Electrovibe Build w/Monk Mods
- Thread starter swelchy
- Start date
Guardians of the analog
Papi Fuego
Paradox916
Well-known member
Ginsly
Well-known member
Well, the title of this thread would seem to support that statement. I guess I missed the drama. I don’t think I need a recap.
Guardians of the analog
Papi Fuego
Big Monk
Well-known member
Chris is not wrong here, at least on the ElectroVibe stuff.
Most of it was just regurgitated off the internet. I just had the distinction of having tried it.
There’s really only a couple of worthwhile mods if I were to recommend any today.
Guardians of the analog
Papi Fuego
Monk right now
anevilspar7an
Active member
Big Monk
Well-known member
I’ll annotate a schematic sometime tonight and post it.
anevilspar7an
Active member
Radical.
Big Monk
Well-known member
Here's a quick list. Reference the Electrovibe Build Doc Board Image on Page 1 and Schematic on Page 5:
Signal Path:
1.) Tweak R2 if you feel you want more signal gain. 3.3k-4.7k should do the trick. Leave the input divider alone.
2.) Try and hit exact values for the phase caps C12, C18, C25 and C28. Use 5% caps and maybe grab a few of each value.
3.) The original preamp transistors were lower gain than 2N5088. Q1 was a B Gain Bucket and Q2-Q9 were all A Gain Bucket. This is probably "inside baseball" type stuff.
Power Supply:
1.) Ditch the charge pump and feed it 18v directly.
2.) Make sure you use L78L12 for the regulator.
Analog LFO:
1.) Replace Q1/Q2 with a single MPSA13.
2.) Change C8 to 2.2u (MLCC)
3.) Change R14/R15 to taste. Besides potentially locking up the LFO, too fast and it loses all definition. I've gone as low as 1.2k with no issues but 2.2k-3.3k is probably fast enough for anyone.
Lamp Driver:
1.) As always, experiment with Bulbs and LDRs. The Advanced Photonix 9203 LDR from Mouser is pretty good, and all the bulbs in the build doc are good. 2102 and 2174 have more exposed bulb so they tend to "throw" more light.
2.) Replace Q1/Q2 with a single MPSA13.
3.) Use a metallic light shield if you can.
4.) I'd go with either 100 ohm or 200 ohm for the gain trimmer. Just helps tighten up the range of available brightness.
5.) You can experiment with the Offset circuit. 250k is too large. There are too many "deadspots" on the dial and it makes really dialing in good range on the Intensity control more difficult. I use R22 = 47k, Offset = 100k and R26 = 68k.
That's pretty much it.
Signal Path:
1.) Tweak R2 if you feel you want more signal gain. 3.3k-4.7k should do the trick. Leave the input divider alone.
2.) Try and hit exact values for the phase caps C12, C18, C25 and C28. Use 5% caps and maybe grab a few of each value.
3.) The original preamp transistors were lower gain than 2N5088. Q1 was a B Gain Bucket and Q2-Q9 were all A Gain Bucket. This is probably "inside baseball" type stuff.
Power Supply:
1.) Ditch the charge pump and feed it 18v directly.
2.) Make sure you use L78L12 for the regulator.
Analog LFO:
1.) Replace Q1/Q2 with a single MPSA13.
2.) Change C8 to 2.2u (MLCC)
3.) Change R14/R15 to taste. Besides potentially locking up the LFO, too fast and it loses all definition. I've gone as low as 1.2k with no issues but 2.2k-3.3k is probably fast enough for anyone.
Lamp Driver:
1.) As always, experiment with Bulbs and LDRs. The Advanced Photonix 9203 LDR from Mouser is pretty good, and all the bulbs in the build doc are good. 2102 and 2174 have more exposed bulb so they tend to "throw" more light.
2.) Replace Q1/Q2 with a single MPSA13.
3.) Use a metallic light shield if you can.
4.) I'd go with either 100 ohm or 200 ohm for the gain trimmer. Just helps tighten up the range of available brightness.
5.) You can experiment with the Offset circuit. 250k is too large. There are too many "deadspots" on the dial and it makes really dialing in good range on the Intensity control more difficult. I use R22 = 47k, Offset = 100k and R26 = 68k.
That's pretty much it.
I need to revisit this. Two of the things that the Helix (sorry but it's my main rig these days) doesn't do are:
- Vibe. It does some of the wacky yoy-yoy Hendrix Machine Gun stuff at a less than convincing level but it blows at getting the sheer evil wobble of say...Trower, especially in his pre Fulltone days, Gilmour, or even Roger Fisher (SIng Child Sing). In my current church gig there's little call for a good vibe but I'm not above gratuitous use of sorely needed effects for effects sake. What Would Robin Do?
- Compression.
