[Fai C]

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

[[email protected]]

On Jan 18, 9:25*pm, Fai C wrote:
I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

No, it was mostly for factory public address applications as an
alternative to transmitting tube based designs. This way the turns
ratio of the transformer was much lower, the voltages were lower, and
in general the unit was cheaper to build.

I assume you mean the design in the GEC book on Pete Millett's web
site..........

[Alex Pogossov]

"Fai C" wrote in message
...
I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

I noticed the control grids of the paralleled output tubes are connected
together and has one bias (grid leak) resistor for a group of five. If one
tube say devolops a dangerous grid current it might bias its mates to a
dangerous current.

Would it be safer to use independent interstage coupling RC circuits for
each tube? Say 470K/0.047uF per each tube, rather than 100K/0.33uF for all?
It would also help to easier identify a leaky tube by scanning cathode
sensing resistors.

Or perhaps if one faulty tube biases the others to high current, the fuse
would blow quicker thus saving the faulty one?

[Iain Churches[_2_]]

"Fai C" wrote in message
...
I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.


As a schoolboy I had a summer time job in an electronics factory.
They used the GEC 400W amp to play "music while you work" to
the assembly line betwen the hours of 10 and 12.

Amps that were used in such an application are not suitable for guitar
or domestic use, as they had 100V line transformers.

Iain

[Fai C]

On Jan 19, 10:46*pm, "Iain Churches" wrote:
"Fai C" wrote in message

...

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

As a schoolboy I had a summer time job in an electronics factory.
They used the GEC 400W amp to play "music while you work" to
the assembly line betwen the hours of 10 and 12.

Amps that were used in such an application are not suitable for guitar
or domestic use, as they had 100V line transformers.

Iain

Are you saying that this is not for high fidelity application? But it
used to play music in the factory you worked with...........??

[[email protected]]

On Jan 19, 8:02*pm, Fai C wrote:
On Jan 19, 10:46*pm, "Iain Churches" wrote:









"Fai C" wrote in message

....

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

As a schoolboy I had a summer time job in an electronics factory.
They used the GEC 400W amp to play "music while you work" to
the assembly line betwen the hours of 10 and 12.

Amps that were used in such an application are not suitable for guitar
or domestic use, as they had 100V line transformers.

Iain

Are you saying that this is not for high fidelity application? But it
used to play music in the factory you worked with...........??

He means the OPT had only a 100v distribution line out winding, not
one for driving loads of say 4 to 16 ohms.

Some had both.

Many old solid state Altec Lansing amps had distribution voltage only
output transformers, allegedly so they would not be stolen and taken
home for stereo amps! Yes, they had output transformers, not
autoformers with only one winding. McIntosh made a couple too,
according to roger Russell.

[Patrick Turner]

On Jan 19, 2:25*pm, Fai C wrote:
I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

Plenty of ppl have used multiple KT88 to make high PO.
http://www.turneraudio.com.au/300w-monobloc-about.html
But by the time the needs for high PO for stadium PAs and theatres et
all got going in the 1960s, ppl began to turn to class B solid state,
and today, using much less weight of parts, an amp may make 5,000Watts
instead of only 400W. Using several pallet fulls of multiple 5,000W
amps, one can produce the necessary 100,000 Watts used where a crowd
of 100,000 young people attend - they pay well for 1 Watt each, to get
deafened by "music" that is little different to noise.

The 6SN7 is considered bt many to be the King Of Triodes. It is
linear, has wide bandwidth, low Ra, low noise and usually sounds
delicious. Of course many ppl insist NOS 6SN7 are best, but a month
ago I tested all my motley collection of 6SN7, with a number of them
removed from their 1941 boxes which rip apart a bit when you remove
them. They were military stock replacements for WW2 stuff. I found
maybe only 30% had low noise, and were not microphonic. The brother of
the 6SN7 has got to be the 6SL7, and again, when I tested all my
stocks, I had some real horrors, worse than the worst 6SN7. Included
was one of a pair of russian made 6SL7 from 1995. It gave very bad hum
and noise, and to the bin it went. The other 1995 sample was fine.

I like 6CG7 better than 6SN7.

Patrick Turner.

[Iain Churches[_2_]]

"Fai C" wrote in message
...
On Jan 19, 10:46 pm, "Iain Churches" wrote:
"Fai C" wrote in message

...

