Looks like On Semiconductor is making the BC860 obsolete, meaning soon enough, you will not get your hands on one. BC850 will probably soon be on its way out, and its not looking any better for BC550/560 either. So what I ended up doing was placing an order for the B grade ([hfe] 200-450) because there is no C grade available. Wether or not this is the one I ultimately will end up with is to early to say, but better to have them at hand than not. I will purchase the Toshiba BJTs as well. So If you want to secure the On Semiconductor BC850/860 before its too late, now is the time.
Digikey article #: BC850BLT1GOSCT-ND
Digikey article #: BC860BMTFCT-ND
Digikey article #: BC850BLT1GOSCT-ND
Digikey article #: BC860BMTFCT-ND
Hi
Do we need that many ?
From Digikey :
BC850BLT1GOSCT-ND : 8,384
Can ship immediately
BC860BMTFCT-ND : 22,335
Can ship immediately
Great project that I will follow closely
Kind Regards
J.R
LOL... yeah. The reason for that amount is anal matching
Power supply.
Too be honest, I haven't given it that much thought as of yet. There is always the original one, but I'll probably end up with something els.
As an example, the Salas SSLV1.3 UltraBiB shunt regulator (or a variant of it)might be part of it. I know I want to use SiC diodes for the bridge rectifier and either R-core or Toroidal (Toroidy audio grade). I was considering SMPS but don't want to spend the time chasing down the "correct one"- that's how far I have come in regards to the power supply
Btw Ine, I have a question for you: do remember or have any notes regarding the Vgss and Idss values flowing through the JFet's at max voltage swing ?
Hello R Dijk.
While I appreciate your input, I am not qualified to investigate modifications as such. Doing paralleled JFet/BJT is as far as I can expand/alter the circuit. As far as I understand it, beyond cascoding and SuSy which this amp feature, there is no real advantage to implement a different circuit topology. It is fairly simple on its own and performance wise, with slightly better component tolerances together with better transistors (yeah I know, 2SK170 etc .. lol) I am confident that this will be a top contender.
If one design a buffer that clearly improves the performance beyond the ones I will work on and use here, then that can be an option for upgrade further down the road. If you are up for it, go ahead and design one, prototype it and report back what you find. But for now, I'll stick to the proven circuits
Oneminde
But you're using current amplification of 2 in your mirrors. Nevermind. Good luck.Hello R Dijk.
While I appreciate your input, I am not qualified to investigate modifications as such. Doing paralleled JFet/BJT is as far as I can expand/alter the circuit. As far as I understand it, beyond cascoding and SuSy which this amp feature, there is no real advantage to implement a different circuit topology. It is fairly simple on its own and performance wise, with slightly better component tolerances together with better transistors (yeah I know, 2SK170 etc .. lol) I am confident that this will be a top contender.
If one design a buffer that clearly improves the performance beyond the ones I will work on and use here, then that can be an option for upgrade further down the road. If you are up for it, go ahead and design one, prototype it and report back what you find. But for now, I'll stick to the proven circuits
Oneminde
Btw im using it in caskode in my amp
As I said, do a full prototype and then we can compare it to the one(s) which will be used, who knows what you'll find
Yea, as i said that was my starting idea.
So the next step for mee would bee a starting comparison. Before considering buffer output. etc etc and so on.
I hope you find what you where looking for
Here is what i was comparing just for fun, and i realy had a lot of fun !
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I have mine for "mine" projects
And doing a transistor variation is basically dobble the current sorces. Either number or current. Typical example stochino input stage.
I have already my MAT's for that too
Can i by a set of boards?
That's a bit odd coming from you, you yourself use "same sex" FET's, N-chn conduct equally well in both directions etc. Even Flatlabs use N-chn only in his M2 buffer stage.
-- EDIT --
If you are thinking about the gate polarity, I can always throw in the Linear Systems LSJ74-SOT-23 3L - there's your P-chn replacement
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Hm... an other way is stil thinking simple. And ther is stil som werry exclusive out there. And if youre going for a exclusive.... Maybee MAT02 replacement is a starting pooint. Unless youre going smd. (Just a monemt have to check my hot air
)There is circuits werry WERRY! GOOD PERFORMANCE ! Been published in diyaudio before, cant remember the sorce,
As i said it al depends on curent sorce, more or less.
Here is the basic "otta my head"
May i say it is better than fet inputs?
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