[Iain Churches]

Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

Regards to all
Iain

[Andre Jute]

Iain Churches wrote:
Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

Ooh, nice.

It's a joint effort together with my pal Markus.

How much for your metalworker, Iain?

He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

Regards to all
Iain

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[John Byrns]

In article ,
"Iain Churches" wrote:

Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

It would be interesting to hear how you implemented the "balanced-line
XLR" inputs and outputs on the "balanced line version" of the Type 203
Pre-amplifier?


Regards,

John Byrns

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

[Phil Allison]

"Iain ****wit Churches"


Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.



** What a pile of masturbation fantasy CRAP !!!!

Bags of non linear distortion added to buckets full of noise.

120 uV at line level is just APPALLING !!!


OK for well used, 78 rpm shellacs !!!!!!!




......... Phil

[Patrick Turner]

Iain Churches wrote:

Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

Regards to all
Iain

Blimey, fancy welcoming comments of interest so soon.

People are already questioning noise levels and
implementation of balanced/unbalanced.

So where is the schematic?

Patrick Turner.

[Arny Krueger]

"Phil Allison" wrote in message

"Iain ****wit Churches"


Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

** What a pile of masturbation fantasy CRAP !!!!

Phil, regrettably, it all seems real enough - no fantasy.

It may be crap, but it is gilt-edged crap. ;-)

Bags of non linear distortion added to buckets full of
noise.

Note the use of the outdated and obfuscatory THD measurement.

120 uV at line level is just APPALLING !!!

Agreed. Gives that nice *sheen* to your vinyl. ;-)

OK for well used, 78 rpm shellacs !!!!!!!

[Iain Churches]

"John Byrns" wrote in message
...

It would be interesting to hear how you implemented the "balanced-line
XLR" inputs and outputs on the "balanced line version" of the Type 203
Pre-amplifier?


Hi John

Broadcast grade line transformers type 3575e and 5069e
from Sowter UK.

Iain

[Iain Churches]

"Phil Allison" wrote in message
...

** What a pile of masturbation fantasy CRAP !!!!

Thanks Phil. I just *knew* you would be enthusiastic:-)))

Bags of non linear distortion added to buckets full of noise.

THD is 0.02%

120 uV at line level is just APPALLING !!!

Ref 2V it equates to -84dB
that's 90 dB A weighted.

With gain at max driving the Radford STA 100 and also my
own EL34 PPP 50Wamp, there is no noise audible from the
listening position.

It sounds very well indeed. Just as a 6SN7 tube amp should.

Iain

[Iain Churches]

"Patrick Turner" wrote in message
...


Iain Churches wrote:

Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

Regards to all
Iain

Blimey, fancy welcoming comments of interest so soon.

This preamp has been auditioned by a lot of people
all of whom have liked it very much, so I was interested
to hear the comments from people here on RAT.

I just knew that Phil and Arny would be the first to
take the hook. I learned long ago not to take either of
them too seriously - neither of them seem to have built
anything. But I am glad they have teamed up, they
deserve each other:-)))

People are already questioning noise levels and
implementation of balanced/unbalanced.

John's question about the symmetrical input/output
is a valid one. Sowter make excellent broadcast
grade transformers for this purpose, which are used
in many studios that have tube equipment. The amp
itself does not need to have a differential in/out.

So where is the schematic?

Its the generic ALCF (Tremaine etc etc)


Regards
Iain

[Iain Churches]

"Andre Jute" wrote in message
ups.com...

Iain Churches wrote:
Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

Ooh, nice.

It's a joint effort together with my pal Markus.

How much for your metalworker, Iain?


Hi Andre,

Building this preamp has been an interesting exercise.
We started off by asking a panel of about twenty people
what they would like to see and hear from a tube amp.

It became clear quite early on that "perceived quality"
is important these days.

We had a huge list of questions, and made up several
chassis and front panels in different formats.

Comments were interesting. Most people were averse to
the ubiquitous silver anodised equipment that seems to
adorn every hi fi shop. Most preferred filament indicator
lamps to LEDs (when someone bothered to show them
the difference)

Most preferred engraved panels to silk screen.
All preferred our laser etched dials to either of the
other two possibilities.

There were three versions built,

a) a mu follower,
b) a cascode
c) this active load cathode follower.

In listening tests, people chose C.
Where CD is the principal source one does
not need a shirtload of gain, so this topology
seems ideal.

Best regards
Iain

[Peter Wieck]

On Apr 10, 3:51 am, "Iain Churches" wrote:
Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

Regards to all
Iain

Well, it is gorgeous. And it appears to offer all sorts of flexibility
with standard RCA and XLR options. I am sure you would not let
anything escape into the world if it did not also sound well too. My
only question offered tongue-in-cheek would be as to whether you
auditioned the circuits to your *listeners* (as compared to your
*viewers*) prior to making the units? The build-quality (electrically/
mechanically) looks as good as the cabinets.

