P3A Problems!

Good night, D1 is connected to the cathode in the -25 volt line, I'll check again! D1 is lit?
 

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In addition, the postioning of VAS vs. Sziklai driver recommended by R. Elliott is not respected in this layout which can result in thermal instability.

J.
I think with a small aluminum plate (heatsink) with Q5, Q6, Q9 would be a solution (be careful to isolate Q5 and Q6 of the heatsink).

Do you use a standard brightness LED (no high-brightness )?
 

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Not to be a skeptic but I wonder if this lay-out produces a clean sound. The location of the fuses does not look good, placing them near the input?...and stargrounding can be improved.

Good Morning! After correcting the problems will do the tests and my impressions post.
 
In addition, the postioning of VAS vs. Sziklai driver recommended by R. Elliott is not respected in this layout which can result in thermal instability.

J.

Yes, I can test this option! The heating occurs only in Q2, I'm thinking that the components I'm using are false. I tested a BD139 in Q2, and it was cold, I'll replace all the BC546. Thank you for opnion.
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
.....In fact my question is whether common transformers are less than toroids.....
Common E-I transformers are fine, if you bear in mind they radiate more hum and noise than toroidal, so you may need a larger case to allow spacing the transformer (and power leads) further from the amplifier. I suggest you listen to the amplifier output whilst you carefully (!) move the transformer or just the twisted leads about in the case before bolting down, until you get least noise and then fasten in that position.

If you are looking for best possible sound quality, even low noise levels become important. Otherwise, it doesn't matter what you use. Even cheap SMPS power supplies will work like any power supply if the current and voltages are adequate for peak output needs and grounding is correctly done.