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Vintage Hi Fi Amplifiers (mostly valve).

Williamson Trix T.633B Quad 11/22 Trio W-400 Leak TP/12 plus, TL50 plus Armstrong Jubilee Mk2
Rogers Cadet III KT66 valves Wharfedale 100.1 Quadraphonics system Rotel RX-602

A pair of Quad 11 power amplifiers

As a teenager I was a Hi Fi enthusiast. Indeed I built a radiogram from parts when I was 14 years old. That was in
the 1960s. Most of the exhibits on this page were either owned by me from new or were bought second hand long
before the advent of ebay or home computers



The Williamson valve amplifier.

We have complete set of parts to make a pair of Williamson valve amplifiers.

Williamson valve amplifier parts.

Williamson valves. Williamson transformers.

Williamson output transformers. Williamson valve amplifier parts.

Shown above is a pair of Williamson output transformers, a pair of Williamson mains transformers
and many other items. These Williamson parts have been in the collection since 1992.
These include,
Partridge output transformers built to Williamson specifications (see advert below).
RS components (used to be called Radiospares) mains transformers built to Williamson specifications.
GEC KT66 valves including matched pairs. Oil filled capacitors and chokes.
No museum would be complete without the Williamson amplifier. The Williamson papers were printed in 1947 and
it is the most famous and important valve amplifier design of all time. It used the new GEC KT66 triode valve
(tube) that was developed by GEC just before WW2. The valve was restricted to military uses during the war
but was absolutely ideal for audio use. Williamson worked for GEC and after the war he printed his valve
amplifier designs in Wireless World magazine. In those days, buying a complete piece of consumer electronics
in the shops was not the only option. Many designs were printed, or in kit form. The Williamson design was
so popular that many manufacturers built transformers to Williamsons specifications
and audio enthusiasts built the amplifier from parts.

A complete set of original components to make a Williamson amp is very very rare. Here we have two sets.

Partridge Transformers for the Williamson amplifier for sale. Williamson valves for sale. Williamson valve amplifier parts.

D. T. N. Williamson wrote,
"It appears then that the design of an amplifier for sound reproduction to give the highest possible fidelity
should centre round a push-pull triode output stage and should incorporate negative feedback. The most suitable
types of valve for this service are the PX25 and the KT66. Of these the KT66 is to be preferred since it is a
more modern indirectly heated type with 6.3 volt heater, and will simplify the heater supply problem.
Triode-connected it has characteristics almost identical with those of the PX25."

Update Feb. 2008. The original "Wireless World" magazines. April and May 1947.

Wireless World April and May 1947

Williamsons original papers.

As shown at the top of this section, reprints are still available of the Williamson amplifier "Wireless World"
publications. Now, in the museum, we have the two original magazines showing both parts 1 and 2 of the
original Williamson articles and these detailed the full designs of the Williamson valve amplifier.

Bert van der Kerk shows how to build a Williamson amp at http://www.xs4all.nl/~ideas/amps/index.html

Some companies did build Williamson amplifiers to Williamson specifications and these are shown below. It was
certainly one of the more expensive amplifiers available at the time mainly due to the large number of high
quality components that were needed to build it. £31 From "Rogers" is approx. $62 and in 1952 that was expensive
- In 1952 in the UK the weekly wage for the working man was about £5 per week and so £31 was 6 weeks pay!
Also remember that this was for a mono amplifier. Two Williamson amps would be required for stereo. No wonder
many people opted to build it themselves and that assumes they could afford the parts. It is interesting
that Rogers Developments Co. who made valve amps and transistor amps for many years are,
in 1952 selling fully assembled Williamson amplifiers. (Adverts from "Wireless World" 1952)

Williamson advert 1952. Williamson advert 1952 Williamson advert 1952



1946 Model. Trix T.633B Amplifier

1946 Trix T.633B valve amplifier 1946 Trix T.633B valve amplifier

1946 Trix T.633B valve amplifier 1946 Trix T.633B valve amplifier

1946 Trix T.633B valve amplifier 1946 Trix T.633B valve amplifier

1946 Trix T.633B valve amplifier 1946 Trix T.633B Amplifier

1946 Trix T.633B Amplifier 1946 Trix T.633B Amplifier

Manufactured by the Trix Electrical Co. Ltd London UK. Portable / AC/ DC equipment. 30- watts. Multi purpose 6 valve
amplifier. The amplifier came with 2 front facias and you could fit the one you liked best. The front panel say -
"De Old Box of Trix" There are two volume controls for mixing two inputs and a tone control. Inputs are for mike or
gramophone. There are 2 output valves and it is a push pull output with negative feedback. Two excellent GEC GT66
output valves are used. The spares below all came with the Trix amp, including two spare KT66 valves. All of
the valves (except the new boxes valve) had been tested in 1977 and had been in storage ever since.

