OOOOpppsss.........
built SOZ since 1998, and this man sings everyday by that!! 😀
the fourth, the fifth, the minor fall the major lift...
the battle sing composing.....Hallelujah!!
WOW you are a lunatic fans too... dont believe my eyes "I'm Your Fan" there 😉
warms regards,
built SOZ since 1998, and this man sings everyday by that!! 😀
the fourth, the fifth, the minor fall the major lift...
the battle sing composing.....Hallelujah!!
WOW you are a lunatic fans too... dont believe my eyes "I'm Your Fan" there 😉
warms regards,
Hi jh6you,
Nice to meet you and are you in SH like I am? If so then could I get advice from you on DIY-ing Aleph2 and so on? Is there any other DIY-er from SH in this forum? Looking forward to hearing from you soon jh6you!
P
Nice to meet you and are you in SH like I am? If so then could I get advice from you on DIY-ing Aleph2 and so on? Is there any other DIY-er from SH in this forum? Looking forward to hearing from you soon jh6you!
P
Hi sugano
I wish I could help you at any time. By the way, at present I¡¯m heavily occupied with company and family duties. In addition, I speak only Korean and Konglish, not Chinese yet. So, I¡¯d like to recommend you to try to contact this nice man: yiw@skoito.saic.com.cn. More, you will find another nice man ¡°john-china¡± in this forum. Both gentlemen know many about diy societies and ele component dealers in SH.
If we have any tech Q in the A2 circuit, we are now at the right place. O... and, you can borrow my soldering station. 😀
Regards
jH
I wish I could help you at any time. By the way, at present I¡¯m heavily occupied with company and family duties. In addition, I speak only Korean and Konglish, not Chinese yet. So, I¡¯d like to recommend you to try to contact this nice man: yiw@skoito.saic.com.cn. More, you will find another nice man ¡°john-china¡± in this forum. Both gentlemen know many about diy societies and ele component dealers in SH.
If we have any tech Q in the A2 circuit, we are now at the right place. O... and, you can borrow my soldering station. 😀
Regards
jH
haha
i live in shanghai and can speak chinese .
if you speak in english , i also can try a little .
hongkong is nice place i have never been to.
i live in shanghai and can speak chinese .
if you speak in english , i also can try a little .
hongkong is nice place i have never been to.
MOSFET
To kill my curiosity and for fun, tried to replace IRFP250Ns of my F1 with IRF240s, which were collected ¡°piece by piece¡±, but got not successful result. It was actually sh@t by sh@t. It seemed that even the matched pairs showed quite different characters in actual application, most probably with respect to transconductance. Could imagine this from the amounts of output offset voltages and also from the unbalanced sound level between the left and right speakers.
After all, unbolted, removed and tossed all ten bull sh@t grade IRF240s into garbage bin and replaced them back with IRFP250Ns, which were more reliable parts. Didn¡¯t do any matching test of them. Just used ten pieces in a row directly out of an anti-static plastic container (probably automatic packaging from the same batch). Got good results. The output offsets with no special treatment were found as 52mV and 9mV. The 52mV was acceptable amount. Nevertheless, by attaching a small R in series with one of DC feedback resistors, could reduce the 52mV down to 2mV. In addition, the sound level between the left and right speakers back to the well balanced!
The Grant Green¡¯s jazz CD was returned to the wonderful sound!
MOSFETs to be reliable pieces from a reliable place . . . !
Regards
jH
To kill my curiosity and for fun, tried to replace IRFP250Ns of my F1 with IRF240s, which were collected ¡°piece by piece¡±, but got not successful result. It was actually sh@t by sh@t. It seemed that even the matched pairs showed quite different characters in actual application, most probably with respect to transconductance. Could imagine this from the amounts of output offset voltages and also from the unbalanced sound level between the left and right speakers.
After all, unbolted, removed and tossed all ten bull sh@t grade IRF240s into garbage bin and replaced them back with IRFP250Ns, which were more reliable parts. Didn¡¯t do any matching test of them. Just used ten pieces in a row directly out of an anti-static plastic container (probably automatic packaging from the same batch). Got good results. The output offsets with no special treatment were found as 52mV and 9mV. The 52mV was acceptable amount. Nevertheless, by attaching a small R in series with one of DC feedback resistors, could reduce the 52mV down to 2mV. In addition, the sound level between the left and right speakers back to the well balanced!
The Grant Green¡¯s jazz CD was returned to the wonderful sound!
MOSFETs to be reliable pieces from a reliable place . . . !
Regards
jH
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