Some questions about the Millenium bypass

[Mexxx]

Hey guys! So the thing is, 3pdt switches in my city are expensive or arent available at all, so I have to wait for them to arrive from abroad, therefore I decided to switch to Millenium.

And I have a few questions that have arisen for me:

1) What are Low leakage diodes? Can you please give me a name (code) of the diodes I can use?
2) Can there be popping issues like with true bypass?
3) Does the tonepad.com offboard wiring schematic for millenium bypass work well? I found it to be the most neatly drawn and understandable on the web.

And sorry if I didn't look carefully enough on this forum, I just couldn't find exact answers to these questions.

[mth5044]

1) RG has written on GEOFEX (where the project came from, I believe) that it's best to use the base-collector junction of a npn transistor. I'd guess a 2N3904 would work.


2) Never built the circuit, but use the search command here and read up on what causes popping in pedals.

3) Do you have a link to what you are referring to?

[Mexxx]

1) Is it really ok to use a transistor, if it says everywhere "diode" (f.e., here - http://www.diystompboxes.com/pedals/pcb/MIL2.jpg)?
3) Offboard wiring 3 -> http://www.tonepad.com/getFile.asp?id=76

[mth5044]

Please refer to the creator's own article, first paragraph

http://www.geofex.com/article_folders/millenium/millen.htm

RG has a link to a layout that shows the wiring at the bottom of the article.

[PRR]

> Is it really ok to use a transistor

A transistor is two diodes.

In a sane universe, a transistor costs more than a diode.

However in DIY economy, the cost of a transistor is very-very-low, much lower than enclosure or knobs, or parts-shipping, so the "higher cost" is un-important.

AND-- diodes are made simple and cheap, transistors have to be made a little better, so the average "transistor diode" is much lower leakage than the average plain diode.

Transistors are widely used as diodes in a few industrial circuits which need eceptionally low leakage.

It is OK.

[merlinb]

1) What are Low leakage diodes? Can you please give me a name (code) of the diodes I can use?

The circuit will work without the low leakage diode. It is only there for static protection, which is not really necessary in a pedal circuit.

2) Can there be popping issues like with true bypass?

The millennium bypass is a way of switching a LED while using true bypass. So yes. It is true bypass, and therefore suffers all the same problems as true bypass.

[gjcamann]

What are the advantages of using the MBP w/ DPDT over a 3PDP?
Is it just a cost thing, or are there other factors like reliability?

[R.G.]

What are the advantages of using the MBP w/ DPDT over a 3PDP?
Is it just a cost thing, or are there other factors like reliability?

Primarily cost and availability. The Millenium bypass comes from a time (... right around January, 2000, oddly enough  ) when 3PDTs were not nearly as available or cheap as they are now. The first time I found 3PDT switches usable for stomp switches back in the mid 1990s, they were nearly $20 each. And they were not stocked at distributor like Mouser. They had to be ordered in big lot, which might take weeks.

Later they got cheaper, and with the literal explosion of the DIY pedal market, they got stocked at several places. So the Millenium solves a problem that is much less severe now than it was.

However, the Millenium is still fractionally cheaper than a DPDT (I think - I don't price this stuff all the time.), although not enough for that to be the deciding factor. The original poster notes that 3PDTs are not readily available to him, and he can get the parts for the Millenium.

The Millenium also lets you rework a pedal that did had a DPDT but was missing either true bypass or an indicator LED to get those things, and without replacing the DPDT switch.

There is an other advantage to me, although I've never seen anyone else use it. The Millenium Bypass is also an indicator of the switch state. It can be used and expanded to do other things by considering the on-off signal to the LED as a logic signal, usable for controlling and interacting with other stuff. That's come in very handy to me a couple of times.

[duck_arse]

I've never had easy acsess (how is that spelt?) to 3pdt, so I've always used dpdt and millenium. I recently bought some cheap surface-mount transistors, which turned out smaller than I thought. now I use them as the low-leak diode, even though I have observed the circuit working without it.

the biggest problem I have with the millenium is fitting it onto the vero board. there never seems to be the right number of holes spare in a corner. I've just recently drawn up a small board to mount on the switch, with the millenium parts, so I won't have to think about it so much.

thanks for the circuit, rg.

