Hey all,
Just fixed a Acoustat TNT-200 (well, replaced one of 6 or so fuses) for a friend and took a listen last night. Sounds very clean and definitely a great amp. An all FET Amp. Coupled to the fact that it can work with very complex 2 ohm loads like Acoustat ESLs make it a real gem.
Anyway, my friend also gave me the schematics and noticed the three pairs of Hitachi output devices (no emitter resistors). Immediately thought of the similar designed P-101 I built a while back and reluctantly sold to a friend that just had to have it. I remembered that the sounds of both were quite similar, probably due to the similarity in the output devices.
Anyway, from my bad memory of the P-101, it had two pairs of 2SK1058 / 2SJ162 and had max rails at around +/-70v and output 380wpc @4 ohms, and biased to 20ma (?).
The TNT-200 has three pairs of 2SJ50 / 2SK135 (TO-3 cans too), rails at +/-72v and outputs 330wpc at 4 ohms. The TNT-200 was biased at 300ma.
Anyway, at higher bias, and one more pair of output devices, why the lesser power from the TNT-200? Am I missing something?
Just fixed a Acoustat TNT-200 (well, replaced one of 6 or so fuses) for a friend and took a listen last night. Sounds very clean and definitely a great amp. An all FET Amp. Coupled to the fact that it can work with very complex 2 ohm loads like Acoustat ESLs make it a real gem.
Anyway, my friend also gave me the schematics and noticed the three pairs of Hitachi output devices (no emitter resistors). Immediately thought of the similar designed P-101 I built a while back and reluctantly sold to a friend that just had to have it. I remembered that the sounds of both were quite similar, probably due to the similarity in the output devices.
Anyway, from my bad memory of the P-101, it had two pairs of 2SK1058 / 2SJ162 and had max rails at around +/-70v and output 380wpc @4 ohms, and biased to 20ma (?).
The TNT-200 has three pairs of 2SJ50 / 2SK135 (TO-3 cans too), rails at +/-72v and outputs 330wpc at 4 ohms. The TNT-200 was biased at 300ma.
Anyway, at higher bias, and one more pair of output devices, why the lesser power from the TNT-200? Am I missing something?
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2pr, +-70Vdc does not sound like it is 4ohm speaker capable.
Yes it should easily drive a 4r0 test load. That would make it 8ohm speaker capable.
Surely 20mA (?) cannot be right.
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