JFET Auto-Biasing

[aethertransit]

[...]
I'm sorry but am I not allowed to start a conversation on this forum?
[...]

A conversation should have at least a topic.

I'm guessing English is your second language....

[...]
You obviously don't work in this industry, and apparently you don't have anything intelligent to add to the conversation either.
[...]

You didn't add anything intelligent to your own conversation, so why would anyone else?
And who gives a rat's ass about working in the industry? The name of this forum is DIYStompboxes.com.

Now I'm certain English is your second language.

[Jdansti]

This is my first post on this thread, so I'm going back to the original post:

So has anyone else figured out how to auto-bias JFETs for use in Fetzer Valve type circuits? By auto-biasing I mean leveling the playing field for all JFETs by using simple fixed value parts, thus eliminating the need for transistor sorting, trimmers, or additional active devices. I'm thinking that from a manufacturing standpoint this would save an enormous amount of time and money.

Welcome to the forum, aethertransit!   I haven't figured out how to auto-bias JFETs for use in Fetzer Valve type circuits. I am very interested in knowing how this is done, as I am a fan of using JFETs.  I'd be happy to discuss your ideas with you.

[aethertransit]

This is my first post on this thread, so I'm going back to the original post:

So has anyone else figured out how to auto-bias JFETs for use in Fetzer Valve type circuits? By auto-biasing I mean leveling the playing field for all JFETs by using simple fixed value parts, thus eliminating the need for transistor sorting, trimmers, or additional active devices. I'm thinking that from a manufacturing standpoint this would save an enormous amount of time and money.

Welcome to the forum, aethertransit!   I haven't figured out how to auto-bias JFETs for use in Fetzer Valve type circuits. I am very interested in knowing how this is done, as I am a fan of using JFETs.  I'd be happy to discuss your ideas with you.

Well hello Texas! So are you currently working on a project or are you wanting to start something new?

[gcme93]

Hi aethertransit,

Again, I'd like to welcome you to the forum but also try and explain why there's been a bit of confusion and negative response to your thread. This whole forum is basically a sharing place for ideas and help on various pedal related things. It relies on people sharing their experiences, knowledge, and hopefully successes, which then in turn sparks off new ideas and there's a very nice organic evolution as new pedals spring up and new solutions are found.

The guys on here don't mean to make you feel unwelcome, it just feels like you've posted saying "I've got something, am I the only one with it?" which doesn't really fit in with the normal content on here. I guess I understand why you want to test the water, find out from an active community if your JFET solution is something that you could do well off, but it's pretty contrary to the normal ethos of this place.

Personally I would have thought that if you have an idea that you researched and developed, you'll inevitably have a fair bit of written (dated) proof that can allow you to claim intellectual property. So why not share an explanation with us? No one here is going to put that into mass production because we'd rather not be sued!

Just a few thoughts from me

George

[aethertransit]

Hi aethertransit,

Again, I'd like to welcome you to the forum but also try and explain why there's been a bit of confusion and negative response to your thread. This whole forum is basically a sharing place for ideas and help on various pedal related things. It relies on people sharing their experiences, knowledge, and hopefully successes, which then in turn sparks off new ideas and there's a very nice organic evolution as new pedals spring up and new solutions are found.

The guys on here don't mean to make you feel unwelcome, it just feels like you've posted saying "I've got something, am I the only one with it?" which doesn't really fit in with the normal content on here. I guess I understand why you want to test the water, find out from an active community if your JFET solution is something that you could do well off, but it's pretty contrary to the normal ethos of this place.

Personally I would have thought that if you have an idea that you researched and developed, you'll inevitably have a fair bit of written (dated) proof that can allow you to claim intellectual property. So why not share an explanation with us? No one here is going to put that into mass production because we'd rather not be sued!

