PDA

View Full Version : Quad 405?



spendorman
01-03-2008, 18:16
Quad 405?? Just a bit of fun to lighten things up a little!!

http://www.youtube.com/watch?v=xbCIC5Q0SXU

Marco
01-03-2008, 18:45
LOL. Nice one, Paul :smoking:

Marco.

greenhomeelectronics
02-03-2008, 09:57
Most excellent!! Reminds me of when I was an apprentice at what was the Royal Aircraft Establishment in Farnborough. They wanted to put a PA system in to the main canteen area but over spent the budget pretty quickly. The guy that put the system together did not have a clue and tried to fill a hall of about 200 foot long by 100 foot wide and 50 foot high with a single pair of Bose 802's - didn't work. Anyway they decided to build their own amps and somebody got hold of the circuit diagram for the 405, the PCB department made up a board for it and it became an orderable item. Not surprisingly word got around and it soon became the most ordered board in the establishment. Some of those ended up looking just like the one in the photo :-) So now you know where a big chunk of your tax money went in the early 1980's :-)

spendorman
02-03-2008, 10:14
Coincidence, I worked 18 years for British Aerospace as an engineer!!

On e bay someone is selling new bare PCBs for Quad 405, Quad 303 also kits and assembled boards for Linn and Nad power amps. These all seem good value if anyone is intertested. Not sure if I am allowed to post the link.

Vinyl Grinder
02-03-2008, 11:09
Coincidence, I worked 18 years for British Aerospace as an engineer!!

On e bay someone is selling new bare PCBs for Quad 405, Quad 303 also kits and assembled boards for Linn and Nad power amps. These all seem good value if anyone is intertested. Not sure if I am allowed to post the link.

Naim not NAD

spendorman
02-03-2008, 11:33
They do have NAD, it is the power amp section of the 3020

http://cgi.ebay.co.uk/2-X-POWER-AMPLIFIER-KIT-BASED-ON-NAD-3020_W0QQitemZ350030446762QQihZ022QQcategoryZ12050 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Vinyl Grinder
02-03-2008, 11:42
Blimey last thing i'd wanna buy Paul, unreliable might be a good word, just hope they revised to circuit..

spendorman
02-03-2008, 11:57
Yes, many blown NAD amps around, their build quality may not be that good, but the cost was not that high. I know of quite a few NADs of this vintage that have given and are still giving excellent and trouble free service. The high curent output capability probably does not help if the amp is abused by shorting. Not even emitter resistors in some of them.

I was given a 3130 that had been abused by shorting the output on one channel (the owner admitted to this). I have now repaired it (thanks to you finding a service manual) and it works fine, sounding not at all bad.

greenhomeelectronics
02-03-2008, 18:15
Being Dc coupled if the output does get shorted it blows everything right back to the pre amp. I don't bother trying torepair them if they came in broken as I know I will never get my money back on them. Shame because they are a fairly decent budget amp when working.

spendorman
02-03-2008, 18:30
Yes I had to replace a lot of transistors in that channel. took quite a bit of time, can understand just junking them.

It works quite well as a pre amp to drive other power amps.

Neil McCauley
01-05-2008, 17:44
FYI:

http://blog.listencarefully.co.uk/?p=2590