Netlist - very good point indeed. There's a lot to be said for hacking around with circuits for the joy of it, even if the result isn't the latest and greatest. That's how you learn. If I get into the germaniums, it will be to satisfy questions like how to properly bias them for thermal stability and deal with the huge (in comparison) leakage current, which could complicate setting the optimum bias point for a circuit. I'm also very curious about how the old germanium transistors would sound. The old point contact and alloy germanium devices are very different beasts from modern silicon transistors.
JBL SG-520
oh,my god.....
I don't follow PMA.PMA just show the performance of the device.but the performance is not equal to the sound,just like what DJK said on here
http://www.diyaudio.com/forums/showthread.php?s=&postid=481422&highlight=#post481422
a Japanese commenter said that JBL SG-520 is one of the best sound pre-amp ever made in the world,and it is a hybrid amp of silicon and germanium transistor!!!.....IIRC,one of Japanese audiophile magazine editer used it as reference pre-amp in 90s.
you can saw the whole article which comment many important classic pre- amps until 80s on here,inluding ARC SP-10,ML-2,Marantz 7,...etc.warning....it is Chinese.
http://www.cndiyclub.com/c_read.php?tid=7512
hi,Netlist
could you collect the schematic of JBL SG-520?.....if anyone share us any more info of JBL SG-520,will be very aprreciated.
X.G.
oh,my god.....
PMA said:I had been working a lot with them in their times.
103NU71, 156NU70, OC71, OC30, OC26, 2NU74, GC511/GC521, GD607/617 and many others.
My advice is - forget them. We were young, but the stuff was horrible
Cheers,
Pavel
P.S. Stone age parts. How about selenium rectifiers? Some hiend power supply?
john curl said:
PMA said:
Narrow bandwidth, lot of noise, ageing /change of parameters/.
Of course - "ideal" building component
I don't follow PMA.PMA just show the performance of the device.but the performance is not equal to the sound,just like what DJK said on here
http://www.diyaudio.com/forums/showthread.php?s=&postid=481422&highlight=#post481422
a Japanese commenter said that JBL SG-520 is one of the best sound pre-amp ever made in the world,and it is a hybrid amp of silicon and germanium transistor!!!.....IIRC,one of Japanese audiophile magazine editer used it as reference pre-amp in 90s.
you can saw the whole article which comment many important classic pre- amps until 80s on here,inluding ARC SP-10,ML-2,Marantz 7,...etc.warning....it is Chinese.
http://www.cndiyclub.com/c_read.php?tid=7512
hi,Netlist
could you collect the schematic of JBL SG-520?.....if anyone share us any more info of JBL SG-520,will be very aprreciated.
X.G.
That's an easy one:
http://www.jblproservice.com/pdf/Vintage JBL-UREI Electronics/JBL-SG520.pdf
Warning: 8.8Mb.
/Hugo
http://www.jblproservice.com/pdf/Vintage JBL-UREI Electronics/JBL-SG520.pdf
Warning: 8.8Mb.
/Hugo
Netlist said:Jan,
No idea but I'll buy you a beer if you don't reveal the fine details behind the blabla.
To me, this thread is just about having fun with simple circuits and eventually see the thread starter build something he's happy with.
/Hugo
Hugo, I'll buy you a beer anytime we meet!
But you are right, maybe I should have more fun.
Jan Didden
PS Come flying again, 24/25 June??
Re: Re: Re: JBL SG-520
Of course. I only find it amusing that the same people that swear now by germanium, at another time and place, condemn anything that has no BG's, .999999 pure copper, expensive plasic film pots etc as sounding horrible.
Isn't audio a great field of human endeavour??
Jan Didden
X.G. said:
thanks a lot.
maybe.....all road to Rome.if it give you the best sound,who care that the performance of its device look like bad sound?
Of course. I only find it amusing that the same people that swear now by germanium, at another time and place, condemn anything that has no BG's, .999999 pure copper, expensive plasic film pots etc as sounding horrible.
Isn't audio a great field of human endeavour??
Jan Didden
Look for some schematics of the early Harman Kardon solid state Citation series, the earliest ss pre-amp in this line used lots of germanium transistors and actually sounded pretty decent.
IIRC It was the Citation A, but I'm not totally sure I have that model # down right.
I'm a tube guy through and through, but the one sample that I have encountered which was working properly actually did sound pretty nice.
Note that germanium transistors seem to deteriorate with age and heat to a degree that you would never see with silicon types.
I have only ever heard one Citation A that was working properly without extensive repairs which included replacing a lot of the transistors with modern silicon types. (Basically all new active circuitry design required.)
IIRC It was the Citation A, but I'm not totally sure I have that model # down right.
I'm a tube guy through and through, but the one sample that I have encountered which was working properly actually did sound pretty nice.
Note that germanium transistors seem to deteriorate with age and heat to a degree that you would never see with silicon types.
I have only ever heard one Citation A that was working properly without extensive repairs which included replacing a lot of the transistors with modern silicon types. (Basically all new active circuitry design required.)
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