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WIGGLING 'LITE' IN GUEST MODE

Two Thousand Six Hundred (TTSH) Ver.1 General build thread
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... , 115, 116, 117  Next [all]
Author Two Thousand Six Hundred (TTSH) Ver.1 General build thread
KlangGenerator
sduck wrote:
Again, double check for continuity, especially where it's not supposed to be, like the circled places, and between legs of transistors and everything else basically. It's handy to have a picture of the unpopulated bard for this, so you can see what's supposed to be connected and what's not.


I did, on both sides. I have a second Rev1 PCB here and used it to cross-check. No anomalies.

The LM301 input pin3 doesn't receive any voltage, therefore no ouput either. Before the last diode (the one between Pin3 and 2n3906 base) I get 0.55v. The transistors are all ok. To be sure I replaced every single one of them.

I also don't get any voltage on the 1uf caps below the attack slider. Moving the sustain and decay sliders has an effect on the voltage meassured at the 1M transistor between LM301 and 2n5460 (range from 7 to 14v), so I guess those work.

Traces are all good. I cross-checked all(!) of them. Right now I really have no idea what I could do next...
KlangGenerator
Ok, just measured the voltage on the IC socket without the LM301 installed. Now I get 2.05v on pin3 and 2.33v on pin6... I tried installing various LM301, but with none of them I get the desired voltage input/ output. Also measured for continuity with the LM301 installed. No shorts. hmmm.....
fuzzbass
KlangGenerator wrote:
Ok, just measured the voltage on the IC socket without the LM301 installed. Now I get 2.05v on pin3 and 2.33v on pin6... I tried installing various LM301, but with none of them I get the desired voltage input/ output. Also measured for continuity with the LM301 installed. No shorts. hmmm.....


This suggests that the portions prior to the op amp input are working. While holding down manual gate, and measuring 2V at pin3 socket, does that reading go down while you move the sustain level slider down?
KlangGenerator
No changes if I press/ hold manual gate.
fuzzbass
KlangGenerator wrote:
No changes if I press/ hold manual gate. I expect this is correct because manual gate should only work for AR?


Manual gate momentarily connects +10V to Gate and Trigger inputs of the ADSR

Rather than make guesses, i just put a working unit up on my bench.

manual gate closed
pin 3 +7.48v
2n5460 S +7.48V
2n5460 D +7.48V
2n5460 G +7.0V

manual gate open
pin 3 +0v
2n5460 S +0V
2N5460 D +7.52V
2n5460 G +14.0V
KlangGenerator
fuzzbass wrote:
KlangGenerator wrote:
No changes if I press/ hold manual gate. I expect this is correct because manual gate should only work for AR?


reread my edited not above. Manual gate works for both EGs and copies gate signal to trigger input on ADSR.


Man, you're too fast. wink I noticed my mistake and edited my first post... Ok, so this is not good then.
fuzzbass
sorry to be confusing, but I edited a previous post with some readings I took on a good ADSR. This with the chip inserted.
nickster
Opened up my rev 1 today and finally added the AR mod suggested by Nordcore. Highly recomended btw as was the swapping out the AR cap from 1 uF to 2.2 uF. Now i have a really snappy Attack and a slighly extended Release which on this envelope just what is needed. Ill be doing the ADSR mod next once the correct switches arrive. Managed to buy 3 pole nor 2 poles d'oh!
KlangGenerator
fuzzbass wrote:


Manual gate momentarily connects +10V to Gate and Trigger inputs of the ADSR

Rather than make guesses, i just put a working unit up on my bench.

manual gate closed
pin 3 +7.48v
2n5460 S +7.48V
2n5460 D +7.48V
2n5460 G +7.0V

manual gate open
pin 3 +0v
2n5460 S +0V
2N5460 D +7.52V
2n5460 G +14.0V


Thanks for your measurements fuzzbass. I really appreciate your help! Unfortunately 2n5460 S and therefore also pin 3 stay at 0v, no matter whether I have the gate closed or open. Damn, this is driving me insane! The ADSR has become my new center of life...
fuzzbass
KlangGenerator wrote:
fuzzbass wrote:


Manual gate momentarily connects +10V to Gate and Trigger inputs of the ADSR

Rather than make guesses, i just put a working unit up on my bench.

manual gate closed
pin 3 +7.48v
2n5460 S +7.48V
2n5460 D +7.48V
2n5460 G +7.0V

manual gate open
pin 3 +0v
2n5460 S +0V
2N5460 D +7.52V
2n5460 G +14.0V


Thanks for your measurements fuzzbass. I really appreciate your help! Unfortunately 2n5460 S and therefore also pin 3 stay at 0v, no matter whether I have the gate closed or open. Damn, this is driving me insane! The ADSR has become my new center of life...


