[Patrick Turner]

"Tynan AgviÐr" wrote:

Eeyore wrote in
:



Patrick Turner wrote:

Eeyore wrote:
Patrick Turner wrote:

Gee, all the guy wants is 6 triodes ( 3 x 6CG7 ) with bjt CCS
anode supplies, then all anodes with 47k to a common point, with
a cap to CF output buffer. Volume pots for each channel can be
before each 1/2 6CG7 triode.

It's very clear that you know nothing about the requirements of
pro-audio working.

If you put a level control BEFORE the gain stage your signal to
noise ratio will be truly appaling.

Not with line level signals and with low µ triodes.

The OP requires a MICROPHONE mixer.

Graham


Yessir. A couple of people have suggested line mixers, but I have no
interest in that.(defeats the whole purpose of the thing for me) Those
are readily available and many to choose from (from well respected
companies too). Ideally I would just have to bring(in addition to an
accessories bag with XLR cables, tape, etc).

1,) mics
2.) mixer

3.) recorder

4.) possibly HQ ADC (depending on which recorder I use...some of them
have ADCs that sound like hot ass..)

Thanks Mr. Turner and Graham(and Rudy and Ian) yall are great.

Please keep discussing, I love learning from you Old Guard guys.

But you will probably want to raise mic signals to line levels
before mixing them.

Hence a line level mixer AFTER the mic amps isn't such a silly idea.

Patrick Turner.

[Patrick Turner]

Eeyore wrote:

John Byrns wrote:

Ian Thompson-Bell wrote:
Tynan AgviÐr wrote:

How does one achieve the 48v phantom standard using tubes, and are there
any tube types that are more suitable for audio applications?


With tubes only you basically need an input transformer and as you know
there are plenty of good ones out there. Phantom power is then easily
applied to the primary of the transformer - it's just another power supply.

As to tube types more suitable to audio applications there is a strong
potential for another flame war here. That said, the ECC81/82/83 series
are popular triode choices along with the EF86 pentode.

Don't forget the 5879 pentode, my personal favorite. Two of these make
a great microphone amplifier. The 5879 can also be strapped for triode
operation if desired.

What bothers me about using a pentode is that you won't get the 'triode sound'
which is what in my estimation most 'tubeophiles' are seeking.

No, when the screen is connected to anode, you DO get triode sound,
and maybe often what is BETTER than pure triode, and better than any
other
device.

Don't get so bothered.

There is NO simple generic one-opinion-fits-all about audio design.



If I wanted to build a truly transparent mic amp I'd use semiconductors out of
preference since such a crcuit will certainly technically outperfrom any
equivalent tube circuitry in terms of outright linearity, noise, bandwidth and
response flatness by several orders of magnitude.

The several orders of magnitude means at least 1,000 times better, or
60dB better.

An preamp or mixer with 0.00001% isn't going to sound better than one
with 0.01%, OK.

And with triodes, 0.1% thd would still sound fine.
This means the design can use low µ triodes and little if any loop NFB.

Patrick Turner.

Graham

[Patrick Turner]

robert casey wrote:

Patrick Turner wrote:

robert casey wrote:

Mixing in the way you suggest will result in intermodulation !



This time I agree with you. Ran some spice simulations of the circuit,
with 3 6CG7 triodes wired up as described. Applied to each one a 100mv
sine wave. One triode got 1KHz, the 2nd 1.1KHz, and the 3rd 1.3KHz.
Got a lot of intermod, some only 70dB down, at 2.7KHz, 2.9Khz and 3KHz.



The natural level of IMD within the main signal being handled is far
greater than that caused by cross talk.
Your analysis is very poor, and you have NOT stated all conditions of
the test you say you have simulated

Upon further review, I found my mistake. I didn't run the simulation
long enough (DUH!), and the Forrier analysis was thus bogus. Ran it a
lot longer, and the IMD is at least 100dB down.

So you'd have to agree with me that utterly negligible IMD is caused by
my design idea.

Patrick Turner.

[Patrick Turner]

Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Ian Thompson-Bell wrote:
Tynan AgviÐr wrote:

How does one achieve the 48v phantom standard using tubes, and are
there any tube types that are more suitable for audio applications?


With tubes only you basically need an input transformer and as you know
there are plenty of good ones out there. Phantom power is then easily
applied to the primary of the transformer - it's just another power
supply.

As to tube types more suitable to audio applications there is a strong
potential for another flame war here. That said, the ECC81/82/83 series
are popular triode choices along with the EF86 pentode.

Don't forget the 5879 pentode, my personal favorite. Two of these make
a great microphone amplifier. The 5879 can also be strapped for triode
operation if desired.

What bothers me about using a pentode is that you won't get the 'triode
sound' which is what in my estimation most 'tubeophiles' are seeking.

You say most "tubeophiles" are seeking the "triode sound", can you
explain what you mean when you refer to the "triode sound", and contrast
it with the sound of pentodes?

The harmonic character of the distortion products created by the non-linear
transfer characteristic. The transfer characteristic of the triode and pentode
are markedly different.

http://www.google.com/search?n&q=%22triode+equation

Graham

Read RDH4 on comparisons between pentode signal tubes and their triode
connection.

In some cases the THD of the pentode is far less at low levels than with
triode.

A large number of fabulous recordings of the golden days of vinyl
were made with gear stuffed full of EF86 in either pentode or triode,
and also full of transformers, and THD was often 0.1% or more,
and not all just 2H.

