Let me lite fire - Nelson Pass F1

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Disabled Account
Joined 2002
A'af

Yeah . . . suuu nice . . .

They tied me this seat right here in the tower of song . . . :drink:


Regards
jH
 

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OOOOpppsss.........:bigeyes:

built SOZ since 1998, and this man sings everyday by that!! :D

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,
:drink:
 
Disabled Account
Joined 2002
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. :D

Regards
jH
 
Disabled Account
Joined 2002
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
 
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