Quad 405-2 clone

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#12
I built few dozen of them more than twenty years ago according to the article from Hungarian magazine. Layout of PCB was exactly like this: Thttp://edl.uw.hu/quad405_2.jpg The most critical part was to make inductors according to recommendations from the article. If components are ok it works without any problems.
 
#13
Allexx said:
I built few dozen of them more than twenty years ago according to the article from Hungarian magazine. Layout of PCB was exactly like this: Thttp://edl.uw.hu/quad405_2.jpg The most critical part was to make inductors according to recommendations from the article. If components are ok it works without any problems.
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Glad to hear that the design works well.
 
#14
So far, we have not seen any clones of the 405-2 in this thread. The hungarian 405's are no clones but seems to be a bit different from the original 405 (-1). Here are some pictures of Quad:

http://quad405.com/modsquad1.jpg
http://quad405.com/modsquad2.jpg

405-2:
http://photos1.blogger.com/blogger/1644/1858/1600/DSC_0003.2.jpg

405 (-1):
http://photos1.blogger.com/blogger/1644/1858/1600/After_0001.jpg

I would like to see new PCBs with a Keith Snook frontend (an the new posistion for C8) and a Bernd Ludwig output (4 output transistors) or even an Audio Linear output (6 output transistors).
 
#16
I spent ages reading up on quads when i did my 405-2 clone and by the time i had finished my 405 clone i wished i had gone and cloned a 707 which is to my knowledge identical to the 909.

The main difference between the 405-2 and the 606,707,909 is the triple output transistor pairs which makes a big improvement on low impedance speaker performance. And the fact that they took the op amp out of the signal path in the 606 onwards which most people consider is a large improvement in sound.

Plus the 707 can do about 140watts into 8 ohm as oppose to the 100 watts the 405-2 can do. And even the hotrodded 405-2 even though it has large improvements probably doesnt sound quite as good as a stock 707 design.

PS, if you do go for one of these amps be careful on the layout of the boards i had nasty oscillation due to my bad layouts.

Regards
Craig
 
#17
Zombie said:
What is better in a hot-rodded/cloned 405-2 compared to a hot-rodded/cloned 306/606/707/909?
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I needed 80-100 W, max, so the 405 is the one I thought of. A 606 clone with lower voltage rails would be fine, too. As it is, 405 board layouts are hard enough to find, I expect info to clone the newer models would be that much harder to find.

IIRC the 707 was not a current dumping design, was it?


Why not clone a 909 instead, it's better in every aspect or is it not or isn't it as fun?
:smash:
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See above.
 
#19
In Quad 405, the base(s) of output transistors are tied together. In Quad 606, the base of upper and lower output transistors are distanced by 1 diode drop. How significant is this, especially in sonics?

How important the "precise" inductor value is? If the DIY inductor is missing the exact value, what could happened?
 
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