Magnavibe vibrato/tremolo blend mod for rotary speaker effect

[duck_arse]

DMichel - whwere does your univibe connection actually go, is that the output or does it connect with the output? or something else?

your J1 - the diagram shows the gate hard to ground, and the "osc" running through three resistors to ground. (personally, I think one resistor to ground would suffice.) ......

and, seeing as you are simming these, can you do me a favour? invert the oscillator output to the second stage, so the leds are 180 degrees outta phase, and tell me wot happens. and, if you can, find a combination of cap values (your C1 and C4) that make the most something/anything happen.

kipper - does your osc run for the full pot range, does it run with a lower stop R (R2), does it run full-pot with a 100k in? also, hah-ha, sucks. and your humpty cap is (C4) 220nF, does it fill the hump or not? [also, also, when they are electos, turn C9 and C11 the other way, and take R10 and R11 to V+ instead of ground, and that cap string will be 100% correct.]

ben - nothing useful new, sorry.



I think we need to get deadastro in to post, so's we can get the thread up to at least 35 pages .....

[Kipper4]

kipper - does your osc run for the full pot range, does it run with a lower stop R (R2), does it run full-pot with a 100k in? also, hah-ha, sucks. and your humpty cap is (C4) 220nF, does it fill the hump or not? [also, also, when they are electos, turn C9 and C11 the other way, and take R10 and R11 to V+ instead of ground, and that cap string will be 100% correct.]

I think we need to get deadastro in to post, so's we can get the thread up to at least 35 pages .....

"kipper - does your osc run for the full pot range?" Sure does.

"does it run with a lower stop R (R2) "
Yep down to 1k with a B50k speed pot. Makes it go slower at slow and faster at fast, like ray gun fast.

"does it run full-pot with a 100k in?" Yessum it do. runs at full pot range too.

humpty cap is (C4) 220nF, does it fill the hump or not? Thanks yer i got that. brb gonna try and hump it.
what pots works best for me B25k That humps best to my ears.
What pots dont work for me 10k and less (went down to 2k) and 50k plus pots (went upto 500k) YMMV.

[also, also, when they are electos, turn C9 and C11 the other way, and take R10 and R11 to V+ instead of ground, and that cap string will be 100% correct.]

hmmm using 1uf box caps actually, but taken on board.


"I think we need to get deadastro in to post, so's we can get the thread up to at least 35 pages ....."
Did you mean pages or leds?

I get my coat.

for info still using a 4mm spaced vactrol 5mm super bright led and waitrony KE10720 (std tayda) LDR
encased in white heat shrink so i can see whats going on and // led.

How am I doing?

ps If you look at top right hand of DM123s drawing D.A you will see his R5. Also shown bottom left in the splitter

[Kipper4]

Oh and good luck England for tonights football game. By which I mean the beautiful game otherwise reffered to as Soccer.
Not the qAussie rules rugby / football mash up.

Hut hum...... 

[Kipper4]

Version 3 with notes

[Kipper4]

Can't say for certain becuase its getting late and I dare not crank the bigger tube amp much more but it sounds like the mofet versions oscillator noise comes through more than the bjt splitters do.
Let me know if you try it guys.

[Ben Lyman]

Rich, I just tried MosVibe V3 and the noise is there when turned up loud. I also noticed you have the output coming from the 2n7000 source (I think?)
Is there a reason for that that I should be reading up on? Duck's appears to be coming from the drain and then thru a buffer and then out the source of the buffer.

Anyway, my main concern with my latest test is that I still can't get it to slow down! This is my first attempt with the 4-stages and I used the above schematic with 1uF caps, etc.
I changed my speed pot to 100k, still didn't slow down, then I just put it in series with a 470k (570k total) and still no slowing! I can always get it to go super fast with less resistance but I just can't slow it down no matter how much resistance I throw at it.
What am I doing wrong?

[Kipper4]

Yer your right there's a mistake there. Take the output from the drain cap 220nf. Make it smaller like 100nf to 10nf. And you can change the roto/vibe pot to 10k again.
To make it slower speed use 100k speed pot. Series 1k resistor.
Sorry chaps

[robthequiet]

Not sure if this has any bearing, but looking at the concept of speed control,

• The ideal method of adjusting the frequency is to use a triple pot, to control all three phase shift sections. This is not always practical, so only one section is usually adjusted.  It is usually best to adjust the last phase shift section, rather than the first one after the amplifier, as it will usually afford a wider range of control.

From  Randall Aiken's site .

[Kipper4]

You can always use your old 3 stage PSO with the mosfet splitter too.

Thanks for that Rob.

Some where's here Jon Patton did an comprehensive PSO thread too.

The source output mistake was copied from the mosfet splitter I nabbed off the net. Ooops.

