MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

ADSR VCA ..huge problem
MUFF WIGGLER Forum Index -> Oakley Sound Systems  
Author ADSR VCA ..huge problem
rarecomponent
I buit the ADSR VCA board (not the upgrade version)

ADSR only triggers on gated loop and loop (not Normal position)
but the signal is a nice correct output.

VCA output is nil..it just dont work.

All IC's replaced (apart from U8- That2180 and U12- 4052)
every component checked and double checked..all joints checked
all wiring double/treble checked

(I left out the N/C's on the jack outputs)

Ive nothing left to try..anyone else had similar problems?
iopop
I have not built this, so I can only speculate.

But given what you say, I would start to check the components around loop switch and the trigger input. Print out a copy of the schematics, start at the input, use your DVM, write down all values, verify against the schema. There are a few 4k7 and 47k on this module, they are pretty easy to mix up. I did that mistake last week.

Since you have a good output on the other two modes it must be something simple. But those errors are always the most frustrating. Go for a walk, watch some telly, take a break, go back with a clear head and you probably solve it directly.
krisp14u
Im sure we can get it working

rarecomponent wrote:
ADSR only triggers on gated loop and loop (not Normal position)
but the signal is a nice correct output.

Do you have the links or jumpers on the headers?
Top right of the board AD and SR
The AD will loop without the links being present but the attack and decay pots will not affect the speed


rarecomponent wrote:

VCA output is nil..it just dont work.
(I left out the N/C's on the jack outputs)


Pin 5 CV_NC Connect to VCA IN NC lug
Without this the VCA out will not output anything unless there is a signal at the input of the VCA

If that’s all ok it would help me if you could post a photo of the board/back of the module
Tony will probably not need a photo
rarecomponent
I'm confused here. In the builders guide is says:

Options depending on front panel design.
New Panel = fit R34 & R36
do not fit R25 R27

In the picture of your completed board R34 and R36 are not there and
R25 & R27 are fitted...do I take it this is the old panel?

Choose what I tried refitting this version on my board and am now getting even less results than the incomplete results I got before.
All jumpers fitted..all wiring correct..Ive even checked every pin connection on each IC for contact.....
krisp14u
Yes looks like the picture of the PCB in the builders guide is built up for an old panel
The builders guide is good I have built quite a few of these and they all work 100%
Synthbuilder
rarecomponent wrote:
In the picture of your completed board R34 and R36 are not there and R25 & R27 are fitted...do I take it this is the old panel.

Yes, the photographs show the module wired to the original panel design.

rarecomponent wrote:
ADSR only triggers on gated loop and loop (not Normal position) but the signal is a nice correct output.

This suggests that the gate signal is somehow being applied even when no gate is connected.

This, along with the fact the VCA is not outputting anything, may hint at the gate and VCA sockets' NC lugs being swapped over. Swap the connections for the NC lugs on those two sockets and see what happens.

Tony
rarecomponent
thanks for that....tried it .....VCA stone cold dead..now there is no output at all from ADSR.....ready for giving up on this module

1. All connections checked re-checked and checked again then re-checked.
2. All components checked ,re-checked, checked and checked again then re-checked.
3. All IC's replaced apart from U2 and U8..all pins on IC's checked for pin contact.
4. All solder joints checked for dry joints and bridges.
5. PSU connections checked and jumpers checked.

The only thing left is a dud That2180
or 4052..but neither ADSR works properly nor VCA works at all.
Synthbuilder
Dead 4052 is possible - 4000 series CMOS can be killed with static discharge and cause all sorts of weirdness - but I've not come across a dead 2180 yet.

If it was looping and now is not then this strongly suggests either an intermittent connection somewhere or perhaps there's been an accidental short circuit at some point. I've done that a few times; a quick slip of the meter probe and away goes another chip into the bin.

OK time to get out the multimeter.

What are the voltages on the following points? The module should be in norm mode & no gate input.

1. Pin 3 of BUSS

2. Pin 8 of I/O

3. Pin 4 of I/O

4. Pin 6 of I/O

All voltages to be measured with respect to ground, ie. empty pin 3 of PWR is easy to get to.

