Greetings from the 70s!

John Willcox

Member
2008-02-13 4:55 pm
Hello diyAudio!

It all started when I heard a friend's Conrad Johnson setup a few months ago. Years of work, kids and ancient motorcycles had reduced me to daily listening to:
(1) A Dyna PAT 5 preamp, sometime after the fall of Saigon somebody told me there was a mod by Leslie that really made it sing... I recently found the mods (not Leslie) on the interweb, and ordered some AD843 opamps to replace the non-FET input Jurrasic originals, (LM301, one generation after the legendary 741)
(2) Amber "Series 70" 200W bridged LM391-IC-and-BJT class AB amps, one has been abused more than the other, and needs to be repaired again. Easy to work on.
(3) An insane QSC 1300 stage amp that I used for an experiment that required an 800 Hz magnetic field. It can make 2000W. It will show 15 amps on an ammeter. My family calls it Ampzilla, it's ugly and not at all housebroken.
(4) Some pretty Marantz receiver from the Quad era. Many friends have played with it, it has a tuner and an interesting processor for when the stereo is -not- four way. Good tuner though.
(5) This Carver C-9 "sonic hologram generator", it sometimes helps with crappy digital sources. With some, it pulls an image out of gloopy sonic murk, others it disintegrates the space, leaving an analogue of Coltrane's head on Miles Davis' body, with the piano inside out hanging from the ceiling. Think alien abduction in sound.
(6) Nice Kef monitors and a 50's style "corner horn" that had been built for an organ and thrown out by a neighbor, so fine that I got it two ersatz ribbon tweeter-thingys that have the magnets fore and aft, with holes in the front magnet insomuch as the music may issue forth.

Speakers have been shoved anywhere they fit. Turntable sits forlorn and mothballed, as is a Revox 707 lurking in the back of an upstairs closet.
AR3s are long gone, and the AR turntable with two motors, all of the homemade amps, Dyna amps, Ultra Linear amps, the battleship amplifier that just needed input filters removed (looking back I should have given it a cutout switch so it could have been labelled "Cannons" or "No Cannons".)

Repairing this stuff has gotten me interested in building again.
I've been finding posts from this forum in the act of getting back involved, and have looked forward to joining.

John
 
Hi John,

The bottom plywood box is the Altec 825 (A7) and the aluminum horns are the 511 for mid and 811 for highs. All Selenium drivers. It is the mid/high cabinet that goes with the 210 (A4) woofers.
 

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John Willcox

Member
2008-02-13 4:55 pm
Great Guns!
That is fantastic.

I've been caught up in using a framed in hole in the ceiling of an impossible room. Something like the horn section of the JBL "Aquarious" from the '70s.
http://www.audioheritage.org/html/profiles/jbl/aquarius.htm
Down the page,the top of the Aquarius 3, inverted. Instead of the flat top of the box, two wooden hemispheres, upper one with the compression driver, lower hemisphere suspended by small wooden pegs.
Something like, yet ~ 2.5 x 10^4 less money:
http://www.cd-konzert.de/Produkte/Ejupiter.htm