[IN STOCK] L-1 VC ADSR, Mouser cart added, page 5.

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fragletrollet
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Post by fragletrollet » Wed Aug 26, 2015 4:31 am

So the EG is working fine, trimmed using the procedure described on the site (0v shorted to ground and 0v with short removed).

However the cv outputs are low. So I increase the middle trimmer?

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fragletrollet
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Post by fragletrollet » Sun Aug 30, 2015 10:32 am

Bumpty

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fragletrollet
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Post by fragletrollet » Tue Sep 01, 2015 5:49 pm

So it feels like the "height" of the envelope is pretty low. It functions in every way, but the range of the amplitude of the envelope seems low. So plucking a filter with short decay and no sustain forces the filter to be more open than it should be when "closed". Using it to control a vca results in a low output.

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Post by Dogma » Tue Sep 01, 2015 6:29 pm

fragletrollet wrote:So it feels like the "height" of the envelope is pretty low. It functions in every way, but the range of the amplitude of the envelope seems low. So plucking a filter with short decay and no sustain forces the filter to be more open than it should be when "closed". Using it to control a vca results in a low output.
HMM - have you put this on a scope? 5v at full sustain? I only just got mine so I havent done any scientific testing with it but I havent noticed this..
look up!

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Post by fragletrollet » Wed Sep 02, 2015 2:40 am

Where do you get 5v at full sustain from? This is what the trimming manual says:

Output VCA offset.
Short GATE IN to ground. Gate will be off (no LEDs light). Trim the middle trimpot to have 0V at the
output

Sustain offset
Now remove a cable from GATE IN. The generator will stop in sustain stage (sustain LED lights). Trim
the edge trimpot to have 0V

3. Repeat for second generator

My peak to peak levels seem to be about 3,2V at full sustain. I can raise the sustain/amplitude of envelope output by trimming the outer trimpots, but then it won`t be 0V when no gate is present. Any help?
Last edited by fragletrollet on Wed Sep 02, 2015 3:15 am, edited 1 time in total.

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Post by Dogma » Wed Sep 02, 2015 2:44 am

fragletrollet wrote:Where do you get 5v at full sustain from? This is what the trimming manual says:

Output VCA offset.
Short GATE IN to ground. Gate will be off (no LEDs light). Trim the middle trimpot to have 0V at the
output

Sustain offset
Now remove a cable from GATE IN. The generator will stop in sustain stage (sustain LED lights). Trim
the edge trimpot to have 0V

3. Repeat for second generator

My peak to peak levels seem to be about 3,2V. I can raise the output by trimming the outer trimpots, but then it won`t be 0V when no gate is present. Any help?
Sorry I got alexi to build this one for me - hes on holidays I believe...
look up!

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fragletrollet
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Post by fragletrollet » Wed Sep 02, 2015 3:17 am

If you have time maybe you could measure your peak 2 peak V with sustain cranked to max?

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Post by L-1 » Sat Sep 05, 2015 5:20 am

fragletrollet wrote:Where do you get 5v at full sustain from? This is what the trimming manual says:

Output VCA offset.
Short GATE IN to ground. Gate will be off (no LEDs light). Trim the middle trimpot to have 0V at the
output

Sustain offset
Now remove a cable from GATE IN. The generator will stop in sustain stage (sustain LED lights). Trim
the edge trimpot to have 0V

3. Repeat for second generator

My peak to peak levels seem to be about 3,2V at full sustain. I can raise the sustain/amplitude of envelope output by trimming the outer trimpots, but then it won`t be 0V when no gate is present. Any help?

Measure the voltages at SUSTAIN pot. Must be +-10V.

Measure your SGO out. Must be 5V at sustain stage.

Have you 3.2V on both generators?

Did you trimmed offsets?

Measure that voltage before VCAs inputs (before 100K resistors near 3 and 14 pins. Must be around 5V too.

I used simulation model from official TI site. It shows 5V in this circuit. All LM13700 I have show 5V too. Sometimes a bit less, then I change 150K resistors near LM13700 with 160K.

If you sure everything working correct, just not enough gain from output VCA, you can increase these 150K resistors to increase VCAs gain.

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Post by L-1 » Sat Sep 05, 2015 5:37 am

forget.

Measure the voltage at LEV jack. Must be 5V.

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Post by fragletrollet » Sat Sep 05, 2015 5:21 pm

L-1 wrote:forget.

Measure the voltage at LEV jack. Must be 5V.
What do you mean the voltage at LEV jack? I mean, it`s an input?

I`ve followed the exact trimming procedure in the file on your site, using both trimmers on both channels, using an oscilloscope.

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Post by L-1 » Mon Sep 07, 2015 2:15 am

fragletrollet wrote:
L-1 wrote:forget.

Measure the voltage at LEV jack. Must be 5V.
What do you mean the voltage at LEV jack? I mean, it`s an input?

I`ve followed the exact trimming procedure in the file on your site, using both trimmers on both channels, using an oscilloscope.
yes, this is an input but there 5V connected to switched pin.

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Post by Neutron7 » Wed Sep 23, 2015 3:21 pm

I just finished mine. everything is working except the sustain CV on one of the envelopes (but the LEV works, so i guess the VCA is ok)

also the level is a little low on mine about 3.1v max sustain. ther is much more volume from the gate out to my VCA.

and a question. what are the DIP switches for? i could not see anything about it.

by the way the envelopes sound fantastic.

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Post by L-1 » Wed Sep 23, 2015 3:45 pm

DIP switch on-off gates from the bus, only top switch is working, bottom one is empty.