You cannot generalize much about the sound of devices, transformers,
resistors, capacitors
and bits of connecting wire or soldering techiques and connector
platings.

It all depends on the integrity of the design.

Patrick Turner.

[Patrick Turner]

John Byrns wrote:

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Ian Thompson-Bell wrote:
Tynan AgviÐr wrote:

How does one achieve the 48v phantom standard using tubes, and are
there any tube types that are more suitable for audio applications?


With tubes only you basically need an input transformer and as you
know
there are plenty of good ones out there. Phantom power is then easily
applied to the primary of the transformer - it's just another power
supply.

As to tube types more suitable to audio applications there is a
strong
potential for another flame war here. That said, the ECC81/82/83
series
are popular triode choices along with the EF86 pentode.

Don't forget the 5879 pentode, my personal favorite. Two of these make
a great microphone amplifier. The 5879 can also be strapped for triode
operation if desired.

What bothers me about using a pentode is that you won't get the 'triode
sound' which is what in my estimation most 'tubeophiles' are seeking.

You say most "tubeophiles" are seeking the "triode sound", can you
explain what you mean when you refer to the "triode sound", and contrast
it with the sound of pentodes?

The harmonic character of the distortion products created by the non-linear
transfer characteristic. The transfer characteristic of the triode and
pentode
are markedly different.

http://www.google.com/search?n&q=%22triode+equation

Graham, you are avoiding the question, I know that triodes and pentodes
have markedly different transfer characteristics. I didn't ask you
about transfer characteristics, I asked you what you mean by "triode
sound", and how it differs from the sound of other devices?

Regards,

John Byrns

Its a somewhat pointless question to ask.

If I set out to make two mixers, one using all pentodes
and the other with all triodes, I doubt anyone could reliably tell them
apart
providing they both had good THD/IMD and BW and function abilities.
I'd try to use a minima of tubes and minima of feedback but obviously
the pentodes
would have more NFB than triodes since they have far more open loop
gain.
I always try to make my gear measure well without doing too many tricks,
ie, excessive NFB.

They both might sound different to an analog box full of opamps or
discrete bjts,
or full of digital counting devices,
and i'd hope that if the 3rd and 4th option were present for comparisons
that
ppl would choose the tubes anyway...

But if someone other than myself did the tubed design, maybe the sound
might be better or worse....

Their choice of loading the tubes and amount of FB and tube choice will
vary....


Patrick Turner.

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

[Patrick Turner]

Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:

You say most "tubeophiles" are seeking the "triode sound", can you
explain what you mean when you refer to the "triode sound", and contrast
it with the sound of pentodes?

The harmonic character of the distortion products created by the non-linear
transfer characteristic. The transfer characteristic of the triode and
pentode are markedly different.

http://www.google.com/search?n&q=%22triode+equation

Graham, you are avoiding the question, I know that triodes and pentodes
have markedly different transfer characteristics. I didn't ask you
about transfer characteristics, I asked you what you mean by "triode
sound", and how it differs from the sound of other devices?

Clearly the specific non-linearities of the transfer characteristic will affect
the sound. Do you not accept that ? Various devices have a 'sonic fingerprint' if
you like in this regard.

What are you trying to get at ?

Graham

The THD and IMD are often quoted as being the root cause of percieved
sound differences between two circuits doing the same job.

In comparisons of 4 different brands of 6CG7 a few years ago,
some were percieved as being better/worse/different to each other.
4 listeners were present on the day to make the comparisons.
For the record, NOS Siemans 6CG7 were percieved as more detailed, far
less harsh
than new made Russian EH6CG7. We concluded that nobody in their right
mind would use an EH6CG7.

Maybe it was a bad batch, but why? ask the GOT, maybe He knows.

I later tested the preamp in which the tests were made and found the THD
could NOT have exceeded 0.01% at any time during the tests.

This means that if the speaker signal was 2Vrms for 4 ohms for 1 watt.
the signal THD due to the preamp = 2Vrms / 10,000 = 0.2mVrms.(
0.0002Vrms )

I ask all of you, can anyone hear 0.2mV of crap signal fed to a normal
speaker of
90dB/W/M?????

So obviously, the idea that THD/IMD is always the cause of perceived
differences in devices is utter BS.

It just ain't necessarily so.

But a single lone triode can sound better than a single lone opamp.

Patrick Turner.

[Tynan AgviÐr]

Patrick Turner wrote in
:

Unfortunately, you are not a very technically literate person and
you said you didn't want to deal with any schematic details.

I will be the first to admit that. I can get down and dirty with music
theory, all forms of American and British literature,theology, and
language, but electronics fly right over my head. A pity because I have a
rabid interest in the subject.



Someone working to make what you want sure will have to deal with
technical issues though,
so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.

Patrick Turner.

Well, ive already stated that I will be using Phantom Powered Condensor
mics, Tube Mics with their own power supplies, ribbon mics, and
occasionally, a decent dynamic..but as far as specifics..

