[Adam Stouffer]

Doing some searching it appears that almost every oscillator used for
tremolo is done with a triode. Any reason why a pentode was never used?


Adam

[Phil Allison]

"Adam Stouffer"

Doing some searching it appears that almost every oscillator used for
tremolo is done with a triode.


** More precisely - one half of a twin triode, usually a 12AX7.


Any reason why a pentode was never used?


** Hard to find twin ones.

Needs two extra parts.

Try using your common sense.


....... Phil

[Patrick Turner]

Adam Stouffer wrote:

Doing some searching it appears that almost every oscillator used for
tremolo is done with a triode. Any reason why a pentode was never used?

Adam

Just about every guita amp has only 12AX7 throughout, because
there are two gain devices within the single tube and its cheaper than
using a pentode, one device, one tube socket, so more expensive.

Pentodes sure can be used, and the ideal tremelo has
a nice clean ability to provide LF amplitude modulation of the HF tones
without a knocking sound on each beat of the tremulation.
Not all tremelos work real well.

Patrick Turner.

[John Byrns]

In article ,
"Phil Allison" wrote:

"Adam Stouffer"

Doing some searching it appears that almost every oscillator used for
tremolo is done with a triode.


** More precisely - one half of a twin triode, usually a 12AX7.


Any reason why a pentode was never used?


** Hard to find twin ones.

But not impossible.


Regards,

John Byrns

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

[John Byrns]

In article .com,
Bret Ludwig wrote:

On Jun 25, 9:38 am, John Byrns wrote:
In article ,
"Phil Allison" wrote:

"Adam Stouffer"

Doing some searching it appears that almost every oscillator used for
tremolo is done with a triode.

** More precisely - one half of a twin triode, usually a 12AX7.

Any reason why a pentode was never used?

** Hard to find twin ones.

But not impossible.

Care to name a few?

While things like 832/839B come to mind they are power tubes with
topside plate pins. They also shared screen grids. Without that you
would be limited to compactrons.

Compactrons are exactly what I had in mind. Compactrons were available
with many different combinations of dual pentodes. The use of
compactrons was not unknown in guitar amps, in the day.


Regards,

John Byrns

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

[John Byrns]

In article . com,
Bret Ludwig wrote:

AFAIK the only Compactron sockets in production guitar amps was in
one or two models of Peaveys from the very early 1970s. They received
a great deal of complaints from dealers and customers. I also seem to
remember an article in the early 70s in one of the guitar magazines
that had a step by step conversion of some Fender into a "super power"
amp for pedal steel-Red Rhodes may have written it-that involved the
use of a Stancor power transformer, the output from something else,
and a tube lineup that might have included a couple of them. I
remember a customer asking "Can You Build This"? and us saying, "Yes,
but it'll cost you the price of two new Mesa Boogies".

In hi-fi the only Compactron application I know of commercially was
in one of the Mc tuner preamps. Maybe the MX-110.

I don't know about McIntosh, but plenty of Hi-Fi manufacturers used
them. A few examples that come to mind from personal experience are the
EICO MX-99 FM stereo multiplex adapter, the H.H.Scott 370 and LT-111(B)
FM stereo tuners, and the H.H.Scott 345 stereo receiver, and I'm sure
there were many more. I saw a very nice all compactron stereo preamp on
eBay a couple of years ago that I would have liked to have, but it went
for an arm and a leg, too much for me.

Really, other than the occasional hobbyist or backwoods CB linear
constructor using cheap 12 pin sweep tubes, GE was the only user of
Compactrons.

??? Nearly everybody tried compactrons in a few products during the
brief period they were on the market before they were eclipsed by
transistors. Just because they didn't replace ordinary tubes wholesale
doesn't mean they weren't used.


Regards,

John Byrns

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

[Phil Allison]

"Bret Ludwig"

AFAIK the only Compactron sockets in production guitar amps was in
one or two models of Peaveys from the very early 1970s. They received
a great deal of complaints from dealers and customers.


** Famous 70s Ampeg models like the V22 , V4 & V4B used a 6K11 triple
triode.

Thousands of these amps were sold.

6K11s are still available as NOS.



......... Phil