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LFO causes volume drop [message #2200]

Thu, 07 May 2009 12:28

Remork
Messages: 25
Registered: May 2009

Junior Member

hi all! first time poster.

built the noise swash on perf, included the LFO.
i notice a pretty severe volume drop when it's engaged - is this normal or did i make a mistake somewhere?
parts of the whole thing are still connected by test leads, so some weird(er than usual) behaviour is to be expected, but this seems to be pretty consistent..

thanks in advance

[Updated on: Fri, 08 May 2009 04:41]

gimme gimme gimme

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Re: LFO causes volume drop [message #2201]

Fri, 08 May 2009 01:29

dann
Messages: 829
Registered: December 2002
Location: Austin TX

Senior Member

No, the volume shouldn't drop when the LFO is on... does its LED flash?

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Re: LFO causes volume drop [message #2202]

Fri, 08 May 2009 04:53

Remork
Messages: 25
Registered: May 2009

Junior Member

yep, the led's flashing alright. it seems to be fully functional and it does what it's supposed to do i.e. modulate the noise, it just seems to eat volume..

i'll try with a different supply/battery today, as i don't have the regulator fitted yet, don't know if that might solve it. will keep u posted on that one.

also the LFO speed knob seems to be of influence on the sound when either of the two wires on it's DPDT are connected and the other isn't.. (that is, the wire going to +9v and the injection wire to the main board respectively.)
i mean, with the LFO getting its +9v but not connected to the injection point, i still hear the LFO modulating the sound, though it's not as obvious as with the injection connected. and vice versa.. even with the LFO not getting any juice, the speed knob still seems to have an effect on the sound. that weirded me out. Confused

is that normal (maybe that's your reason to switch the supply in and out)?

gimme gimme gimme

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Re: LFO causes volume drop [message #2203]

Fri, 08 May 2009 10:21

dann
Messages: 829
Registered: December 2002
Location: Austin TX

Senior Member

Quote:

even with the LFO not getting any juice, the speed knob still seems to have an effect on the sound.

That's normal, the LFO draws current when it's on, and the swash can pick that up through the voltage supply lines. That's why a DPDT is necessary: either side of the switch alone is not enough to completely take out the LFO

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Re: LFO causes volume drop [message #2204]

Fri, 08 May 2009 21:39

Remork
Messages: 25
Registered: May 2009

Junior Member

okay- hooked everything that is LFO up to a decent switch instead of running through pins on the breadboard. problem solved.
could've figured that one out myself Embarassed

am seriously considering an LFO depth control, and a second LFO (squarewave maybe?) with assignable modulating tasks - after some more poking around today, i found i got some pretty neat results with two LFO's.
candidates for extra modulation: Gate, Swash, Low power, clipping on/off (and possibly (if i get it in somehow) LFO I depth?)

also found a bend with interesting results hooking up 2 wires from the two different clipping sections. (don't have switches for those yet either..)
don't know which ones they are actually, like which side of which IC, i marked them but they're all the same color and twisted together so i'll have to measure. that is, if anybody's interested.

gimme gimme gimme

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Re: LFO causes volume drop [message #2205]

Sat, 09 May 2009 12:05

dann
Messages: 829
Registered: December 2002
Location: Austin TX

Senior Member

Congrats on getting it working Smile

Yes, I'm interested in the bend you found, if you tell me where they are, I'll try it...

I just found a new one, too, connecting the third lead of swash (the lead that's normally not connected to anything) to places in the tone section through a photocell (or a 1M or 500k pot works).

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Re: LFO causes volume drop [message #2206]

Sun, 10 May 2009 13:15

Remork
Messages: 25
Registered: May 2009

Junior Member

hey dann!

measured and checked against the schematic.

first off:
apparently, the postclip switch has the 0.1uF cap sitting on the other side of the switch in my perf layout, based on the DIY board layout: http://commonsound.com/swash/swashboard.pdf
as opposed to where it is drawn in the schematic:
http://www.commonsound.com/swash/mNS/schematic131.pdf

for its own purpose this doesn't matter, but it might for the bend. dunno.

basically it connects the outputs of both clipping opamps - pin #7 on the 062 and pin #1 on the 072. which would theoretically mean bypassing the tone control and half the 072, and running straight from the 062 into the final stage.. strange.

it works fine on its own, or together with either of the clipping modes engaged. just seems to go silent when all three are on - nothing a substitution for an on/off/on in either pre or postclip couldn't take care of.

will try out that bend of yours but i drilled my box already, so that'll have to wait for the next one i build.. unless it's really a must-have, of course Wink

gimme gimme gimme

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Re: LFO causes volume drop [message #2207]

Sun, 10 May 2009 17:37

Remork
Messages: 25
Registered: May 2009

Junior Member

box drilling template Laughing

will keep u posted..

Attachment: het idee.jpg
(Size: 113.27KB, Downloaded 331 time(s))

[Updated on: Sun, 10 May 2009 17:38]

gimme gimme gimme

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Re: LFO causes volume drop [message #2211]

Tue, 12 May 2009 12:17

80k_
Messages: 71
Registered: May 2003

Member

Remork,
If you haven't boxed it up yet, I'd give it a try to replace the 1K noisegait pot for a 500K pot and see what you think. This was on the older versions, and I've always liked this the best. There are just so many interesting sounds you can get with a 500K pot that you can't get with the 1K. If you have room for another knob, perhaps try a 500K pot and a 1K or 10K fine-tuning pot in series.

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Re: LFO causes volume drop [message #2212]

Tue, 12 May 2009 17:37

Remork
Messages: 25
Registered: May 2009

Junior Member

yeah, i tried both while it was still breadboarded..
problem with the 500K to me was that all the interesting sounds were on both extremes of the pot rotation, and the whole 75% in the middle just sort of sounded the same.. so i went with the 1K. maybe, on a second version, i might add a toggle switch for an extra 470K resistor or something, dunno.
right now, especially with the second LFO, i think there's already too many sounds available Razz

so somehow i don't think the difference between the 1 or 500K will cause any complaints, haha Cool

gimme gimme gimme

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Re: LFO causes volume drop [message #2219]

Wed, 13 May 2009 23:02

dann
Messages: 829
Registered: December 2002
Location: Austin TX

Senior Member

i go back and forth between liking the 1k and 500k noisegate. The 500k noisegate definitely makes the self-osc control much more interesting, but the 1k has so much more of the sweet-spot.

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