Omron here in Japan has a miniature self latching DPDT relay with a 9 volt control voltage that looks suitable for FX bypass. It would not need any logic circuit to maintain it's state and also doesn't need a voltage for this. Anybody here using relays for bypass? It seems like it would be a step above the mechanical switch that I'm using now. An Alpha momentary switch could save a little space in the enclosure too while eliminating the wiring from the 3PDT switch.
I'm thinking that this could be the best of both worlds. The soft feel of a momentary switch without the tone sucking of the FET arrangement.
Maybe RG's Millenium circuit for the LED also.
sometmies they are noisy but i have had good luck so far.
http://www.geofex.com/FX_images/relays2.gif
i wouldn't use one after having bad experience with one when building the super fuzz a few years back. these devices are not ment to be used all the time like the carling or blue switches are designed and these are pretty cheap today (get the blue switches right here from aron) so why would you stick more moving parts in there anyway ?!?
Although you cut down on wiring by using a momentary, relays aren't exactly small themselves and will take up a fair bit of PCB space. They're not exactly battery friendly either...
From gtrmac:
QuoteOmron here in Japan has a miniature self latching DPDT relay with a 9 volt control voltage that looks suitable for FX bypass. It would not need any logic circuit to maintain it's state and also doesn't need a voltage for this.
That's kind of a dream come true. What's the particulars - part number, price, etc?
From arielfx:
Quotei wouldn't use one after having bad experience with one when building the super fuzz a few years back.
That's a little like saying that you wouldn't have anything to do with females after having a bad experience with one a few years back. All relays are not equal.
Quotethese devices are not ment to be used all the time like the carling or blue switches are designed and these are pretty cheap today
The design life on the EA2 relays is 100 million operations. That's a pretty favorable comparison to footswitches. A hundred million stomps is a ...lot... of gigs. If you clicked a stomp switch once every ten seconds day and night, it would take over thirty one years to wear out the relay. I don't use my pedals that hard. Maybe someone does.
Quotewhy would you stick more moving parts in there anyway ?!
Relays typically have exactly one moving part, the armature. There are either four or five moving parts inside an on-on push switch.
The devil is in the details.
for sure I have to agree with R.G., and:
the battery-friendlyness has been stated in the first post:
Quote...self latching DPDT relay..... It would not need any logic circuit to maintain it's state and also doesn't need a voltage for this
The relays I'm interested in are in the Omron G6K series, the G6KU-2P-Y is the latching model with pins for through-hole soldering. I'm planning to breadboard a test circuit and see how they work out with the Milenium Bypass.
The main reason that they are interesting to me is that there is no voltage required to maintain the switch state, it's done mechanically. So there is no battery drain while in a fixed state, current is only needed for the momentary pulse to change state.
Thanks for the reference.
I took a look at the datasheet. The one you mention is a single coil latching version, meaning that you pull one end high, the other low to set it one way, then reverse the two polarities to set it the other way. This isn't too hard, as a CD4013 is all you really need to do the logic. You'll still need buffers on the logic chip's output to drive the relays, but that isn't too hard either. I couldn't come up with a simple way to get both toggle action and momentary drive from just the relay.
The harder part is that the relay relies on the drive circuit to turn the drive current off. To do that, you need some kind of timer that turns on the drivers for just long enough to flip the relay state.
I went through some of this when I did my latching relay driver circuit at http://geofex.com/FX_images/ltchrly.gif.
I used a single CMOS hex inverter and made a toggle flipflop by interconnecting two stages. The first two sections, with the 100K feedback resistor do that function. This flipflop toggles on and off with a single momentary switch.
The right most two inverter sections and the transistors do the turn on pulse and drive the relay coils.
This circuit is set up for a two coil latching relay instead of the single coil, largely because a two-coil can be run by pulling down one or the other coil from the common positive connection, no pulling both up and down needed.
The EA2-9NJ is a two-coil latching relay desiged to work from 9V. Mouser carries the EA2-5NJ (5V) and EA2-12NJ (12V) for $2.50 each, although not the 9V 9NJ version. I suspect you could get the 9V version by special order, or make 12V from 9V with a charge pump.