sorry, I have a PC problem right now
shoot, just noticed bjt N symbol turns opposite of jfets
means the bjt is a PNP
what can I say
PNP bjt emitter connects to power, at jfet Drain resistor
and base connects directly to jfet drain
collector goes to jfet source out
shoot, just noticed bjt N symbol turns opposite of jfets
means the bjt is a PNP
what can I say
PNP bjt emitter connects to power, at jfet Drain resistor
and base connects directly to jfet drain
collector goes to jfet source out
ah, I see it now, its much like the upper half of the one Juma suggested in F5 preamp thread(post53), running on single 0/+ supply
I was thinking about a half Nelson, but now its a half Juma 😀
I was thinking about a half Nelson, but now its a half Juma 😀
Could it be something like this (cascoded SE buffer)?
CCS (here Q3 & Q4) can be executed in many different ways.
Attachments
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 ?
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 ?
It would be easier if you put the link in that post, but generally any circuit with high Zin and low Zout can be called a buffer.
If we proclaim that buffer has to have gain of about 0dB then usually we see a cathode/gate/emitter follower in that role.
If we proclaim that buffer has to have gain of about 0dB then usually we see a cathode/gate/emitter follower in that role.
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
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
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
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
then tell me why this se jfet pre I built with components pulled out of 30 year old radios outperforms all my commercial units
I meant on Jfet based preamps , made by ppl who knows what , where, how ..... not commercial drek ditto from text books 
hey, thats a real cool looking buffer
I have those BC547 🙄
looks like it could be a good mate to the se boz (on symmetric power supply)
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 😀