Search found 105 matches

by feedbackl00p
Sun Feb 16, 2020 9:01 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

glad its working. so, if you take out the pot (or just disconnect the wiper), and read the resistance from the wiper to the 2 ends, you should get 2 resistances that add up to the total of the pot. for example, 75k and 25k for a 100k pot. you can then just replace the pot with those fixed resistors...
by feedbackl00p
Sun Feb 16, 2020 8:58 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

So the Centronics 2n5457s have arrived, and all problems were fixed by replacing the apparently fake or out of spec Fairchild ones I got from the net. Ive now got the noise toaster modular fully working and its ridiculous fun for analog patching on the couch. Ill be posting the project once ive clea...
by feedbackl00p
Fri Feb 07, 2020 4:26 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

there are 2 things that need adjusting: offset and gain. R44/45 do most of the work here. personally, i would remove R39/40/44/45. then take a potentiometer (50k or 100k) and connect the two ends from ground to the BN. connect a 47k resistor from the wiper to the gate of the JFET. the pot will allo...
by feedbackl00p
Thu Feb 06, 2020 7:48 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

there are 2 things that need adjusting: offset and gain. R44/45 do most of the work here. personally, i would remove R39/40/44/45. then take a potentiometer (50k or 100k) and connect the two ends from ground to the BN. connect a 47k resistor from the wiper to the gate of the JFET. the pot will allo...
by feedbackl00p
Thu Feb 06, 2020 6:13 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

Another question about biasing.

If im trying to find the right range for the Jfet, what components should I play with? Can i add a trimmer or the like instead of a resistor to make it simpler?
by feedbackl00p
Wed Feb 05, 2020 9:11 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

2$ is a bit expensive, but JFETs are a little hard to come by these days, so not suprising. i find jameco to be the best place to get outdated things. depending upon where youre located, there might be a store with a decent substitute. so, cutoff was full open before, and now its full closed? what ...
by feedbackl00p
Wed Feb 05, 2020 8:49 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

oh, i see. the gate is at -1V to -2V? that makes a lot more sense. at startup the voltages havent settled out, so its possible that the JFET is fine and it goes through a decent state at startup before settling into a bad state. or its possible that the JFET is busted inside, and risidual charge in...
by feedbackl00p
Wed Feb 05, 2020 8:33 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

the JFET side of R45 should be the same as the gate voltage you were measuring before. so maybe the resistor isnt connecting to the JFET, or you werent measuring the right pin on the JFET? do you have any pictures of your board? It is the same voltage as the gate, i think i omitted the negative sym...
by feedbackl00p
Wed Feb 05, 2020 7:03 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

it sounds like a bad JFET, or R45 isnt soldered to BN. measure the voltage on either side of R45, and make sure its at -4.5V on the opposite end from the JFET. the JFET gate should never be more than 0.7V or so above the source, so 1.5V is way too much. OK so the BN side of R45 measures -4.3v and t...
by feedbackl00p
Wed Feb 05, 2020 5:47 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

Something else Ive just noticed. Turn unit on, vco to filter off, noise to filter on. Envelope set to repeat, VCF set to Areg. The unit will sweep the cutoff once at the correct AReg settings as soon as I turn it on, then will stop. Ive verified this by changing the attack and decay settings, settin...
by feedbackl00p
Wed Feb 05, 2020 5:39 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

guest wrote:
Tue Feb 04, 2020 11:12 pm
what are you using for your ground reference on this measurement? 1.5V is way too high if youre using signal ground. if youre using the battery/wallwart ground, then increase R44 to 220k and see if it makes a difference.
Have changed R44 to 220k. Now the gate pin oscillates between 1v and 2v.
by feedbackl00p
Wed Feb 05, 2020 5:10 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

what are you using for your ground reference on this measurement? 1.5V is way too high if youre using signal ground. if youre using the battery/wallwart ground, then increase R44 to 220k and see if it makes a difference. Im using the virtual ground of the psu module(4.5v). Im just measuring this wi...
by feedbackl00p
Tue Feb 04, 2020 10:38 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

use your scope to take a look at the signals on the JFET. this is probably best done without audio going through the VCF. turn the mod pot full up. the source should be at 4.5V, with a bit of signal on it (10mV? maybe a bit more?), and the gate should be a bit under 4V, with +/-300mV signal or so. ...
by feedbackl00p
Tue Feb 04, 2020 10:12 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

my first guess is a bad mod depth pot on the VCF. does the LFO rate indicator LED still blink when you have the LFO set to control the VCF? does this blinking change at all depending upon the waveform selected. for square wave, which does work, does the blinking change at all when you switch betwee...
by feedbackl00p
Tue Feb 04, 2020 10:05 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

