I posted a link on the Masterpiece thread where measurements where made on PSUs to explain why they sound different.
Well, it is a bit more noisy then 2SK170 but much less input capacitance.
I think this is best for MM stages or several have to be paralleled for MC.
I think this is best for MM stages or several have to be paralleled for MC.
Allready knew about Miyajima but did not know about cross ring coils..... nice presentation they have.
As for 489, I did some calculations and to get the same gain in a common source compared to a k170, I would need much larger Rs and also large Vdd, so I agree it would be noisier.... maybe it has other advantages I am not aware of.
As for 489, I did some calculations and to get the same gain in a common source compared to a k170, I would need much larger Rs and also large Vdd, so I agree it would be noisier.... maybe it has other advantages I am not aware of.
For example 2 x 2SK170 would have approximate the same noise then 4 x 489.
With the 2 x 2SK 170 input capacitance is 60pF then and 4 x 489 would only have 16pF.
With the 2 x 2SK 170 input capacitance is 60pF then and 4 x 489 would only have 16pF.
if you do not cascode, miller will create distortions and IMO 60p is a VERY conservative number when you set up a high gain stage.
For MC this is not a big problem and cascoding helps. Still the input capacitance creates some ( minor ) distortion that can not be canceled by feedback unless it is shunt to the input.
At 60 Vgds, more interesting for power amp input stages, for those with a dislike of cascoding.
(20V higher than the LSK389, 10 points up from the 2SK389)
(20V higher than the LSK389, 10 points up from the 2SK389)
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