Just a few thoughts from me

George

Hi George, thanks for the welcome. Unfortunately I know all too well how ideas of this sort get taken advantage of by certain people in the industry, and I know exactly who is trolling this forum. It is for this reason alone that I'm being cautious and trying first to establish a relationship with like minded individuals and get the gears turning so to speak. Be that as it may, I have no intention of cashing in on this idea because frankly I don't see that happening with the economy on the verge of total collapse, and patenting electronic circuits doesn't stop other people from capitalizing on them anyway. My point for being here is to start a conversation with people who have taken a similar approach to achieve the same goal, and share my knowledge with those who will use it wisely, not for their own personal gain at the expense of others. Apparently some of the members here can't understand this and are trying to make me feel unwelcome, as I haven't provided them with instant gratification typical of what they're used to receiving. All that being said, the topic is still open for discussion.

[mistahead]

I'm going to be short with you mate.

You know the list of common / key posters and seem to be "familiar" with the board - so I'm going to ask if this is the only user name you have here.

You claim that you've a novel approach to a very old problem, which would be great to share and give to the community, but really you've not given anything and have asked others to provide their thoughts on the problem which you have apparently already solved...

How did you solve the problem bro? Describe the methodology if you're not willing to post shem/proofs.

[aethertransit]

I'm going to be short with you mate.

You know the list of common / key posters and seem to be "familiar" with the board - so I'm going to ask if this is the only user name you have here.

You claim that you've a novel approach to a very old problem, which would be great to share and give to the community, but really you've not given anything and have asked others to provide their thoughts on the problem which you have apparently already solved...

How did you solve the problem bro? Describe the methodology if you're not willing to post shem/proofs.

First of all Sherlock, I'm not your "bro". Second, what part of "starting a conversation" don't you understand? Now would anyone else like to chime in and bust my balls before I take this to another forum?

[Jdansti]

This is my first post on this thread, so I'm going back to the original post:

So has anyone else figured out how to auto-bias JFETs for use in Fetzer Valve type circuits? By auto-biasing I mean leveling the playing field for all JFETs by using simple fixed value parts, thus eliminating the need for transistor sorting, trimmers, or additional active devices. I'm thinking that from a manufacturing standpoint this would save an enormous amount of time and money.

Welcome to the forum, aethertransit!   I haven't figured out how to auto-bias JFETs for use in Fetzer Valve type circuits. I am very interested in knowing how this is done, as I am a fan of using JFETs.  I'd be happy to discuss your ideas with you.

Well hello Texas! So are you currently working on a project or are you wanting to start something new?

Howdy!  Nothing in the works right now except honey-do's.   As a life-long electronics hobbyist, I'm always learning new things just for the sake of knowledge and sometimes to file away if/when I'm ready to use it in a project. Having limited formal electronics education, I often struggle with more complex (at least to me) theory such as "auto-biasing".

Having built several tube, JFET, and other transistor based projects, I understand the general concept of bias, and I'm aware of how to manually adjust the bias of these devices. While I've had good success with the Tillman Preamp , I have had some problems with RunoffGroove's Umble tone stack, which has four J201s. When I manually dialed in the four bias voltages stated in the build doc, I was getting oscillation when the volume, master volume, and three tone pots were in certain positions.  Trying to simultaneously bias the four transistors by ear didn't work well for me. So in this case, having an auto-bias would have helped immensely.

Anyway, bottom line is that whenever someone presents a concept that is new to me, I want to learn about it.  I'm very interested in how you recommend dealing with bias. If you decide to present your ideas here, I'll definitely have to crack open my old Umble and do a little auto-bias surgery.

[deadastronaut]

I'm interested too , fire away...

[mistahead]

I'm going to be short with you mate.

You know the list of common / key posters and seem to be "familiar" with the board - so I'm going to ask if this is the only user name you have here.

You claim that you've a novel approach to a very old problem, which would be great to share and give to the community, but really you've not given anything and have asked others to provide their thoughts on the problem which you have apparently already solved...