AKG 426B, highly modified from SPAudio with original CK12 capsules(brass,
not the mylar/pet garbage of recent times) modified to sub-micron
dimensions(greater transient response, sensitivity, detail)

Schoeps CMC 621, 641, 62s, 68

Gefell M296

Gefell MK221/MK202 Capsules with Josephson C617 bodies

Coles 4040 Ribbons

Gefell CMV 563

Mojave Audio MA200 modified for omnidirectional charactaristic

Electrovoice RE-16, RE20

SPaudio Modified U87

Klaus Heyne Modified u67

I mainly use the 426B(pretty much on every job it is in use..such a great
microphone, I bought the last 3 ever made) and the Gefells, and sometimes
the Coles 4040s in blumlein for the main pair..the others are used
sparingly, mainly when a client has to have "schoeps because thats what
everyone uses for classical yadda yadda"

(I normally do a main array with "outriggers" plus an ambience pair mixed
way down)

I also carry DPA 4006s with me to drive nails and practice drumming.

[Eeyore]

Patrick Turner wrote:

"Tynan AgviÐr" wrote:

Mr. Graham, and Mr. Turner(and anyone else)

does adding a mic amp section for each channel make a project like this
much harder?

Of course it does.

If you want each mic amp fully tubed...

But you need to KNOW exactly what you really want,
and be able to specify to a designer what microphone types are likely to
be used and design accordingly.

The 'microphone type' is going to be 150-600 ohm balanced studio mics. This
doesn't present any trouble.

Knowing what kind of 'voicing' he's looking for is the troublesome part. I've
been looking for schematics of classic German Telefunken mic amps of the 50s and
60s. These may represent a suitable starting point for a more modern design.

Graham

[Eeyore]

Patrick Turner wrote:

Attenuation may or may not worsen SNR

Signal attenuation ALWATS degrades SNR. Possibly by only a tiny bit but the
direction is invariably negative.

Graham

[Eeyore]

Patrick Turner wrote:

so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.

This is NOT an issue any more than it is for modern mic amps. Variable gain
between 20 and 80 dB plus a 20dB pad for high level signals will handle all
eventualities.

The input impedance will be ~ 2kohms which is a suitable load for all mics from
150-600 ohm source impedance. A switch selected 600 ohm input Zmay prove useful
to 'damp' certain more 'lively' mics.

Graham

[Eeyore]

Patrick Turner wrote:

But you will probably want to raise mic signals to line levels
before mixing them.

That's what a mixer DOES !

Graham

[Ian Thompson-Bell]

Eeyore wrote:

Patrick Turner wrote:

so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.

This is NOT an issue any more than it is for modern mic amps. Variable gain
between 20 and 80 dB plus a 20dB pad for high level signals will handle all
eventualities.


I would venture to suggest that for the vast majority of applications
and mics that 60dB max gain will be ample. At 80dB gain, even the
quietest preamps will give a S/N no better than about 50dB from a 200
ohm source.

Ian

[Ian Thompson-Bell]

John Byrns wrote:

What does the presence or absence of buffering have to do with the level
at which mixing is done?

As the OP already pointed out he said impedance not level.

Crosstalk only becomes an issue if a single
input must feed more than one bus, in which case a buffer serves a
useful purpose. What does buffering have to do with "noise issues"?


Two things. Mixing at high impedance introduces more noise so it is
better to mix a relatively low impedances. To drive a relatively low
impedance you need a buffer.


Second, the buffer is after the fader and pan pot and it directly feeds
the mix bus. Therefore, all the buffers, used or not, contribute noise
to the mix bus. 8 buffers adds 9dB of noise. The normal way to minimise
this is to include a channel cut switch after the buffer which switches
the bus feed from the buffer to ground.

Cheers

Ian

[Ian Thompson-Bell]

Patrick Turner wrote:

The THD and IMD are often quoted as being the root cause of percieved
sound differences between two circuits doing the same job.

In comparisons of 4 different brands of 6CG7 a few years ago,
some were percieved as being better/worse/different to each other.
4 listeners were present on the day to make the comparisons.
For the record, NOS Siemans 6CG7 were percieved as more detailed, far
less harsh
than new made Russian EH6CG7. We concluded that nobody in their right
mind would use an EH6CG7.

Maybe it was a bad batch, but why? ask the GOT, maybe He knows.

I later tested the preamp in which the tests were made and found the THD
could NOT have exceeded 0.01% at any time during the tests.


Yes, but what was the IM distortion?

Ian

[Eeyore]

Ian Thompson-Bell wrote:

Eeyore wrote:
Patrick Turner wrote:

so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.

This is NOT an issue any more than it is for modern mic amps. Variable gain
between 20 and 80 dB plus a 20dB pad for high level signals will handle all
eventualities.

I would venture to suggest that for the vast majority of applications
and mics that 60dB max gain will be ample. At 80dB gain, even the
quietest preamps will give a S/N no better than about 50dB from a 200
ohm source.

Whilst true, that didn't stop Neve consoles having an 80dB gain position and they
were noisier back then too. I think it's 70dB max now.

60dB isn't always enough.

Graham

[Eeyore]

Ian Thompson-Bell wrote:

Second, the buffer is after the fader and pan pot and it directly feeds
the mix bus. Therefore, all the buffers, used or not, contribute noise
to the mix bus. 8 buffers adds 9dB of noise.

I don't know where you get that from. The buffers I have in mind are
effectively noiseless.

Graham

[Ian Thompson-Bell]

Eeyore wrote:

Ian Thompson-Bell wrote:

Eeyore wrote:
Patrick Turner wrote:

so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.
This is NOT an issue any more than it is for modern mic amps. Variable gain
between 20 and 80 dB plus a 20dB pad for high level signals will handle all
eventualities.
I would venture to suggest that for the vast majority of applications
and mics that 60dB max gain will be ample. At 80dB gain, even the
quietest preamps will give a S/N no better than about 50dB from a 200
ohm source.