What are the other readings compared to mine?

What trigger does here is reset the ADSR so it restarts (or starts) its charge discharge cycle. What is charging are the two 1u electrolytic caps sitting between those fets. So when +14V is present on the G pin of the 2N5460, its turns on and allows these caps to discharge. When they are discharged, you have 0V on pin 3.

Down at the bottom right (schematic), where the trigger comes in is a 10n cap, and this ensures that whether a quick trigger, or a sustained gate comes in here, it will come out the other side of this cap a transient. One thing that may be going wrong here is that processed trigger signal is not quick, but sustained, keeping +14V on G of the 2N5460 as long as manual gate is high, and keeping the caps discharged. Follow the trigger signal through the the various paths and see if the result of putting a GATE signal here is resulting in a transient, or a sustained condition. Watch carefully on your scope because the transients are hard to see.

Think of the the gate and trigger processing circuitry like a NOR gate. Those caps will charge if either a. Gate is high; or b. Trigger is low.
KlangGenerator
fuzzbass wrote:

What are the other readings compared to mine?

What trigger does here is reset the ADSR so it restarts (or starts) its charge discharge cycle. What is charging are the two 1u electrolytic caps sitting between those fets. So when +14V is present on the G pin of the 2N5460, its turns on and allows these caps to discharge. When they are discharged, you have 0V on pin 3.

Down at the bottom right (schematic), where the trigger comes in is a 10n cap, and this ensures that whether a quick trigger, or a sustained gate comes in here, it will come out the other side of this cap a transient. One thing that may be going wrong here is that processed trigger signal is not quick, but sustained, keeping +14V on G of the 2N5460 as long as manual gate is high, and keeping the caps discharged. Follow the trigger signal through the the various paths and see if the result of putting a GATE signal here is resulting in a transient, or a sustained condition. Watch carefully on your scope because the transients are hard to see.

Think of the the gate and trigger processing circuitry like a NOR gate. Those caps will charge if either a. Gate is high; or b. Trigger is low.


I meassured as suggested. I can follow the transient from the 10n cap to ADSR Q8 (G of 2N5172). From there it's gone. Output on D of Q8 is 14,8v and 1,64v on S. On a second path I could follow the transient until ADSR Q6 (D of 2N3906).

On Q4 (2n5460) I get 14.03v on G and 10.05v D. These values don't change with manual gate closed or open.
KlangGenerator
I found the reason for my ADSR not working! I installed 2k2 instead of 22k! d'oh! Changed to the correct value and now it's doing the job. This is the first time I mixed up resistor values. Usually I am always very careful about this... I thought I'd checked all of them, but it seems like I've missed the two standing resistors.
Anyway, thanks fuzzbass for your lessons on the ADSR. I definately learned something in the past days, thanks to you! thumbs up
sduck
Yay! I know that feeling - spent way too much time troubleshooting a music easel once, finally gave up and sent it out to someone else for a fresh look, he found the 10K resistor where a 10R was supposed to be, everything worked then.
KlangGenerator
sduck wrote:
Yay! I know that feeling - spent way too much time troubleshooting a music easel once, finally gave up and sent it out to someone else for a fresh look, he found the 10K resistor where a 10R was supposed to be, everything worked then.


Yes, I was also close to sending it out to someone else. In the end I'm glad I did not. wink
KlangGenerator
Nordcore wrote:
I think the suggested wiring is total crap ( ... and that is already the diplomatic version ... ).


I hooked up the headphone jack directly at the speaker output on my build.
It works well and I don't see any problem.


This is how I did it too. With this wiring method I was able to eliminate the hum coming from the speakers when the headphone jack was plugged in. Unfortunately now I have pretty annoying hum coming through the headphones. The closer my hand comes towards to either one of the 1uf caps in the amp section, the louder the hum get's (it's extremely loud when I touch it). When I touch the ground with my fingers (especially at the left speaker), the hum disappears. I have shielded RG174 coax installed between amp and headphone jack connections, but that doesn't seem to help.

Another thing I am not satisfied with is the volume difference I get between the AR and ADSR envelope. The overall output I get with the ADSR cranked up in the VCA is much higher than the one from the AR.

