THF-51S and 51T
dady suggested to check these out so I picked a pair of each from a shop to see how they look.
According to the specification they have double the gain of 2SK182ES (so my speculation in post #311 was wrong, those really were 182ES and not THF-51T), and my tracer board is running out of gas to give meaningful results.
The curves are spaced 1V apart, they seem to be holding on to the drain resistance (straight) but my untrained eyes can't tell if they're good or bad transistors.
@Michael, if you could comment on these curves, thanks 🙂
dady suggested to check these out so I picked a pair of each from a shop to see how they look.
According to the specification they have double the gain of 2SK182ES (so my speculation in post #311 was wrong, those really were 182ES and not THF-51T), and my tracer board is running out of gas to give meaningful results.
The curves are spaced 1V apart, they seem to be holding on to the drain resistance (straight) but my untrained eyes can't tell if they're good or bad transistors.
@Michael, if you could comment on these curves, thanks 🙂
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My calibrated eyeball says the one on the right looks nice, and the one on the left might just be starting to flop. Of course, it only needs to behave where you'll use it and they certainly have the gain. 🙂
Since this is a higher frequency part, do we know anything about its input capacitance?
Since this is a higher frequency part, do we know anything about its input capacitance?
With all that gain and that much capacitance, you'll definitely want to drive that one with a really low source impedance.
Hello, initially I used 182, but now I use thf51. I am very happy with results. My pre is unbalancer of Broskie with 6n6p for output tube.
@Christoph, yes this is the report from Tokin but the important is the envelope of the curve and the parallelism between them. CWTIM01 uses the curve tracer with probably insufficient voltage and current for give a more vivid scenario. jama, my Spaniard friend obtain good sound (without curves) or the sweet point" with two lamps of 150volts (500watt) 22,5 ohms in the drain, 65volts of power supply and the tension directly between S-D in 19.5volts. He used an AER 1 of 16ohm of load charge, the second harmonic was very low respect to the fundamental and the square wave was amazing in 50KHz but better when he low the charge until 8 ohms (in a phantom resistance charge)
@Juan Antonio, The output impedance of the unbalancer is 100ohms if uses ECC88 but could be lower with the 6N6.
So Jama you are Tokins THF sits sound flavor rare expert 🙂
Two compared are subtle or more audible diference ?
I do not know, soundhappy, for me sound better thf, but it is possible 182 mine are not good. I have only two units of 182 and when I tried with thf all change. Also It is possible I do not find optimum point of operation for 182. I have use only a scope and ears...
Woody, my friend dady got a few units one year ago in China, same I got some units of sk180. Now I do not know where get them. Sorry.
Only one word: E X C E L L E N T!
Many thanks.
I'll keep def. watching.
Ulrich
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