Whilst true, that didn't stop Neve consoles having an 80dB gain position and they
were noisier back then too. I think it's 70dB max now.

60dB isn't always enough.

Graham


Agreed, but given the mics and the applications the OP has listed I
suspect 60dB will be plenty in this application. Also, if we assume 10dB
in hand on the channel fader there's a total of 70dB gain available.

Cheers

Ian

[Ian Thompson-Bell]

Eeyore wrote:

Ian Thompson-Bell wrote:

Second, the buffer is after the fader and pan pot and it directly feeds
the mix bus. Therefore, all the buffers, used or not, contribute noise
to the mix bus. 8 buffers adds 9dB of noise.

I don't know where you get that from. The buffers I have in mind are
effectively noiseless.

Graham


Assume the buffers are identical and their output noise is -90dBu.
Select two channels and the total buffer noise on the bus will rise by
3dB. Select two more and it will rise another 3dB. Select four more and
it rises another 3dB - total 9dB.

I have been experimenting with CF buffers recently and it is hard to get
their output noise below -85dB. What were these noiseless buffers you
had in mind?

Cheers


Ian

[Eeyore]

Ian Thompson-Bell wrote:

Eeyore wrote:
Ian Thompson-Bell wrote:
Eeyore wrote:
Patrick Turner wrote:

so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.
This is NOT an issue any more than it is for modern mic amps. Variable gain
between 20 and 80 dB plus a 20dB pad for high level signals will handle all
eventualities.
I would venture to suggest that for the vast majority of applications
and mics that 60dB max gain will be ample. At 80dB gain, even the
quietest preamps will give a S/N no better than about 50dB from a 200
ohm source.

Whilst true, that didn't stop Neve consoles having an 80dB gain position and they
were noisier back then too. I think it's 70dB max now.

60dB isn't always enough.

Graham

Agreed, but given the mics and the applications the OP has listed I
suspect 60dB will be plenty in this application. Also, if we assume 10dB
in hand on the channel fader there's a total of 70dB gain available.

Cheers

Ian

I meant 60dB isn't enough even with 10dB in hand actually. He has some ribbons for
example. These are notoriously low output typically. It all depends on application of
course. It doesn't hurt to have an extra 10dB of gain on a switch but if you haven't
got it when you need it, the thing's useless.

Graham

[Eeyore]

Ian Thompson-Bell wrote:

Eeyore wrote:
Ian Thompson-Bell wrote:

Second, the buffer is after the fader and pan pot and it directly feeds
the mix bus. Therefore, all the buffers, used or not, contribute noise
to the mix bus. 8 buffers adds 9dB of noise.

I don't know where you get that from. The buffers I have in mind are
effectively noiseless.


Assume the buffers are identical and their output noise is -90dBu.

That's a big assumption. Is even a cathode follower that noisy ?


Select two channels and the total buffer noise on the bus will rise by
3dB. Select two more and it will rise another 3dB. Select four more and
it rises another 3dB - total 9dB.

I have been experimenting with CF buffers recently and it is hard to get
their output noise below -85dB. What were these noiseless buffers you
had in mind?

They're that bad ?

I was planning on cheating and using an enhanced complementary Class A emitter
follower solid-state buffer. It's easy to get sub 100 ohms output Z that way
and not influence the 'tube sound' adversely.

Graham

[John Byrns]

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:

You say most "tubeophiles" are seeking the "triode sound", can you
explain what you mean when you refer to the "triode sound", and
contrast
it with the sound of pentodes?

The harmonic character of the distortion products created by the
non-linear
transfer characteristic. The transfer characteristic of the triode and
pentode are markedly different.

http://www.google.com/search?n&q=%22triode+equation

Graham, you are avoiding the question, I know that triodes and pentodes
have markedly different transfer characteristics. I didn't ask you
about transfer characteristics, I asked you what you mean by "triode
sound", and how it differs from the sound of other devices?

Clearly the specific non-linearities of the transfer characteristic will
affect
the sound. Do you not accept that ? Various devices have a 'sonic
fingerprint' if
you like in this regard.

What are you trying to get at ?

I am trying to understand what this "triode sound" is that you talk
about? I understand that different transfer characteristics will have
different "sonic fingerprints", but that doesn't help me understand what
the "triode sound" is as applied to microphone amplifiers and mixers?


Regards,

John Byrns

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

[John Byrns]

In article ,
Ian Thompson-Bell wrote:

Patrick Turner wrote:

The THD and IMD are often quoted as being the root cause of percieved
sound differences between two circuits doing the same job.

In comparisons of 4 different brands of 6CG7 a few years ago,
some were percieved as being better/worse/different to each other.
4 listeners were present on the day to make the comparisons.
For the record, NOS Siemans 6CG7 were percieved as more detailed, far
less harsh
than new made Russian EH6CG7. We concluded that nobody in their right
mind would use an EH6CG7.

Maybe it was a bad batch, but why? ask the GOT, maybe He knows.

I later tested the preamp in which the tests were made and found the THD
could NOT have exceeded 0.01% at any time during the tests.


Yes, but what was the IM distortion?

Aren't THD and IMD levels pretty highly correlated unless there are
serious frequency response anomalies involved?