Spare valves for the Trix T.633B Amplifier

Spare valves for the Trix T.633B Amplifier

From our early collection of Wireless World magazines (August 1946) we were able to find the
advert below for the Trix T.633B (New model for 1946).

1946 Trix T.633B Amplifier advert



1953. Pair of Quad 11 power amplifiers. 1958. 22 pre-amp control unit.

These units are in mint condition and complete with manuals.

A pair of Quad 11 power amplifiers A Quad pre-amp

Quad brochure Quad manual

Hi Fi News magazine. April 1958. Quad 11 Preamp

The Quad 11 power amplifiers were first introduced in 1953 and the 22 pre-amp control unit was first introduced in 1958.
Quad advert from Hi Fi News magazine 1958 including the Quad 11 amps and 22 valve pre amp. Also in the advert is
the Quad valve tuner unit and Quad electrostatic speakers. The Quad II power amps were sold for 18 years. In
1958 the Quad FM tuner was also introduced. These Quad valve amps have been in the collection since 1990.

Update. A big effort was made in Jan. 2010 to fully service the Thorens TD 124 turntable and use it with the
Quad amps, Here are some new pictures of the amps now in use. They are driving a pair of JBL speakers.
The valves are original GEC KT66s. Two matched pairs of KT66s with very low hours.

Quad Amps Quad Amps

A very interesting site which includes notes and pictures about restoring Quad valve amps can be found at
http://www.dc-daylight.ltd.uk
In particular, how to upgrade the old resistors and capacitors to protect those valuable KT66s.



1960/62. Trio WX-400 valve (tube) receiver

Trio WX-400 valve receiver

Trio WX-400 valve receiver

Trio WX-400 valve receiver Trio WX-400 valve receiver

Little is known about this very interesting receiver (tuner amplifier). It is likely to have been built between
1960 and 1962. Kasuga Radio Co., Ltd was established in 1946 and renamed Kasuga Radio Industry Corporation in
1950 and then again renamed in 1960 - Trio Electronics, Inc. In 1962 Trio introduces the first transistor products and
by 1966 all products are fully transistorised. This Trio WX-400 receiver was also known as the Kenwood KW-70.
Trio eventually became known as Kenwood Corporation. (Kenwood Electronics in the UK). In the States Trio has
always been known as Kenwood and it is likely that the Kenwood KW70 was the US version of the Trio WX-400. There
was also a WX-500 although not sure what the differences were. The WX-400 has 22 valves and is an AM/FM Wide Band
Stereo Receiver. This receiver contains 22 valves and has an output of 20 watts per channel. The appearance, with
it's chrome edging is typical of early Japanese domestic Hi Fi and consumer electronics. It has been in the collection
since the early 1980s and was bought from a friend who died in 2000. There is almost no information about this
unit on the internet and as usual manufacturers web site are of no help. Any information would be most welcome.



1957. Leak TL/12 Plus valve (tube) amplifier

Leak TL/12 Plus valve (tube) amplifier Leak TL/12 Plus valve (tube) amplifier

Leak TL/12 Plus valve (tube) amplifier Leak TL/12 Plus valve (tube) amplifier

Manufactured by H. J. Leak & Co. Ltd, of London, England in 1948. H. J. Leak & Co started in 1934 and was sold to Rank
in 1969. They manufactured amplifiers, tuners, loudspeakers pickup arms and turntables. In 1945 they introduced the
"Point One" (valve) amplifier. Unlike amplifiers at the time with distortion levels of 0.2% or higher, this amplifier
had a distortion level of 0.1%. Three years later in 1948 the TL/12 with a simplified circuit was introduced with similar
performance to the Point One but was cheaper to make and cheaper to buy. The TL12 is quite sought after these days.
Price when new (1948/49) 25 Pounds and 15 shillings (£25.75) and the pre-amplifier cost 6 Pounds 15 shillings (£6.75)

