Messages

Sweet!!!

Is that an enclosure dipped in an etch bath?


Josh

Yeah. It was totally disgusting to handle, too. I had to keep a wet paper towel handy to wipe my hands when building. I really should have clear coated that one.

Last one for now. Demos are next.

Finally!



bigger: http://www.madbeanpedals.com/builds/gallery/BabyBoardMulti.jpg

Rotagilla--I would go ahead and socket then lower R3 then. Try halving it to 15k or so. If you have a spare LM324 it would not hurt to pop that in IC1 as well.

This is a GREAT demo! I don't know why, but your whole style of demoing just draws me in...when you start talking about lazers and fog, I'm like "yeah...that's friggin' right"!

Anyway, good choice on the clipping diodes. I think I will go back and mod mine like yours. Other than the difference in clipping, this is exactly what the pedal should sound like and is pretty spot on to mine.

Thanks for posting and for the plug!

build building builds build
builds build builds build building builds
building builds building

Collosalus BOM from pg.3 is missing one 500k trimpot for the clock. So, you need 2x 20k and 1x 500k trimpots to build it. These are fitted for the 3362 type trimmers.

http://www.mouser.com/ProductDetail/Bourns/3362P-1-203LF/?qs=GslmPyR0hhHvIkHCd7y6E58BhWkKm%2fOH9Z9or69%2fkl8%3d

http://www.mouser.com/ProductDetail/Bourns/3362P-1-504LF/?qs=PcXFNxoHkaLec6MJ%252blthnuGnTCU05vYbxhc%2foGYiVnw%3d

Sorry-my bad. You need two 20k and one 500k trimpots. The 3362s are ideal.

Two suggestions: Increase R12 to lower the intensity of the the LED brightness and/or reduce the value of the BAL control to 10kB/C to reduce the amount of signal cutoff of the guitar signal. I think the R12 thing is probably what you are after.

Hi Thomas,

Please note the following modifications which have been found to improve further upon problems with distortion when using the v3205: http://www.madbeanpedals.com/forum/index.php?topic=3366.0

Of these the most critical are changing IC6 to a buffer by jumpering R16 and omitting R17, and the 1uF/6k8 combo in place of R10. IIRC, on the Memory Boy I read an output voltage on pin7 of the compander to be about 6.3-6.4v, but it's been a few months since checking. If you are reading high, you can lower the two 47ks -- 39k or 36k will probably do the trick.

These mods take the place of the earlier one suggested (R21.C14) and gave the bests results after a lot of trial an error.

The clock and BBDs do not have to be run at the exact same voltage AFAIK since it is the clock frequency driving the BBDs, not the supply voltage. This is something I have checked out before and I found no difference in terms of distortion in running the two at slightly different voltages.

I'm a bit confused as to what you means by "the clock signal is no filtered out in the later stages"....do you mean on your build, or by design? In the latter, this is exactly what the de-emphasis filtering is doing before getting to the expander portion of the circuit. If you are hearing clock signal, it may be due to the clock frequency running the BBDs running below the actual filtered signal. I think the lowest it can be run before bleeding into the audio was a little below 7kHz.

Also, here is a list of some good voltages you can use as reference in debugging: http://www.madbeanpedals.com/forum/index.php?topic=3380.0


One other thing I have found since the different mods/solutions were talked about---some v3205s are just noisier than others. I've got about a dozen in the workshop and I've found myself digging through them more than once to swap out. The degree to which this is a manufacturing issue, or just because I abuse the hell out of my parts through all the building and prototyping I've done with them I don't know. I'm not saying your particular BBDs are at fault and you should run out and replace them, but rather one thing I would also try is swapping in whatever you've got in IC4, audio probe the outputs while biasing it up and see if you hear any variation between them as far as noise or distortion.

What mgwhit said, and down position is off.

Also, don't forget max fuzz is fully counter-clockwise, not clockwise like we are used to. A more accurate description of the the control would probably be "Clean".

Rotagilla-

Sorry this thread slipped passed me. Couple things- the differences in a few values came from two sources...one based on feedback that was given to me from a person who had built a couple of the original Dipthonizer PCBs and two from my own experimentation. I picked what I felt sounded best, given the factory schematic seems to have a few values that were partially illegible and/or questionable.

The biggest change was R10---both R10 and R7 values have a big impact on the filtering setup and I felt 1k on both worked best because it produces a very pronounced effect. You can certainly change these around and see for yourself----increased values on both tend to tame it down a bit.

Anyway, as far as the Fuzz problem, my guess is that is completely unrelated. It's not "fuzz" in the truest since, since these are just diodes in a feedback loop. Really, it's more akin to overdrive. The two things that will have the biggest effect on the total fuzz/overdrive are R2, R3 and C2. Assuming that you do indeed have the correct values for R2 and R3, perhaps consider lowering C2 from the stock value to something smaller, as suggested in the doc. Lowering this value will pass more high end, which may in turn make the overdrive more pronounced. I ended up with 560pF there, and I think some have gone even lower. Whatever value you choose, if it still is not making an impact, I suggest audio probing the output of that part of the op-amp directly, and also the output of the fuzz control directly. The fuzz/overdrive is always at maximum, and the actual Fuzz control just attenuates the signal like a volume control.

The box is a full enclosure etch. I wanted a really dirty, grungy look, which I got for sure. But, the actual artwork part did not come out as well as I had hoped. I let it etch a little too long, and a lot of the fine detail in the monster character got lifted. But, whatever...it still looks pretty neat.

It sounds fantastic too! Quiet as a sleeping kitten. I like the full range of flange offered---slow flange is very thick and fast flange is very liquid. There's a tiny bit of volume drop which can be fixed by increasing R7. It's not so much as to bother me, so I'm just going to leave it as is. I left off the 2M2 pull-down as well since there is no pop when engaging the bypass.

Demo will be done later this week.

Check the datasheet for the recommended vactrol. It will have the approximate light/dark resistance for the photocell.