Orange Squeezer

[Kipper4]

I'll rebuild it (marks mods) tonight. I've tried breadboarding this all day (3 differant schematics inc madbeans, beavis) and i havent managed to get signal out of it yet.
despite having built it on real board and it works
when you say pull Q1 you mean just the transistor (leave all the connections that went to it as was?)
or is that a dumb question.

[midwayfair]

I'll rebuild it (marks mods) tonight. I've tried breadboarding this all day (3 differant schematics inc madbeans, beavis) and i havent managed to get signal out of it yet.
despite having built it on real board and it works
when you say pull Q1 you mean just the transistor (leave all the connections that went to it as was?)
or is that a dumb question.

Yes, just pull out the JFET. It disconnects the compression circuitry from the dry path. If you still don't have sound, your problem rests in the op amp section, which is a fairly basic amplifier stage. You should be able to debug that. What are your voltages like on the op amp?

EDIT: Maybe pull the diode as well.

[Kipper4]

tried that it didnt make any differance.
my voltages where all over at the ic
ref v 6.5v

1=0.85
2=0.83
3=1.74
4=0
5=4.7
6=0
7=0.24
8=6.5

i think i may as well build this (marks modded orange squeezer) on a proper board.

http://www.generalguitargadgets.com/diagrams/orangesqueezer_marks_variable.gif

i guess this is verified by now and theres no additional information i need

This breadboards getting on my nerves now.

[samhay]

Pin 8 should be at 9V ish. Your battery/wall wort is at 9.4V - pin 5 is at half this.
So, first things first, what is between your voltage source and pin 8?

[Kipper4]

pin 8 goes straight to battery + + ref voltage 6.5 v

[midwayfair]

pin 8 goes straight to battery + + ref voltage 6.5 v

You need a fresh battery for one thing.

Pin 5 should be grounded, with 6 and 7 connected. EDIT: RG probably just took it as read that everyone would ground the second half of the op amp ... it won't keep it from working, but it might make things noisy.

[Kipper4]

pin 8 goes straight to battery + + ref voltage 6.5 v

You need a fresh battery for one thing.

Pin 5 should be grounded, with 6 and 7 connected. EDIT: RG probably just took it as read that everyone would ground the second half of the op amp ... it won't keep it from working, but it might make things noisy.

Please explain the last comment.
"pin 5 should etc"
Is this a convention? it its whats expected when half a dual opamp is not being used? Ground pin 5?
I have no EE background. I'm just two months into this hobby and so far i still have a lot to learn.

I reckon i should go back to basics on the breadboard and start with single transistor buffers.


I did however make Marks modded Orange Squeezer as in the schematic i posted earlier in the thread.
It's nearly 2 am so i wont know if it works until tommorow.
My quick and dirty test oscillator has a nasty habit of waking the wife in the next doors bedroom.
wish me luck.

[samhay]

pin 8 goes straight to battery + + ref voltage 6.5 v

You need a fresh battery for one thing.

Pin 5 should be grounded, with 6 and 7 connected. EDIT: RG probably just took it as read that everyone would ground the second half of the op amp ... it won't keep it from working, but it might make things noisy.

The schematic the OP posted uses the 2nd half of the op-amp as an output buffer. Seems like a good idea. In this case, pin 5 should be at half the supply voltage.
If half an op-amp is not used, it is good practice to do something with it. See e.g. here: http://www.maximintegrated.com/app-notes/index.mvp/id/1957
It won't stop the circuit working (usually), but will stop it oscillating.

[Kipper4]

Ok thanks Sam
I'll try to get my head around that later.
I've a feeling i may need to google some terms
cheers

[midwayfair]

The schematic the OP posted uses the 2nd half of the op-amp as an output buffer.

http://www.geofex.com/FX_images/orgsqz.gif

[samhay]

Jon - I was working off the GGG version that Kipper posted. Had not seen it before, but it has the gain mod you mentioed earlier and an output buffer. Seeing as the orginal leaves half a dual op-amp unused, an ouput buffer seems like a nice touch.

i think i may as well build this (marks modded orange squeezer) on a proper board.

http://www.generalguitargadgets.com/diagrams/orangesqueezer_marks_variable.gif

i guess this is verified by now and theres no additional information i need

This breadboards getting on my nerves now.

[midwayfair]

Jon - I was working off the GGG version that Kipper posted. Had not seen it before, but it has the gain mod you mentioed earlier and an output buffer. Seeing as the orginal leaves half a dual op-amp unused, an ouput buffer seems like a nice touch.

i think i may as well build this (marks modded orange squeezer) on a proper board.

http://www.generalguitargadgets.com/diagrams/orangesqueezer_marks_variable.gif

i guess this is verified by now and theres no additional information i need

This breadboards getting on my nerves now.

Oh, sweet, I didn't realize that. I've got one built on their previous board. Didn't even know they had revised it, so I had never clicked on that link.

[samhay]

Yeah, it's got some nice features. Mine has a switchable buffer (so it can be on when the OS isn't) anyway, but I like the idea of using the other side of the op-amp.
Is the op-amp gain mod worth the effort? I have swapped out the OS on my board for my optical compressor, but my tastes will change again and an OS with more squish sounds quite tasty.

[Kipper4]

Jon can you post up a link to the one you built because i spent all day and night yesterday trying to breadboard The GGG modded one but it still didnt work.
Then i got fed up and actually used some strip board and made it. I'll post the pics in my drop box and if i get a second later i'll post up the voltages and start to diagnose and trouble shoot it too.
This circuits so frustrating.

[Kipper4]

https://www.dropbox.com/sh/7ma9n53c5jqdgsr/d-0TvwYXDL?m

heres the photos

Substituttions
instead of 10k resistors i used up two values withing 10% of the 10 there abouts
Instead of 10k bias pot i used a 20k trim pot

i think the rest is as per

voltage at source 8.99

IC
pin
1=4.96
2=4.88
3=4.02
4=00
5=0.06
6=8.16
7=8.27
8=8.89

Q nearest to IC

D3.32
S1.89
G0.25

Q furtherst from IC

D4.06
S8.89
G3.33

[Kipper4]

forgot
all pots used are 10k

[samhay]

You should have about 4.5V on pin5 of the op-amp. Like this, I don't think it will pass signal. Can you hear audio on pin 2 of the level pot? You might need an audio probe for this, but I think you have mentioned that you have one? Are you taking pin 2 of the level pot to the op-amp?
Once you have signal, biasing the OS is a little tricky. The bias pot is a variable resistor to ground, so any value of 10k or more should work, but the sweet spot may be very small.

[Kipper4]

centre lug of level pot goes to pin 5 of opamp yeppers.
I'll get the probe out and check it mate brb

[Kipper4]

yep i have signal at centre lug of level pot. I just probed it as suggested.
So the problem must be between there and the output.
mmmmmmmmmmm

[samhay]

There should be one 330k (ish) resistor from your positive voltage supply (battery +) to pin 5 and another resistor of the same size going from pin 5 to ground. That's a voltage divider giving you half V+ at this pin. Without it, a non-inverting op-amp (like this one) will not work.

Anyway, you have a working OS - the original version doesn't have an output buffer and stopped at the level pot. Well done.