Ok Ive finally found some time to knock off this project. Ill be replying separately to posters that have helped me directly. Ive gone back to using my own modular layouts for ease of building and editing, attached. Its a bit inefficient in terms of component use (ie 6 x LM324 instead of 2) but the ...
by feedbackl00p
Sun Jan 26, 2020 8:25 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

Both builds exhibit the same problem. The AR Gen will not apply to the VCF cutoff. Also, the top LFO shape will also not apply to the cutoff whereas the square wave will. Heres the confusing bit. Using the trigger button will activate the ARgen to correctly mod the VCF. But it will not work in repe...
by feedbackl00p
Fri Jan 24, 2020 6:26 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

use your scope to take a look at the signals on the JFET. this is probably best done without audio going through the VCF. turn the mod pot full up. the source should be at 4.5V, with a bit of signal on it (10mV? maybe a bit more?), and the gate should be a bit under 4V, with +/-300mV signal or so. ...
by feedbackl00p
Fri Jan 24, 2020 6:25 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

also, does the AR signal still control the VCA when its patched to control the VCF? or does it stop altogether? the thing thats odd to me, is that the square wave from the LFO can control it, but the other signals can not. the main difference in that signal is that its stronger. so its possible the...
by feedbackl00p
Fri Jan 24, 2020 5:25 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

Do you have an oscilloscope so you can monitor the signal path? That would be very valuable as to find out where the problem actually lies. What are you specifically suggesting? The signal path checks out according to the schematic, and by continuity tests. The same AR signal works fine when applie...
by feedbackl00p
Fri Jan 24, 2020 5:21 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

can you give a link to the stripboard layout youre following? and maybe put up some pictures of the build? Thanks for the reply. Heres one of the layouts which i know is verified as working. Im pretty satisfied its not a build or layout issue as Ive gone over the schematics and layouts many times. ...
by feedbackl00p
Thu Jan 23, 2020 8:33 pm
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

Re: MFOS Noise Toaster DIY Troubleshooting

Quick bump.

Any and all theories about what might be causing this issue is very welcome.
by feedbackl00p
Thu Jan 23, 2020 1:08 am
Forum: Music Tech DIY
Topic: MFOS Noise Toaster DIY Troubleshooting
Replies: 38
Views: 1125

MFOS Noise Toaster DIY Troubleshooting

Hi Wigglers, ive built the Noise Toaster out on stripboard, both using my own layout and a layout ive found online. Both builds exhibit the same problem. The AR Gen will not apply to the VCF cutoff. Also, the top LFO shape will also not apply to the cutoff whereas the square wave will. The ARGen is ...
by feedbackl00p
Tue Oct 01, 2019 12:38 am
Forum: Eurorack Modules
Topic: Experienced wigglers Please help the NEWBS with their gear!
Replies: 308
Views: 9531

Who’s the troll? What’s the definition of a troll to you ggillon? If I said only mostly would be more accurate regarding kind of music. They don’t and I am and I never said the last comment that’s your negative disposition shining through making shit up that I said which is pretty trolly in my opin...
by feedbackl00p
Mon Sep 30, 2019 6:22 pm
Forum: Eurorack Modules
Topic: Experienced wigglers Please help the NEWBS with their gear!
Replies: 308
Views: 9531

Who’s the troll? What’s the definition of a troll to you ggillon? If I said only mostly would be more accurate regarding kind of music. They don’t and I am and I never said the last comment that’s your negative disposition shining through making shit up that I said which is pretty trolly in my opin...
by feedbackl00p
Mon Sep 16, 2019 5:14 pm
Forum: Eurorack Modules
Topic: a rack of only $250 or less modules
Replies: 33
Views: 1062

You can build a wild rack using NLC and Noise Reap. Fully analog and deep synthesis. Nearly all of their modules are under $250, often more like $100.

There’s really an entry level price point for most things in euro now.

Go to advanced search