I also noted the engraved lettering (same laser, I guess?). A very
nice touch.

I will look at the kluge I have presently sitting to one side of the
bench and dream about putting it in better surroundings. It "works",
so far, but has a long way to go before it is fit for polite society.
I have no capacity to bend gauge-metal in-house but I can punch and
drill accurately. So a lot of thought will have to go into the chassis
before I send out to have it bent. This also precludes laser work as I
cannot justify the cost, but silk-screen work or even photo-etching is
possible and within my skill-set. We shall see... July/August at best
for a product worthy of pictures.

Thanks for the inspiration.

Peter Wieck
Wyncote, PA

[Iain Churches]

"Peter Wieck" wrote in message
ps.com...
On Apr 10, 3:51 am, "Iain Churches" wrote:
Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html


Well, it is gorgeous. And it appears to offer all sorts of flexibility
with standard RCA and XLR options. I am sure you would not let
anything escape into the world if it did not also sound well too. My
only question offered tongue-in-cheek would be as to whether you
auditioned the circuits to your *listeners* (as compared to your
*viewers*) prior to making the units? The build-quality (electrically/
mechanically) looks as good as the cabinets.

Yes indeed. They got to listen to all three topologies.
Both the mu follower and the cascode have considerable gain
so we had to make sure that all units played at the same level.
The viewers were also the listeners.

It's fun to start with a blank sheet of paper as it were,
and to ask people what they would like to see. Many
don't want to commit themselves. It is quite a different
matter when faced with a fait-accomplis for them to be
able to ask "why did you do it like that?" :-))


I will look at the kluge I have presently sitting to one side of the
bench and dream about putting it in better surroundings. It "works",
so far, but has a long way to go before it is fit for polite society.

For me that has always been the major problem with home made
amps - to make them look like hand-made amps. My first
attempt at a power amp was distinctly "agricultural" even
though it performed as well as a commercially produced unit,
and still does. This amp is nearly forty years old. It was
originally housed in a gold hammer finish chassis.


http://www.kolumbus.fi/iain.churches...ier/252.02.jpg


I have no capacity to bend gauge-metal in-house but I can punch and
drill accurately. So a lot of thought will have to go into the chassis
before I send out to have it bent. This also precludes laser work as I
cannot justify the cost, but silk-screen work or even photo-etching is
possible and within my skill-set. We shall see... July/August at best
for a product worthy of pictures.

Please keep us up to date. You have a lot more technical
knowledge than I have. Your thread will be of great interest.
RAT needs a massive injection of vitamin T


Best regards
Iain

[Andre Jute]

Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

I'm not surprised that that quality of casework gives people a
perceived sense of high added value and that this carries over into
their perception of the sound. Nor am I at all surprised that they
chose the active load cathode follower topology. There is a lot going
on below the official limit of audibility that remains to be
investigated because it definitely affects people's reactions.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Phil Allison]

"Iain Churches"

"Phil Allison"
** What a pile of masturbation fantasy CRAP !!!!

Thanks Phil. I just *knew* you would be enthusiastic:-)))

Bags of non linear distortion added to buckets full of noise.

THD is 0.02%


120 uV at line level is just APPALLING !!!

Ref 2V it equates to -84dB



** Shame how that is way below normal hi-fi standards.

No way the noise level sound be THAT high in a unity gain tube stage.

What the hell did you do wrong ?




........ Phil

[west]

"Iain Churches" wrote in message
.fi...

"Peter Wieck" wrote in message
ps.com...
On Apr 10, 3:51 am, "Iain Churches" wrote:
Andre asks what all the tubeheads are doing.
You can see what this tubehead is doing at:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html


Well, it is gorgeous. And it appears to offer all sorts of flexibility
with standard RCA and XLR options. I am sure you would not let
anything escape into the world if it did not also sound well too. My
only question offered tongue-in-cheek would be as to whether you
auditioned the circuits to your *listeners* (as compared to your
*viewers*) prior to making the units? The build-quality (electrically/
mechanically) looks as good as the cabinets.

Yes indeed. They got to listen to all three topologies.
Both the mu follower and the cascode have considerable gain
so we had to make sure that all units played at the same level.
The viewers were also the listeners.

It's fun to start with a blank sheet of paper as it were,
and to ask people what they would like to see. Many
don't want to commit themselves. It is quite a different
matter when faced with a fait-accomplis for them to be
able to ask "why did you do it like that?" :-))


I will look at the kluge I have presently sitting to one side of the
bench and dream about putting it in better surroundings. It "works",
so far, but has a long way to go before it is fit for polite society.

