design help needed

And everywhere else. In _any_ of the computer programming related forums:

op - this dont work rply - That's because you didn't do this. op - how do I do that? rply - Like this. op - that dont work

Etc., etc., on and on, ad infinitum. Everybody seems to want their hand held, and *no*body wants to go through the effort to actually learn, and become good at something.

expect

of

Exactly.

Jeff

While you were right there, I'm surprized you didn't spot the short from Q2e to R14.

Since self-abuse is the most sincere form of flattery, I offer Version 2.3 of the circuit in question.

It needs some more work but you guys stopped abusing me so I felt unloved.

What are the LEDs for, besides distortion?

Why have R3 and 4?

Value of C10?

Why have the volume control lower end tie to the positive voltage from the emitter of Q1? C9 seems to be in a strange place. What is its purpose?

Are you saying that you expect to get 20 db gain from the amplifier following the volume control? What input impedance are you shooting for at the wiper of the volume control?

What is the supply voltage?

So silly I couldn't see it. That is really gonna hurt battery life.

I have no aversion to Op-Amps..rather I read that some people do have such an aversion and designed around that aversion

Do you have a specific aversion to using op-amps ? Your discrete amplifer sections will certainly add some 'colouration' ! It's not even as if they make for especially low current consumption.

AC coupling of the drains of J1 and J2 will cause some interesting intermodulation too.

The level control after the passive eq will cause a loading effect that'll most likely screw up the eq itself. Active eq is the answer.

Graham

I read in alt.binaries.schematics.electronic that The unknown Posterchild wrote (in ) about 'design help needed', on Sat, 17 Sep 2005:

Battery life may be a bit short.

Why have you still got 3 Mohm input impedance? Everyone told you that for capacitor microphones you need something between 1.5 kohm and 4.7 kohm. You also show a number of non-standard resistor values, which you can't get.

Is he using a 'low impedance' capacitor mike ?

It's going to be horribly noisy if it goes through that lot ! Not to mention a level mismatch between a low-z mike and a guitar pickup !

It needs active variable gain stages at the front end to minimise noise and optimise level matching followed by a low noise active EQ section and overall level control.

Graham

This "design" terribly looks alike my first hobbyist attempts as a kid in the 60s. Obviously the OP has still to arrive at the opamp aera.

I'm sure some ppl were still doing stuff like this for MI in the early 70s.

Graham

'Some ppl' are also fuckwits !

Use some op-amps to do this and not only will the battery last longer but there will be less hum and noise and it will be distortion free.

Of course some ppl *like* the distortion of rather poor discrete designs. I guess they like the hum and noise too ?

Graham

that

in

That's an excellent testament to the saying, "Every expert was once a beginner."

Last night I was watching "Rick Steves' Europe" on PBS. This episode was about the Cote D'Azure, and he said that some of the most expensive real estate in Europe was located between Villefranche and Monaco. Like, it's nice to know that you live in an upscale neighborhood. ;-)

Back in the '60s, you probably didn't have low noise silicon BJTs and FETs, and were still using Germanium. I think it's okay to use discretes as long as the appropriate now noise metal film resistors are used. Opamps often get used in audio without any blocking caps, and when there's a bit of leakage and consequent DC shift, it can do some odd things to the signal. But it's nice to be able to scramble your friend's livers with a couple hundred watts of infrasonic power. ;-)

That's not a short. It's a shunt regulator to ensure Vbatt = 0 :-)

LoL I like that one. hehehehe

Yeah, it's not so nice if you need to rent a place and pay $$$. Even a small country hut costs as much as an appartment in Milan, which is already quite costly. But the climate is nice in Nice. That's where I will be going today with my new GF, (and that is also the reason why I got thrown out of home and look for something to rent). :-( We will visit the Museum of Modern Art and the Miro Museum. Last week we went to Chagall Museum, which is my favorite.

New Version:

mic impedence: 200 ohms each

flame away

Last time I asked you polite questions and made a design suggestion and got no reply at all. I think I'll pass, this time.