Naaah, the news from Monte Carlo simulations of matching is surprisingly positive.
Resistor matching error starting with six 1% resistors
I encourage you horse around with MC simulations and find out how many matches-within-0.1V you typically get, from a pool size of 4000, 6000, 8000, and 10000 starting devices.
Resistor matching error starting with six 1% resistors
I encourage you horse around with MC simulations and find out how many matches-within-0.1V you typically get, from a pool size of 4000, 6000, 8000, and 10000 starting devices.
Naaah, assume the worst case distribution, the one guaranteed to give the smallest number of matches. MC with that and be pleasantly surprised.
Then buy a smaller pool, save time, spend less money, and get your 1000 matched pairs anyway. If you're unhappy with the number of matched pairs this yielded, you can buy some more units and do some more measurements.
Then buy a smaller pool, save time, spend less money, and get your 1000 matched pairs anyway. If you're unhappy with the number of matched pairs this yielded, you can buy some more units and do some more measurements.
The reason behind matching in this case is equal current sharing.
So if the bias current differs by 20%, there will be 20% more heat, and hence 20% higher dT.
If the JFET has -ve tempco at bias, it is self regulating, then not critical.
If it has +ve tempco, it tends to run away thernally (gets hotter and hotter).
So you are then trying to get 2000x within 0.1V Vp.
For the circlotron, from purely distortion point of view, you want 1000 pair, each pair well matched (to probably much better than 0.1V).
But you still need to solve the thermal issue somehow.
Patrick
So if the bias current differs by 20%, there will be 20% more heat, and hence 20% higher dT.
If the JFET has -ve tempco at bias, it is self regulating, then not critical.
If it has +ve tempco, it tends to run away thernally (gets hotter and hotter).
So you are then trying to get 2000x within 0.1V Vp.
For the circlotron, from purely distortion point of view, you want 1000 pair, each pair well matched (to probably much better than 0.1V).
But you still need to solve the thermal issue somehow.
Patrick
Just to complete the collection, why not just use ONE pair of matched Semisouths ?
Super simple to build, can even do P2P.
And since Semisouth is known to be about zero tempco, you can take full risk and use no source resistor.
Great performance as well.
Patrick
PS Unzip the LIB file and place in same directory as .asc.
Super simple to build, can even do P2P.
And since Semisouth is known to be about zero tempco, you can take full risk and use no source resistor.
Great performance as well.
Patrick
PS Unzip the LIB file and place in same directory as .asc.
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Okey, thats interesting, if what you are telling me is true.
Because low distortion does not seem to be the issue, that makes true musicality, of what i know to this date.
But i am going to build the H2 generator, and the Korg preamp, in the fall. And doing some more cool hifi testing.
But i am truely skeptic. Better then Aleph J. Naaah. Seems extremely unlikely, to be really honest 😇
And if it possibly sounded better: The marigin from Aleph J to Full Nirvana is slim to none. 💕😎
But unbeliveable things sometimes happens.
well, we al know who made uberspecial one, The Beast with Thousand Names
all other amps are as poor nameless orphans, comparing to https://www.diyaudio.com/community/...ds-or-not-your-fathers-j2.343073/post-5923308
(though, can't find defining sentence, via phone)
