I tried different ways but to hard to keep the two masters close by without routing issues( long traces and via etc). But if they are kept cool it probably less of an issue rt?
Hi,
just shortly ... You may want to read the thread 'Preamp Buffers ...' from around #220 - #250 and #322.
There are small layouts from Curryman and RudiRatlos and me showing the placement of the JFETs and cooling idea for the JFETs and the bipolars.
jauu
Calvin
just shortly ... You may want to read the thread 'Preamp Buffers ...' from around #220 - #250 and #322.
There are small layouts from Curryman and RudiRatlos and me showing the placement of the JFETs and cooling idea for the JFETs and the bipolars.
jauu
Calvin
Hmmm...I have no "grudge" in mind. Not sure how you arrive at this conclusion nor do I really care.😉
When I was building my Calvin buffer examples, Calvin was of the upmost help to me even though he and I had didn't see eye-to-eye on some things.
The clipped component leads in the carpet thing is still a bunch of nonsense as far as I'm concerned for justification to use all SMDs.
You do want you want kinku. After all, it is DIY as Jan stated.😀
Yes...I totally UNDERSTAND why you're using a servo to reduce offset since you're using SM JFETs(BF862) that are more challenging to match than the TO-92 devices I used in my examples.
Apparently you're too lazy or lack the knowledge to Idss match the PF5102 and J107 devices that work well in this design and used by myself...eliminating the need or complexity of a DC servo.
As for buffers that sound better than Calvin's buffer, there are numerous op-amp circuit designs that sound better from Walt Jung and others.
I also have a PCB layout for a buffer from an older Mark Levinson preamp that easily smokes Calvin's buffer for SQ at the expense of a more complicated layout.
Good luck with your Calvin servo layout and have fun!
Hi,
Oh come on gimme a break ... OPAmps better sounding????
And an old ML device easily smoking the Buffer??
Well, there are numerous users around who certainly differ very much with Your judgement.
If the general judgement would equal Your´s, Id say ok, nice try, but the circuit failed to perform well.
But since the general verdict is so positive and since You had difficulties in getting the Buffer to function properly at first, I wouldn´t exclude that something isn´t still fully ok with Your implementation.
jauu
Calvin
Oh come on gimme a break ... OPAmps better sounding????
And an old ML device easily smoking the Buffer??
Well, there are numerous users around who certainly differ very much with Your judgement.
If the general judgement would equal Your´s, Id say ok, nice try, but the circuit failed to perform well.
But since the general verdict is so positive and since You had difficulties in getting the Buffer to function properly at first, I wouldn´t exclude that something isn´t still fully ok with Your implementation.
jauu
Calvin
Ammel , sorry to say the servo is used not because Smd jfet is hard to match. In fact matching has very few things to do with servo and and using a servo won't void the need for Idss matching the master JFet. BF862 is considered even better in some aspects ( low gate Capacitance) than LSK in whichever thread I read. And the reason why I am looking for a discrete preamp/ buffer is to avoid opamp in the first place. I saw the threads and even in my personal interactions Calvin has more patience than anyone else around in this forum.May be time for you to move on. At the end I may or may not like what I make, or I may like it for sometime and then start looking for something" better", but that is what DIY is all about.
Hello Calvin
I am having difficulties simulating the Calvin buffer according to your design.
If I use Re = 6r8 and Ri = 2r2 as per the building guide (paradise) I have too much idling current.
The best compromise I found is with Re = 15 and Ri = 6r4 but even so idling is around 40mA.
Would you care to guide me here ?
Best
Ricardo
I am having difficulties simulating the Calvin buffer according to your design.
If I use Re = 6r8 and Ri = 2r2 as per the building guide (paradise) I have too much idling current.
The best compromise I found is with Re = 15 and Ri = 6r4 but even so idling is around 40mA.
Would you care to guide me here ?
Best
Ricardo
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