SKA GB150D now public domain...

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hi kacernator,

Please see the attachment.

regards


Note: I have double-checked the schematic but there is always a chance I missed something. Please let me know of any errors.
 

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  • SKA GB150D Public Domain sch 1.pdf
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BC556C

The BC556C are obsolete parts and very hard to find. The B grades are unsuitable because of their lower gain and the BC560C are only usable if the rails are kept below 40V. Therefore, it would be usefull if someone could come with a good replacement for them.
 
Are you correct?

There are many BC5xxc manufacturers. Are they all no longer making these transistors?

I can't say all manufacturers but some time ago I was searching for the C grades and I was only able to find some at a local shop. I was then informed the C grades were obsolete and no longer manufactured. However, the NPN complement - BC546C - are easy to find.
 
Have you compared it with other designs?

When I first build the GB150D I had a NAD C320BEE that I used in a daily basis. After building the SKA I immediately sold the NAD. The difference was so huge that I couldn't stand the NAD anymore.

I've built other amps as to name a few: P3A, gainclones, Symasym, DX, LM4930 with IRFP9240/240 outputs, some kit from eBay with 2SJ201/2SK153.
None could reach the heels of the SKA.

What most impresses my in the GB150D it's the huge dynamics and the smooth highs, never harsh, very detailed with extended note decays, very natural sounding. I read somewhere that the GB150D sounds like powerful tube amp and I agree entirely.

Now I'm buiding the VSSA, Shaan's version. It's too soon to comment in the sound and make a comparison between the two, but I can say it's a contender to the SKA. It has a more forward like sound, the SKA is more laid back. They're both impressive amps, the 2 bests I built.

Here are some SKA reviews:
http://www.diyaudio.com/forums/solid-state/72172-simple-killer-amp-listening-impressions.html
 
I've built other amps as to name a few: P3A, gainclones, Symasym, DX, LM4930 with IRFP9240/240 outputs, some kit from eBay with 2SJ201/2SK153.
None could reach the heels of the SKA.

I didn't mean to imply the mentioned amplifiers are bad sounding, quite the opposite - they're very good pieces of art and work that should made proud their designers and they trash many good commercial amplifiers.

However, I also must say that my personal preference, by far, goes to the SKA. :eguitar:

One aspect that I think it's important to the sound of the SKA is it's huge PSRR making it sound very good even with a modest and noisy PSU - a simple arrangment of 3 x 4700uF per rail is enough to make this amp sing!
 
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