Tony
rarecomponent
Thanks for reply Tony..looping ADSR is back (broken wire joint due to much testing)
ADSR on Normal..dead
still no VCA..dead.

voltages are:- (no inputs/all controls 0 anticlockwise/switches to normal)

1.pin 3 Buss = 0v
2.pin 8 l/O = 0v
3.pin 4 " = 5v
4.pin 6 " = 0v
Chopper28
Rarecomponent - where are you located? As a 'veteran' of 20 odd modules I'd be happy to help out if I can.....
Synthbuilder
rarecomponent wrote:

1.pin 3 Buss = 0v
2.pin 8 l/O = 0v
3.pin 4 " = 5v
4.pin 6 " = 0v

OK, these are correct.

Did you say it loops in GATED LOOP mode as well as LOOP even with no gate input connected? And does the looping stop when you turn the sustain pot up?

If yes to both of those questions then it does look like you have two faults. One the VCA and two the ADSR. These are essentially two different circuits joined only by the CV output of the ADSR. If the ADSR is looping in loop mode the VCA output should respond accordingly.

We'll take the ADSR first. Does the sustain pot alter the voltage of the output of the ADSR socket? If so Q4 could be bad or the wrong type. R54 could be too low.

But what sort of gate signal are you using? The ADSR requires standard gate or V-trig outputs, ie. +5V to 15V for an active trigger and 0V for no trigger. I've just noticed another post a while back when you talked about using this with a Moog modular. You probably know that the Moog ADSRs use S-trig which are the opposite of V-trig. The Kenton should provide both, but you'll need the gate outputs to fire the Oakley ADSRs.

Tony
rarecomponent
Hi Tony

The gate is present when LOOP occurs, its frustrating because I can hear the correct ADSR output in there but not on NORMAL , then its dead.
The LED works as it should (i.e. varying brightness/speed with attack/decay controls and hitting keys) and the LOOP stops when sustain is turned up.

There is no voltage at all from ADSR when Sustain pot is increased.

The Moog is a faithful recreation clone built from schematics using 901b's,
all modules function correctly. The gate signal to the ADSR VCA module is via the Kenton AUX output which runs between 6-10v. This triggers the module correctly (but again only on LOOP not on NORMAL)

I have not connected the N/C tags on the module as to test the VCA I am using VCA in and out.
The ADSR works fine with the 904 but as I say, only on loop function.

Ive got BC549 C's in there..could that be a problem?

With the VCA being stone dead it must be a dud THAT ? (all pins have been checked for connection)
Synthbuilder
rarecomponent wrote:
The gate is present when LOOP occurs, its frustrating because I can hear the correct ADSR output in there but not on NORMAL , then its dead.

Just to be sure because I'm not sure I understand: The module should only produce a looping AD waveform in 'gated loop' mode when the gate is present. It shouldn't loop at all without a gate signal present. However, it should produce an AD waveform in 'loop' mode with or without a gate present.

rarecomponent wrote:
There is no voltage at all from ADSR when Sustain pot is increased.


OK. What about in loop mode? Does increasing sustain now produce a voltage? It should produce a fixed voltage from around 0.6V to 5V once looping has stopped.

rarecomponent wrote:
The gate signal to the ADSR VCA module is via the Kenton AUX output which runs between 6-10v. This triggers the module correctly (but again only on LOOP not on NORMAL)


This puzzles me. It shouldn't do anything to the module in 'loop' mode. It should only trigger the module in 'gated loop'.

Actually, you haven't got a normal SPDT switch in there have you? If that is wired up wrong that may give you the funny results you are getting.

rarecomponent wrote:
With the VCA being stone dead it must be a dud THAT ? (all pins have been checked for connection)


The THAT2180 is used in the ADSR not the VCA circuit. The VCA uses a LM13700. Now that could be dead.

Tony
rarecomponent
Hi Tony


GATED LOOP only works when GATE IN connected and keyboard hit, by itself it doesnt work.
LOOP works both with and without GATE IN

In loop mode with variable sustain I'm getting 1.5v to about 6v output from ADSR

The SPDT is on- off- on type
Heres the strange bit !!

When set to Normal, the keys dont trigger the ADSR however, if I press a key slow then again quickly I sometimes get a signal thru and its ADSR (ish) But playing normal notes..nothing.
I'm suspecting the GATE IN
VCA still stone dead..I've tried a 3rd LM1700 swap.
BUT..when I disconnect the PSU I get a signal thru providing the gate is present.