Regards,

John Byrns

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

[Eeyore]

John Byrns wrote:

Eeyore wrote:

Clearly the specific non-linearities of the transfer characteristic will
affect the sound. Do you not accept that ? Various devices have a 'sonic
fingerprint' if you like in this regard.

What are you trying to get at ?

I am trying to understand what this "triode sound" is that you talk
about? I understand that different transfer characteristics will have
different "sonic fingerprints", but that doesn't help me understand what
the "triode sound" is as applied to microphone amplifiers and mixers?

Yes, as I expected you're trolling.

Graham

[John Byrns]

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Eeyore wrote:

If I wanted to build a truly transparent mic amp I'd use
semiconductors
out of preference since such a crcuit will certainly technically
outperfrom

any equivalent tube circuitry in terms of outright linearity, noise,
bandwidth and response flatness by several orders of magnitude.

How much "transparency" do you really need? Once you achieve a certain
level of transparency you reach a point of diminishing returns, and
other factors become more important in a recording than overkill in the
microphone amplifier and mixer.

How much transparency do you want ? Why take risks on choosing an
inadequate
figure ? If the circuit can be made so linear as to provide say 0.001%
THD
(at the same time as having excellent noise and frequency response) why
not do
so
? It doesn't cost much. Only a few dollars.

The dollars all add up in the end.

About $3.50 for an LME49720 and 4810 in place of more humble offerings like
the
NE5532 or NJM4580 in a 3 op-amp mic amp and about 6c extra for 2 additional
ultra-linearing transistors for the discrete front end on a design I have in
mind..

No, you won't find them in a Behringer but that's not the kind of product
we're
discussing here.


What is the point in providing a THD of say 0.001%? Surely there are more
important things to worry about and to spend ones money on.

What is the point in NOT making the very best mic amp you can ?

We're talking a tiny fraction of the cost of an input transformer. The added
cost
of a couple of extra transistors and highly linear op-amps is negligible in
this
respect.

I repeat.. Why would you knowingly make something for high-end recording
worse than
it need be ?

Graham, you seem to have lost track of the fact that one of the bullet
points in the checklist for this design is that it is to be tube based.
All this talk of transistors and ICs doesn't move the ball forward as
much as a single mm.


Regards,

John Byrns

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

[John Byrns]

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:

http://www.normankoren.com/Audio/Tub...e_article.html

I incorporated the work of those two gentleman into my spice models more
than a decade ago IIRC.

Some how I doubt you made any SPICE models ever.

Can you explain how you come to that conclusion?

But I don't understand how you are making the jump from transfer curves to
the
"triode sound"?

You must be fairly stupid in that case or simply hankering after an argument.

Please note that as I stated in another post, I'm not saying that
different transfer curves don't have different sonic effects, I am
simply asking what the subjective effect of the "triode sound" is? In
the end we don't judge audio equipment by the shape of the transfer
characteristic of the active devices used, we judge it by what it sounds
like in the end.

Can you explain what you mean by the "triode sound"?

You're just trolling now. Stop being a ****wit.

Call it what you will, you used the term "triode sound" and I still have
no idea what you might mean by that? I am not an audiophile, however I
imagine the audiophiles reading this may think they know what it means,
but for all I know their notion of "triode sound", whatever it amy be,
is not necessarily congruent with yours.


Regards,

John Byrns

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

[John Byrns]

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:

So from that can we conclude that it is not necessary to use either a
cathode follower buffer, or a virtual earth scheme in a tube based mixer
of this sort?

If you don't buffer, the mixing will have to be done at relatively high
impedance and that has both cross-talk and noise issues.

What does the presence or absence of buffering have to do with the level
at which mixing is done?

I said IMPEDANCE not level. Can't you bloody well read ?

I guess not, sorry, I never said I was perfect.

Stop going off at a tangent to suit your own stupid argumentative agenda.

It was a mistake in reading as you point out, it was not intended as a
tangent. I do note however that you rarely or never answer questions
about what you say, perhaps you are lacking in understanding of the
information you like to regurgitate?


Regards,

John Byrns

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

[Eeyore]

"Tynan AgviÐr" wrote:

It's the critical section. That doesn't mean it's *hard* per se but
mic pres are an area where subjective opinions tend to carry weight
over technical specs.

so when I work with a designer, how to I go about conveying my ideas of
what sounds good, component wise?

The biggest problem is understanding what you mean by 'sounds good'. Since
scientific measurement has lattery been eclipsed to some degree by objective
assessemnts involving words like speed, imaging colour and depth (all of which
are IMHO entirely phoney concepts dreamt up only to market indifferent
products) that may be tricky !

A design engineer will classicly regard the 'component' with the most linear
frequency repsonse, lowest distortion and lowest noise as 'sounding good' but
certain people believe otherwise. What suggestions do you have in this regard ?



I mean, how does one go about selecting
transformers, tubes, etc?(The builder should be able to select items based
on what I tell them about my sound preferences, yes/?) I know of the
Lundahl that I mentioned because my electronaut m63 uses it(it had a Jensen
before that, and I did not like the sound as much).

Lundahl transformers are known to be technically excellent (in a truly
scientific way) so your preference comes as no surprise there. They would be my
choice too. I'm slightly surprised that you feel Jensen don't match them
though. Of course it may not have been the transformer at all that was the
reason why the M63 didn't please.