For me that has always been the major problem with home made
amps - to make them look like hand-made amps. My first
attempt at a power amp was distinctly "agricultural" even
though it performed as well as a commercially produced unit,
and still does. This amp is nearly forty years old. It was
originally housed in a gold hammer finish chassis.


http://www.kolumbus.fi/iain.churches...ier/252.02.jpg


I have no capacity to bend gauge-metal in-house but I can punch and
drill accurately. So a lot of thought will have to go into the chassis
before I send out to have it bent. This also precludes laser work as I
cannot justify the cost, but silk-screen work or even photo-etching is
possible and within my skill-set. We shall see... July/August at best
for a product worthy of pictures.

Please keep us up to date. You have a lot more technical
knowledge than I have. Your thread will be of great interest.
RAT needs a massive injection of vitamin T


Best regards
Iain

Simply gorgeous Iain. What type of RCA connectors are you using? The way
they are seated looks smart, but this is the first time I seen that
configuration type. Also, are those Jensen Oil Caps used for the coupling?
You only needed 1 per stage? Maybe there's another turret in there. Anyway,
I think you set the bar real high for us, at least as looks go.

west

[John Byrns]

In article ,
"Phil Allison" wrote:

"Iain Churches"

"Phil Allison"
** What a pile of masturbation fantasy CRAP !!!!

Thanks Phil. I just *knew* you would be enthusiastic:-)))

Bags of non linear distortion added to buckets full of noise.

THD is 0.02%


120 uV at line level is just APPALLING !!!

Ref 2V it equates to -84dB


** Shame how that is way below normal hi-fi standards.

No way the noise level sound be THAT high in a unity gain tube stage.

What the hell did you do wrong ?

For the first time in a long time I have to agree with Phil, something
just doesn't add up here. By the way, where did these specs. come from,
did I miss a link on Ian's page?


Regards,

John Byrns

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

[Phil Allison]

"John Byrns
"Phil Allison"
"Iain Churches"

** What a pile of masturbation fantasy CRAP !!!!

Thanks Phil. I just *knew* you would be enthusiastic:-)))

Bags of non linear distortion added to buckets full of noise.

THD is 0.02%


120 uV at line level is just APPALLING !!!

Ref 2V it equates to -84dB


** Shame how that is way below normal hi-fi standards.

No way the noise level sound be THAT high in a unity gain tube stage.

What the hell did you do wrong ?

For the first time in a long time I have to agree with Phil, something
just doesn't add up here. By the way, where did these specs. come from,
did I miss a link on Ian's page?



** The specs are at the bottom of the page.

120uV of input noise is equivalent to that of a 50 Mohm resistor !!

The figure ought to be more like 5 or 10 uV.




......... Phil

[Patrick Turner]

Andre Jute wrote:

Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

I think perhaps you could be guessing about what is in Iain's preamp.

He has avoided giving us a schematic.

He started off saying it was generic 6SN7 used as a gain stage followed
by cathode follower,
as Tremaine may have desribed in 1963, but then talks about listening
tests
using vastly fifferent topolgies, and just what is in the box is a
complete mystery.

Perhaps he don't want to give away copyable secrets.
This is not very nice. At r.a.t we are supposed to be a free tube-craft
information outlet for the WWW.
I have 18mB at a website and page after page of schematics which anyone
is free to use.

But Allan Wright's special super cathode follower is only just that, and
whether
it dramatically increases sonic heaven's enthralling qualities is a moot
point.

Patrick Turner.



I'm not surprised that that quality of casework gives people a
perceived sense of high added value and that this carries over into
their perception of the sound. Nor am I at all surprised that they
chose the active load cathode follower topology. There is a lot going
on below the official limit of audibility that remains to be
investigated because it definitely affects people's reactions.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Patrick Turner]

John Byrns wrote:

In article ,
"Phil Allison" wrote:

"Iain Churches"

"Phil Allison"
** What a pile of masturbation fantasy CRAP !!!!

Thanks Phil. I just *knew* you would be enthusiastic:-)))

Bags of non linear distortion added to buckets full of noise.

THD is 0.02%


120 uV at line level is just APPALLING !!!

Ref 2V it equates to -84dB


** Shame how that is way below normal hi-fi standards.

No way the noise level sound be THAT high in a unity gain tube stage.

What the hell did you do wrong ?

For the first time in a long time I have to agree with Phil, something
just doesn't add up here. By the way, where did these specs. come from,
did I miss a link on Ian's page?

Regards,

John Byrns


It should be possible to select a 6SN7 which has no more than 4uV of
input noise,
with input grounded via a shorting plug in an RCA input socket.
If the gain is a typical 16, noise should then become 64uV at the
output.

If we only want 64mV of signal to give healthy levels in a power amp,
the SNR would then be -60dB, unweighted.

In Leak amp whose sensitivity is 100mV for 20 watts, 64mV is too much,
but in a modern amp needing 1V for 100W, 64mV could be about right
to make a very loud 2.8V at the speaker. So perhaps only 16mV is needed
for ordinary listening, so the SNR would then be only -48dB, unweighted.

