950s, although I am not going to look for any links right now.


You could theoretically build a DAC with a few dozen tubes, but you
would need a precision resistor network. These days DACs are usually of
the delta-sigma type that do not need precision parts but do use
thousands of transistors, they work much better.

Keith

[Eeyore]

cipher wrote:

These seem to be popping up everywhere in audiophile circles..

You mean audiophool circles. The same people who pay hundreds upon hundreds
for speaker wire and silver plated mains cables.

The Shakti Stone and Tice Clock are probably some of the most extravagant
examples of this nonsense.

http://www.gcaudio.com/products/reviews/infoshakti.html
http://electronicdesign.com/Articles...ArticleID=6134

A personal favourite is this though !
http://www.museumofhoaxes.com/hoax/w...comments/4309/


what would be the purpose of such a device?

To add distortion.


Yes, I am young and ignorant re electronics.

something about the whole thing seems counter intuitive to me.

You have good sense.

Graham

[Eeyore]

John Byrns wrote:

However I don't agree that a tube DAC would "would be the size of a large
building and require its own power plant". I suspect that the real problem with
building a tube DAC would be achieving the required 16 bit accuracy, and not
that a totally unreasonable number of tubes would be required, as you suggest.

It would have to be a very primitive DAC as used in early CD players. No
oversampling or internal DSP filtering.

Graham

[Eeyore]

Andy Evans wrote:

The good thing about a "tube DAC" is that you can feed the DAC's
converted analog signal straight into the grids of the input tubes
together with the DC on the signal, which becomes part of the bias.
It's an elegant way of doing it and many including myself believe it
sounds better than transformer out or a solid state output stage.

How can added distortion 'sound better' ?

Graham

[Eeyore]

Peter Wieck wrote:

My guess is that at-best, the unit uses a tube at the analog output
end - nowhere in the actual conversion process.

I should have made that clear in my response too.

Graham

[Eeyore]

TT wrote:

Perhaps people should accurately call these things what they really are a
"tubed output stage DACs"

You presume the sellers care about accuracy whether descriptive or sonic.

Graham

[Eeyore]

LGLA wrote:

"cipher" wrote
These seem to be popping up everywhere in audiophile circles..

what would be the purpose of such a device? Yes, I am young and ignorant
re electronics.

something about the whole thing seems counter intuitive to me.

One thing I have noticed about stereo stacks... everything has an output
in one way or another, even if it is the sound itself, from a speaker. And,
the output stage of a DAC would be the point, just for that tube's worth
of sound quality. Any output stage to another component, is an amplifier.

But tubes have WORSE audio quality than solid state !

http://www.national.com/pf/LM/LME49720.html
And it'll cost less than a tube and not require special power supplies.

Graham

[Eeyore]

Patrick Turner wrote:

If you did all the functions of a D to A converters using tubes,
methinks you'd have no room to keep a wife at your house and you'd be
horrified by the power bills. The Green Police would call to arrest you
for causing so much greenhouse gas. Rather a lot of tubes are needed.

Which would mean rather a lot of time spent hunting down the failed ones and replacing them !

Graham

[Eeyore]

Patrick Turner wrote:

Hu nose?

A Chinese friend ?

Graham

[Eeyore]

John Byrns wrote:

Patrick Turner wrote:

If you did all the functions of a D to A converters using tubes,
methinks you'd have no room to keep a wife at your house and you'd be
horrified by the power bills. The Green Police would call to arrest you
for causing so much greenhouse gas. Rather a lot of tubes are needed.
However, their purpose would be to perform un-digitalling tasks which
can be done better with zillions of transistors in a chip.
But the tubes are very nice things to use as the fist device to handle
and filter the audio coming from the DA chip.

Patrick, methinks that you are confusing "D to A converters" with DSPs. A tube
D to A converter wouldn't be anywhere near as complex as you imply, the problem
is how to achieve the desired 16 bit accuracy. I believe D to A converters
built from tubes, of less than 16 bit accuracy, actually existed back in the
1950s, although I am not going to look for any links right now.

And you'd be back to analogue anti-aliasing and anti-imaging filters too.

Graham

[Eeyore]

Patrick Turner wrote:

But the tubes are very nice things to use as the fist device to handle
and filter the audio coming from the DA chip.

In what way are they nice for this task ?

Graham

[Eeyore]

flipper wrote:

A 16 bit DAC is, basically, a current/voltage source, 16 switches, 16
precision resistors, a summing junction and output buffer. That's
hardly a 'house' full of tubes, much less 'conservative'.

As a pure DAC, sure.

Modern ones however take a serial (single wire) I2S signal input and clock.

