diyAudio - Are this amp's transistors worth upgrading?

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Are this amp's transistors worth upgrading?

Hi

I have this PCB made a long time ago that was intended to become an amp but was put on hold. I've come accross it a few days and I was wondering if it would be worth to replace the output transitors with MJ1500x's. I've searched on the forum and I saw that the question of swapping 2N3055 with MJ1500x's has been asked before but the answer generally was that it depends on the particular schematic. So here's my schematic. What do you think?

Re: Are this amp's transistors worth upgrading?

Quote:

Originally posted by terrorizer
Hi

I have this PCB made a long time ago that was intended to become an amp but was put on hold. I've come accross it a few days and I was wondering if it would be worth to replace the output transitors with MJ1500x's. I've searched on the forum and I saw that the question of swapping 2N3055 with MJ1500x's has been asked before but the answer generally was that it depends on the particular schematic. So here's my schematic. What do you think?

The 3055's are one of the crappiest performing OP devices... however there are some 3055 design's that sounded very nice.

If you wanted to play with devices, I'd begin with the following in that order:

1) D1047 (very cost effective, good gain)
2) C5200 ( will probably improve the distortion of the amp without any mods)
3) 2sd424 (not widely available but are excellent replacements for the 3055)
4) MJ15003

and so on.

There are better transistors than the 2N3055. But looking a the circuit you posted I doubt you would improve the overall product.

The input stage and second stage are quite basic and really only meant for a "general purpose" amplifier. This configuration would not take much benefit from a "better" (faster, more linear) output transistor.

My personal view is that often designers go overboard in specifying the output transistors. The 2N3055 really ain't that bad when used in a low power amp circuit.

Cheers