incoming mki tonebender

joeyowen

ICBM;395157" said:

It's a shame that with the undoubtedly neat and careful build quality of a lot of these things, the makers don't know how to wire a true bypass switch properly.

All these look like they have the usual crap scheme where the bypass path goes through both switch poles in series and the circuit input is not grounded - which maximises unreliability and can leave the circuit open to oscillation.

No shakeproof washers on the jacks either.

Any pics of correct wiring for a tb switch?

allicio

The grey mkii gutshot above was taken before the writing was completed as I wanted a picture. The red MKI above shows the switch as andrew wires all of his pedals. The input is grounded at the switch and the output is grounded at the volume control. That switch wiring seems to be good enough for the likes of Creepyfingers, Jerms, etc.
"Shake proof" plastic washers are garbage and prone to having the entire switch coming lose as you cannot tighten them properly. Very few builders worth their salt use them. Dam and pigdog don't use them either
Andrew of Arcane Analog uses locking metal wasers as I suspect most other top builders do!

Forge

I am curious about your MKI, I have one of the first Skinpimp which I love but geese that thing is raucous and sputtery! How is yours tonally compared to your MKII?

allicio

I haven't received the mki yet, its shipping out this week along with a violet rams head muff, a oc75 loaded mki.v and an NKT275 fuzz face.
I can't wait!
Andrew tuned my mki and my mkii for that matter for a smooth decay as I'm not a fan of spluttery Fuzzes. Its still raucous though apparently ha!
I'll let you know when it arrives

allicio

Oh and here's a completed build gutshot, the footswitch is wired up and everything!

allicio

Forge;395134" said:

joeyowen said:

The guts on this thread are so nice!



Really nice work by the builders

Thats a really nice build! There's not many builders use that enclosure, which is a shame, I really like it. Nice one!!

Forge

allicio said:

I haven't received the mki yet, its shipping out this week along with a violet rams head muff, a oc75 loaded mki.v and an NKT275 fuzz face.
I can't wait!
Andrew tuned my mki and my mkii for that matter for a smooth decay as I'm not a fan of spluttery Fuzzes. Its still raucous though apparently ha!
I'll let you know when it arrives

Some would say you went nuts for it, personally I think you can never have too many fuzzboxes or dirtboxes.

allicio

Definately agree with you there!

ICBM

joeyowen said:

Any pics of correct wiring for a tb switch?

How not to do it: (and how most TB pedals are wired)

http://www.muzique.com/news/images/3PDT_3.jpg

Notice that the bypass goes through two contacts to and from the 'u' shaped jumper wire, and the PCB input is left floating. If you don't need to ground the PCB input, you can use an 'x' between all four lower contacts instead of the 'u' - that makes the bypass much more reliable.

How to do it:

http://www.premierguitar.com/ext/resources/archives/13c3a712-1837-45df-b030-e9bd77991957.JPG

Now the bypass only goes through one contact and the FX input is grounded in bypass.

It amazes me how many builders don't seem to know this.

allicio said:

The input is grounded at the switch and the output is grounded at the volume control.

It's the switch bypass wiring that's wrong, not the jack grounding.

allicio said:

"Shake proof" plastic washers are garbage and prone to having the entire switch coming lose as you cannot tighten them properly. Very few builders worth their salt use them. Dam and pigdog don't use them either

Who said anything about plastic ones? They're crap. Use metal only.

allicio said:

Andrew of Arcane Analog uses locking metal wasers as I suspect most other top builders do!

So why aren't there any on the jacks in that pedal? Or any in this thread.

Actually, many don't. I know because I have to repair a lot of them...

joeyowen

Really useful stuff, fair play!

Out of curiosity, why do you think most people decide to use the 'wrong' / regular way?

ICBM

joeyowen said:

Really useful stuff, fair play!

Out of curiosity, why do you think most people decide to use the 'wrong' / regular way?

Probably because that's the way they've seen most builders do it. Even if you want to use only the simplest possible method, it's still wrong - you only need to go through *one* of the two bypass contacts. Using both is just making it needlessly unreliable.

Particularly when switch failure is the most common fault with any of these boutique pedals.

Disclosure: I hate true bypass.

Arcane

 

Each and every time the switch is engaged all of the lugs are switched as in following diagram. Regardless of where you solder your wires, these contacts are made each and every time the switch is engaged. Since you have offered your expertise, can you explain how a mechanical switch is more prone to failure or is less reliable due to flipping a few lugs around?

 

ICBM

Because in the 'standard' true bypass scheme, the bypass is run through two switch contacts in series (eg 2-3 and 6-5 if the bypass link is between 3 and 6, with 2 as the pedal input and 5 as the output), which doubles the chance of a failure. At the very least, if you don't want to use the grounding-type scheme, only use one of the two contacts - connect either 2-5 or 3-6 - the other is totally unnecessary. Even better, 'x' wire it which means that it takes a failure in both contacts at the same time to prevent the bypass working, which becomes highly unlikely. OK, it does not improve reliability of the 'on' signal path but at worst you have more chance of being able to get bypass signal through the pedal. This really matters on a pedalboard with multiple true bypass switches where you might not easily be able to re-route to avoid a failed switch.

It is in fact possible to use both the 'x' wiring *and* the grounding of the circuit input, if you arrange the LED switching so the centre switch pin is ground. So you can achieve much better reliability *and* mute the circuit input compared to the standard scheme, just by "flipping a few lugs around".

1&9 - circuit input

2&6 - input jack

3&5 - output jack

4 - circuit output

7 - LED ground connection

8 - ground

Arcane

If any of the contacts fail, the switch fails. Given the diagram above on how a 3PDT works it does not matter which order they are in. .

All due respect sir, but your method is simply a personal preference. It is no more reliable.

 

 

Forge

Very good and clear explanation. The point Arcane was making was that a failure would still happen regardless of where the wires are connected to the switch. The grounded input style allows statistically for 50% less probability the failure to happen in the bypassed path as you mentioned.

Arcane

There is no difference on how I have my input grounded and ICBMs method. They offer the same protection. My method is simply my preference as it is symetrical and allows for better wire routing.

Arcane

I would be very interested in seeing ICMBs work. Where can I have a look at your builds?

ICBM

Arcane said:

If any of the contacts fail, the switch fails. Given the diagram above on how a 3PDT works it does not matter which order they are in. .

All due respect sir, but your method is simply a personal preference. It is no more reliable.

The 'x'-wiring in bypass is. It needs two contacts to fail *at the same time* to stop the signal, because they are in parallel. This means that the chance of failure is not halved, it's *squared*, which for a small probability in the first place makes the result tiny. Assuming that the chances of failure of the two contacts are truly independent, which unfortunately they aren't quite - but it's still much lower than for one contact alone, you don't often find a switch with more than one bad contact.

I agree, it makes no difference to the reliability when the pedal is on because you can't avoid the switches being in series. Obviously the order of the three switches makes no difference either, that's not the point I'm making at all. It's all to do with probability of failure and how you can either use that to your advantage or not.

ThePrettyDamned

@icbm does that basically mean a failure would result in you, at the very least, having a true bypass signal rather than silence regardless of where the switch is set? Or more often having this possibility, rather than just silence?

If so, seems a pretty logical thing to do. Doesn't cost any more to do either, bar a few minutes extra soldering.

Actually, it could probably be a marketable thing for a builder!

ThePrettyDamned

You just concisely answered my question.