foot switch with no pop

[dr. who]

In either hunter or aspens book there is a part where ken fischer is being interviewed and says that he made a circuit with two relays and timed them differently to get rid of the pop when the foot switch is engaged. Does anybody know how this is done?

[nickt]

Don't know about that but isn't pop usually caused by shifting DC? Like a cap lead hanging in air then being connected by the relay. I thought the solution was a big resistor to ground?

.. just 2c

[Allynmey]

In either hunter or aspens book there is a part where ken fischer is being interviewed and says that he made a circuit with two relays and timed them differently to get rid of the pop when the foot switch is engaged. Does anybody know how this is done?

You would have though if it was true, he would have put it in the Komet to make the Fast/Gradual switch useful!
UR12 and I are putting together a switcher for the Komet amps.

[heisthl]

Has anyone had this problem with a Dclone? I've never had relay pop with this design.

[Funkalicousgroove]

if you use the diode across the coil and a cap across the footswitch there should be no pop.

[pedro]

After months of popping with this circuit - 50w ODS hrm - I found out that my phenolic board was the culprit ( slightly conductive )

New board built - relay and diode across the coil and its silent.
If built properly there should be no popping at all.

Rgds
Pete

[ampdoc1]

I have had no popping trouble on the D'Lite I built, but I have a problem with my Leslie 122. I'm using a (70's vintage) Hammond X-5 combo organ with it. The organ has an on-board switch that uses those "springs" contacts, so the switch mechanism kind of "glides" to make the contact. This does not cause any noise. However, I added a footswitch jack, and am using a Yamaha sustain pedal (momentary sw) with it. This cause a relatively large pop when going from fast to slow. I tried both a cap and a diode across the relay within the Leslie amp and also on the footswitch to no avail.

Any ideas?

[dr. who]

The Guitar Amp Handbook, by Dave Hunter
Pg. 203 In an interview with Ken Fischer
-Ken
"My own basic principle is 'keep it simple.' When techs see inside a Trainwreck for the first time, they say, "There's nothing in here..." I say, "That's right." I'm not putting down anybody else's amps, because I'm not into that, but when I see triple and four-channel amps, how could they possibly sound good with all that circuitry and all that switching?
And when I did switching, by the way - besause I did that to modifications to people's amps even though I never did it in Trainwreck amps - I always used relay switching because those LDRs (light dependant resistors) and other switching devices, they really extract a big toll on the tone. People say that the trouble with relay switching is that it's noisy, you can't switch back and forth without getting a pop in the speaker. But I'd make channel-switching amps for people out of Fenders and whatever, and they'd make no noise in the speaker at all. If you put you head against the chassis you'd hear the relay clicking inside, but you wouldn't hear any other noise other than that. A lot of times I'd use dual relays that were timed, and I'd cut the circuit at one point a hundredth of a second different than at the other point, and that prevents the pop. It's just a matter of timing the relays.

Has anyonehere done this?

[Pete]

if you use the diode across the coil and a cap across the footswitch there should be no pop.

I don't seem to need anything else

[heisthl]

if you use the diode across the coil and a cap across the footswitch there should be no pop.

What value cap across the footswitch?

[BobW]

Try a 10k or greater across the footswitch, that works most of the time.

I also haven't had any problems with my two ODS clones.

[heisthl]

Try a 10k or greater across the footswitch, that works most of the time.

I also haven't had any problems with my two ODS clones.

You put a 10K resistor across? I was inquiring about a cap - probably a .01 or .02 but was curious as to what others might use... personally I don't use anything at the switch and haven't had any pop issues but would like to file it away for future reference.

[novosibir]

Here's the inside of my DINO amp, a 100W head with 3 channels and altogether 5 different voices 'on the floor' - and as you can see also 5 relays:

[img:800:533]http://www.larry-amplification.de/dino9 ... 001-01.jpg[/img]

The amp does have some slightly switching pop, but it's so less, that it's definitely negligible - although two of the voices are brute high-gain.

I've experienced, that sometimes the switching pop w/o the additional cap across the FS is even less, than with a cap there.

Shure, you'd need the diode as close as possible to the relay's coil.

But you also need the 'right' relay, to minimize switching noise. Among relay's there are sometimes huge differences concerning their switching time, drop-out time and especially their duration of bounce - and this last term, the duration determines, how much or less popping you'll have by switching.

I'm using Panasonic relay's there, 12V types w/a coil resistance of about 1K - and I'm very contended with it!

Larry

[ampdoc1]

Larry,

That's some beautiful work! I would love to hear the Larry amp. Post clips when you can.

ampdoc

[BobW]

The 10k, provides a small current draw, but not enough to switch the relay. Switching from zero current draw to full draw in a relay circuit is where the current spike/noise is created. Providing a small draw (via 10K or more) to full draw helps reduce the current spike.