Often, a 'technically inferior' mic pre may be judged to 'sound
better'. Of course this is all related to what the 'tube sound' is all
about.

My requirements are that 1.) No detail is lost...no rolled off highs, lows,
etc(and yes, I know Ribbon Mics are quite famous for this, but they work
very well for certaain applications)2.) that no details are lost,

OK. A technically accurate mic preamp will do all of that without even thinking
about breaking out a sweat. It's quite simple. Did you know that most of the
classic and well regarded vintage tube mic pres actually have very POOR
frequency repsonse by modern standards though ? -3dB at the extremes of the
audio range would not be at all unusual.


and that the signal sounds "sweeter" than how it did before..bigger,
Euphonic,
smooth..nothing taken away, just everything sweetened..

Well, an accurate amplifier can't add anything any more than it doesn't detract
them either.

It's your search for this euphony that is probably leading you in the direction
of atube preamp with their attendant colourations (primarily low harmonic order
distortion).

One way to establish what you want here would be to ask for a reference product
or device that already has the characterisitcs that you like and use that to
define how much and what type of distortions you like.


Fine. You ned to consider how you want that gain to be adjusted. A
rotary switch with 10dB steps would seem to be the most suitable
method here I reckon. You WILL less than 60/70dB gain most of the
time.

Yes Sir.
I like sliding faders better for "feel" but the rotaries are able to yield
better sonic results, yes?

Sonic results in what way ?


(because of the ability to use stepped attenuation)

NO. It makes no difference whatever. Certainly stepped attenuators have no
advantage whatever. Where did you get these ideas ? Is it perhaps influenced by
an 'older is better' idea that someone suggested ?


A pad is easy. However using a pad in place of adjustable gain leads
to significantly poorer signal-to-noise ratio. I typically offer a pad
ONLY to deal with very high level sources.

yes, but sometimes a pad is necessary with the mics that I have. For
example , I have a couple pairs of josephson c617 bodies with Gefell MK221
and MK202 capsules..those things are so sensitive that with any moderate
levels at all, it is out of control without a pad. . Just impossible. Just
as in mics, I like having the PAD as a safety device.(I am thinking about a
limiter too)

Yes. I would unquestionably include a pad. I'm just saying you only actually
need to use it when the input signal is very large.


You mean how do you provide a tube regulated 48V DC supply ?

Yes Sir. Sorry for my poor wording. Ill get better, I promise.
I wasnt suggesting anything, I am just curious as ive seen t

I already have a VERY low noise 48V phantom supply design using
semiconductors. If you believe that the choice of tubes for a DC
supply would have ANY audible effect, I'd rather not take you on as a
client since I hate dealing with idiots.

Graham

Well, I am an idiot when it comes to this stuff,

I doubt you're actually an idiot, simply not technically knowledgeable. That's
no crime and the fact you acknowledge your limitations here is a good thing
since it'll help avoid misunderstandings.


so I guess that rules you out to work with me. I only know what sounds I
like.

Not at all.


How to get there
electroncally..hell if I know. I always rely on specialists for that.
So no...I wasnt suggesting anything. I was asking a question....If there
comes a time when I want to make a statement, I will do so in a manner that
leaves no doubts as to what I was doing. . If I had my own ideas about this
stuff I wouldnt be looking for help.

Understood. From what you've said so far I've managed to get a pretty clear
idea of what you're looking for I reckon.


I can tolerate "idiots" as they can
learn, provided they want to. Inflammatory and disrespectful assholes are
the only people I refuse to work with(one big reason I dont sing nearly as
much as I used to)..Opera and Classical Music--full of Arrogant Assholes.
Can not stand that type of person.

thanks for your continued help, Sir. It is much appreciated

You're welcome.

Graham

[Eeyore]

John Byrns wrote:

Eeyore wrote:

I repeat.. Why would you knowingly make something for high-end recording
worse than it need be ?

Graham, you seem to have lost track of the fact that one of the bullet
points in the checklist for this design is that it is to be tube based.

And you seem to have lost track of this section of the thread in that case.

Graham

[Eeyore]

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Eeyore wrote:

http://www.normankoren.com/Audio/Tub...e_article.html

I incorporated the work of those two gentleman into my spice models more
than a decade ago IIRC.

Some how I doubt you made any SPICE models ever.

Can you explain how you come to that conclusion?

You're not technically literate enough.

Graham

[John Byrns]

In article ,
Patrick Turner wrote:

robert casey wrote:

Patrick Turner wrote:

robert casey wrote:

Mixing in the way you suggest will result in intermodulation !



This time I agree with you. Ran some spice simulations of the circuit,
with 3 6CG7 triodes wired up as described. Applied to each one a 100mv
sine wave. One triode got 1KHz, the 2nd 1.1KHz, and the 3rd 1.3KHz.
Got a lot of intermod, some only 70dB down, at 2.7KHz, 2.9Khz and 3KHz.



The natural level of IMD within the main signal being handled is far
greater than that caused by cross talk.
Your analysis is very poor, and you have NOT stated all conditions of
the test you say you have simulated

Upon further review, I found my mistake. I didn't run the simulation
long enough (DUH!), and the Forrier analysis was thus bogus. Ran it a
lot longer, and the IMD is at least 100dB down.

So you'd have to agree with me that utterly negligible IMD is caused by
my design idea.

Yes, but you are going to have a hard time getting Eeyore to buy in.


