"Little Angel" - Super Simple PT2399 Mini Chorus

[boog]

you are correct sir! 5.05V on the regulator (powerful ratshack rated for 35V). swapped chipped, beautiful again. bummer about the PT tho, really wanted to make another one of these and didn't wanna spend any money for awhile. oh well. thanks again, both to you for the help and frequencycentral for this sweet little circuit!    

[frequencycentral]

I think the regulator should have survived. 78L05 are rated for 35 volts. But that doesn't mean the PT2399 survived too. Yeah, it's still only getting 5v at it's VCC (pin 1) so would have survived in that respect, but it's REF (pin 2) may have received a big fat lot of voltage from the LFO running at 24 volts.

Ok boog, you posted while I was typing - glad it's working again and sounding sweet!

[boog]

sneaky that way sometimes, like a cat with a xylophone tied around it's neck.

[Scruffie]

So... Simplified BOSS DC-2 Anyone? 

[frequencycentral]

So... Simplified BOSS DC-2 Anyone? 

I spit on your DC-2 with it's HUGE PCB and it's unneccesarily complex schematic!! 

[Scruffie]

So... Simplified BOSS DC-2 Anyone? 

I spit on your DC-2 with it's HUGE PCB and it's unneccesarily complex schematic!! 

Wellll Your Mother was a Hamster And Your Father Smelled of Elderberries 

[frequencycentral]

bummer about the PT tho, really wanted to make another one of these and didn't wanna spend any money for awhile.

Yeah bummer. If it's any consolation, over the summer I paved my driveway using only PT2399 and LM13700 that I destroyed while originally breadboarding this circuit and Causality 4. 

[boog]

that is unfortunate; casualty 4 is on my list, i spent the first year and a half building dirt boxes so now i've moved on to modulation. of course, i built my bench around dirt circuits so that means a whole bunch o' reinvesting.

[Earthscum]

So, I built a second LAC... this one has a horrible LFO thump! I'll play around with it tomorrow (and reread some posts). I didn't hear it until I plugged into my TKO, then I had a nice steady heartbeat. I'm gonna try running with the TL072 and see if the thumping goes away, cuz I don't hear it at all in my first build, and it's exact  same components except the IC and the depth pot.... just laid out on a DIP board instead of the nice PCB. Maybe some LFO mods in my future, lol.

I'll get pics up tomorrow... it's a pretty box!

[boog]

well here i was all prepped to show off my snazzy build and when i box it up i get nothing but the 'deathbuzz' again; standard troubleshooting procedures shall apply, but i think i'm doomed. so.......this lead me to a noob question: my 7805 is in one of those to-220 packages. rocket scientist here didn't heat sink it so when i boxed it, the 7805 bent over and touched the 5532, would the heat off of the 7805 zap the 5532? and isn't that tag at the top (where you mount it to the heat sink) a ground connection? so if it touched the enclosure it really shouldn't do anything?

[John Lyons]

There shouldn't be any heat with the regulator.
But shorting something out, yeah that would do it.
Don't know off hand about the tab being at ground or not.

[frequencycentral]

.....and isn't that tag at the top (where you mount it to the heat sink) a ground connection? so if it touched the enclosure it really shouldn't do anything?

The metal tab is connected to COMMON (pin 2) and therefore is at 5 volts. You need to isolate it form the (grounded) enclosure or you'll have a short circuit. Use insulation tape.

[boog]

oh bugger then; looks like i'll have to try that for round 3, so far no luck in troubleshooting and there is definately some heat being generated somewhere. lessons learned i spose.

[soggybag]

I tried adding a 50K pot between the 100R and pin 6 of the 2399. Though this does work, you get a delayed signal, the sound was not very exciting. There is a single short delay and the modulation seems less obvious. The best sounds seem to be at the shortest delay times. There might be use for a smaller pot say 1K to 10K to adjust the delay length a small amount for different sorts of sounds.

I wonder if a regeneration pot might be more useful as a sort of resonance control?

I noticed on my build that I hear some hiss/noise. Not sure if this was there before I added the 50K pot or not. Though I don't think the pot itself would add any noise. I notice the noise seems to increase when I play. Have to sort this out before boxing up.

I mentioned this before but, I notice the LFO is not symmetrical. It seems a little lopsided. The lopsidedness seems to be effected by speed.

[frequencycentral]

I wonder if a regeneration pot might be more useful as a sort of resonance control?

It's on my breadboard right now. 

[Pigyboy]

ok, got it sorted

[soggybag]

I wonder if a regeneration pot might be more useful as a sort of resonance control?

It's on my breadboard right now. 

It's hard to keep up with you Rick, you are tireless!

[clamup1]

hey i got mine to work. i had to reetch the whole thing but i got it. now lets see if i can put a switch on it and it still work. thanks for a great pedal

[clamup1]

hey i got a stupid ?. is this pedal npn or pnp.

[earthtonesaudio]

It's neither... and both.


NPN and PNP are different bipolar transistor types.  There are dozens, maybe hundreds, of each type in the ICs (integrated circuits) used in this project.  However there is not one single discrete (by itself, not part of an IC) transistor, either NPN or PNP, used in the build.