Nickel-Iron-Steel switch 
Shadow Hills Industries Mastering Compressor - Vintage King Pro Audio Outfitter
Shadow Hills Industries Mastering Compressor - Vintage King Pro Audio Outfitter
Attachments
Chul parts I
some report.....
here you see Chul SITs in black
(picture most left)
the most right black curves are the THF-51 and the orange are normal P channel.
You see the crossing point is in the best case 1A and in the worst 0.6A. We would need a compensation circuit.
BUT….
I asked about four vendors of P channels for some parts with a low Vgs threshold and one delivered better ones….
In red the P channel parts with lower Vgs threshold and look, happily we have 1.5A at the crossing point with the THF and in the worst case still 1.1A.
Again red the "special" P channel, green a Harris 9140 and orange the normal IRFP240.
(second left picture)
What a progress Chul parts are for me you can imagine here.
All the black one more left are the SITs I have, much more gab between the two parts
(right picture)
Big thanks to you Chul!
Some hearing impressions will follow today.
some report.....
here you see Chul SITs in black
(picture most left)
the most right black curves are the THF-51 and the orange are normal P channel.
You see the crossing point is in the best case 1A and in the worst 0.6A. We would need a compensation circuit.
BUT….
I asked about four vendors of P channels for some parts with a low Vgs threshold and one delivered better ones….
In red the P channel parts with lower Vgs threshold and look, happily we have 1.5A at the crossing point with the THF and in the worst case still 1.1A.
Again red the "special" P channel, green a Harris 9140 and orange the normal IRFP240.
(second left picture)
What a progress Chul parts are for me you can imagine here.
All the black one more left are the SITs I have, much more gab between the two parts
(right picture)
Big thanks to you Chul!
Some hearing impressions will follow today.
Attachments
A bit hearing experience...
with the 1.5A and no source resistors the sound was straight forward, maybe to much pos phase k2.
Adding two 0R47 in parallel as source resistor for the P channel changed sound completely, I still could go the 1.48A.
But now more of the darkness and softness and more room I mostly prefer.
Only point the drain voltage rose to 19.5V maybe a bit too high.
So i decided inspired by the 1.2A of your original DEFiSIT to go down to 1.2A. So still more room and softness. Drain voltage around 17V now.
Means you really have to dial the bias current, source resistor and observe the drain voltage to get the "right" sound.
with the 1.5A and no source resistors the sound was straight forward, maybe to much pos phase k2.
Adding two 0R47 in parallel as source resistor for the P channel changed sound completely, I still could go the 1.48A.
But now more of the darkness and softness and more room I mostly prefer.
Only point the drain voltage rose to 19.5V maybe a bit too high.
So i decided inspired by the 1.2A of your original DEFiSIT to go down to 1.2A. So still more room and softness. Drain voltage around 17V now.
Means you really have to dial the bias current, source resistor and observe the drain voltage to get the "right" sound.
Now my wild horses are better off in other continent...
But for mutual happiness
I knew they needed the right touch and they are having the best massage!
I am trying to apply the separate bias to THF-51 and IRFP9240. Setting the bias 1.5A is possible but..
Exactly mentioned by ZM, I am having noise at the speakers.. weak but there.
My dilemma is that I prefer the most straightforward sound, DAC to bare DEFiSIT circuit.
This is the most enjoyable times in DIY, because great musics are there waiting.
Again, salute to the man called Papa here.
But for mutual happiness
I knew they needed the right touch and they are having the best massage!
I am trying to apply the separate bias to THF-51 and IRFP9240. Setting the bias 1.5A is possible but..
Exactly mentioned by ZM, I am having noise at the speakers.. weak but there.
My dilemma is that I prefer the most straightforward sound, DAC to bare DEFiSIT circuit.
This is the most enjoyable times in DIY, because great musics are there waiting.
Again, salute to the man called Papa here.
In my short experience, 2SK180 is not a donkey, but not so wild.
The Vgs is not as jumpy as THF-51 I remember. I used in L'Amp circuit with iron inductor load.
.....
Again, salute to the man called Papa here.
well , I thought him everything he knows
Tnx for the clarification.
My ears are jumpy too, so usually I try to catch the very first impression. THF-51 is like a fresh fish. Like you said livelier or more true to the music.
It was the same for me with normal L'Amp and follower circuit.
I wish I expressed right.
you said it clear enough , what's important that you compare them in same circuit , and you said it was L'Amp
that's common source amp , while DEFiSIT is kind of bstrd ...... well , as I said - ∀ Class amp , but we can say that difference in transfer characteristics between THF51-S and 2SK180 are less pronounced here
say , what is range of Vgs values you had for 2SK180 , exactly , or compared with THF ?
that's common source amp , while DEFiSIT is kind of bstrd ...... well , as I said - ∀ Class amp , but we can say that difference in transfer characteristics between THF51-S and 2SK180 are less pronounced here
say , what is range of Vgs values you had for 2SK180 , exactly , or compared with THF ?
Thanks guys.
Looks like I should head over to the fish market.
not yet ;
we'll see what is Chul going to write