[bluebunny]

I keep building these from Vero offcuts, particularly the skinny one on the right which comes off the small 9x25 boards.

[mth5044]

^Handy. Thanks for sharing.

[bluebunny]

I should have said that Q1 is the MOSFET (facing left for BS170, right for 2N7000) and Q2 is the BJT.  The resistor variously labelled 1.2K or 1K5 is the CLR; season to taste.

Edit - here's another for an even smaller (4x6) off-cut:

[robmdall]

Going forward I would like to start using the Mil2 in all of my builds. I see on here, along with other resources that most all folks that use this method of bypass are using a daughter board of sorts for the build. I would rather skip the secondary board and simply add the Mil2 to the effect PCB. Are there advantages to using the secondary board? Are there disadvantages to adding it to the main board?

I have searched the forum and really didn't find any specific answers to the above questions (although I may have missed some pertinent info due to my lack of knowledge).

Appreciate any comments on the above. Thanks in advance.

Bob

[merlinb]

Going forward I would like to start using the Mil2 in all of my builds. I see on here, along with other resources that most all folks that use this method of bypass are using a daughter board of sorts for the build. I would rather skip the secondary board and simply add the Mil2 to the effect PCB. Are there advantages to using the secondary board? Are there disadvantages to adding it to the main board?

I think people only use daughter boards because the pre-existing FX PCB designs do not include Mil bypass. There's no reason not to use a daughter board. It's certainly easier this way, since you only need one wire going from the Mil bypass to the footswith- no extra wires for the 9V/ground needed. I always include Mil bypass on my PCB designs, if applicable.

[zombiwoof]

What are the advantages of using the MBP w/ DPDT over a 3PDP?
Is it just a cost thing, or are there other factors like reliability?

Primarily cost and availability. The Millenium bypass comes from a time (... right around January, 2000, oddly enough  ) when 3PDTs were not nearly as available or cheap as they are now. The first time I found 3PDT switches usable for stomp switches back in the mid 1990s, they were nearly $20 each. And they were not stocked at distributor like Mouser. They had to be ordered in big lot, which might take weeks.

Later they got cheaper, and with the literal explosion of the DIY pedal market, they got stocked at several places. So the Millenium solves a problem that is much less severe now than it was.

However, the Millenium is still fractionally cheaper than a DPDT (I think - I don't price this stuff all the time.), although not enough for that to be the deciding factor. The original poster notes that 3PDTs are not readily available to him, and he can get the parts for the Millenium.

The Millenium also lets you rework a pedal that did had a DPDT but was missing either true bypass or an indicator LED to get those things, and without replacing the DPDT switch.

There is an other advantage to me, although I've never seen anyone else use it. The Millenium Bypass is also an indicator of the switch state. It can be used and expanded to do other things by considering the on-off signal to the LED as a logic signal, usable for controlling and interacting with other stuff. That's come in very handy to me a couple of times.

As I recall, the first version of the "Millenium" bypass was your analysis of the Rat pedal's TB circuit, in fact I remember you referring to it as something like "Rat-style Bypass" on your GEO site on the bypass page.  I guess you reworked the circuit, and then called it the "Millenium II"  bypass, and deleted the reference to the Rat bypass.  Isn't this correct?.  Rat pedals later changed to using a 3PDT switch, when they became cheap enough to replace the original TB circuit they were using.

Al

[bluebunny]

Going forward I would like to start using the Mil2 in all of my builds. I see on here, along with other resources that most all folks that use this method of bypass are using a daughter board of sorts for the build. I would rather skip the secondary board and simply add the Mil2 to the effect PCB. Are there advantages to using the secondary board? Are there disadvantages to adding it to the main board?

Yep, I'm with Merlin here - dead easy to add to an existing board.  But if I'm designing the layout myself, and I have room, I'll put the M2 on the same board as the rest of the circuit.

[duck_arse]

I've always struggled and fit the mil2 on the main board. I'm just now fighting my first daughter baords into custom cases. fighting because of a lack of measuring-before-cutting type fit problems. hopefully, it will neater my wiring, with only 4 wires to the circuit board from the daughter, what with the battery/switched power/led all to the daughter.

hopefully. and I can make 3, 4, 6 daughter boards in a go, and they sit about ready to go, no redesigning for each new vero.