Regards,

John Byrns

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

[RickH]

On Jan 12, 12:09*pm, "Arny Krueger" wrote:
"RickH" wrote in message



Mixing in the digital domain for the most part sounds
compromised,

Not enough noise and distortion for you, I take it?

there is nothing quite as open and deep as a good analog mix.

Why?

Take a
listen to the 1960's Frank Sinatra / Antonio Carlos Jobim album, the
mix on that puts ALL digital recordings of late to shame.

Talk about a BS comparison - where is the comparable digitally mixed
recording of 1960's Frank Sinatra / Antonio Carlos Jobim to compare with?

What the writer is doing is comparing a nice legacy album with a creation of
his imagination. He imagines that the same album produced digitally would
sound crappy, and that supposed to be definitive proof?

LOL!

It was most *likely mixed on a custom tube mixer, incredible as it
seems but I dont
see digital domain mixing (unless you've spent $80,000 on the
equipment) matching the best analog mixers which are much
cheaper.

The best analog mixers don't cost less than $80,000. It is easy to get up
into the quarter-half $million range if you're talking about a top quality
analog mixer.

I'll bet money you've never mixed anything of consequence digtally, and
you're talking out the back of your neck.

The OP is on the right track if he is attempting to match the quality
of that Frank/Jobim album for example.

In any performance the talent and quality of execution provided by the
performers is of the essence.

The next time I see Frank and Tony hanging out looking for a gig, I'll send
them your way... ;-)

Oh you'd rather have 32 DtoA conversions up front (on a 32 channel
panel for example) then do it all in DSP. Vs. keeping it all analog
then do one DtoA conversion for the master mix. I'll tell you right
now which one will sound "better", it will be the analog mix. The
digital mix with 32 DtoA conversions up front will sound compressed
and artificial, the nuances of the microphones will be lost in the
"too soon" DA conversion.

[John Byrns]

In article ,
Patrick Turner wrote:

Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Ian Thompson-Bell wrote:
Tynan AgviÐr wrote:

How does one achieve the 48v phantom standard using tubes, and
are
there any tube types that are more suitable for audio
applications?


With tubes only you basically need an input transformer and as you
know
there are plenty of good ones out there. Phantom power is then
easily
applied to the primary of the transformer - it's just another power
supply.

As to tube types more suitable to audio applications there is a
strong
potential for another flame war here. That said, the ECC81/82/83
series
are popular triode choices along with the EF86 pentode.

Don't forget the 5879 pentode, my personal favorite. Two of these
make
a great microphone amplifier. The 5879 can also be strapped for
triode
operation if desired.

What bothers me about using a pentode is that you won't get the 'triode
sound' which is what in my estimation most 'tubeophiles' are seeking.

You say most "tubeophiles" are seeking the "triode sound", can you
explain what you mean when you refer to the "triode sound", and contrast
it with the sound of pentodes?

The harmonic character of the distortion products created by the non-linear
transfer characteristic. The transfer characteristic of the triode and
pentode
are markedly different.

http://www.google.com/search?n&q=%22triode+equation

Graham

Read RDH4 on comparisons between pentode signal tubes and their triode
connection.

In some cases the THD of the pentode is far less at low levels than with
triode.

A large number of fabulous recordings of the golden days of vinyl
were made with gear stuffed full of EF86 in either pentode or triode,
and also full of transformers, and THD was often 0.1% or more,
and not all just 2H.

Yes, and the premium versions, I forget the type numbers, of the 6SJ7
were used to good effect here in the U.S., The 5879 also ccquitted
itself well.


Regards,

John Byrns

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

[John Byrns]

In article ,
Patrick Turner wrote:

John Byrns wrote:

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Ian Thompson-Bell wrote:
Tynan AgviÐr wrote:

How does one achieve the 48v phantom standard using tubes, and
are
there any tube types that are more suitable for audio
applications?


With tubes only you basically need an input transformer and as
you
know
there are plenty of good ones out there. Phantom power is then
easily
applied to the primary of the transformer - it's just another
power
supply.

As to tube types more suitable to audio applications there is a
strong
potential for another flame war here. That said, the ECC81/82/83
series
are popular triode choices along with the EF86 pentode.

Don't forget the 5879 pentode, my personal favorite. Two of these
make
a great microphone amplifier. The 5879 can also be strapped for
triode
operation if desired.

What bothers me about using a pentode is that you won't get the
'triode
sound' which is what in my estimation most 'tubeophiles' are seeking.

You say most "tubeophiles" are seeking the "triode sound", can you
explain what you mean when you refer to the "triode sound", and
contrast
it with the sound of pentodes?

The harmonic character of the distortion products created by the
non-linear
transfer characteristic. The transfer characteristic of the triode and
pentode
are markedly different.

http://www.google.com/search?n&q=%22triode+equation

Graham, you are avoiding the question, I know that triodes and pentodes
have markedly different transfer characteristics. I didn't ask you
about transfer characteristics, I asked you what you mean by "triode
sound", and how it differs from the sound of other devices?

Regards,

John Byrns

Its a somewhat pointless question to ask.

If I set out to make two mixers, one using all pentodes
and the other with all triodes, I doubt anyone could reliably tell them
apart
providing they both had good THD/IMD and BW and function abilities.
I'd try to use a minima of tubes and minima of feedback but obviously
the pentodes
would have more NFB than triodes since they have far more open loop
gain.
I always try to make my gear measure well without doing too many tricks,
ie, excessive NFB.