But we have no schematic of what Iain has done inside the fancy-shmancy
box.

I've found that 6CG7 generally have less noise than 6SN7, with the same
gain & Ra,
and some samples measure only 1uV of input noise.

If there is no gain, and the input signal from the CD player is just
attentated
with a pot from 1V to 16mV, ( -36dB, or about 9am pot position ),
then fed to a CF then tube noise isn't amplified, and a
good SNR is maintained.

Patrick Turner.


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

[Patrick Turner]

Phil Allison wrote:

"John Byrns
"Phil Allison"
"Iain Churches"

** What a pile of masturbation fantasy CRAP !!!!

Thanks Phil. I just *knew* you would be enthusiastic:-)))

Bags of non linear distortion added to buckets full of noise.

THD is 0.02%


120 uV at line level is just APPALLING !!!

Ref 2V it equates to -84dB


** Shame how that is way below normal hi-fi standards.

No way the noise level sound be THAT high in a unity gain tube stage.

What the hell did you do wrong ?

For the first time in a long time I have to agree with Phil, something
just doesn't add up here. By the way, where did these specs. come from,
did I miss a link on Ian's page?


** The specs are at the bottom of the page.

120uV of input noise is equivalent to that of a 50 Mohm resistor !!

The figure ought to be more like 5 or 10 uV.

If the gain is 16, typical for a 6SN7,
getting 10uV of output noise even with a grounded input seems
unlikely/impossible. The only way to achieve it would be to throw out
the tube and use
fet input such as a 2SK369/2SK170/2SK147 etc, or perhaps a high gm
triode, 6C45pi,
417A etc.
But all these devices have far too much gain necessitating lots of NFB.

Perhaps he did not test with a grounded input.

And perhaps he used a noisy 6SN7.

We do not really know anything much about Iain's amp without
seeing the schematic.

There is no accompanying Draft Report of several pages about his amp.

Patrick Turner.

........ Phil

[Phil Allison]

"Patrick Turner"


If the gain is 16, typical for a 6SN7,


** The stage is a cathode follower.

Has unity gain.

The first line on Iain's page says so.




......... Phil

[Phil Allison]

"Patrick Turner"


It should be possible to select a 6SN7 which has no more than 4uV of
input noise,
with input grounded via a shorting plug in an RCA input socket.
If the gain is a typical 16, noise should then become 64uV at the
output.


** The stage is a cathode follower.

Has unity gain.

The first line on Iain's page says so.




......... Phil

[Iain Churches]

"west" wrote in message
news:9tWSh.1407$ok6.1308@trnddc07...

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

Simply gorgeous Iain. What type of RCA connectors are you using? The way
they are seated looks smart, but this is the first time I seen that
configuration type.

Hi West.

They are the size D Neutrik pattern NF-2D-B-W
They are standard issue in studio and broadcast
facilities.

You can see them at:
http://www.audiogear.com/Neutrik-RCA-Plugs.html

They are isolated from the chassis, so that you can make a
separate star ground back to a single point. Also they
use the same hole as the XLR connector, making it
possible to "mix and match" inputs and outputs
using the same panel.


Also, are those Jensen Oil Caps used for the coupling?

Those are the output caps. They are copper foil
paper in oil type. There is a silver version, several times the
price. I am not sure if this can be justified.

You only needed 1 per stage? Maybe there's another turret in there.
Anyway,
I think you set the bar real high for us, at least as looks go.

It sounds well too.

West. Posting anything to RAT is inviting a hail of
ridicule and derision from a few people who do not
actually build anything themselves. You know who
they a-) Don't be discouraged by this. A great
many people avoid Usenet to keep away from these
belligerents. That's a great loss to the subscribers
here on RAT.

I have received as many replies and comments re
this preamp, by e.mail direct as I have on the NG,
and people off-list are usually much
more helpful and constructive.

Best regards
Iain

[Iain Churches]

"Andre Jute" wrote in message
ups.com...
Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

This is not the Wright Schematic, but the generic active load
cathode follower which can be found in many textbooks.

I'm not surprised that that quality of casework gives people a
perceived sense of high added value and that this carries over into
their perception of the sound. Nor am I at all surprised that they
chose the active load cathode follower topology. There is a lot going
on below the official limit of audibility that remains to be
investigated because it definitely affects people's reactions.

I got the idea for this unit while recently working at a
CD mastering facility that had an all tube listenening room,
set up for clients to approve their CDs at the pre production
stage. Their system had a mu-follower which sounded very
good indeed, but had too much gain.