Any ideas?
KlangGenerator
Maybe I should try this out? It's the interfering 1uf cap...

effegee wrote:

Then I shielded the electrolytic cap at the bottom of the left amp section. I did this by wrapping some desoldering braid around a similar-sized cap and soldered it in a few spots to make a tube, which I then covered with some shrink tubing. I soldered a wire to the bottom end of the tube:



I slipped the tube over the cap and soldered the wire to the free ground hole, making sure to not contact the shield to the cap's leads:



It significantly reduced the noise, though it didn't completely eliminate it.

Now if someone can tell me how to eliminate the oscillator bleed through that can be heard through the speakers, especially when the OSC's are cranked up to higher frequencies confused
fuzzbass
KlangGenerator wrote:
I have shielded RG174 coax installed between amp and headphone jack connections, but that doesn't seem to help.

Another thing I am not satisfied with is the volume difference I get between the AR and ADSR envelope. The overall output I get with the ADSR cranked up in the VCA is much higher than the one from the AR.

Any ideas?


I don't recommend coax for your speaker connections. Regular 22 or 24 hookup wire with both leads lightly twisted.

Good thing you reworked your speaker/headphone wiring. If before you heard anything coming from your speakers when the phones were plugged in, then the wiring was dead wrong.

The exponential CV input to the VCA is just that... exponential. If you put 10V p-p signal into the audio input and raise that slider all the way, apply +10V to the Exponential CV input and raise that slider to ~70%, you will get 10V p-p out of the VCA. Moving the Exponential CV input slider higher will overdrive the VCA. It's a feature, not a bug.
tadan
moderator edit: sorry, you can't sell stuff here until you have 100 posts, and then only in the For Sale Trade forum. You could try doing a trade in the pcb/parts trade thread above.
Cablebasher
Guys

Finally got round to doing the version 1 fixes.

Regarding the VCO 2/3 bleed fix of cutting the trace and running shielded cable:

where did people solder the shield of the cable?

Ledman said he soldered to ground on the VCO sub board but I can't see where exactly on the pictures on his site.

Any ideas?
LED-man
the submodule has a power input next to the SMD caps (including ground)
further you can use a other ground connection - use a recifier test to check where┬┤s a further ground.
sduck
I connect the shield ground to one of the jack ground points on the main board, and no connection at the sub module end. As LED-man suggests, use a DMM to make sure you've found an actual ground point. It doesn't really matter which one, and you only need one end connected.
Cablebasher
Hey guys

Regarding VCO2/3 bleed fix again.

Thanks for the info sduck and ledman and sorry for the late reply.

So I followed DSLmans notes on his excellent website and cut the trace and replaced it with a shielded cable.

With the Shield NOT soldered to ground (or anything) it works.

When I solder the shield (the outer silver bit I assume) to ground the VCO stops giving out sound.

I have tried several grounds on the pcb and they all have the same result.

I am using RG174 cable.

Any ideas.

Thanks as always.
fuzzbass
Cablebasher wrote:
Hey guys

Regarding VCO2/3 bleed fix again.

Thanks for the info sduck and ledman and sorry for the late reply.

So I followed DSLmans notes on his excellent website and cut the trace and replaced it with a shielded cable.

With the Shield NOT soldered to ground (or anything) it works.

When I solder the shield (the outer silver bit I assume) to ground the VCO stops giving out sound.

I have tried several grounds on the pcb and they all have the same result.

I am using RG174 cable.

Any ideas.

Thanks as always.


Sounds like either the coaxial jumper is shorted, or you have not yet found a good 0V reference point for the connection. Its also possible that RG174 is not the best choice here. You might not need the shield.

Do you still have a bleed issue w/o shield connection?
sduck
As above and... you should only have one end of the shield part of the coax grounded. The other end should be unwound, cut off and taped off or covered with heat shrink, leaving only the interior wire exposed. I've used this end to connect to the submodule end, and the other end with the shield still attached at the lower end, with the shield grounded. If you do it this way and you're still having it cut off the signal, there's something wrong with your coax - some of these have very soft and thin inner plastic shielding, it's easy to melt through it and short the inner wire to the shield.
Cablebasher
Thanks for replies dudes.

I have tried various grounds including directly off the power header and all cause silence.

I must have damaged the shield in some way.

But the cable, even without grounding the shield, has fixed the bleed so I'm going to leave it.

If it's not broke, don't fix it.

Now I just need to fix the speaker hum and work out the VCA exponentional gain and I'm finally there. After 4 years!

I think I might be the only person who finished his arp 1601 before his 2600!
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