accent trigger out mod output level

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skweeegor
 
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accent trigger out mod output level

Post by skweeegor »

I've been trying to get an accent trigger out mod going most of the day with some success using the information presented by bcbox in this post:

http://forums.adafruit.com/viewtopic.ph ... 08&start=0

So I have a wire going from the collector of Q35 to a 100k resistor which goes to the tip of a 1/8" jack. Ground of the jack going to ground on the x0x.

Without an accent, the jack puts out ~0.5V. If I hit the accent button, it drops to 0V, so it appears to be giving me an inverted trigger, which is fine and dandy. However, if I try to trigger something in my modular, it doesn't do anything; this seems to be because the level is too low. When I send the signal through a mixer before hitting the modular (thus boosting the level), it works perfectly. What I'm wondering is if there's any way perform this boost within the x0x so I can take it straight to my modular without any amplification in between. I noticed that on bcbox's x0xi0 mod, the accent out is going through the headphone amp - is that in order to boost the signal? I'm still pretty new to reading schematics so a point in the right direction would be appreciated.

Thanks

guest
 
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Joined: Fri Feb 17, 2006 5:35 am

Re: accent trigger out mod output level

Post by guest »

you could try replacing the 100k resistor
with a 1k resistor

if that doesnt work
then you will need to build a small amp for it
which wont be too difficult

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

Well, I initially tried without a resistor at all, which would be the strongest possible signal, correct? If so, same result. I just put the 100k resistor in there afterwards since it was suggested as a standard value for a CV out mod.

I'm not averse to building a small amp for it, but would injecting the signal through the x0x's headphone amp be sufficient? I never use the headphone output anyways. Not sure where the best place to send the signal would be though...

guest
 
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Re: accent trigger out mod output level

Post by guest »

what is the input to your modular like
is it expecting a 0 to 5v signal
or a 0 to 12v signal
the headphone amp can only do 6v

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

0-5V. Even 2 or 3V should be enough to trigger the module I need though, so the headphone amp should do. Where would be the best place to run the signal?

Looking at the schematic, the input seems to be at R159?

guest
 
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Joined: Fri Feb 17, 2006 5:35 am

Re: accent trigger out mod output level

Post by guest »

you should just take the digital signal then

take a 100k resistor
from the end of r141 that doesnt connect to r140
and if that doesnt work
try a 1k resistor

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

OK, just tried that. Interesting results.

It works better now, but it seems to only trigger certain things. However, If I run it through an active attenuator, it will trigger everything.

Could this have something to do with DC/AC coupling?

*edited for wrongness

guest
 
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Re: accent trigger out mod output level

Post by guest »

do you have a schematic of what your driving with it
basically the input of the modular

a lot of triggers are only edge sensitive
and the accent holds its level
for as long as the accents are active

its strange that the voltage was only .5v
when you first tested with q35
the output should have gone from 0v to 12v

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

Hmm, that is strange. No schematic of the module I'm trying to ping, but I do have a schematic of a filter that exhibited similar behaviour:

http://www.elby-designs.com/panther/cgs ... matics.pdf

So basically, if I run the accent straight to that module's CV In, nothing happens. If I run it through the active attenuator on this module (http://www.makenoisemusic.com/MATHSmanual.pdf) the filter will respond to the accent CV. So the attenuator is doing something to the signal to make it work. I can't imagine it would alter the edges of the trigger, and it doesn't boost the voltage any either.

Just double checked Q35; yep, still 0.5V. What's strange is the accent seems to be working properly on my x0x.

guest
 
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Joined: Fri Feb 17, 2006 5:35 am

Re: accent trigger out mod output level

Post by guest »

measure the q35 point again
but without the cable plugged in

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

I un-wired that jack for the digital trigger, so when I re-tested it, it was right on the board. Still peaks at about 0.5v

guest
 
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Re: accent trigger out mod output level

Post by guest »

what is the voltage on either side of r139
for both accent on and off

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

~12V both on and off

edit: woops, getting different readings on the other side...will have those in a sec

skweeegor
 
Posts: 29
Joined: Wed Sep 16, 2009 7:14 pm

Re: accent trigger out mod output level

Post by skweeegor »

Other side of 139 fluctuates wildly. From 0 to 3V, to 0 to 9V at times.

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: accent trigger out mod output level

Post by guest »

something is not right
what are the voltages on either side of r141
for accent both on and off

are your multimeter cables good
put it on resistance mode
and short them together
and wiggle them around to see if the value fluctauates
then check the solder joints around q35

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