When we did the original aural evaluation of the three
possible formats, we had a completed
psu, with three bare chassis, each with its own board.
Most people listened with their eyes closed:-)

The pics are perhaps not good enough to show them
but there are some very nice design touches. For
example the stainless steel graduation disc on each knob
is 45mm in diameter by 2mm. These are set into a milled
out circular recess in the front panel 45.5mm by 2.4mm
so that the disc sits flush with the front panel.

Removing the stainless steel grille to change the tubes
reveals what appears like an empty compartment with
just the tubes and the tube bases set horizontally into a
4mm bulkhead. There is a "false floor" under which
the cable harness runs to the input selector and
switched attenuators at the front.

Regards
Iain

[Iain Churches]

"John Byrns" wrote in message
...


For the first time in a long time I have to agree with Phil, something
just doesn't add up here. By the way, where did these specs. come from,
did I miss a link on Ian's page?

Morning John.

Last night, I listened to Shostakovich 2nd Symphony (Op 14)
the excellent interpretation by Gothenburg Symphony Orchestra
conducted by Neeme Järvi.

I turned up the level so that I could not stay in the room.
Then, using the remote, I put the CD player onto pause,
and returned to my listening chair. There was silence, so I
think the performance of the preamp is as it should be.

There are two possibilities here.
a) The pair of tubes I have fitted (RCA cleartops) are noisy
(possible but unlikely)

b) My noise measurement methods are incorrect (much
more likely)

The preamp has been packed up now, and shipped off
to the first of several people who want to hear it. So I
shall not be able to investigate further for a while.

What sort of a SNR (A weighted) should I expect
from an active loaded cathode follower?

Many thanks for your input
Iain

[Iain Churches]

"Patrick Turner" wrote in message
...


Andre Jute wrote:

Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

I think perhaps you could be guessing about what is in Iain's preamp.

He has avoided giving us a schematic.

He started off saying it was generic 6SN7 used as a gain stage followed
by cathode follower,
as Tremaine may have described in 1963, but then talks about listening
tests
using vastly fifferent topolgies, and just what is in the box is a
complete mystery.

Tremaine 4th edition dates from 1975.

No mystery Patrick. I stated clearly that it is an active load cathode
follower, which was chosen after comparison with a mu-follower and
a cascode.

I have no schematic drawn. It can be found in any one of a dozen
books


Perhaps he don't want to give away copyable secrets.

Copyable secrets? LOL. People have been using this topology
for 50 years:-)) It was used in line and distribution amps in studios
and broadcast everywhere. I can remember seeing racks and racks
of 'em.

But Allan Wright's special super cathode follower is only just that, and
whether
it dramatically increases sonic heaven's enthralling qualities is a moot
point.

I thought the Allen Wright super deluxe sounded rather good.

Iain

[Patrick Turner]

Phil Allison wrote:

"Patrick Turner"


If the gain is 16, typical for a 6SN7,

** The stage is a cathode follower.

Has unity gain.

The first line on Iain's page says so.

You are right. My Netscape 4.8 browser didn't open the page up very well
at all, but
its much clearer in OE, and sure, 2.1V in, 2.0V out, and 120uV of noise
is, well,
quite attrocious as you say.

I did Iain's post where I had asked...

So where is the schematic?

and he answers.....

Its the generic ALCF (Tremaine etc etc)

Am I supposed to be able to read minds or something?

Eventually, we will coax a schematic from the man, and why the noise is
so high.

Patrick Turner.




........ Phil

[Patrick Turner]

Iain Churches wrote:

"west" wrote in message
news:9tWSh.1407$ok6.1308@trnddc07...

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

Simply gorgeous Iain. What type of RCA connectors are you using? The way
they are seated looks smart, but this is the first time I seen that
configuration type.

Hi West.

They are the size D Neutrik pattern NF-2D-B-W
They are standard issue in studio and broadcast
facilities.

You can see them at:
http://www.audiogear.com/Neutrik-RCA-Plugs.html

They are isolated from the chassis, so that you can make a
separate star ground back to a single point. Also they
use the same hole as the XLR connector, making it
possible to "mix and match" inputs and outputs
using the same panel.

Also, are those Jensen Oil Caps used for the coupling?

Those are the output caps. They are copper foil
paper in oil type. There is a silver version, several times the
price. I am not sure if this can be justified.

You only needed 1 per stage? Maybe there's another turret in there.
Anyway,
I think you set the bar real high for us, at least as looks go.

It sounds well too.

West. Posting anything to RAT is inviting a hail of
ridicule and derision from a few people who do not
actually build anything themselves. You know who
they a-) Don't be discouraged by this. A great
many people avoid Usenet to keep away from these
belligerents. That's a great loss to the subscribers
here on RAT.


I have invited a hail of criticism at times but
made sure I was well covered with facts and answers.

I am continually making piles of stuff, and am repairing/re-engineering
gear all through my days, and the results of the thought behind the
dull boring donkey work of arrangeing bits of metal to fit together
are all carefully displayed and explained at my website.


