Pic of my diode switcher

[luap77]

Hi,

Here is a pic of something I built yesterday. It allows me to switch between 12 different diode types in any of the numerous clipping configurations  - 2 diodes, 3 diodes, 4 diodes etc. I'm using it to optimise clippers in distortion circuits.



Paul E

[luap77]

Sorry!

Please try this:



Paul E

[KerryF]

WOWWWW!!! 

[JimRayden]

WOWWWW!!! 

You can say that again... 

Now that's what DIY is about. Great job!

---------
Jimbo

[luap77]

Here is a picture of the internals. Very untidy, but functional.



I had to cut the metal tabs of the IRF520's to make them fit on the back of the switches.

The idea is that I can optimise clippers in new distortion circuits, or, use it is a plug-in module on pre-existing pedals.

Paul E

[rockgardenlove]

Woah!  Cool!

What kind of box is that btw?

[bwanasonic]

That looks very cool, and makes it possible to do some more scientific testing on how much of diode differences are just the *placebo* effect.

Kerry M

[luap77]

It's a Tawainese version of the 1590BB available from Electus distribution (also Jaycar) here in Sydney.

The dimensions are approx. 115 by 90 by 32mm. The front is etched and will hopefully provide many years of service. I haven't bothered with this one, but these boxes can be polished to a authentic mirror finish by 240 grit (to get a flat face), 320 grit, then 600, 1200, 2400, Brasso and finally a good metal polish (autosol etc). The mirror will last for a fair while without clear-coat, though this is a good idea from the start as it's a pain to re-polish once you populate with knobs and switches etc

I etched this with a salt etch (a copper(II) salt + table salt + a few drops of acid) as I wasn't after fine detail.

Paul E

[Paul Perry (Frostwave)]

Very nice! and thanks for the reference to 'salt' etching, I'd come across it before in some artist etching guides & promptly forgot all about it. Hell of a lot better than those ferric chloride witche's brews..

[joelap]

impressive!  bravo!

I'd also be interested in knowing your findings of whether there are a big difference between certain diodes or not.  I got a killer deal on some 1N270 germaniums (free, courtesy of my school, they just didnt know they were offering them for free  ) and I havent used a 270 on a switch with a 34A to see if there's an audible difference.

[WGTP]

Excellent.  A diode combo for every mood.  Definitely report your findings.   

[Ben N]

That is an awesome breadboarding aid.  I assume the wires are to probes you can plug into a breadboard or sockets.  What do all the mini-toggles do?
Ben

[DDD]

Great!
By the way one can use the box as a separate pedal.

[Izzy]

One BIg question though.
Does the change in diodes make significant change?
I means esp when yuo change from 1n4001 to 1n4002 or 1n4007? arent they almost teh same?

[Barcode80]

the point of the box is to test that same idea, Izzy. i think it depends on the circuit, as they do have different voltage drops and therefore slightly different sounds. though i don't think in most cases it is a drastic enough effect to hear a great difference.

[luap77]

I'll elaborate:

The 1N400x diodes can have very similar Vf, but IMO the differences in the batches that I have are enough to warrant investigation.

The unit has shielded wire probes. It allows me to insert this a diode clipping section into a circuit very easily, then unclip and solder in the optimal diode configuration.

The unit is also designed to be used as a plug in module. For example, if I have a particular pedal that I want to use in the studio etc, then I have a bypass switch (on/off toggle) built into it to bypass the clipping diodes on the pcb. The diode clipping box is then plugged into the pedal (via two sockets for the probes on the side of the pedal) and acts as a diode switching plug-in module. If I want to use a different pedal, I just close the toggle on the pedal (reverting back to on-board clippers) and plug the diode clipping module into the other pedal.

The mini toggles near the corners allow me to bypass individual diodes (each rotary switch being a "diode"). The toggle in the middle allows me to change the diode configuration between either a total of 2 diodes in parallel (e.g. Tube screamer, multi-rat, Shaka series with the combined IRF520/1N34A diode etc), 4 diodes in parallel (e.g. Bluesbreaker, etc) or 3 diodes in parallel (two diodes in series in parallel with a third diode, e.g. Screamer+, Liquid drive, multi-rat etc)

I'll report my findings, though it will be some time unfortunately.

Paul E

[aron]

Great idea. I will be interested in what you find 

[sfr]

I haven't bothered with this one, but these boxes can be polished to a authentic mirror finish by 240 grit (to get a flat face), 320 grit, then 600, 1200, 2400, Brasso and finally a good metal polish (autosol etc). The mirror will last for a fair while without clear-coat, though this is a good idea from the start as it's a pain to re-polish once you populate with knobs and switches etc

Any recommendations for a clear coat to apply over a mirror-polish like you mention here?  I've done something similar like that before, and the clear coat seemed to have problems adhering.  It was cheap rattle can stuff, just what I had kicking around, I haven't tried anything else, so I don't know if it was just my crappy clear coat, but if you've got a recomendation before I start looking for other stuff, it'd be appreciated.

[luap77]

Yes, a 2-pak clear works the best, but needs to be hand mixed and applied via a gun. The 2-pak system is also VERY hazardous (isocyanate) and really shouldn't be used in a household. Isocyanates are sensitizers, which means that you will become more sensitive to them with continued use, and hence experience their bad effects at lower and lower concentrations as you continue to use them. People who use isocyanate-based coatings generally have a full body suit and respirator plumbed to an outside air supply.

Alternatively, clear coat for brake calipers or for wheels works well (VHT), or high temp clear enamel for engines works as well (VHT). I generally allow these to dry and them carefully bake them. Remember to clean the surface with methylated spirits etc to remove the thin film left by the metal polish. The trick with clear over black etched lettering is to either:

a) Apply a super light clear first (just a mist) and then cure before applying the remainder - seals the pigment and stops it dissolving into the paint solvent and running.

or

b) Do the black colour for the lettering via chemical anodization/dye 

Hope this helps.

Paul E

Paul E

[dr]

....I built something similar for my MXR Distortion plus, but much smaller on a piece of perfboard with a 10-position dip switch to switch any combination of five pairs of diodes......