Graham

[John Byrns]

In article ,
Eeyore wrote:

John Byrns wrote:

Patrick Turner wrote:

If you did all the functions of a D to A converters using tubes,
methinks you'd have no room to keep a wife at your house and you'd be
horrified by the power bills. The Green Police would call to arrest you
for causing so much greenhouse gas. Rather a lot of tubes are needed.
However, their purpose would be to perform un-digitalling tasks which
can be done better with zillions of transistors in a chip.
But the tubes are very nice things to use as the fist device to handle
and filter the audio coming from the DA chip.

Patrick, methinks that you are confusing "D to A converters" with DSPs. A
tube
D to A converter wouldn't be anywhere near as complex as you imply, the
problem
is how to achieve the desired 16 bit accuracy. I believe D to A converters
built from tubes, of less than 16 bit accuracy, actually existed back in
the
1950s, although I am not going to look for any links right now.

And you'd be back to analogue anti-aliasing and anti-imaging filters too.

Show me a solid state DAC that doesn't require "analogue anti-aliasing and
anti-imaging filters too"?

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[Arny Krueger]

"John Byrns" wrote in message


However I don't agree that a tube DAC would "would be the
size of a large building and require its own power
plant".

http://www.analog.com/library/analog...Tech%20 F.pdf

"In 1954 Epsco introduced an 11-bit,
50-kSPS vacuum-tube based SAR ADC called the DATRAC. This converter, shown
in
Figure 4.3, is generally credited as being the first commercial offering of
such a device.
The DATRAC was offered in a 19" × 26" × 15" housing, dissipated several
hundred
watts, and sold for approximately $8000.00."

Figure 4.3 says that the total power usage was 500 watts. Two would be
required for stereo.

I suspect that the real problem with building a
tube DAC would be achieving the required 16 bit accuracy,

Agreed.

and not that a totally unreasonable number of tubes would
be required, as you suggest.

If enough accuracy and stability were possible, the SAR DAC technology would
seem to increase the parts count linearaly with the number of bits. Since
speed of components would also increase linearly with the number of bits,
the total power usage per part might increase similarly. A 16 bit version
would have needed to be about 50%. more parts and more than twice as much
power.

[Arny Krueger]

"Eeyore" wrote in
message
John Byrns wrote:

However I don't agree that a tube DAC would "would be
the size of a large building and require its own power
plant". I suspect that the real problem with building a
tube DAC would be achieving the required 16 bit
accuracy, and not that a totally unreasonable number of
tubes would be required, as you suggest.

It would have to be a very primitive DAC as used in early
CD players. No oversampling or internal DSP filtering.


Right the oversampling and the DSP filters would put the parts count over
the top.

BTW, I don't think that modern DACs include a DSP to do the digital
filtering, but rather use combinatorial logic.

Based on the info in this page

http://www.analog.com/library/analog...0 F.pdfFigure 4.2, I would expect that a stereo 16 bit DAC, were it even possibleto achieve that kind of precision, would have at least 3 times the partscount and at least 4-5 times the power usage. So we're talking about afull rack and a couple-three kilowatts.

[Arny Krueger]

"John Byrns" wrote in message

In article ,
Eeyore wrote:

And you'd be back to analogue anti-aliasing and
anti-imaging filters too.

Show me a solid state DAC that doesn't require "analogue
anti-aliasing and anti-imaging filters too"?

In modern ADCs and DACs, the actual brick-wall filtering is implemented in
the digital domain via oversampling. There are analog filters, but they are
usually merely 4th order, and have a ultrasonic corner frequency.

[Arny Krueger]

"Eeyore" wrote in
message
Patrick Turner wrote:

If you did all the functions of a D to A converters
using tubes, methinks you'd have no room to keep a wife
at your house and you'd be horrified by the power bills.
The Green Police would call to arrest you for causing so
much greenhouse gas. Rather a lot of tubes are needed.

Which would mean rather a lot of time spent hunting down
the failed ones and replacing them !

We been there and done that with tubed digital computers during the 50s and
early 60s. In the mid-60s when I worked for IBM our field office still had
one client with a 650 that did thier books, and the tubed computer at
another shop had not been gone that long - some of the repair parts were
still around.

There was a funny story about the second computer. The tubed computers made
so much really hot air that their ductwork was more like a chimney than
ducts, right down to the damper. The 650 mentioned above looked like a
large hot air furnace in a basement with ducts leading off in all
directions.

At any rate one client inadvertantly left the damper open one summer
weekend. On Saturday, we had a cold snap and cold air chilled the computer
down to the 50s. On Sunday there was then a hot, humid heat wave and there
was massive condensation. The first shift on Monday morning came in and
powered the thing up. Filament supply - no problem. A brief warm up, and
then on with the HV...

Kaahhh-whhham!