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

As a schoolboy I had a summer time job in an electronics factory.
They used the GEC 400W amp to play "music while you work" to
the assembly line betwen the hours of 10 and 12.

Amps that were used in such an application are not suitable for guitar
or domestic use, as they had 100V line transformers.


Are you saying that this is not for high fidelity application? But it
used to play music in the factory you worked with...........??

Yes. As I understand it, that was the intened application.
If you are buying one for guitar or hifi use, make sure it does
not have a 100V line transformer. The cost of an 8 Ohm
replacement will probably exceed the value of the amplifier.

There were several companies in the UK who made
amplifiers and speakers for "industrial reproduction"
Vortexion and Tannoy are the first that come to mind.

I can't think why anyone would want a 400W valve/tube
amp for domestic use. I have a fairly large listening room,
with Tannoy Lancasters, and a Radford STA25 valve amp
that can fill that room with sound to a more-than-realistic level:-)

Iain

[Fai C]

On Jan 20, 7:03*pm, "Iain Churches" wrote:
"Fai C" wrote in message

...
On Jan 19, 10:46 pm, "Iain Churches" wrote:





"Fai C" wrote in message

....

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

As a schoolboy I had a summer time job in an electronics factory.
They used the GEC 400W amp to play "music while you work" to
the assembly line betwen the hours of 10 and 12.

Amps that were used in such an application are not suitable for guitar
or domestic use, as they had 100V line transformers.

Are you saying that this is not for high fidelity application? But it
used to play music in the factory you worked with...........??

Yes. As I understand it, that was the intened application.
If you are buying one for guitar or hifi use, make sure it does
not have a 100V line transformer. The cost of an 8 Ohm
replacement will probably exceed the value of the amplifier.

There were several companies in the UK who made
amplifiers and speakers for "industrial reproduction"
Vortexion and Tannoy are the first that come to mind.

I can't think why anyone would want a 400W valve/tube
amp for domestic use. *I have a fairly large listening room,
with Tannoy Lancasters, and a Radford STA25 valve amp
that can fill that room with sound to a more-than-realistic level:-)

Iain- Hide quoted text -

- Show quoted text -

Yes, I agree. But someone out there still making high power components
for 400W tube amp design:

http://www.tec-sol.com/products/trans/spec/PAT-4141.pdf

And pretty exotic too, also not many speaker very efficient as the
Tannoy

[Fai C]

On Jan 20, 2:12*pm, Patrick Turner wrote:
On Jan 19, 2:25*pm, Fai C wrote:

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

Plenty of ppl have used multiple KT88 to make high PO.http://www.turneraudio.com.au/300w-monobloc-about.html
But by the time the needs for high PO for stadium PAs and theatres et
all got going in the 1960s, ppl began to turn to class B solid state,
and today, using much less weight of parts, an amp may make 5,000Watts
instead of only 400W. Using several pallet fulls of multiple 5,000W
amps, one can produce the necessary 100,000 Watts used where a crowd
of 100,000 young people attend - they pay well for 1 Watt each, to get
deafened by "music" that is little different to noise.

The 6SN7 is considered bt many to be the King Of Triodes. It is
linear, has wide bandwidth, low Ra, low noise and usually sounds
delicious. Of course many ppl insist NOS 6SN7 are best, but a month
ago I tested all my motley collection of 6SN7, with a number of them
removed from their 1941 boxes which rip apart a bit when you remove
them. They were military stock replacements for WW2 stuff. I found
maybe only 30% had low noise, and were not microphonic. The brother of
the 6SN7 has got to be the 6SL7, and again, when I tested all my
stocks, I had some real horrors, worse than the worst 6SN7. Included
was one of a pair of russian made 6SL7 from 1995. It gave very bad hum
and noise, and to the bin it went. The other 1995 sample was fine.

I like 6CG7 better than 6SN7.

Patrick Turner.

But the 6FQ7 and 6SN7 is not interchangeable, is it? The socket is
different.

[MarkS]

"Iain Churches" wrote in message
...


"Fai C" wrote in message
...
On Jan 19, 10:46 pm, "Iain Churches" wrote:
"Fai C" wrote in message

...

I saw people recently posted on other forum about this design. I
always thought most vintage design is around 70-100W the most. But I
couldn't imagine it has such high power exist!!

http://oestex.com/tubes/Circuits/GEC400w.gif

Are they made for guitar application?

