Two ZEN325 was sold quickly! Welcome to the germanium investigators club
Who are this Diyer the lucky one ?Attachments
ahh..Ge revival...
Its so happened that i have those Big TO-3 2SB216(SHINDENGEN) (100v/30a.80w) germaniums and some Motorola 2n511a, 2n1011, 2n1540, 2n1546 2n2567, Ad161,Ac128 and Japanese 2SB410,2sa221,2sa329 and RCA SK3035 and SYLVANIA ECG176.
Its so happened that i have those Big TO-3 2SB216(SHINDENGEN) (100v/30a.80w) germaniums and some Motorola 2n511a, 2n1011, 2n1540, 2n1546 2n2567, Ad161,Ac128 and Japanese 2SB410,2sa221,2sa329 and RCA SK3035 and SYLVANIA ECG176.
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Yes - this phono is for the chassis from message 117 . The chassis is slowly beginning to grow insides ....
Could You please write more about last Ge phono, what different or similar , better and specyfications ?
Congratulations for such cool interesting build, I stay in tune for more news.. Have a great Sunday
Congratulations for such cool interesting build, I stay in tune for more news.. Have a great Sunday
Hello. The new germanium phono is based on the JBL SG-520 scheme ( 1964). I had to make some changes to the circuit - because I used other transistors . I couldn't get the original 2n508 transistors . Used GT-308V (T1), P-416B ( T2) and MP-16B ( T3) ( all transistors USSR ) ..... I took measurements using RMAA . The signal level when measured - the output of the corrector was 2 volts from peak to peak (gain about 40 dB /1kHz). Noise - minus 73 dB ( weighted), and minus 69 dB (unweighted ) . Harmonics - 0.05 %, but this measurement is controversial-the Board was not installed in the case and just lay on the table . And the measurement was made through the built-in laptop card
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The sound of this phono is very good . I liked. Voluminous , very balanced . This is a good scheme . I powered it from a 24-volt power supply (the original circuit was powered by 21 volts). When checking, I used Empire cartridges .
Changes I made to the original circuit-increased the value of the resistor in the bias circuit of the transistor T2 ( applied 68 K instead of 43 K). And increased the gain of the feedback circuit ( used 68 ohms instead of 160 ohms). The original JBL circuit had a gain of about 32 dB . I changed that .
Very nice Vs. I am new to the analog turntable stuff and want to try it out. Actually i had in mind a comparison between your phono, the famous 'preconsonant' (2sa872) and 'the pacific' (2sk170). Did you have the time or the oportunity to compare yours to one of these? (to make my life easier)
I am not that much interested in 0.00..%dist, 0.1% is sufficient for me but it has to have excelent musicality. That is what i'm searching for....
Cheers
Ps: In my humble opinion the only Si transistors that sound alike with germaniums from my amp prototipes and tests (in the small signal stages) are the 2sa872,870,970 and ksa 992 (genuine) but cleaner overall in the mid region; the germaniums ads tiny bit more emotion and soft hights to the sound ... I always heard the hights from germaniums to be 'puff' like and the Si brothers to sound crisper. More like the tda1541 vs 1543 (Si), so is just a matter of taste.......
I am not that much interested in 0.00..%dist, 0.1% is sufficient for me but it has to have excelent musicality. That is what i'm searching for....
Cheers
Ps: In my humble opinion the only Si transistors that sound alike with germaniums from my amp prototipes and tests (in the small signal stages) are the 2sa872,870,970 and ksa 992 (genuine) but cleaner overall in the mid region; the germaniums ads tiny bit more emotion and soft hights to the sound ... I always heard the hights from germaniums to be 'puff' like and the Si brothers to sound crisper. More like the tda1541 vs 1543 (Si), so is just a matter of taste.......
Lets brake the ice
From my personall collection:a very musicall amp. It outputs 2-3w in 8ohms and almost 4w in 4ohms at 2-3% dist. It needs 1v max input. It works from the start. It had an output transformer in the originall schm but i modified the nfb to suport a choke for convenience. I used a shielded 10A@12v smps but would sound very very nice from a clasic CLC or 10000uf+10uF in parallel with a 65A car battery (best).
From my personall collection:a very musicall amp. It outputs 2-3w in 8ohms and almost 4w in 4ohms at 2-3% dist. It needs 1v max input. It works from the start. It had an output transformer in the originall schm but i modified the nfb to suport a choke for convenience. I used a shielded 10A@12v smps but would sound very very nice from a clasic CLC or 10000uf+10uF in parallel with a 65A car battery (best).
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Lowering the 11k to 200-500ohms gives you an input sensitivity of about 50-100mV and the lowest NFB feedback possible. Basically you can use it directly from the phono pre.
There is no point in comparing the sound of germanium and silicon devices . They are different . I had phonopreamps on jfet ( 2SK170 and 2SK117). I now have preamps on silicon BC-149c and BC550/560 . But I like the sound of germanium preamps better . Now I have 3 germanium devices ( they are built according to different schemes )
Some amplifiers even old designs use transistors mixture with silicon and germanium.
From inputs to the outputs 100 % pure germanium only signal path is very little know
or practicaly unknow in non compromise class A.
Example on YouTube video show amplifier with very small heatsinks btw
Germanium investigations
Thanks Vsmusic!
With such beautiful chassis this phono bring back old good days style 😀
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My new phono will look vintage . It will be equipped with good military switches and knobs made in the 70s . In addition, it has original Panasonic level indicators