How did you solve the problem bro? Describe the methodology if you're not willing to post shem/proofs.

First of all Sherlock, I'm not your "bro". Second, what part of "starting a conversation" don't you understand? Now would anyone else like to chime in and bust my balls before I take this to another forum?

And with an attitude like that you may never be!

"Starting a conversation" with a statement that you have gold but you won't share it with the villagers unless they tell you how they prospected theirs is baiting.

Again - I can understand its great if you've devised a relatively reusable methodology for this, what have you brought to the "conversation" however doesn't really have any "Content". Others have had a crack with mixed results and have discussed in some depth - what is your methodology, theory, idea?

I'm not sure what you are threatening to take elsewhere, but it will at least be a light load to carry...

[Thecomedian]

actually mista, its more like stating that you know how to turn lead into gold, but want the villagers to show how they might do it first.

*popcorning intensifies*

[aethertransit]

I'm going to be short with you mate.

You know the list of common / key posters and seem to be "familiar" with the board - so I'm going to ask if this is the only user name you have here.

You claim that you've a novel approach to a very old problem, which would be great to share and give to the community, but really you've not given anything and have asked others to provide their thoughts on the problem which you have apparently already solved...

How did you solve the problem bro? Describe the methodology if you're not willing to post shem/proofs.

First of all Sherlock, I'm not your "bro". Second, what part of "starting a conversation" don't you understand? Now would anyone else like to chime in and bust my balls before I take this to another forum?

"Starting a conversation" with a statement that you have gold but you won't share it with the villagers unless they tell you how they prospected theirs is baiting.

And where exactly did I state this? I'm not sure if they have 'Hooked On Phonics' down under but you might want to look into it.

[aethertransit]

actually mista, its more like stating that you know how to turn lead into gold, but want the villagers to show how they might do it first.

*popcorning intensifies*

Apparently neither one of you know how to read. Good luck with that.

[mistahead]

Apparently neither one of you know how to read. Good luck with that.

Communications, being transactional in nature, require the message being sent in a manner which allows for the intended recipient to recieve and decode/understand the message.

So - back at the plot - I have a design with six independant JFET stages which each require I bias the FET's individually. For a one-off this is fine as I can pick my components... but I suppose I'm more interested in making heaps of them as I see the trimmers as the flaw in my design. While other posted links here helped ease this pain in some designs none of them work in this particular one sadly, so a new and novel approach is required and I am overjoyed to find out someone has one and will trade it with the Internet for "conversation"...

How do you reckon I approach this then?

[Thecomedian]

it's hard to start a dialogue with someone who keeps insulting everyone and refusing to consider alternative viewpoints. food for thought.

[Joe]

A while back there was an article or app-note about this. IIRC there was a way to calculate ideal values based on datasheet curves.

[aethertransit]

it's hard to start a dialogue with someone who keeps insulting everyone and refusing to consider alternative viewpoints. food for thought.

You are absolutely full of yourself. Not to mention the fact that you started heckling me before I could get an intelligent conversation going. Nice job.

[aethertransit]

So far I've gathered that at least one other person on here has figured it out and he's keeping it to himself for what I'm sure are the same reasons. Maybe if you guys heckle him enough he'll tell you his secrets. At this point the only thing I have left to say is that this biasing method is possible, it works great, and it's easy. Anyone else who's interested can send me a PM.

[Thecomedian]

it's hard to start a dialogue with someone who keeps insulting everyone and refusing to consider alternative viewpoints. food for thought.

You are absolutely full of yourself. Not to mention the fact that you started heckling me before I could get an intelligent conversation going. Nice job.

I was one of the first people to openly discuss this with you, but then you went on your rant, and my opinion of the nature of the thread and intentions of the author were modified as a result.

Life gets a little more surreal every day..

[slacker]

The thing Gus posted is the closest I've seen without using other active components, works great but that still needs some tweaking for different types of fet. Something simple for "any fet" would be certainly be interesting.