1956. Leak Varislope III valve pre-amplifier

Leak Varislope III pre-amplifier Leak Varislope III pre-amplifier

1960s. Leak Varislope Mono valve pre-amplifier

Leak Varislope Mono pre-amplifier Leak Varislope Mono pre-amplifier

1948. Leak TL/50 Plus valve (tube) amplifier

Leak TL/50 Plus valve (tube) amplifier Leak TL/50 Plus valve (tube) amplifier

Leak TL/50 Plus valve (tube) amplifier Leak TL/50 Plus valve (tube) amplifier

Leak TL/50 Plus valve (tube) amplifier Leak TL/50 Plus valve (tube) amplifier

Leak TL/50 Plus valve (tube) amplifier Leak TL/50 Plus valve (tube) amplifier

Manufactured by H. J. Leak & Co. Ltd, of London, England in 1957. The TL50 was rare and is very desirable amongst HiFi
enthusiasts. It is cable of the very highest sound quality. It uses the wonderful high output KT88 valves. These are
the high output version of the KT66 valve. These valves worked in push pull and the amp had an ultra linear design.
This amp could deliver a good 60 watts into 8 ohms. These were the highest powered and the highest priced amps
built by Leak and the highest quality even by today’s standards. They came into my possession .. probably in the 1990s
The two side edges of the chassis were touched up where there were some scratches and these side edges could do with
painting but otherwise the amp is in great condition. The KT88s are original low use GEC valves.
There is a brand new spare Brimar GZ34 pre-amp valve in a box.



1963. Armstrong Jubilee Mk 2 valve receiver.

Armstrong Jubilee Mk 2 valve tuner amplifier Armstrong Jubilee Mk 2 valve tuner amplifier

Armstrong Jubilee Mk 2 valve tuner amplifier Armstrong Jubilee Mk 2 valve tuner amplifier

Armstrong Jubilee Mk 2 valve tuner amplifier Armstrong Jubilee Mk 2 valve tuner amplifier

The Armstrong Jubilee Mk 2 tuner amplifier chassis has an output of 8w and cost 29 Guineas which is about £30.45
The chassis was installed in a third party recommended cabinet. Armstrong recommended the best products to
use with their equipment. The tuner was vhf/mw/lw with AFC on VHF and the amp had tone controls. There were
pickup and tape inputs. Armstrong Wireless &Television Co. Ltd., from London was a British manufacturer of radios
and other audio equipment and was founded by Claude Charles Jackson in 1932. The company is now called
"Armstrong Audio" (www.armstrong-audio.com). They are a specialist repair centre and they will repair vintage
audio equipment. From their web site "please visit us at our workshop where we have our vintage audio equipment
on display alongside other Armstrong memorabilia. Alternatively, if you have any Armstrong equipment or stories
involving our past, we would very much like to hear from you." sounds like they are real audio Hi Fi enthusiasts.



1958. Rogers cadet III valve receiver.

Rogers cadet III valve receiver. Rogers cadet III valve receiver.

Rogers cadet III valve receiver. Rogers cadet III valve receiver.

Rogers cadet III valve receiver.

I have owned this amp since the 1980s, maybe even the 1970s, I built the case and inside it has the Cadet III
pre-amplifier and stereo power amplifier. Also note the ventilation grill on the top. On the back the
labelling was not that good but adequate. A non captive mains lead is always preferable. Notice the two
power outputs (American type and more appropriate to 110V) which would not be acceptable these days.
It was a great little amp, only about 10W per channel so efficient speakers were needed.



1956. Matched pair of GEC KT66 output valves.

GEC KT66 output valves. GEC KT66 output valves.

GEC KT66 output valves.

A friend of mine who sadly passed away in 2000 was a tank radio engineer in the second world war. He told
me some interesting stories. He was in North Africa (8th Army) Italy and then France and Germany. After the
war he was a successful TV and radio engineer. In his workshop he had many valves and he also had a large
advanced valve tester. In the 1990s I purchased the Trio amplifier from him (see above) and some of the
components to build a Williamson amplifier (see above) including valves and capacitors. and I purchased
this matched pair of KT66 valves. many of his KT66 valves were tested and he selected these two as
they had close test results. It is not uncommon to find these valves used in parallel ultra linear
push pull output stages and here a matched pair is very desirable. The KT66 was first introduced in 1937.
These ones can be identified as being pre 1970 as after the 1970s KT66s lacked the internal carbon dust
coating inside the glass bulb. The z mark on the valve tell us the date is 1956. You can see on the
stickers they were tested in 1988. They have been in storage ever since. The excellent KT66 valves
were used in the Trix, Quad, and Williamson amplifiers all shown above. They are widely considered
the be the finest output valves ever made.



Although this is the valve amplifier page, the rest of the page
contains some interesting transistor amplifiers.




