VIIB Build

[slowpogo]

I don't know if anyone else went ahead and built their VIIB even before build docs are posted...well I couldn't wait! Without biasing instructions I'm just guessing but I've got it in a place where distortion is minimzed and the vibrato happens sometimes (see below). Running at 9V, it draws 10-12mA. I'm testing with Depth turned up pretty high and Rise Time turned down. Here are a few initial issues..

- I get sound in bypass, then volume jumps up 5-6db when pedal is "On"
- LED does not light at all. Using what I thought was the recommended red/blue one from Small Bear, still works when testing with my multimeter
- only time I hear the vibrato effect is if I turn the Rate knob up from full CCW, then the vibe comes in briefly (and sounds great!) but quickly flattens to a regular signal

Only substitution is a 500k trim instead of 470k. BBD is a Panasonic MN3207 from Banzai Music (text is very faded). Clock is an MN3102 I stole from a previous build so I know it works. I'm using the posted footswitch and the relay bypass system does seem to work, in that it will latch on/off with quick taps, but is momentary with longer hold times. I'm not sure how to switch between True Bypass and Classic modes.

No expectation of comprehensive help at this early stage of the board's availability but if anyone wants to chime in that'd be great.

 

[Wizardofwoz66]

Yes, in fact there are several pictures above demonstrating this

btw I still haven't gotten this to work. Pretty much given up on it at this point

Sorry to be that guy I'm using my phone and somehow I missed like the top 3/4s of this thread, my apologies. Best of luck with it! I'll report back once I've built mine

 

[Stickman393]

Double check your c22 & C23 values?

check C8 while you're at it too...

Gut feeling? Sounds like an undersized cap. Maybe. I dunno, my gut's got shit for brains. Fwiw.

Take IC voltages and I'll hook ya up with my own...compare/contrast, mine fired up on the first go.

 

[slowpogo]

Sorry to be that guy I'm using my phone and somehow I missed like the top 3/4s of this thread, my apologies. Best of luck with it! I'll report back once I've built mine

No worries, I've done the same. Just in a facetious mood

Double check your c22 & C23 values?

check C8 while you're at it too...

Gut feeling? Sounds like an undersized cap. Maybe. I dunno, my gut's got shit for brains. Fwiw.

Take IC voltages and I'll hook ya up with my own...compare/contrast, mine fired up on the first go.

Thanks! I'll check this when I get a chance

 

[slowpogo]

Double check your c22 & C23 values?

Turns out my C23 was a mislabeled Russian cap. Although it was actually an oversized cap, it was 470n instead of 47n! I got it in a grab bag from some Russian transistor seller on ebay...foolish not to check it first. I thought I'd add some "Russian mojo," and I guess I did in a way Thank you Stickman, I was running out of motivation and it would have been awhile til I found that myself, if at all.

So it basically works now! And being someone who can't be satisfied for even a moment, I immediately have a complaint lol. I'm disappointed that the lowest Rate is about 2 Hz. For some reason I had it in my head that it got much slower.

Would it be possible to shift the entire rate range downward? or somehow make the lowest rate something like 0.5 Hz or even slower, by changing some values? I'd love to get a barely perceptible, drifting cassette tape kind of sound.

 

[slowpogo]

I didn't try messing with the trims yet -- I realized they might affect the rate range(?). I'm still not entirely sure what the trims do without docs but I'll give that a shot.

 

[Stickman393]

Got ya covered here:

These photos were NOT particularly easy to find on the interwebs.

 

[Chris411]

The LED is common cathode, it's part 2306B from Small Bear.


I tried a working 3207 from my Low Tide build and got the same behavior. I've actually not had any problems with Banzai but it's good to know others have.

I would note here that I ordered a Common Cathode LED from small bear, but what arrived was actually Common Anode when I tested it.