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valve amp design

G

george-b

Jan 1, 1970
0
can anyone send a circuit diagram for self build power amps using
valves.Thankyou George Black.
 
J

Jamie

Jan 1, 1970
0
george-b said:
can anyone send a circuit diagram for self build power amps using
valves.Thankyou George Black.
push pull using an output transformer?
 
R

Robert Baer

Jan 1, 1970
0
george-b said:
can anyone send a circuit diagram for self build power amps using
valves.Thankyou George Black.
How about a transformerless output?
 
A

Adrian Tuddenham

Jan 1, 1970
0
Robert Baer said:
How about a transformerless output?

Philips/Mullard produced one in the late 1950 or early 60s. I think it
needed a 120-ohm speaker.

I don't believe it was ever published as a project in any of their
amplifier designs books, but an outline of it was given in one of their
training manuals. It looked as though the circuit was taken from one of
their contemporary commercial hi-fi amplifiers.

I can't remember the name of the book but I'm pretty certain the authors
were Nijsen, Schobemma and Slot.
 
J

Joerg

Jan 1, 1970
0
Hello Robert,

Is "valve" rightpondian for "tube"? (hold the tomatoes...)
How about a transformerless output?

We did one when I was a kid and had less respect for what 900VDC could
do. Rewound a speaker coil on one of those monster speakers and that was
no fun at all. Then we placed large labels onto the wires, warning
everyone to never ever mess with these. The first twang on that E-guitar
was phenomenal. We thought the rafters would come crashing down.

Oh, and since a transformer was way over budget we opted for a
"transformerless power supply". Three cascades from 230V and huge
capacitors so we had enough oomph. In fact so much oomph that we could
trip a 230V/16A circuit breaker.

Regards, Joerg
 
R

Robert Baer

Jan 1, 1970
0
Joerg said:
Hello Robert,



Is "valve" rightpondian for "tube"? (hold the tomatoes...)



We did one when I was a kid and had less respect for what 900VDC could
do. Rewound a speaker coil on one of those monster speakers and that was
no fun at all. Then we placed large labels onto the wires, warning
everyone to never ever mess with these. The first twang on that E-guitar
was phenomenal. We thought the rafters would come crashing down.

Oh, and since a transformer was way over budget we opted for a
"transformerless power supply". Three cascades from 230V and huge
capacitors so we had enough oomph. In fact so much oomph that we could
trip a 230V/16A circuit breaker.

Regards, Joerg
What i meant was no capacitor coupling to the speaker, and use of a
stadard 8 ohm speaker.
The directly related patents are:
C.T. Hall Mar 1955 #2,705,265 (filed June 1951)
J. Futterman Dec 1956 #2,773,136 (filed July 1953)
R. Karsten Jan 1988 #4,719,431 (filed Apr 1986)
R. Karsten Jun 2001 #6,242,977 B1 (filed May 1999)
And it is fun using the new design, touching the plates and ground -
and feel zilch.
And a gas, unplugging a tube or three while operating - and having
zero problems.
The "classic" Futterman design was a bitch to operate and caused a
lot of bad ingrained ideas as how bad OTL "is".
Modern OTL is very stable and robust.
 
A

Adrian Tuddenham

Jan 1, 1970
0
Joerg said:
Hello Robert,


Is "valve" rightpondian for "tube"? (hold the tomatoes...)

No tomatoes, but just a clarification:

The word 'tube' is used in the UK to mean a CRT, the picture tube of a
TV or a computer monitor. 'Valve' is a thermionic device for
rectification or amplification (remember when they didn't used to be
tubular?).


I'm sure you all knew that anyway.
 
J

Joerg

Jan 1, 1970
0
Hello Adrian,
The word 'tube' is used in the UK to mean a CRT, the picture tube of a
TV or a computer monitor. 'Valve' is a thermionic device for
rectification or amplification (remember when they didn't used to be
tubular?).

I remember that from my days in Scotland. Turn on the tube or "telee".
After that, hoover the carpet. Then off to pub (pronounced something
like "poub") for a few pints of McEwan's Heavy. Ah, the good times.

My first tube looked the shape of a Russion Babuschka. The others were
actually all tubular, including the steel ones.

Regards, Joerg
 
F

Fred Stevens

Jan 1, 1970
0
Joerg said:
Hello Adrian,


I remember that from my days in Scotland. Turn on the tube or "telee".
After that, hoover the carpet. Then off to pub (pronounced something
like "poub") for a few pints of McEwan's Heavy. Ah, the good times.

My first tube looked the shape of a Russion Babuschka. The others were
actually all tubular, including the steel ones.

Regards, Joerg

Try the book by the late John Linsley-Hood:

http://www.amazon.com/exec/obidos/t.../103-1171476-7699058?v=glance&s=books&n=50784

fred.
 
J

Joerg

Jan 1, 1970
0
Hello Fred,

Thanks. Interesting. But I was more into RF gear in my tube days. Big
tubes. I grew up with tubes because they were available for free when I
was a teenager. Discarded transistorized TVs showed up much later and
then I could lay my hands on hotrods like the AF126.

Audio tube amps presented in the electronic magazines were often a
disappointment. To me 10 or 20 watts wasn't anything to write home
about, we could build that with a few 2N3055 in those days. The monster
tube amps that some of us built had to be calculated from scratch. The
only reason the kilowatt range could hardly be cracked was that the
typical circuit in Europe had "only" about 15 amps. One chord on the
guitar and the lights went out.

Regards, Joerg
 
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