Lost inside Acoustic G120 2x12 (Model 127)

[nsubulysses]

So many helpful replies in this thread thanks everyone

I have ordered some MJ15003 and a few other parts and will take it from there.

Gbono - Digi-Key sells the 2N4033 (PNP) and 2N3029 (NPN) from Central Semiconductor in a TO-5 "metal can".
When I search 2N4033 and 2N3029 on mouser and digikey I see 2N4033 easily and it's around $1.50 but 2N3029 is usually out of stock and over $100 each. Is this a typo?

The 2SC1586 I have does have a thick based compared to 2N3055. Is there such a thing as a real 2SC1586 or is that part # in general a knockoff part?

[gbono]

Senior moment - should read 2N4039......

[J M Fahey]

The 2SC1586 I have does have a thick based compared to 2N3055. Is there such a thing as a real 2SC1586 or is that part # in general a knockoff part?
[ATTACH=CONFIG]35495[/ATTACH]

In general, the ultra thick base indicates a fake.

Now, the original one *****MIGHT***** have an ultra thick *copper* base to improve heat transfer.

Easy to check in 2 different ways (I suggest you try both):
1) iron is magnetic, steel is not, check with any small ceramic magnet speaker that the rhomboidal base sticks or not.
2) steel is hard and silver coloured, copper is soft and red coloured , although it might be tinned .
I'd try to cut a small notch with a file, or bite an edge with some cutting plier tip, to check whether we get to see some copper colour or it's silver coloured inside.
Also the file teeth will have a harder job to bite the metal.

MAYBE Sanyo was so bent into making a great product that they made a TO3 metallic can out of tinned copper.
Never saw one, though, but it's not impossible.

On the other side, TO220 and TO218/247 transistor chips are usually mounted on a (tinned) pure copper base.

[nsubulysses]

This thing has been shelfed for a while. Back for more fun.

I realized part of my problem was also that R10 4.7K resistor was paralleled with an 18K from previous work. With that removed it idles around .120V drop over R23, R24 0.24 ohm ballast resistor. Was about .400V before removing 18K.

I can parallel R11 1.2K and get the voltage over 0.24 ohm ballast resistors down to .003 and there is still no crossover notch in the output, into a load. What kind of voltage drop should I be expecting over 0.24 ohm R23 and R24? JM suggest a few mV drop. Sorry for so many questions this output section has sent me a few thousand miles up the creek and I want to be done with it once and forever.

[Jazz P Bass]

If the output does not have any crossover notch, I wouldn't worry about it.

The cooler it idles, the better.