Bag O Fun 2

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The one and only
Joined 2001
Paid Member
Here are 3 more scans for Bag O Fun:

www.passlabs.com/temp/thr_os89.tif

www.passlabs.com/temp/thr_fe89.tif

www.passlabs.com/temp/thr_fe90.tif

os89 was the generic output stage for the Threshold
products in 1989. You will see that it is divided up into
sections for different products. It used the MJ15022 thru
25 type devices.

fe89 was the so-called "optical bias" front end.

fe90 was the last bit of circuitry I did at Threshold, and was
an improved front end which had less thermal drift. I am
unsure that it ever went into production, but I did hear that
it was being offered as an update mod.
 
Ahhhh, so thats what was inside of my S-300 back in the 1980's. I always liked that amp alot! Am now constructing a pair od Aleph 2's though and am looking foreword to the experience.

Thanks for all your articles and construction projects over the years. The DIY audio community couldn't exist with out you!!
Mark Gulbrandsen
Salt Lake City
 
Thanks Nelson Pass !
(twice actually - I somehow missed that before, sorry)

Some questions:
J2 switches to higher gain - with the input adjustments it looks MC ready: But good and noiseless enough ?

What is the job of the cap parallel to the output?

What transistor substitutions would you recommend for the NPD5566(totally unknown to me) and the 3N172 ?

Klaus
 
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