Inspiration in new approaches

[Bill Mountain]

I have been working on an opamp based distortion for a few months and I have 90% of it figured out but what kept eluding me was how to set a high and low gain switch to work perfectly with my two guitars.

After several frustrating weeks with a calculator and simulators and a few hot months on the breadboard (I get to tinker like twice a week at most) I needed a change of pace.  I built up a simple JFET preamp with a switch to bypass the first stage's source resistor for a gain boost.  I liked it a lot.  It was clean and I could get good gains with either guitar because of the boost switch.  Then it hit me...maybe I could use JFETs for the gain element in my design and I grabbed some diodes and made a good sounding distortion.

I was high on this idea all last night and I have been thinking about JFET biasing schemes all morning.  I prefer opamps because of the consistency but I got the gain ranges I wanted with the JFETs.  Then about 30 minutes ago I had another revelation.  I can design the opamp stages with the same gains as my JFET stages plus I don't have to redesign my effect from the ground up.  I first sim'd a design with an opamp replacing each JFET (plus a boost switch) and then I matched the gain from both stages with a single opamp.  I didn't revolutionize anything but I realized the amount of gain I should have been working with from the start and the amount of boost needed to blur the volume difference of each guitar.

I still need to test my new circuit but I'm pretty sure it'll work.  The only variable is whether or not I'll miss any sweetening from the JFETs (I ran them mostly clean).  There is of course Murphy's Law...

The reason I'm posting this is to bring up a lesson I always seem to forget.  If you get stumped on something just try it a different way.  You never know what inspiration you'll find.

[tubelectron]

The reason I'm posting this is to bring up a lesson I always seem to forget.  If you get stumped on something just try it a different way.  You never know what inspiration you'll find.

Indeed !

This drove me to replace Op-Amps by tubes (on HV) with some success (see the Tubelectron Overdrive, the HCTO overdrive... somewhere on the forum...), but I really need to enter the use of the FETs : my empirical quick trials were not very successful with them (harsh sounding, inexplicably). I would like to find a simple "starter" design to be breadboarded for an overdrive... May be you can direct me ?

A+!

[R.G.]

When looking for inspiration, it's important to remember that necessity is NOT the mother of invention.

It's Desperation. Desperation is the real mother of invention.

[artifus]

you can't look for it. it finds you.

[Earthscum]

It's Desperation. Desperation is the real mother of invention.

Ingenuity in general. It's easy to get slothed out when the going is easy.

[R.G.]

Ingenuity in general. It's easy to get slothed out when the going is easy.

Actually, if Desperation is the mother of invention, laziness is the father. How many things were invented because someone didn't want to get up and do X?

The bucket, for instance. Can you imagine how welcome the idea of bringing water back from the creek was, compared to walking down there every time you were thirsty?

[Earthscum]

Ingenuity in general. It's easy to get slothed out when the going is easy.

Actually, if Desperation is the mother of invention, laziness is the father. How many things were invented because someone didn't want to get up and do X?

The bucket, for instance. Can you imagine how welcome the idea of bringing water back from the creek was, compared to walking down there every time you were thirsty?

+1

[Bill Mountain]

The reason I'm posting this is to bring up a lesson I always seem to forget.  If you get stumped on something just try it a different way.  You never know what inspiration you'll find.

Indeed !

This drove me to replace Op-Amps by tubes (on HV) with some success (see the Tubelectron Overdrive, the HCTO overdrive... somewhere on the forum...), but I really need to enter the use of the FETs : my empirical quick trials were not very successful with them (harsh sounding, inexplicably). I would like to find a simple "starter" design to be breadboarded for an overdrive... May be you can direct me ?

A+!

Admittedly, I haven't had much luck with JFETs myself.  But, my most recent excursion proved most fruitful.  Basically I used higher voltages and biased for clean (24V).  I just grabbed some MPF102's, put 10k resistors on the drain, 2.2M on the gate to ground, and I put a 22uf bypass cap and 10k pot on the source and adjusted to 1/2V and replaced it with a fixed resistor.  I haven't worked on biasing for distortion yet.

[Bill Mountain]

When looking for inspiration, it's important to remember that necessity is NOT the mother of invention.

It's Desperation. Desperation is the real mother of invention.

Good point.  Sometimes I get so worked up in coming up a novel idea that I get desperate for a solution and I go with something tried, true, and easy.

[midwayfair]

Ingenuity in general. It's easy to get slothed out when the going is easy.

Actually, if Desperation is the mother of invention, laziness is the father. How many things were invented because someone didn't want to get up and do X?

The bucket, for instance. Can you imagine how welcome the idea of bringing water back from the creek was, compared to walking down there every time you were thirsty?

So invention is the product of lazy, desperate, needy parents?

[amptramp]

Ingenuity in general. It's easy to get slothed out when the going is easy.

Actually, if Desperation is the mother of invention, laziness is the father. How many things were invented because someone didn't want to get up and do X?

The bucket, for instance. Can you imagine how welcome the idea of bringing water back from the creek was, compared to walking down there every time you were thirsty?

So invention is the product of lazy, desperate, needy parents?

Guilty on all three counts.

[teemuk]

Ingenuity in general. It's easy to get slothed out when the going is easy.

Actually, if Desperation is the mother of invention, laziness is the father. How many things were invented because someone didn't want to get up and do X?

The bucket, for instance. Can you imagine how welcome the idea of bringing water back from the creek was, compared to walking down there every time you were thirsty?

Not to mention The Wheel.