SUS pot is working but SUS CV is not working? There is only CV IN buffer between them. It's first opamps (1-3 pins) at leftmost and rightmost horizontal placed TL074. CV IN is connected direct to 3 pin (positive input).

About output VCA gain.
Seems to I used fake LM13700. It gives more gain than must. So it gives 5V with 150K resistors which are responsible for VCA gain.

Now I ordered LM13700 from Farnell. Will check this next week.

Presumably 261K resistors will be needed instead of 150K. (Increasing these resistors increases VCA gain).

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Post by L-1 » Wed Sep 23, 2015 3:56 pm

You can not wait for my investigation and make following:

at first trim sustain zero level as described in trimming procedure.

remove 150K near LM13700

solder a 500K or 1M trimpot with wires on place of 150K

trim this trimpot to have exact 5V at max sustain.

check again zero level.

desolder trimpot wires and measure its resistance

place a resistor of that value.

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Post by Neutron7 » Wed Sep 23, 2015 5:19 pm

L-1 wrote:DIP switch on-off gates from the bus, only top switch is working, bottom one is empty.

SUS pot is working but SUS CV is not working? There is only CV IN buffer between them. It's first opamps (1-3 pins) at leftmost and rightmost horizontal placed TL074. CV IN is connected direct to 3 pin (positive input).

About output VCA gain.
Seems to I used fake LM13700. It gives more gain than must. So it gives 5V with 150K resistors which are responsible for VCA gain.

Now I ordered LM13700 from Farnell. Will check this next week.

Presumably 261K resistors will be needed instead of 150K. (Increasing these resistors increases VCA gain).
the sustain CV is fixed, thanks. It was indeed pin 3 on that IC. no solder touching the actual pin duh.

ill wait untill you get the LM13700 and have an official fix. i can live with it like this for now.

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Post by fragletrollet » Sat Sep 26, 2015 8:16 am

My outputs are even lower, about 2.7 V at max decay/sustain. Haven`t gotten around to check the voltage at the lev input yet, but is this problem somehow related to bad 13700`s? I got mine from Tayda, and have gotten several bad chips from them in the past...

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Post by L-1 » Sat Sep 26, 2015 9:29 am

fragletrollet wrote:My outputs are even lower, about 2.7 V at max decay/sustain. Haven`t gotten around to check the voltage at the lev input yet, but is this problem somehow related to bad 13700`s? I got mine from Tayda, and have gotten several bad chips from them in the past...

I investigate this now. Read my posts a bit above.

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Post by fragletrollet » Sat Oct 03, 2015 8:02 am

Any news? :hmm:

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Post by L-1 » Sat Oct 03, 2015 10:39 am

fragletrollet wrote:Any news? :hmm:
I received 13700 yesterday. Now assembling one device for testing.
I think Monday will be results.

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Post by L-1 » Mon Oct 05, 2015 7:24 pm

I've received LM13700 from Banzai and built a module for testing.

Simulation showed 261K but really a 255K gives exactly 5V at max sustain.
261K gives 5.1V,
249K gives 4.9V
It's for 5V CV. When you will measure, consider this because LEV jacks are connected to 5V source via switched pins. The 78L05 voltage regulator gives not exact 5V but with some pretty wide variations.
Also a grade of the LM4040 regulators have an influence on this level. 'A' grade is most precise.

So I will install 255K on boards.

I'm sorry for this issue. I used fake LM13700 for my builds and even didn't know that.

Who have this issue - low output level, and have difficulties in buying 255K resistors - email me, I will send them for free. I will have them next Monday.

Replace these 150K marked red with 255K to have 5V at max sustain.

Image

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Post by sammy123 » Mon Oct 05, 2015 8:12 pm

I'm glad you figured it out. Nice work. I'm hoping to start my build soon.

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Post by fragletrollet » Tue Oct 06, 2015 1:19 am

As my values are pretty far from 5V (more like 2,8/2,9V), is this a problem related to the mentioned resistor? Do I need to change both the LM13700 and the resistors? I used a 13700 from Tayda, that has been sold me several bad chips lately, so I could see it being faulty.

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Post by woodster » Tue Oct 06, 2015 3:51 am

Swapping out your LM13700 sounds like it's required from reading this thread.
It's such a quick thing to do (if you have more) that's it's certainly the first thing I'd do to see if the reading is brought closer to the expect 5V, then do the resistor mod if required.

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Post by L-1 » Tue Oct 06, 2015 7:53 am

fragletrollet wrote:As my values are pretty far from 5V (more like 2,8/2,9V), is this a problem related to the mentioned resistor? Do I need to change both the LM13700 and the resistors? I used a 13700 from Tayda, that has been sold me several bad chips lately, so I could see it being faulty.
Yes, swap both resistors, one for each generator.
No need to change 13700.
2.9V it's correct with 150K.

I used fake therefore this difference in gain.

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Post by fragletrollet » Tue Oct 27, 2015 12:23 pm

Got the resistors you sent me today, they are now allready in the circuit :party:
Re-trimmed and now it`s spitting out 5,2-5,3 volts and working beautifully.
I can really feel that this adsr is optimized towards all the other L-1 modules I have. With the FC sys-100 adsr`s, I overdrive the l-1 quad VCA and have to attenuate (which sounds about right as they are jolting out a 8V+ signal), however with the l-1 adsr I can just slightly overdrive the quad vca with no attenuation (bigger sweetspot).

Modules are obviously set up to work within different voltages. My MI Ripples wants a huge amplitude from the adsr to fully open the filter from a closed state, so there I`ll use the FC`s. But my L1 filters (2180 & Mutant) seem to respond perfectly to the l1 adsr.

I allready got all the parts I need for a second unit, just gotta save up the cash for a second set of panels/pcb`s!

:nana:

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