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.

triptone

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.

int4000

Good history of Amstrad here:

http://www.amshold.com/social_media/The_Amstrad_Times.pdf

The story of the first Amstrad computer the CPC 464

http://www.theregister.co.uk/Print/2014/02/12/archaeologic_amstrad_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:

http://diy.torrens.org/Sinclair/inside/NktRd.php http://diy.torrens.org/Sinclair/inside/NktRd.php

Interesting article on distortion from the valve era:

http://www.roger-russell.com/truth/campbellsineward.htm

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

http://www.audiophool.com/Misc/50W_1954.pdf

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:

http://www.audiophool.com/Misc/3Kpdf.pdf