And the funny thing is that the driver tube is 6SN7 that is very
popular nowadays in most power amplifier for both SE or PP type.

As a schoolboy I had a summer time job in an electronics factory.
They used the GEC 400W amp to play "music while you work" to
the assembly line betwen the hours of 10 and 12.

Amps that were used in such an application are not suitable for guitar
or domestic use, as they had 100V line transformers.


Are you saying that this is not for high fidelity application? But it
used to play music in the factory you worked with...........??

Yes. As I understand it, that was the intened application.
If you are buying one for guitar or hifi use, make sure it does
not have a 100V line transformer. The cost of an 8 Ohm
replacement will probably exceed the value of the amplifier.

There were several companies in the UK who made
amplifiers and speakers for "industrial reproduction"
Vortexion and Tannoy are the first that come to mind.

I can't think why anyone would want a 400W valve/tube
amp for domestic use. I have a fairly large listening room,
with Tannoy Lancasters, and a Radford STA25 valve amp
that can fill that room with sound to a more-than-realistic level:-)

Iain

__________________________________________________ __________________________________________________ ______

Hi Iain,

But more is better!

Mark 8)

[Patrick Turner]

I said ........
like 6CG7 better than 6SN7.

Someone replied.....
But the 6FQ7 and 6SN7 is not interchangeable, is it? The socket is
different.-

Well of course. 6FQ7 = 6CG7 and nine pin mini socket, wheras 6SN7 has
an octal socket ...DUH!.

All 3 have equal electronic character, although some versions of the
tubes by different manufacturers give variations in Ra, gm or µ of up
to +/- 10%.

Al 3 work well in audio amps.

Patrick Turner.

[Fai C]

On Jan 22, 4:07*pm, Patrick Turner wrote:
I said ........
like 6CG7 better than 6SN7.

Someone replied.....

But the 6FQ7 and 6SN7 is not interchangeable, is it? The socket is
different.-

Well of course. 6FQ7 = 6CG7 and nine pin mini socket, wheras 6SN7 has
an octal socket ...DUH!.

All 3 have equal electronic character, although some versions of the
tubes by different manufacturers give variations in Ra, gm or µ of up
to +/- 10%.

Al 3 work well in audio amps.

Patrick Turner.

I should say they both will work if modified the socket. Sorry! And
you are correct, I've listened to both 6CG7 and 6SN7, loves the CG7
more.

[Patrick Turner]

On Jan 23, 1:46*pm, Fai C wrote:
On Jan 22, 4:07*pm, Patrick Turner wrote:





I said ........
like 6CG7 better than 6SN7.

Someone replied.....

But the 6FQ7 and 6SN7 is not interchangeable, is it? The socket is
different.-

Well of course. 6FQ7 = 6CG7 and nine pin mini socket, wheras 6SN7 has
an octal socket ...DUH!.

All 3 have equal electronic character, although some versions of the
tubes by different manufacturers give variations in Ra, gm or µ of up
to +/- 10%.

Al 3 work well in audio amps.

Patrick Turner.

I should say they both will work if modified the socket. Sorry! And
you are correct, I've listened to both 6CG7 and 6SN7, loves the CG7
more.- Hide quoted text -

- Show quoted text -

Tubes with the same type numbers made by different makers may sound
different, and if you got a dusty old crate full of 1941 WW2 stocks of
6SN7 military spares, "new" in sealed boxes, but really very old,
maybe you'd find big variations in sound, noise, microphony etc. You'd
wanna chuck quite a few into the bin. I went through this experience
recently. Old bottles of wine can become sour with age, hell, they'd
never been drunk, NOS in sealed bottles. Old things are often quite
crook, so keep an open mind. Siemans 6CG7 made in 1960s were good, but
cost far too much now. NOS is a worry. Maybe you can find a genuine
NOS tube worth having that hasn't been used for 4,000 hours in some
*******'s amp, then removed, put back into the original box, and sold
AGAIN as NOS. Maybe you can't find any, all gone, or shoved under some
rich *******'s bed, now getting older, slowly degrading, owner snoring
above, lost all interest in hi-fi, and he is also now degrading and
losing his hearing but he won't sell anything.
But I remember ppl arguing about whether Toshiba transistors sounded
better than Motorola, back in 1970s. Ppl forgot that one, then they
said NFB sounded terrible........so it goes on.

Patrick Turner.