So when anyone else presents their gear with what seems to be a noise
problem, and no schematic,
and only some rather hard to see dark photos,
indicating the obvious craftwork on the metal and fittings, I wonder
just how good it is, because metalwork has almost zero effect on the
sound
and electronic functions. Its your grasp of electronic understanding
that we wish to witness.

If all you have in the box is a cathode follower, fine, it should
definately
sound fine, and have low THD, and low noise.

But is there not a gain stage? what are all the bits I see on the turret
board?

Patrick Turner.



I have received as many replies and comments re
this preamp, by e.mail direct as I have on the NG,
and people off-list are usually much
more helpful and constructive.

Best regards
Iain

[Patrick Turner]

Iain Churches wrote:

"Andre Jute" wrote in message
ups.com...
Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

Allan Wright's super CF or whatever he calls it has the anode supply
to the actual signal handling CF bootstrapped of the signal CF by a
seconf CF.
And I recall there is an active cathode load.

This is not the Wright Schematic, but the generic active load
cathode follower which can be found in many textbooks.

But there are more ways than one to do active loading and such details
are rare in texbooks.

So where is the schematic?

Patrick Turner.


I'm not surprised that that quality of casework gives people a
perceived sense of high added value and that this carries over into
their perception of the sound. Nor am I at all surprised that they
chose the active load cathode follower topology. There is a lot going
on below the official limit of audibility that remains to be
investigated because it definitely affects people's reactions.

I got the idea for this unit while recently working at a
CD mastering facility that had an all tube listenening room,
set up for clients to approve their CDs at the pre production
stage. Their system had a mu-follower which sounded very
good indeed, but had too much gain.

When we did the original aural evaluation of the three
possible formats, we had a completed
psu, with three bare chassis, each with its own board.
Most people listened with their eyes closed:-)

The pics are perhaps not good enough to show them
but there are some very nice design touches. For
example the stainless steel graduation disc on each knob
is 45mm in diameter by 2mm. These are set into a milled
out circular recess in the front panel 45.5mm by 2.4mm
so that the disc sits flush with the front panel.

Removing the stainless steel grille to change the tubes
reveals what appears like an empty compartment with
just the tubes and the tube bases set horizontally into a
4mm bulkhead. There is a "false floor" under which
the cable harness runs to the input selector and
switched attenuators at the front.

Regards
Iain

[Patrick Turner]

Iain Churches wrote:

"Patrick Turner" wrote in message
...


Andre Jute wrote:

Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

I think perhaps you could be guessing about what is in Iain's preamp.

He has avoided giving us a schematic.

He started off saying it was generic 6SN7 used as a gain stage followed
by cathode follower,
as Tremaine may have described in 1963, but then talks about listening
tests
using vastly fifferent topolgies, and just what is in the box is a
complete mystery.

Tremaine 4th edition dates from 1975.

No mystery Patrick. I stated clearly that it is an active load cathode
follower, which was chosen after comparison with a mu-follower and
a cascode.

I have no schematic drawn. It can be found in any one of a dozen
books

Hardly any of us have a copy of Tremaine's 4th Edition, Audio
Encyclopedia.

There IS a MYSTERY.

How can we talk about your amp details without a schematic????????

It will be just bull****ting into the wind without one.

You may indeed have a nice device, but here you have to proove it.

Here is where when someone says something, it better be right,
and reasons given, or its deemed to be wrong.
When you show something, its prudent to offer the full story
with a schematic.



Perhaps he don't want to give away copyable secrets.

Copyable secrets? LOL. People have been using this topology
for 50 years:-))

Gee, I wish I knew what they were copying.


It was used in line and distribution amps in studios
and broadcast everywhere. I can remember seeing racks and racks
of 'em.

But we have no schematic.

Studios used a huge range of gear


But Allan Wright's special super cathode follower is only just that, and
whether
it dramatically increases sonic heaven's enthralling qualities is a moot
point.

I thought the Allen Wright super deluxe sounded rather good.

But it's extremely difficult to make a bad sounding triode catholic
follower.

Patrick Turner.



Iain

[Andre Jute]

Iain Churches wrote:
"Andre Jute" wrote in message
ups.com...
Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

This is not the Wright Schematic, but the generic active load
cathode follower which can be found in many textbooks.

I know, Iain. I was making a joke about the way Allen in his book
makes it sound as if his guru received the cathode follower and the
constant current source from the finger of God himself.

Anyway, you're not ready to be an audio guru yet. You're too young and
you have too much hair. Allen Wright and Holger Stein and Dieter
Ennemoser and I decided long ago that the only people who are
qualified to build good audio equipment are over fifty and going light
on top -- like us.

