Class A using B&K Video 5

[cygnus x1]

I'm thinking of building an Aleph J out of parts form a B&K Video 5. Outputs are 2 pair of 2SJ115/2SK405. Five input/front end stages, 5 output. Ant thoughts? Any Aleph boards out in the world?

 

[Zen Mod]

pics/links to show us, what's Video 5?

 

[Andersonix]

Is it like this one? If so, then just add more PS caps and bias up the output stage in one pair of amps, disconnect the other channels, and have a listen. As shown it does not have enough heat sinking to make a real class A amp.
https://reverb.com/item/46324649-ex...wer-amp-five-audiophile-grade-105w-amplifiers

 

[cygnus x1]

Yep, that's the one. I was thinking of keeping the B&K as a stereo amp and putting the extra 2 channels as "Class A" into another chassis with more heat sink area. My question was will the Toshiba output Fets work? Or another design, as matched J74 are hard to find?

 

[Zen Mod]

try finding appropriate schematic using 2SJ49/50 and 2SK134/135 and build any of those with your mosfets

for common type FW amp, regular IRFP mosfets are better choice - more power, greater xconductance

and - do not count to have more than 25W of dissipation per device (of yours) with proper heatsinking - those are "just" 100W devices with somewhat smaller case

 

[cygnus x1]

A 20~25W amp was what I wanted to do. Heat sink~Chassis size...4U?

 

[cygnus x1]

I would like to use the parts from the input stage if possible...but reduced...KISS is better.

 

[Andersonix]

Everything you need is waiting for you at the store:
https://diyaudiostore.com/products/...79273&pr_ref_pid=6578322669641&pr_seq=uniform

 

[cygnus x1]

Thanks