1k5 drain resistor, 243R source resistor, 243R gate stopper, 330k "gate leak" and 100R (IIRC) in series with the output.
The drain and source resistors were determined by a quick look at the datasheet and then I took the closest values I had, which happened to be 1k5 and 243R.
This linestage is no longer in service since I needed the RCA connectors for another (tube) project.
The drain and source resistors were determined by a quick look at the datasheet and then I took the closest values I had, which happened to be 1k5 and 243R.
This linestage is no longer in service since I needed the RCA connectors for another (tube) project.
Hello everyone.... I'm new here. 
This is a very interesting thread. I make JFET preamps for low impedance bass guitar pickups I make using a similar design that was derived from a preamp made by Alembic. The circuit is about 25 years old.
I'm curious to try this JFET BOZ design using 18 volts, from 2 9V batteries.
Here's the circuit I've been using, except I use a MPF-102 and the output cap is 4.7uF.
It's variable gain, and I usually use it all the way up.
This is a very interesting thread. I make JFET preamps for low impedance bass guitar pickups I make using a similar design that was derived from a preamp made by Alembic. The circuit is about 25 years old.
I'm curious to try this JFET BOZ design using 18 volts, from 2 9V batteries.
Here's the circuit I've been using, except I use a MPF-102 and the output cap is 4.7uF.
It's variable gain, and I usually use it all the way up.
Attachments
Well, I'm a Johnny-come-lately with this Jfet BOZ project. But now that I have an F4 in operation, I had to find a gain stage to compliment the arrangement. The Jfet BOZ maybe just the ticket!
As of the last listening session, this combo is my next audio Nirvana
I've been playing around with the values: PS=15V; Drain R is 1.5k--which passes 7.5V setting bias at 5mA; no pot on the front end--receiver feeds directly into 1meg/1k resistor network. Source R is stock and reads 50mV--which also works out to 5mA
I tried Chokey's 10k network: sounds nice, but the F4 can't afford to lose that much BOZ gain. I'll save it for amps with higher gain!
All in all, this has been a sweet adventure. I've read this thread twice and everyone here has been an inspiration. Many thanks to all.
I'm going to play around with JCM's tone controls. They seem like just the ticket to enhance the bottom-end.
This has been more fun than watching the local all-girl mud-wrestling events. Well almost.
As of the last listening session, this combo is my next audio Nirvana
I've been playing around with the values: PS=15V; Drain R is 1.5k--which passes 7.5V setting bias at 5mA; no pot on the front end--receiver feeds directly into 1meg/1k resistor network. Source R is stock and reads 50mV--which also works out to 5mA
I tried Chokey's 10k network: sounds nice, but the F4 can't afford to lose that much BOZ gain. I'll save it for amps with higher gain!
All in all, this has been a sweet adventure. I've read this thread twice and everyone here has been an inspiration. Many thanks to all.
I'm going to play around with JCM's tone controls. They seem like just the ticket to enhance the bottom-end.
This has been more fun than watching the local all-girl mud-wrestling events. Well almost.
Are you using the 2- 9 volt battery power?
I am and have found that if you are careful about turning it off when you are not in the room, it lasts a longs time. I am finishing off my Kari GB BOSOZ which I know won't have enough guts to drive the F4 to max output, but I will be running 96 db efficient speakers with full balanced F4 monoblock. The single ended 25 watts is presently sufficient, so I figure that if I can only hit half of the 100 watt output with the BOSOZ I should be in true audio nirvana.
We shall see. The parts should be here this week.
I am and have found that if you are careful about turning it off when you are not in the room, it lasts a longs time. I am finishing off my Kari GB BOSOZ which I know won't have enough guts to drive the F4 to max output, but I will be running 96 db efficient speakers with full balanced F4 monoblock. The single ended 25 watts is presently sufficient, so I figure that if I can only hit half of the 100 watt output with the BOSOZ I should be in true audio nirvana.
We shall see. The parts should be here this week.
Give her all you've got, Dave.
I'm using a regulated 15V power supply--I hear no noise from the 110db 1w1m horn.
I'm now interested in exploring a cascode (perhaps the ZVN3310) to place atop the Jfet. All suggestions are most welcome. There's plenty of examples at DIY Audio and PassDiy to implement, and one way or another, I'm sure to find success.
BTW, because porn is not PC around my household, I would have to watch with the sound off--so much for my pretty little amplifiers.
I'm using a regulated 15V power supply--I hear no noise from the 110db 1w1m horn.
I'm now interested in exploring a cascode (perhaps the ZVN3310) to place atop the Jfet. All suggestions are most welcome.
There's plenty of examples at DIY Audio and PassDiy to implement, and one way or another, I'm sure to find success.BTW, because porn is not PC around my household, I would have to watch with the sound off--so much for my pretty little amplifiers.
carpenter said:Give her all you've got, Dave.
I'm using a regulated 15V power supply--I hear no noise from the 110db 1w1m horn.
I'm now interested in exploring a cascode (perhaps the ZVN3310) to place atop the Jfet. All suggestions are most welcome.
BTW, because porn is not PC around my household, I would have to watch with the sound off--so much for my pretty little amplifiers.
use plain vanilla BJT little critter on top of it ; it's quickie and easy
Zen Mod said:
I'm all ears, master.
I'm studying the Zen 2 article, in particular, the current source. Applying a current source to the Jfet-BOZ is a learning step that was to precede the cascode.
I'm not up on using a BJT, so I have been exploring what I do know--Mosfets. Please, direct me towards a resources, or share a few crumbs of knowledge.
Many thanks, Choky
Nelson Pass said:I measured the circuit this afternoon, and it came out mostly
as expected, but the best distortion numbers came from a
16V supply value.
So, this got me thinking: I'm running a 15 volt supply, which--after the Drain resistor--leaves me with 7.5 volts. Does this mean that the Jfet only wants 8 volts DC, or so, on its Drain? This part of amplifier theory always confounds me.
Zen Mod said:
look atschematic ;
is it anything familiar ?
ya have eeny weeny jfet , cascoded with eeeny weeny bjt
with ratio of resistors up and down from base of little bjts , you can set different voltages for jfet .
Why, thanks for reminding me, Choky. I've been reading Nelson's works and it slipped my mind that you have material for me to read as well.
I'll get right on it!
carpenter said:
Why, thanks for reminding me, Choky. I've been reading Nelson's works and it slipped my mind that you have material for me to read as well.
I'll get right on it!
you obviously forgot all pirate things I sent you ?
don't try to read entire books , if you aren't in mood or shape for that ; just find exact problematic in which you are interested , and read about .
find cascodes ....... in scribings of Papa , and in these pirate stuff
