ijr

1178 FET substitute
« on: July 10, 2004, 06:06:54 PM »
Hello to all!
1178 have different vca and bias circuit than 1176.
But it can be made with DOA instead of soundpath opamps
and run +/-24 PS....

Some questions to guru's:

Can BF245A be FET substitute here?
Have anyone schematic version of 1178 with "distortion trim" pot?
So-called "british mode": how can it be implemented here?
Thank You.
"The ear is the only judge of tonal balance."
Radio Designer's Handbook, 1953, p.632.


flyingfader

1178 FET substitute
« Reply #1 on: July 10, 2004, 06:17:13 PM »
hi IJR,
I've been told 2N5566 /Siliconix would be a good replacement for the original DIL8/dual fet NPD5566 /National Semiconductor.

friendly

Fly
"Any instrument when dropped will roll into the least accessible corner."

ijr

1178 FET substitute
« Reply #2 on: July 10, 2004, 06:37:08 PM »
Thank You Fader! :-)))
Are these  /dual fet NPD5566 / were used in 1178?
Schematic shows dual fet q7 and anything more;
one 1178 I repaired year or more ago
had strange numbering on fet (I did not find it on NET)...
"The ear is the only judge of tonal balance."
Radio Designer's Handbook, 1953, p.632.


 

Related Topics

  Subject / Started by Replies Last post
22 Replies
4823 Views
Last post January 17, 2006, 06:23:02 AM
by MrZpliff
13 Replies
4707 Views
Last post September 13, 2005, 10:40:40 AM
by bcarso
4 Replies
2100 Views
Last post October 14, 2006, 12:59:11 PM
by ruairioflaherty
0 Replies
189 Views
Last post August 06, 2019, 02:50:00 AM
by Zebra_PD