[tubegarden]

Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source under the
shared cathode of the 6J6

Merry Christmas and Happy New Ears!

Al


PS, I may us 5J6 or SV572-10 ...

[John Byrns]

In article
,
tubegarden wrote:

Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source under the
shared cathode of the 6J6

Merry Christmas and Happy New Ears!

What qualities does the 6J6 possess that recommend it for this service
over say an ECC81? I remember when some people considered the 6J6 to be
junk for audio purposes, but times change.


Regards,

John Byrns

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

[tubegarden]

On Dec 17, 12:05�pm, John Byrns wrote:

What qualities does the 6J6 possess that recommend it for this service
over say an ECC81? �I remember when some people considered the 6J6 to be
junk for audio purposes, but times change.

Regards,

John Byrns

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

Hi John,

I dunno, that is what the poster used. My guess is the shared cathode,
as the circuit brings the signal in on one grid and the parallel grid
is gounded, giving a one stage splitter/driver.

I ignore all comments on audio junk tubes

A few of us get circuits to sound good. Everybody is a "Knowledgeable
Critic". Sigh.

Happy Ears!
Al

[Doug Bannard]

"John Byrns" wrote in message
...
In article
,
tubegarden wrote:

Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source under the
shared cathode of the 6J6

Merry Christmas and Happy New Ears!

What qualities does the 6J6 possess that recommend it for this service
over say an ECC81? I remember when some people considered the 6J6 to be
junk for audio purposes, but times change.


Regards,

John Byrns

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

From looking at the transfer characteristics of both the 6J6 and the ECC81,
I see no overwhelming reason why the 6J6 would be considered to be junk for
audio purposes. The only potential "gotcha" is perhaps the maximum grid
circuit return resistance of 500kohms, but I think that biasing with a CCS
in the common cathode is certainly worth a try as long as the two sections
are well matched at the standing current selected.

As to the qualities that recommend it over an ECC81, price is the one that
jumps out at me. The 6J6 is dirt cheap and many of us probably have quite a
few in our collections (at least 50 new ones in my own collection).

Best Regards : Doug Bannard

[Andre Jute]

On Dec 17, 9:10 pm, "Doug Bannard" wrote:
"John Byrns" wrote in message

...



In article
,
tubegarden wrote:

Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source under the
shared cathode of the 6J6

Merry Christmas and Happy New Ears!

What qualities does the 6J6 possess that recommend it for this service
over say an ECC81? I remember when some people considered the 6J6 to be
junk for audio purposes, but times change.

Regards,

John Byrns

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

From looking at the transfer characteristics of both the 6J6 and the ECC81,
I see no overwhelming reason why the 6J6 would be considered to be junk for
audio purposes. The only potential "gotcha" is perhaps the maximum grid
circuit return resistance of 500kohms, but I think that biasing with a CCS
in the common cathode is certainly worth a try as long as the two sections
are well matched at the standing current selected.

As to the qualities that recommend it over an ECC81, price is the one that
jumps out at me. The 6J6 is dirt cheap and many of us probably have quite a
few in our collections (at least 50 new ones in my own collection).

Best Regards : Doug Bannard

Perhaps a question of tone not revealed by the transfer curves? The
12AT7, 12AU7 and 12AX7 each has a distinctive tone, for instance.

Andre Jute
A little inaccuracy sometimes saves tons of explanation. --H.H.Munro
("Saki")(1870-1916)

[robert casey]

Perhaps a question of tone not revealed by the transfer curves? The
12AT7, 12AU7 and 12AX7 each has a distinctive tone, for instance.


Those do have differing curves. And the "tone" will depend on the
circuit the tube is in as well. Swapping one for another will sound
different.

[Patrick Turner]

John Byrns wrote:

In article
,
tubegarden wrote:

Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source under the
shared cathode of the 6J6

Merry Christmas and Happy New Ears!

What qualities does the 6J6 possess that recommend it for this service
over say an ECC81? I remember when some people considered the 6J6 to be
junk for audio purposes, but times change.

6J6 is OK for the app considered in the LTP driver for EL84.

But it can be microphonic. I had a few smaples that were terrible in a
phono stage where
I thought they'd be just great because like the 12AT7/ECC81, the GM is
high so input noise would be low.

Patrick Turner.

Regards,

John Byrns

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

[Andre Jute]

On Dec 17, 4:21 pm, tubegarden wrote:
Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source

I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?

under the
shared cathode of the 6J6

Merry Christmas and Happy New Ears!

Al

PS, I may us 5J6 or SV572-10 ...

Now you're speaking in tongues a middle-aged bovver-boy like me can
understand! The SV572-10 is the real heavy metal rocker's amp out of
those Svetlana SV572-xx tubes, the -3 being a vocalist's delight with
one of the best midranges in the business, the -30 sounding pretty
punchy, verging on crude unless you matched it carefully to very
polite speakers, and the -160 being a pentode in drag (dunno what Svet
was thinking of adding it -- maybe some transmitting purpose outside
my ken).

Andre Jute
Perception is a skill that requires study and careful development over
a long period of time. Few have it as a natural gift. -- Iain Churches

[J.P.]

On Mon, 17 Dec 2007 14:03:36 -0800 (PST), Andre Jute
wrote:

On Dec 17, 4:21 pm, tubegarden wrote:
Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source

I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?

http://www.pmillett.com/current_source.htm

[Andre Jute]

On Dec 18, 12:54 am, J.P. wrote:
On Mon, 17 Dec 2007 14:03:36 -0800 (PST), Andre Jute

wrote:
On Dec 17, 4:21 pm, tubegarden wrote:
Hi RATs!

