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.😉
carpenter said:
Jfet BOZ, F4 and xxx-movie sound track might be the best combo
for ah ah ah . . . 😉
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.😀 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.
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:
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.
carpenter said:
look at
schematic ;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 .
Zen Mod said:
look at
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:
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
Ah yes. Never forget to cheat when possible. Shortcuts and copying existing work is certainly the quickest way.
carpenter said:
Parts have "sweet spots" at which their distortion is at a minimum.
For this JFET with this amount of gain at this bias and with this
load, 8 Vds is the sweet spot for small signals.
For more on this sort of thing, look at the discussion of load lines
in ZV8 and ZV9.
😎
EB's article "The All FET line-amp" has a good writeup on what is basically the same circuit (to start). You might find some useful information there.
JJ