1971. Wharfedale 100.1 Multiplex Receiver. (This prototype - 1969/70)

Wharfedale 100.1 Muliplex Receiver Wharfedale 100.1 Muliplex Receiver

Wharfedale 100.1 Muliplex Receiver Wharfedale 100.1 Muliplex Receiver

Wharfedale 100.1 Muliplex Receiver Wharfedale 100.1 Muliplex Receiver

Wharfedale 100.1 Muliplex Receiver Wharfedale 100.1 Muliplex Receiver Wharfedale 100.1 Muliplex Receiver

Whafedale 100.1 (prototype) Multiplex Receiver / stereo amplifier. Production models were available from 1971. This prototype
would have been developed in 1969/70. You will see in one of the pictures the words “Pre-Prod” (Pre-production) on an internal
label. Typical of 1970s British design it has a wooden case. The receiver is AM / FM and the amplifier has an output of 35W
per channel. It is interesting to note that the “100.1” model number came from “100W peak power and 0.1% distortion”. The
retail price was at £131. This was one of the first transistorised Hi Fi receivers. Don Barlow was one of the designers who
worked for Wharfedale. This prototype amplifier was donated by “Helen”, the late Don Barlow’s daughter. Don Barlow worked at
“H.J. Leak ” in the 1950s and 1960s. In January 1969 Rank-Wharfedale acquired Leak and Don then worked for Wharfedale until
1974. This prototype was passed on to his daughter after his death. H.J. Leak manufactured many Hi Fi products and Don was
instrumental in the development of many of these products. He invented the Leak Sandwich Speaker (see below) which used a
new concept sandwich constructed piston rather than a paper cone in the drive units. Work started in the late 1950s and the
speaker went into production in the mid. 1960s. In the early 1960s he also worked on the development of the Leak Dynamic
pickup cartridge (but the product was never launched), the “Truspeed” turntable and many other products. Much more
information about H.J. Leak and Don’s achievements can be found in the book –
“Firsts in High Fidelity: The Products and History of HJ Leak & Co. Ltd by Stephen Spicer. ISBN 9781882580316”.

Leak Sandwich Speaker Leak Sandwich Speaker



1968. Quadraphonic sound system

Quadraphonic sound system. Marantz Amplifier

Quadraphonic sound system. Marantz Amplifier

Quadraphonic sound system. Marantz Amplifier. Quadraphonic sound system. Marantz Amplifier

Quadraphonic sound system Demodulator CD-400B. Quadraphonic sound system Demodulator CD-400B

Quadraphonic sound system. Quadraphonic sound system.

Teac A-2340R reel to reel quadraphonic tape recorder Teac A-2340R reel to reel quadraphonic tape recorder

Kenwood KL-555A quadraphnic 4 speaker system Kenwood KL-555A quadraphnic 4 speaker system

Kenwood KL-555A quadraphnic 4 speaker system Kenwood KL-555A quadraphnic 4 speaker system

The Marantz 4300 Quadradial tuner amplifier is a 2 channel or 4 channel receiver with Dolby B Noise Reduction.
It also has an optional plugin for and SQ (Model CD-400B) demodulator. In 4 channel mode it is rated at 40 watts
per channel. In a 2 channel setup it is rated at 100 watts per channel. It was $899.95 in 1972
The Kenwood KL-555D is a 3-way loudspeaker system from 1976. Made i9n Japan. Weight 13.5Kg each
The TEAC A-2340R recorder could be used in a 4 discrete channel quadraphonic surround sound system.
Click here to see the complete system. This is a Semi-professional tape deck.
Track system - 4-track, 4-channel, stereo/monaural/multi channel system, Heads- 1 x record, 1 x playback, 1 x erase
Motor - 1 x capstan, 2 x reel, Reel size: up to 7 inch reel, Tape speeds: 3.75ips and 7.5 ips,
Semiconductors - 24 x transistors, 8 x diodes. Weight: 20kg
TEAC stands for "Tokyo Television Acoustic Company". The original company was founded in 1953 and became TEAC in 1956.
This is a obsolete surround sound system capable of taking a 4 discrete channel input from the mid 1970s.
The complete kit came with a Marantz CD- Calibration vinyl disc. It would have needed a special pickup cartridge
(turntable) to play it. The kit is complete with all of the manuals and paper work.



1976. Rotel RX-602 Receiver.

Rotel RX-602 Receiver. Rotel RX-602 Receiver.

Rotel RX-602 Receiver.

Black facia and many controls. This is a tuner amplifier I used in the 1970s and 1980s. It worked well.
Rotel were originally in Japan but currently (2018) have moved to China. They are still in business.



Any info?

The Jason Mercury 2 see below. Any information on this would be most welcome.

Jason Mercury 2 manual



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