I'm not surprised that that quality of casework gives people a
perceived sense of high added value and that this carries over into
their perception of the sound. Nor am I at all surprised that they
chose the active load cathode follower topology. There is a lot going
on below the official limit of audibility that remains to be
investigated because it definitely affects people's reactions.

I got the idea for this unit while recently working at a
CD mastering facility that had an all tube listenening room,
set up for clients to approve their CDs at the pre production
stage. Their system had a mu-follower which sounded very
good indeed, but had too much gain.

When we did the original aural evaluation of the three
possible formats, we had a completed
psu, with three bare chassis, each with its own board.
Most people listened with their eyes closed:-)

The pics are perhaps not good enough to show them
but there are some very nice design touches. For
example the stainless steel graduation disc on each knob
is 45mm in diameter by 2mm. These are set into a milled
out circular recess in the front panel 45.5mm by 2.4mm
so that the disc sits flush with the front panel.

Music is an artistic experience. It should be accompanied by tactile
pleasure and pleasing design of the equipment. Black on black just
shows a lack of thought.

Removing the stainless steel grille to change the tubes
reveals what appears like an empty compartment with
just the tubes and the tube bases set horizontally into a
4mm bulkhead. There is a "false floor" under which
the cable harness runs to the input selector and
switched attenuators at the front.

The Quad 22 pre was built that way, with turrets screwed into the
metal to attach the components on the underside of the chassis holding
the tubes on top, and thus very easy to work on.

Regards
Iain

Slainte!

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Peter Wieck]

On Apr 10, 4:20 pm, "Iain Churches" wrote:
"Peter Wieck" wrote in message

ps.com...

On Apr 10, 3:51 am, "Iain Churches" wrote:

http://www.kolumbus.fi/iain.churches...ier/252.02.jpg

Wowsers... looks vaguely like:

http://www.radfordaudio.co.uk/ mid-page right.

Is yours the chicken or the egg?

Peter Wieck
Wyncote, PA

[John Byrns]

In article . com,
"Peter Wieck" wrote:

On Apr 10, 4:20 pm, "Iain Churches" wrote:
"Peter Wieck" wrote in message

ps.com...

On Apr 10, 3:51 am, "Iain Churches" wrote:

http://www.kolumbus.fi/iain.churches...ier/252.02.jpg

Wowsers... looks vaguely like:

http://www.radfordaudio.co.uk/ mid-page right.

Is yours the chicken or the egg?

How do you tell, which came first, the chicken or the egg? My wild
guess would be that Ian's amp was the "egg".


Regards,

John Byrns

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

[Phil Allison]

"Andre Jute"


I know, Iain. I was making a joke about the way Allen in his book
makes it sound as if his guru received the cathode follower and the
constant current source from the finger of God himself.


** Well, as a life long Scientologist - he would imply that, wouldn't he.

Only the "God" in question was his implanted, operating Thetan.



Anyway, you're not ready to be an audio guru yet. You're too young and
you have too much hair. Allen Wright and Holger Stein and Dieter
Ennemoser and I decided long ago that the only people who are
qualified to build good audio equipment are over fifty and going light
on top -- like us.


** Whaaaaattt ???

Kiwi ex pat Scientologist " Alien " Wright was going very thin on top way
back in 1980.

Looked a like some demented woman's idea of Yul Brynner.

I know, cos I briefly worked for the shonky idiot and met his various "
ladyfriends ".


LOL !!




........ Phil

[John Byrns]

In article ,
"Iain Churches" wrote:

No mystery Patrick. I stated clearly that it is an active load cathode
follower, which was chosen after comparison with a mu-follower and
a cascode.

I have no schematic drawn. It can be found in any one of a dozen
books

The cathode follower part sounds straight forward enough, but the
"active load" part could be anyone of a number of things. Is the
circuit what I think is called a "White" cathode follower?


Regards,

John Byrns

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

[John Byrns]

In article ,
"Iain Churches" wrote:

Removing the stainless steel grille to change the tubes
reveals what appears like an empty compartment with
just the tubes and the tube bases set horizontally into a
4mm bulkhead. There is a "false floor" under which
the cable harness runs to the input selector and
switched attenuators at the front.

Wouldn't it be better to eliminate the false floor and provide a steel
grille on the bottom to provide improved air circulation for better
cooling?

Maybe I shouldn't even suggest that as the steel grille on top is the
one design element that doesn't look quite right to my eye, although I
am not sure why.


Regards,

John Byrns

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

[Andre Jute]

Patrick Turner wrote:
Andre Jute wrote:

Iain Churches wrote:

c) this active load cathode follower.

In listening tests, people chose C.

Shh! Allen Wright will come demand a royalty. That's the big secrets
his guru passed on to him, to use cathode followers and to tie the
wright (sic -- heh-heh!) currents down tight.

I think perhaps you could be guessing about what is in Iain's preamp.

