Calling all deaf people - 4500 Watt wireless speaker

[The Natural Philosopher]

Dont think Purple existed in 1969.

[The Natural Philosopher]

Yes. The JBL rippoff horns we used to use were over 100dB/W

The cone speakers could manage 95dB/W

typical cheap hifi is 85dB/W

[harry]

[Trevor Wilson]

**I remember it well. The schematic for the 1,000 Watt amplifier was sound. Lots of paralleled NPN, high Voltage output devices. Only one teeny, tiny hitch: NO power transformer. It was operated directly from 240VAC mains and employed capacitor coupling to the speakers. Some possible OH&S issues there. The bass drivers were aluminium cone types (allegedly). April 1972 issue, if I recall correctly. I have it somewhere. And of course, the reason why the room required frequent re-plastering, was because the turntable needed to be housed in a separate building, due to positive feedback concerns. The stylus was frequently dropped onto the LP hastily, so he could make his way back from the garden shed to his listening room.

Wonderful article.

[Brian Gaff]

Have you seen the Film Yesterday, based on a very unlikely premise, its supposed to be a comedy who pinches all the beetles tunes if for himself as some event erases them from everyone except him. It is crap. Brian

[Bob Eager]

Formed in 1968.

[Gareth's was W7 now W10 Downst]

Sorry, missed the 2-back-OP.

The article in WW was an April Fool penned by "George Izzard o'Veering"

[Cursitor Doom]

Reminds me very much of Douglas Adams and his literary creation, the plutonium rock band Disaster Area, "the loudest band in the universe" LOL. Maybe that's where he got the idea.

[tony sayer]

Which ones, not 3055's surely?.

We were building 5-7 odd kW audio amps back in the sixties using DA100's IIRC but they were used for AM transmitter modulators;)..

[Trevor Wilson]

**Of course not. I would have to locate the article to ascertain what they were. I do recall that they were capable of (just) dealing with the rectified mains Voltage.

Points:

• I recalled incorrectly several details. It was the April 1970 issue and mains supply was not rectified.

• The output devices were MJ413, rated at 400 Volts.

• Here is a reference to a scanned copy of the article:

**You'd need a few to get that much power.

[Bill]

Oh dear, that makes the valve (807's?) amps driving the capstan motors of Ampex tape machines to get varispeed sound very puny.

I used them mainly to tune the timing of the slapback echo when trying to get something like the "Sun" sound when recording bands.

[tony sayer]

Yes very interesting wasn't aware devices like that were around over here back in those days;!

Yes it wasn't DA100 come to think of it they sounded similar in number around 10 inches high and about 3 inches in diameter and a few kV on the anodes but a long time ago now!..

[whisky-dave]

Here's the loudest in earths history.

[Terry Casey]

Oh yes, I remember it very well!

It ends up "... it has been possible to purchase several of the adjoining properties at a very advantageous price, and this has undoubtably offset a large part of the constructional costs."

You can read the full article here:

or

[Pamela]

What a strange looking design.

Bluetooth seems a bit too unreliable for $3,000.