To be clear I'm using Kenton Pro Solo Aux out - Velocity Control - default range with an Alesis Keyboard controller. Maybe I could be missing something?
I'll give it a few more trys then its probably best to call it a day.
Synthbuilder
rarecomponent wrote:
To be clear I'm using Kenton Pro Solo Aux out - Velocity Control


As your gate or the CV input to the VCA?

If as the gate then this is probably the problem. Use the gate output from the Kenton. The Aux CV set to velocity will give you a constant voltage that is dependant on how hard the key's are hit. It won't go low when you take your hands off the keys. The gate must fall low again for the ADSR to trigger.

You could use the Aux CV as the CV input to the VCA. That is what I do often - but you still need a gate to trigger the ADSR.

Tony
rarecomponent
I'm using Kenton aux output to gate in.

Well if this is the case I was missled regarding the module's ability to be used touch sensitive with the Kenton, Ive wasted my time and money.
I intended to use Kenton S-trig for the Moog EGs and the Aux out for this module.

quote from forum:-
"BTW, I esp like sending aux1 from the Kenton to the signal input on the ADSR/VCA. That may be an obvious application, but worth mentioning because the ADSR/VCA can use it and most other EGs can't. If you have the VC ADSR/VCA, you could also use aux2 and aux3 to add variation to the envelope.
So, not only do they work together, they work really well together!"


The VCA is still stone cold dead no matter how the unit is triggered, no signal whatsoever unless PSU removed.
Synthbuilder
Touch sensitivity can be done. You feed a standard gate output (ie. 0V to +5V ) to the gate input of the ADSR. You then feed the velocity CV to the VCA IN. That way the ADSR output appears on the VCA OUT socket with the amplitude of the ADSR being set by the velocity CV.

The problem is that the Kenton only spits out three outputs. If you use one for gate, one for S-trig and one for Key-CV that leaves you without velocity.

Here's what I would do:

Build an gate (called V-trig here) to s-trig convertor.



You can then drive your Moog modules with this from the gate output of the Kenton.

You could also build this into the Moog style modules.

This would give you compatibility with the rest of the synth modules out there on the market as only Moog use the S-trig. Older Korgs sort of do too but the rest of us these days use gates.

The other alternative is to mod the Oakley for S-trig. This is actually quite easy but I need to be at work to grab the circuit so if you want to do this give me an hour or two to sort it out.

If you want me to have a look at your module for you I can do so. I do charge for this service but I can normally fix these sorts of things within half and hour.

Tony
Synthbuilder
If you would like to run the Oakley ADSR from an S-trig then you can do the following:

Keep panel wiring the same but remove any connection from the NC lug of the gate socket. Normally this is pulled to ground but you don't want this in an S-trig system.

Remove R58.

Take a short piece of wire and connect the left hand (now empty) pad of R58 to the right hand pad of R55. Left and right in this case work only when the board is presented so that bottom of the board is nearest you and the components are facing up.

This will only work if the Kenton is a true S-trig and not some reverse gate system. It will only work with a proper open collector output. I think the Kenton does have this but you can only try it out and see.

One other thing comes to mind is that Oakley modules do need to be run from a +/-15V supply and not the usual Moog +12/-6V system.

Tony
Synthbuilder
Actually I've just thought about one problem with that modification. The above modification will only work if you are driving the Oakley modules with an S-trig output that is dedicated to those modules. You cannot share an S-trig signal so that it controls both Oakley and Moog modules.

In this case I would recommend using the V-trig to S-trig conversion circuit to drive the 911 clones from the gate output of the Kenton.

The original Moog 961 also features V-trig to S-trig conversion.

Tony
rarecomponent
many thanks for all your help Tony..I guess I will go with the V trig option
which did occur to me. I do get a nice AD output into the filters but of course I'm having problems with the trigger so if thats sorted the module could do the job I hoped it would. I do have a seperate + - 15 supply in the cabinets (their big enough)
I'll need another week so will get back to the forum with results but again thanks for all your support.
MUFF WIGGLER Forum Index -> Oakley Sound Systems  
Page 1 of 1
Powered by phpBB © phpBB Group