He has avoided giving us a schematic.

He started off saying it was generic 6SN7 used as a gain stage followed
by cathode follower,
as Tremaine may have desribed in 1963, but then talks about listening
tests
using vastly fifferent topolgies, and just what is in the box is a
complete mystery.

Perhaps he don't want to give away copyable secrets.
This is not very nice. At r.a.t we are supposed to be a free tube-craft
information outlet for the WWW.
I have 18mB at a website and page after page of schematics which anyone
is free to use.

But Allan Wright's special super cathode follower is only just that, and
whether
it dramatically increases sonic heaven's enthralling qualities is a moot
point.

Patrick Turner

RAT is a voluntary association. Everyone publishes what he likes in
whatever form he likes, and whatever he chooses to share with us is a
favour. We have no right to demand any more.

Your demand in another post that anyone who wants to post an amp on
RAT should document it fully, *and be prepared to defend it*,
encourages exactly the sort of adversarial procedure that has made RAT
the sewer it is.

Andre Jute

[Andre Jute]

Phil Allison wrote:
"Andre Jute"


I know, Iain. I was making a joke about the way Allen in his book
makes it sound as if his guru received the cathode follower and the
constant current source from the finger of God himself.

** Well, as a life long Scientologist - he would imply that, wouldn't he.

Only the "God" in question was his implanted, operating Thetan.

Anyway, you're not ready to be an audio guru yet. You're too young and
you have too much hair. Allen Wright and Holger Stein and Dieter
Ennemoser and I decided long ago that the only people who are
qualified to build good audio equipment are over fifty and going light
on top -- like us.

** Whaaaaattt ???

Kiwi ex pat Scientologist " Alien " Wright was going very thin on top way
back in 1980.

Naw, he didn't see the light about the best designers being over fifty
until he was himself over fifty... The minute he explained it to me, I
saw it too, probably because I'd just turned fifty.

Looked a like some demented woman's idea of Yul Brynner.

I know, cos I briefly worked for the shonky idiot and met his various "
ladyfriends ".

LOL !!

Allen's a guy of sudden enthusiasms, which is a kind way of saying
eccentric. I wonder how he goes down in Germany.

....... Phil

Thanks for the giggle, Phil.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[west]

"Iain Churches" wrote in message
.fi...

"west" wrote in message
news:9tWSh.1407$ok6.1308@trnddc07...

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

Simply gorgeous Iain. What type of RCA connectors are you using? The way
they are seated looks smart, but this is the first time I seen that
configuration type.

Hi West.

They are the size D Neutrik pattern NF-2D-B-W
They are standard issue in studio and broadcast
facilities.

You can see them at:
http://www.audiogear.com/Neutrik-RCA-Plugs.html

They are isolated from the chassis, so that you can make a
separate star ground back to a single point. Also they
use the same hole as the XLR connector, making it
possible to "mix and match" inputs and outputs
using the same panel.


Also, are those Jensen Oil Caps used for the coupling?

Those are the output caps. They are copper foil
paper in oil type. There is a silver version, several times the
price. I am not sure if this can be justified.

You only needed 1 per stage? Maybe there's another turret in there.
Anyway,
I think you set the bar real high for us, at least as looks go.

It sounds well too.

West. Posting anything to RAT is inviting a hail of
ridicule and derision from a few people who do not
actually build anything themselves. You know who
they a-) Don't be discouraged by this. A great
many people avoid Usenet to keep away from these
belligerents. That's a great loss to the subscribers
here on RAT.

I have received as many replies and comments re
this preamp, by e.mail direct as I have on the NG,
and people off-list are usually much
more helpful and constructive.

Best regards
Iain

Thanks for the kind words, Iain. When you throw a rock at a pack of jackals,
the closest one screams. Look at the follow-up thread. Need I say more?

Cordially,
west

[Ian Iveson]

Iain:

http://www.kolumbus.fi/iain.churches/Preamp/203A.html

It's a joint effort together with my pal Markus.
He is a very skilled metal worker and made the
casework, and also laser-cut the stainless steel
top grille.

We decided to do as much possible ourselves.
Any comments would be of interest.

Nice power plugs.

Screws holding the grill spoil the plot IMHO, more than your
accustomed eyes might suggest.

Difficult to know what to think of it otherwise without knowing what
the circuit is, exactly. Depends on context.

Things I build for myself, I try to style like weird science, rather
than engineering from the days of Edison, and your use of a double
skin chassis is well OTT.

As something styled for market, it would be interesting to know which.
These days, reliability and precision are hardly associated with
weightiness. People have learned the opposite.

All that metal should look like art, because it is obviously not
engineering.

Look at Border Patrol, or Audio Note. Chunky is out, svelte is in, for
the longer view.

But where is the circuit diagram. What did you hope we might discuss?

cheers, Ian