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I agree. IMO you'll be kicking yourself someday if you can't switch this locally as well. It's not like you don't have the room in there for another small power supply and relays

BTW... Do you make these chassis' yourself? They look great

Joe G

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Definitely..... Especially when the board is trying to put 48 volts of phantom the other way!

My JP is different tha the Triwatt, but I wasn't taking any chances......

After more consideration, I agree.

FWIW, I rarely leave the house without my pedalboard, and was thinking I'd never use the panel switch. It was also close to 3:00 am and I had just finished my evening toddy!

The only other amp that I own that switches channels is a Traynor YCV50 (It's also the ONLY PCB amp that I own, so don't banish me..... It's my grab and go amp, and I also love it, is that a crime? ), and I probably used the panel OD switch a handful of times.

So are you going with a regulated power supply in the chassis? I am thinking that it would be the easiest and noise free way to do it. Too bad the use of the rectified heater supply is too noisy. That seemed an elegant and convenient way to get the power for the relay.....

Also, have you guys settled on a particular relay yet?

Just finished the first compact PSU for the relay. Very cute!!

PCB transformer, Bridge rectifier, 9V supply with 1000 uf filtering.

If it's noisy, I have a plan for regulation that will fit on the board but I did a test external supply without regulation and it was fine so ...

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yeah, it's no big deal to do it, so I'm gonna do the panel switch, and while I'm in there, and have a 9vdc supply, probably a panel mounted LED to indicate when the OD is active and possibly one for when the inputs are linked. I was just unleashing scotch induced mental diarrhea in the wee hours last night.


The chassis I've been using are from a guy called Allynmey on the boards. I wish I could make something that nice! He's another Hiwatt sicko, and along with Mark Huss, had these made, using a Biacrown chassis as the template. They are beautiful, but are slightly different than the Hylight chassis in a few ways, most importantly in the input hole spacing as well as the mounting hole positioning. No big deal, but it's nice to know when ordering panels!

This is the 3rd one I've worked with.

Cool! I'll probably go that route to keep it simple.

I built a regulated pedal power supply a few years ago.... It was one of the first things I ever built, and while it worked, I had some hardware issues (machining the box) that I never bothered to fix. I have to look in my junk bin and see if I still have it. It even had a pot to drop the voltage to simulate a dying battery for fuzzes........

Stephen seeing as your now using a separate xformer and not tapping off the filaments...why not use a little regulator?

Seeing as your not drawing much current at all (now with the separate supply) you dont need one rated for much current at all. A little cheap LM7812 or whatever would be fine. Seems like a cheap easy way to reduce any extra noise if there is any.

Problem with regulators is that they also require a resistor or two and a couple of caps around them, in addition to the regulator device itself - and you start to lose some simplicity. So far the circuit seems to be dead quiet with just the rectifiers, connected via a 50 ohm snubbing resistor to a 1000uF cap, giving a nice clean 9V DC. We have considered using regulators, and we're still open to using them if we hit some unexpected snag.

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Extra resistors? What for, decoupling?

Add a pre and post regulator cap. Seems like you already have a pre regulator cap.

I'm going by my recollections of National Semiconductor's 78XX/79XX series design guide from a few years back. I may be wrong here, but I seem to remember there were a few other recommended components around the regulator, including a resistor, I forget what it was for. Anyway, a regulator is overkill IMO unless you really run into problems. And I generally prefer the elegence of simpler solutions if they get the job done.

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I think the resistor is to set the output of a variable regulator. They do put a small value cap on both side of a fixed regulator though.

FWIW... You shouldn't need a regulated power supply for a relay coil IMO either, especially running a small 5 volt relay off of a 9 volt supply. Plenty of room to adjust if you need a few more volts to allow for a long cable run to the footswitch, maybe some LED's Can you tell I love those things??!!

Joe G

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Some assembly required,
Brain sold separately...

Hey, great idea! IIRC the forward voltage of a typical GaAs LED is around 2V to 2.5V. So you could simply wire a LED in series with the contact to the relay coil. You just need to be conscious of the fact that the relay coil operates at around 40mA, so you would need to use an LED that would work OK at that current level.

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Find me one of those please! Sounds like a plan!!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Blue Water-Clear high brightness LEDs also have a forward voltage of approx 2.5V give or take. I use them in all my pedals.

They also draw much less current than the typical diffused LED. A diffused LED draws I think it was 16mA vs water-clear high brightness which draws 0.32mA. Those were the numbers when I did some tests with current draw some time ago. I was using a 9V source and a 16K limiting resistor btw.

I found some high intensity blues and whites (470nm) and a gorgeous green (518nm) that will blow your socks off. 3.5-4v forward voltage. I dropped them to 10Ma and they're still too bright for a dark studio IMO They would be great on stage though

Joe G

_________________
Some assembly required,
Brain sold separately...

We need to run the LEDs at higher current in this case, rather than lower current, so that you get the 40mA required to activate the relay. Maybe you could use a couple of 20mA LEDs in parallel.

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Well, using only haldf of a DPDT relay does have it's benefits.

I see an LED in our future!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Relay Board -------------------------------------------- PSU Board


Size of the PSU board is about 2" X 3" ; Relay board half that.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Installed & Working.

Zaphod came over and we wrapped up #2 up today. Made a small housekeeping mod to the PSU to hopefully make it less susceptible to flourescent lights!

I's working - footswitch and all.



Might try a regulated PSU simply as an experiment on #3.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

The new switch circuit worked better than all my expectations. It's real quiet, without hum or buzz. It switches both from the front panel or the footswitch, without pops and clicks. And with the boost engaged, at least with this amp, the amp's already very low background noise level actually decreased! This was something really unexpected, and I wish I could pretend it was deliberately designed in. All I can guess is that some kind of a phase cancellation effect is happening here, which is reducing the noise level.

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Great tones come in small glass jars!