Voodoo Lab Micro Vibe lfo/bulb Problems

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Manicstrat2112
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my favorite amplifier: Egnater Rebel 30 MK I
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Post by Manicstrat2112 »

I built the micro vibe from an etched pcb from storybordists layout on perf and pcb layouts found here: http://effectslayouts.blogspot.com/2018 ... ovibe.html
The only component change was I subbed a 2.2m for the 2.4m and a 3.2k for a 3.3k resistor.
It passes sound, but the bulb only pulses for a second after I hook the battery up. Then it stops and goes dim. Also when I turn the trimmer up and down it comes on, but goes dim instantly.
I made a video that shows what I mean:

If anyone has any ideas I would be grateful.
".....and when I'm sad......I slide!"

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plush
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Post by plush »

1. what bulb are you using
2. do you have access to oscilloscope to check lfo and bulb driver?

What if you replace the bulb with a combination of LED and current limiting resistor - will it work the same?

I assume that something is wrong with bulb driver transistor, or bulb is pulling excessive current.

Also, schematic for reference: viewtopic.php?f=1&t=13912&p=158132&hili ... e&#p158132

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Manicstrat2112
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Posts: 14
Joined: 23 Nov 2019, 05:49
my favorite amplifier: Egnater Rebel 30 MK I
Completed builds: Partial list: Creepy Fingers EQ Exciter Fuzz, Tonebender MK II, Silicon Tonebender MK II, Fuzzrocious Ram the Manparts, Thunderdrive, Fuzz Face. Silicon Fuzz Face, EHX Muff Fuzz, Brian May Treble Booster, DAM Grease Box, DAM Meathead, Lovepedal Woodrow, Lovepedal Eternity, Silicon Fuzz Master, Fuzz Factory, Mastotron, Super Hard On, 73 Rams Head BM, Katzenkonig, Phase 45, Black Dust, RAH, Tentacle, MXR Distortion +, DOD 250 Preamp, Distortron, Naga Viper, JHS Andy Timmons, Pro co Rat, Celine Mark 4, EQD Dunes, EHX OD Glove,, Lemon Drop, 59 Sound, Formula No 5, Formula No. 55, Black Ash, Plexi Drive, 65 Deluxe, Hummingbird, Fuzzolo, Univibe, EQD The Depths, Guzzling, Maestro FZ-1 and FZ-1A, Tonebender MKI, Harmonic Percolator, Zonk Machine, Hybrid Si/Ge Zonk Machine, MBP Harbinger 1.5, MBP Pork Barrel (to original CE-2 specs) and it all started with the Bazz Fuss =)
Location: Portland, Oregon
Has thanked: 13 times
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Post by Manicstrat2112 »

plush wrote: 19 Jun 2021, 05:23 1. what bulb are you using
2. do you have access to oscilloscope to check lfo and bulb driver?

What if you replace the bulb with a combination of LED and current limiting resistor - will it work the same?

I assume that something is wrong with bulb driver transistor, or bulb is pulling excessive current.

Also, schematic for reference: viewtopic.php?f=1&t=13912&p=158132&hili ... e&#p158132
I am using a #7371 bulb (which is the standard uni vibe bulb), as this circuit is suppose to use the same lfo driver as a univibe. It is a 12 Volt/.04 amp bulb.
After comparing various schematics of the uni vibe and clones...it does seem to use an almost identical lfo driver.
Unfortunately the micro vibe schematic doesn't say what lamp was used, only that it is a lamp and not a led.
The only other actual "bulb" I have is a 18 Volt/.026 amp bulb I got for the mad bean harbinger 1, but beings the micro vibe is a 9 volt effect I went with the 12 volt .04 amp bulb......maybe its drawing to much amperage?
No, unfortunately I don't have access to an oscilloscope.
As far as an led goes...I'm not sure where I would accommodate a clr on the board. I may end up trying it if I can't figure out something with the bulb.
I tried a bunch of different transistors and combinations, with all different gains. All that did was make the bulb glow brighter or dimmer.....it did nothing to effect the pulsing.
Do the op-amps have anything to do with the lfo? It doesn't look like they do judging from the schematic.....unless I'm missing something?
Could it possibly be a bad capacitor?
Thanks-
".....and when I'm sad......I slide!"

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