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July 16, 2011 / consort3

My new amplifier

My new amplifier I like the way they mis-spelled Presence. I am disappointed that there is no Tremble control or better still Knee Trembler control

Takes me back to Tripletone amps whose unique selling feature was a ‘middle’ control but I think they called it presence.

No, actually they called it middle.  Guitar amps have presence controls apparently. One of the early Amstrad amps had a middle control too. That was when Amstrad was based in Ballspond rd Hackney, actually Ridley rd. The service department was like a vet’s surgery with people waiting with their pets on their knees except these pets were amps! Alan Sugar has come a long way……….. I think the Amstrad was the Integra 4000 which seemed to be a copy of the Metrosound ST60, both having  slider controls and a Middle control.


Good history of Amstrad here:

The story of the first Amstrad computer the CPC 464

Amstrad was a customer of NEC semiconductors whose salesman was one Alan Shaw. Mr Shaw bought the ailing Harbeth speaker company from Dudley Harwood 30 years ago and made it successful. Alan Shaw is another inspiring entrepreneur.

🆕Another entrepreneur was Clive Sinclair. History of Sinclair Radionics here:

Interesting article on distortion from the valve era:

Here is a technical piece on the design of a valve amp including the transformer winding which tended to be a commercial secret:

3000 watt amp by the same author, the filaments take 21A at 7.5V. The 4-1000A tube can be used as an oscillator, modulator and amplifier, and, in poorly designed equipment, they have been known to operate as all three simultaneously! Note that the amp only does 400 to 4kHz and has lethal voltages Link here:

The famous Williamson amp from the same era, this booklet was issued in 1952
Williamson 1952 The Williamson Amplifier

🆕Contemporary Australian view of the Williamson:

2,500V op amp!

3400 Farad capacitor

Make your amp more efficient with envelope tracking

Where I come from we used to call this configuration a Cherry Pair after an article by E.M Cherry. Its good for video amps


According to this article, it is a Staggerda configuration–High-frequency-transistors

Smart microphone

🆕I am going chronologically backwards here, they cost $7.60 in 1953 which in 2018 dollars is 72 (courtesy Rfcafe)


Vietnamese maker Thivans latest and greatest!


80 inch diameter woofer


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