Jfet BOZ

I have seen a se output buffer with jfet and a bjt inserted in the drain, and connected to source(out)...

Could it be something like this (cascoded SE buffer)?
CCS (here Q3 & Q4) can be executed in many different ways.
 

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Ex-Moderator R.I.P.
Joined 2005
hey juma
no, I checked that too, and definately not a cascode
its almost like a copy of the upper half of your jfet/bjt
preamp suggested for F5, some time ago
in Preamp ideas for F5, post53
maybe with minor adjustments
no upper resistor on emitter
but it was only a basic curcuit shown
claimed to be low noise pre curcuit

btw, using only upper half of your complementary preamp curcuit makes it a buffer, right ?
 
Ex-Moderator R.I.P.
Joined 2005
found another similar one by R.G.Keen, calling it jfet buffer

thanks Zen mod, but it doenst work
I better wait with this until I got my PC fixed

and yet another one calling it direct coupled jfet/bjt buffer, and 'common textbook curcuit'
I think its originally a bjt curcuit
the jfet is only 'adopted' to give hi-z input

my idea was to place a att/pot between the simple se jfet boz, and this buffer
as I see it, the reason here to use the relatively high gain jfet boz is if having source with too low signal
and thus it makes less sense to place the att/pot in front of it, lowering the input signal even more
seems to me it would make more sense to try and control the high output gain
 
Official Court Jester
Joined 2003
Paid Member
there is no need to reinvent the wheel

there are numerous guitar/bass preamps around , certainly on DiyA too ;

point is that they're already optimized and we don't need to do that from scratch

especially if you aren't able to post links or pictures , in this moment , to help us visualize what you are thinking
 
Ex-Moderator R.I.P.
Joined 2005
for me personally, series resistors are out, sorry

I have to take that back, sorry (again)

done 'correctly' a series resistor seem to work ok
in my case it means placing it right after the first smoothing cap
and bleeder res/LED is placed there too, on the first cap
this way it also 'isolates' the res/LED better from draining the caps closer to the amp curcuit
sounds like I got a little more 'sweetness' this way
and just by a small change in how things are connected
and also amazing that the thing still works after me poking around with a monster solder iron about a hundred times now :D