They both might sound different to an analog box full of opamps or
discrete bjts,
or full of digital counting devices,
and i'd hope that if the 3rd and 4th option were present for comparisons
that
ppl would choose the tubes anyway...

But if someone other than myself did the tubed design, maybe the sound
might be better or worse....

Their choice of loading the tubes and amount of FB and tube choice will
vary....

It's not pointless at all, Eeyore has injected "triode sound" into this
discussion as a supposed requirement.


Regards,

John Byrns

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

[Ian Thompson-Bell]

Eeyore wrote:

Ian Thompson-Bell wrote:

Eeyore wrote:
Ian Thompson-Bell wrote:

Second, the buffer is after the fader and pan pot and it directly feeds
the mix bus. Therefore, all the buffers, used or not, contribute noise
to the mix bus. 8 buffers adds 9dB of noise.
I don't know where you get that from. The buffers I have in mind are
effectively noiseless.

Assume the buffers are identical and their output noise is -90dBu.

That's a big assumption. Is even a cathode follower that noisy ?


Doesn't matter what the actual noise level is, the principle still
applies. If the buffer noise was -110dBu then I'd agree you could ignore it.



Select two channels and the total buffer noise on the bus will rise by
3dB. Select two more and it will rise another 3dB. Select four more and
it rises another 3dB - total 9dB.

I have been experimenting with CF buffers recently and it is hard to get
their output noise below -85dB. What were these noiseless buffers you
had in mind?

They're that bad ?


The ones I have at the moment are. I need to do more tests to confirm
it. The output Z is about 500 ohms so they are way noisier than the pure
resistive noise.

I was planning on cheating and using an enhanced complementary Class A emitter
follower solid-state buffer. It's easy to get sub 100 ohms output Z that way
and not influence the 'tube sound' adversely.


I think you may be on dodgy ground there. ;-)

Ian

[John Byrns]

In article ,
Ian Thompson-Bell wrote:

Eeyore wrote:

Patrick Turner wrote:

so you need to spell out clearly what mics you plan to use
so that levels and attenuation can be all tailored to suit
a best outcome.

This is NOT an issue any more than it is for modern mic amps. Variable gain
between 20 and 80 dB plus a 20dB pad for high level signals will handle all
eventualities.

I would venture to suggest that for the vast majority of applications
and mics that 60dB max gain will be ample. At 80dB gain, even the
quietest preamps will give a S/N no better than about 50dB from a 200
ohm source.

For those of us that are not "pro audio" designers, can you tell us what
the reference is for these gain figures, gain from input to what point?


Regards,

John Byrns

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

[Ian Thompson-Bell]

John Byrns wrote:

Aren't THD and IMD levels pretty highly correlated unless there are
serious frequency response anomalies involved?



Both depend on the non-linearities of transfer function of the device.
So for a particular device they will doubtless be correlated but between
different devices I don't know. As a rule IM tends to be higher than THD
and more unacceptable to the ear.

Ian

[John Byrns]

In article ,
Eeyore wrote:

John Byrns wrote:

Eeyore wrote:
John Byrns wrote:
Eeyore wrote:

http://www.normankoren.com/Audio/Tub...e_article.html

I incorporated the work of those two gentleman into my spice models more
than a decade ago IIRC.

Some how I doubt you made any SPICE models ever.

Can you explain how you come to that conclusion?

You're not technically literate enough.

Your logic is flawed, which isn't a big surprise, how does a lack of
technical literacy prevent one from messing about with the creation of
spice models?


Regards,

John Byrns

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

[Ian Thompson-Bell]

John Byrns wrote:

For those of us that are not "pro audio" designers, can you tell us what
the reference is for these gain figures, gain from input to what point?



Usually it is from mic input to a final output.

Cheers

ian

[Arny Krueger]

"RickH" wrote in message


Oh you'd rather have 32 DtoA conversions up front (on a
32 channel panel for example) then do it all in DSP. Vs.
keeping it all analog then do one DtoA conversion for the
master mix.

Absolutely.

I'll tell you right now which one will sound
"better", it will be the analog mix.

Only if you define "better" as poorer frequency response and more noise and
distrotion.

The digital mix with 32 DtoA conversions up front will sound compressed
and artificial

Maybe in some alternative universe.

, the nuances of the microphones will be lost in the "too soon" DA
conversion.

Tain't no such thing. A/D converters are getting so good that even the need
for mic preamps as we knew them is slipping. How so? Do the math and figure
out what 124 dB below +0 Vu is. Now compare that to the noise floor of a
good mic preamp.

[John Byrns]

In article ,
Ian Thompson-Bell wrote:

John Byrns wrote:

Aren't THD and IMD levels pretty highly correlated unless there are
serious frequency response anomalies involved?

Both depend on the non-linearities of transfer function of the device.
So for a particular device they will doubtless be correlated but between
different devices I don't know. As a rule IM tends to be higher than THD
and more unacceptable to the ear.

I agree that IMD is much more unacceptable to the ear than is simple HD,
and IMD may well be higher than THD, but I was simply trying to point
out that IMD and THD are highly correlated and as a rule you don't have
one without the other, and they pretty much track one another, when one
is higher, the other is also higher. In other words you can't build an
amplifier with high THD that doesn't also have high IMD, and if it has
low THD, as a rule it will also have low IMD.


Regards,

John Byrns

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