OK, 6J6 driving 6BQ5 P-P. Using IXYS constant current source

I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?

http://www.pmillett.com/current_source.htm

Thanks. Saved. -- AJ

[tubegarden]

On Dec 17, 3:03�pm, Andre Jute wrote:


I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?


Hi RATs!

http://ixdev.ixys.com/DataSheet/98704.pdf

Happy Ears!

Al

[Ian Iveson]

Al said:

http://ixdev.ixys.com/DataSheet/98704.pdf

Is "9 - 900k" dynamic R OK?

Seems a wide range. Just wondering.

Ian

[Fred[_8_]]

"Ian Iveson" wrote in message . uk...
Al said:

http://ixdev.ixys.com/DataSheet/98704.pdf

Is "9 - 900k" dynamic R OK?

Seems a wide range. Just wondering.

Ian

Sounds like a very good current regulator to me,
capable of a 100:1 dynamic range. You, as the
designer, control how low the dynamic R goes in
your circuit by controlling how low the dynamic
voltage across the device goes during operation
- the lower the instantanious voltage, the lower
the instantanious R required to maintain the
design current.

Fred

[Ian Iveson]

Thanks Fred

Sounds like a very good current regulator to me,
capable of a 100:1 dynamic range. You, as the
designer, control how low the dynamic R goes in
your circuit by controlling how low the dynamic
voltage across the device goes during operation
- the lower the instantanious voltage, the lower
the instantanious R required to maintain the
design current.

The same would be true of a resistor. The greater the
voltage you have to play with, the greater you can make the
resistance for a given required current.

I hadn't read far enough into the datasheet to see under
what circumstances that dynamic R might vary, so thanks for
the info.

But is 100k OK? Fine if it were a resistor in most cases,
IMO, and for most ppl maybe fine even for a non-linear
device. But I would bet that some would argue that 100k is
not great enough to guarantee that the sound of silicon
can't seep in under the back door.

OTOH, I have seen many claims that simple discreet silicon
circuits achieve many Megohms, but with no mention of
frequency response, as if it didn't exist or didn't matter.

If the ixys device achieves 100k at all frequencies of
interest, it's just about good enough, IMHO. It's certainly
convenient.

cheers, Ian

[Andre Jute]

On Dec 18, 3:20Â*am, tubegarden wrote:
On Dec 17, 3:03�pm, Andre Jute wrote:



I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?

Hi RATs!

http://ixdev.ixys.com/DataSheet/98704.pdf

Happy Ears!

Al

Thanks. Of course, since the regulator is drawn as one block, some
benighted person will argue that you are using ***silicon^&*()$£@! in
the signal path...

Andre Jute

[John Byrns]

In article
,
Andre Jute wrote:

On Dec 18, 3:20Â*am, tubegarden wrote:
On Dec 17, 3:03?pm, Andre Jute wrote:

I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?

Hi RATs!

http://ixdev.ixys.com/DataSheet/98704.pdf

Happy Ears!

Al

Thanks. Of course, since the regulator is drawn as one block, some
benighted person will argue that you are using ***silicon^&*()$£@! in
the signal path...

Isn't he?


Regards,

John Byrns

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

[Andre Jute]

On Dec 19, 12:17 am, John Byrns wrote:
In article
,
Andre Jute wrote:



On Dec 18, 3:20 am, tubegarden wrote:
On Dec 17, 3:03?pm, Andre Jute wrote:

I suppose I could look it up, but we're short of something to discuss
on RAT. So, what is an "IXYS current source"?

Hi RATs!

http://ixdev.ixys.com/DataSheet/98704.pdf

Happy Ears!

Al

Thanks. Of course, since the regulator is drawn as one block, some
benighted person will argue that you are using ***silicon^&*()$£@! in
the signal path...

Isn't he?

Regards,

John Byrns

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

Okay, the ultrafidelista, and others, say loosely that every component
can be heard. But some can be heard more or less than others because
of one or more of the intrinsic qualities of the component, the
relative quality of its manufacture or materials, and its relative
position in the circuit. It is this last factor, relative position in
circuit we want to discuss. A notorious case is the load capacitor in
parallel shunt feed SE output topologies, aka parafeed. (Abstracting
for the moment whether the ungapped trx or the cap is relatively more
to blame for any solecism in the sound.)

Notice that I distinguish in the headline between a constant current
load (CCL), which operates in the plate circuit, and a constant
current source (CCS), which operates in the tail of the tube.

It seems to me that the CCL might be a little more blameless, in that
the signal takes a right turn to either the next tube or the output
transformer before it reaches the CCL. It also seems to me that the
grunge of CCS silicon might enter the signal circuit via the ground
line without first being attenuated by the triode's inherent NFB.
Those are certainly impressive attenuations that Pete Millett
measured.

Of course, any or this will become a consideration only if the
residual noise of the silicon alters the quality of the noise as well
as the amount, which might come down to a fine psycho-acoustic
judgement; if there is no observable difference either by meter or by
psychological test, then we could just accept the noise reduction as A
Good Thing.

I'm too old to worry about whether silicon is bad on principle just
because some uncouth obsessive I have never heard of says so.

Andre Jute
Neutrinos seek positrinos to party with