SC Studio 350 amp

[Clifford Heath]

Ok, so I see the kit from Jaycar, and the article in the magazine in the
library. Looks good for a bass (guitar) amp... I have a +-55V power
supply capable of 1200W (weighs 16Kg with 2 80,000uF capacitors
bigger than beer bottles. I'm guessing that the Studio 350 will run
ok on +-55V instead of +-70, at a lower power. It looks like it should
be safe with this supply driving 2ohms even - but does anyone want to
reassure me of that?

Jaycar don't seem to sell the transisters separately - what if they
need replacing? There don't seem to be many suppliers for the MJL15030/1

Finally that heatsink they show the amp with doesn't look big enough
to dissipate that much continuous power. Reckon Leo had a big fan on
it or just didn't operate it long enough to prove it?

Clifford Heath.

 

[Phil Allison]

"Clifford Heath"

There don't seem to be many suppliers for the MJL15030/1

** Exactly none I would say.

Try MJE15030/1 - been around for decades.




........... Phil

 

[Clifford Heath]

Phil Allison wrote:

There don't seem to be many suppliers for the MJL15030/1
** Exactly none I would say.
Try MJE15030/1 - been around for decades.

Ahh. I typed in the number from the first page of the article text
without checking the circuit diagram - there's a typo in the mag.
And the main o/p transistors (MJL21194/93) are listed on Jaycar's
site for around $10. Internet ordering drops that to about $6 but
then you have to pay postage...

What about my other questions? It seems that the amp will swing
within 6.5V of the rails, so reducing them to +-55V would drop the
power to 60% - but that's still quite a bit.

Would it be safe into 2 ohms with the reduced rails? Based on the
graphs shown, it would stay under the max-power curve for a resistive
load, but a reactive load looks like it'd go over. I don't remember
how to compute these reactive load curves.

Clifford Heath.