Field engineers with hair dryers worked for 3 days before the thing would
power up again.

[John Byrns]

In article ,
"Arny Krueger" wrote:

"John Byrns" wrote in message

In article ,
Eeyore wrote:

And you'd be back to analogue anti-aliasing and
anti-imaging filters too.

Show me a solid state DAC that doesn't require "analogue
anti-aliasing and anti-imaging filters too"?

In modern ADCs and DACs, the actual brick-wall filtering is implemented in
the digital domain via oversampling. There are analog filters, but they are
usually merely 4th order, and have a ultrasonic corner frequency.

So what you are saying is that "modern ADCs and DACs" use digital filters in
addition to analog filters. They don't eliminate analog filters, they simply
relax the constraints on them. I think Eeyore needs to hit the books.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[Ian Bell[_2_]]

John Byrns wrote:
In article ,
"Arny Krueger" wrote:

"John Byrns" wrote in message

In article ,
Eeyore wrote:
And you'd be back to analogue anti-aliasing and
anti-imaging filters too.
Show me a solid state DAC that doesn't require "analogue
anti-aliasing and anti-imaging filters too"?
In modern ADCs and DACs, the actual brick-wall filtering is implemented in
the digital domain via oversampling. There are analog filters, but they are
usually merely 4th order, and have a ultrasonic corner frequency.

So what you are saying is that "modern ADCs and DACs" use digital filters in
addition to analog filters. They don't eliminate analog filters, they simply
relax the constraints on them.

Precisely, which is exactly why oversampling DACs were invented.

Cheers

[John Byrns]

In article ,
Ian Bell wrote:

John Byrns wrote:
In article ,
"Arny Krueger" wrote:

"John Byrns" wrote in message

In article ,
Eeyore wrote:
And you'd be back to analogue anti-aliasing and
anti-imaging filters too.
Show me a solid state DAC that doesn't require "analogue
anti-aliasing and anti-imaging filters too"?
In modern ADCs and DACs, the actual brick-wall filtering is implemented in
the digital domain via oversampling. There are analog filters, but they
are
usually merely 4th order, and have a ultrasonic corner frequency.

So what you are saying is that "modern ADCs and DACs" use digital filters
in
addition to analog filters. They don't eliminate analog filters, they
simply
relax the constraints on them.

Precisely, which is exactly why oversampling DACs were invented.

I thought oversampling DACs were invented because Philips only had a 14 bit DAC
available when they compromised with Sony on the CD spec. and needed a way to
get 16 bits out of their existing 14 bit converter? ;-)

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[Andy Evans]

On Nov 29, 3:24*pm, Eeyore
wrote:
Andy Evans wrote:
The good thing about a "tube DAC" is that you can feed the DAC's
converted analog signal straight into the grids of the input tubes
together with the DC on the signal, which becomes part of the bias.
It's an elegant way of doing it and many including myself believe it
sounds better than transformer out or a solid state output stage.

How can added distortion 'sound better' ?

Graham

I think the phrase you're searching for is "How can that sound
better?"

andy

[Andy Evans]

But tubes have WORSE audio quality than solid state !

Graham

So what makes you hang out on rec.audio.tubes-have-worse-quality-than-
solid-state?

Sheer perversity?

This is exactly the one place where nobody is likely to believe you.
Sounds like banging one's head against a brick wall to me. Maybe in
life's rich pageant somebody somewhere has to do it.

andy

[Eeyore]

John Byrns wrote:

Show me a solid state DAC that doesn't require "analogue anti-aliasing and
anti-imaging filters too"?

Are you kidding me ?

Graham

[Eeyore]

Arny Krueger wrote:

"John Byrns" wrote
Eeyore wrote:

And you'd be back to analogue anti-aliasing and
anti-imaging filters too.

Show me a solid state DAC that doesn't require "analogue
anti-aliasing and anti-imaging filters too"?

In modern ADCs and DACs, the actual brick-wall filtering is implemented in
the digital domain via oversampling.

Exactly.


There are analog filters, but they are
usually merely 4th order, and have a ultrasonic corner frequency.

Just to roll off some residual ultrasonic trash. There's not much of it anyway.

Graham

[Eeyore]

John Byrns wrote:

I think Eeyore needs to hit the books.

Eeyore builds with them. The very mild filtering is NOT there for anti-aliasing
or anti-imaging purposes.

Read a ****ing data sheet ! An UP TO DATE one perhaps ?

Graham

[Eeyore]

John Byrns wrote:

I thought oversampling DACs were invented because Philips only had a 14 bit DAC
available when they compromised with Sony on the CD spec. and needed a way to
get 16 bits out of their existing 14 bit converter? ;-)

Clearly you're a bit muddled.

Graham