[Ben Lyman]

Thanks guys, very helpful, I'll try swapping the speed pot with R16 10k and see how it responds.
I read Rob's link and learned a little more about it, thanks Rob.
I put 3 100k pots in between the 4 caps in the PSO? LFO? POS? what's it called?
By adjusting two of them to a certain point (I didn't measure them yet) I was able to use the third to control the speed and got it down to a much slower speed than before, I'd guess about half.
The trade off is that the top speed is not quite as fast and sickly as before. Gotta rack out now, maybe I'll try some more tomorrow.

[Kipper4]

According to Robs link try putting speed pot at R11 Ben


Edit.
We won 2 to 1. Not that I know anything about football. Ive got to say that has to be a first England winning anything against Oz.

[duck_arse]

foopball? sorry, was there a game ....... ?

we'll have no triple pots in this thread, thanks rob. we're letting DMichel get away with suggestions of dual gang, but he's new here. and DMichel, yes, I am a goose, it struck me in the shower this morn, your odd fet connections are for the simming, to stop the osc, as per your "hard to understand/follow" note. for penance, I tried your chorus connection, sort of. but from the source of the mosfet, 2 stages, to the output like-a-lpb1 gain stage. different, swooshy, especially with the two phase clock.

kipper - I almost missed your leds. not in parallel, unless with a resistor each. always! you can use a lower value for the depth resistor, and higher for the vactrol, if you like, but 2 resistors. or else.

and ben - go back to that circuit I posted with milllions of parts, and look at the way I've done the depth pot and led connection. try those values, up or down the value of all the caps to suit. it is quite probable that your very low stop resistor is wot makes it run so fast.

[edit :] also note I'm using 22k stop in the led string. I noticed a lower value there affected the oscillator range, dying at both ends of the pot. it might hold up with a lower value there, but didn't see the need to try.

I would say I haven't had the slightest off osc noise coming thru, but that would be tricking. I've got the osc feeding an LM358, with some sine-shaping and inverting to provide the out of phase led drive. very quiet, also very swishy, more complex swoopsings. also, more parts!

and it doesn't seem to matter for the lyman cap if you take from the source or the drain as far as I can tell, or even both (I think I've tried every connection combination of two caps and two ldrs there is there), as to the phinal phased sounds, they just get mashed together again anyway.

[Marcos - Munky]

Kipper, when you say 4 stage mosfet magnavibe, do you mean you're running 4 magnavibes in series?

[Ben Lyman]

Ok Duck, I'll give it a shot. I had to hand copy your schematic because you use that blackout background to prevent people from printing out your designs, don't you? Deadastro too. Pretty tricky!

Marcos, kipper and Duck just mean we've been trying to add an extra cap and resistor to the POS.. yes, the POS, that's what I call it now. Some have said LFO, now I see PSO, so as long as we can make up any name we want for it, I'm going with POS 

[Kipper4]

Hey Markus.
I refer to the 4 stage phase shift oscillator seen in reply #68.
The four stages are in the oscillator. I'm not using four concertina splitters seen on the right of the schematic one only.

Duck haha what game?

I might just try the series LEDs instead. Or else ??

[Kipper4]

I just simmed the 4 stage PSO and it wouldnt start unless I had a 100~200k in R16 reply #64
Ben.

I'm not super at simming stuff. Not sure if it was a quirk of the sim why it wouldn't start or the values used. Hence changing R16.
Changing the feedback/bias resistor R9 to 1M5 can make a difference too.

I'll breadboard it later and let you know if it has a good speed range mate.

[Ben Lyman]

cool. thanks kipper. I went back to my 2n5088 Q1 with an MPSA18 in the 4-stage POS. I didn't have any 680nF so I used 470nF and Duck's resistor values. It sounds great and goes very fast but I still can't get it to go slow enough for my liking, even with a 500k pot it only slows to a certain point and no more. I can see where a triple gang pot or even dual gang would help but i think I would rather just try to adjust the resistors a little here and there, find a compromise

[Marcos - Munky]

Ah got it. Thanks for the replies. This is getting interesting.

Also, Rich, in the mosfet version, do you mean output should be taken from the point between C4 and the LDR, correct?

[Kipper4]

You should be fine taking it from c5 to as long as it's go a cap there. You will probably get more highs from C5 as proved by the Lyman cap in another thread.
If there's no cap you will get thumpy trem and no vibe. Been there too.

Have fun Markus

Ben I've seen 4 stage PSO without the extra resistor, google it. Or just take it out on the breadboard see if it achieves a slower rate. It's such a personal thing with the speeds.
You can always try a different lfo. Like the one from the folie a deux schematic I sent you now that will go slower than my wife thinking about making a coffee.

I'm thirsty.

[Ben Lyman]

Kipper, I don't think I'm quite at that level yet, with the U1a, b, c, d's and stuff.
Here's what I've been learning, if it's common knowledge feel free to skip to the video:
oops, edit:
It seems like maybe the smaller cap values in the POS make it go faster/deeper and the larger values do the opposite so I'm trying to find a happy medium. Right now I have 4 1uF caps with Duck's resistor values, 250k speed pot with 2k2 stopper.
Here's a comparison with the double waggler: