Amp/Cab switcher patchbay box thingamajig

[Lt. Bob]

it occurs to me: What happens in the in-between spaces on that switch?
Does it ever make a direct short connection, even briefly as it moves from one contact to another?

[Greg_L]

it occurs to me: What happens in the in-between spaces on that switch?
Does it ever make a direct short connection, even briefly as it moves from one contact to another?

On my design, with the switches I have in mind, it will not short. The in-betweens will be open.

On that expensive thing, I have no idea. I think it must electronically divert unselected amps to the dummy load.

[Greg_L]

So revisiting this thing....

I think I've decided to just build a basic patch bay instead of the rotary switching thing.

With a basic patch bay I can have dummy loads to protect each amp in the event of operator error. And it's fewer moving parts. Selecting amps and cabs would be just a matter of moving one patch cable like a 40s phone operator.

[JD01]

You look beautiful, Greg.

[rayc]

Are you going to buy a cheap patch bay to mod or build from scratch?

[Greg_L]

Are you going to buy a cheap patch bay to mod or build from scratch?

Build the patch from scratch!

This is what I've come up with so far....first draft....

ampcab patchbay.jpg

So, it's a box. Like a stage snake. A box with a bunch of wires snaking out of it. Each red line is a speaker cable hardwired to each jack inside of the box. The male ends will connect to the amps and cabs.The 8 amp-side jacks will be switching jacks and each jack will have a 16 ohm/100w resistor connected to the shorting switch, as shown by the green blocks. If there is nothing plugged into an amp-side jack, it shunts to the dummy load. So if I mistakenly try to use an amp that isn't patched to a cab, there will still be a 16 ohm load present. Safety! As soon as you patch into a jack, it bypasses the dummy load and goes on to the cab like it's supposed to. The cab-side jacks will be just regular 1/4" mono jacks, hardwired internally and connected to cabs. To choose an amp and cab I'd just run a small patch cable from the amp side to the cab side of the box.

The advantages to this are fewer (no) moving parts, easy implementation of dummy loads for amp safety, and I don't have to hunt down appropriate rotary switches. I can also still use multiple amps and cabs at the same time if I want to - just run more patch cables.

The disadvantage is basically that it's a lot messier being a box with a bunch of cables running out of it. I could make the from-the-amp inputs and out-to-cab outputs jacks as well and then just run separate speaker cables in and out of it, but that's twice the jacks, twice the hole drilling, and umpteen times the wiring from jack to jack to jack to jack....it's a lot more connections to make, and that's a lot more room for error and failure.

So I need...
Some kind of enclosure box - I might try to use something cute for this, like an old kid's lunchbox or something.
8 - 16 ohm/100 watt resistors
8 - 1/4" switching jacks
4 - 1/4" standard mono jacks - I probably have these already.
12 to 16 - Tip/sleeve male 1/4" jacks. I can probably harvest half or more of these off of old busted instrument cables I have laying around everywhere.
50-60 ft of 16 AWG speaker wire or basic ol lamp cord.
Grommets


It just might work.

[rayc]

Looks good to this layman.
Will the load resistors generate heat (I assume they will but for a very short time)?
Could you wire in LEDs to indicate which has a signal running to & through (piggy backed to the resistor or somewhere else)?

[JD01]

That's kind of genius, Greg.

[Greg_L]

Looks good to this layman.
Will the load resistors generate heat (I assume they will but for a very short time)?
Could you wire in LEDs to indicate which has a signal running to & through (piggy backed to the resistor or somewhere else)?

It's possible I could figure out LEDs or some kind of indicator....but really the patch cable itself will be the indicator. If I label the jacks smartly it will only take a quick glance to know which amp and cab are patched together.

The dummy loads will not make any heat. The only time they will see action is if I accidentally try to use an amp that isn't patched to a cab. At that point it will take less than a second to realize that I'm not making any sound and I'll stop to investigate why. One thing I know is that when you think you're supposed to be making sound and you aren't, you better stop and figure out why. Don't keep banging chords.

And like the previous design idea, I'm not going to have all of the amps on all the time. I'm still going to power them on and off one at a time like I usually do. This will just make choosing amps and cabs much quicker and require less gymnastics to get behind everything to move cables around.

[Greg_L]

That's kind of genius, Greg.

Thanks, I have my moments. Not many, but sometimes.

[Minerman]

So I need...
Some kind of enclosure box - I might try to use something cute for this, like an old KISS lunchbox or something.
8 - 16 ohm/100 watt resistors
8 - 1/4" switching jacks
4 - 1/4" standard mono jacks - I probably have these already.
12 to 16 - Tip/sleeve male 1/4" jacks. I can probably harvest half or more of these off of old busted instrument cables I have laying around everywhere.
50-60 ft of 16 AWG speaker wire or basic ol lamp cord.
Grommets


It just might work.

kiss lunchbox.jpg

Yes, I did carry one just like this from about age 6 until about 10-11...I found it at my parent's house a few years ago, pretty much rusted & destroyed...I had no idea all those years ago things like this might be worth something later in life...Matter of fact, I had all kinds of KISS stuff as a kid...

[einstein magoo]

Im sure you have thought of this, but running multiple amps at same time with your amp jacks all commoned on a metal lunchbox, do you think there may be any ground loop issues? May be better to mount the jacks on a phenolic plate or something to insulate the rings? Then mount the plate on the Barbie Goes To College lunchbox. Please advise if I'm totally fucking stupid.

[Greg_L]

Im sure you have thought of this, but running multiple amps at same time with your amp jacks all commoned on a metal lunchbox, do you think there may be any ground loop issues? May be better to mount the jacks on a phenolic plate or something to insulate the rings? Then mount the plate on the Barbie Goes To College lunchbox. Please advise if I'm totally fucking stupid.

I had not thought of that, but I'm not sure it would be a problem because the actual grounding of the amps will still go to the same place - the outlet.

If I had amps on different outlets, then maybe something like that could happen.

I'm not sure though. We'll just have to see what happens.

[SweetDan]

...I'm not sure though. We'll just have to see what happens.

[BBvideo=560,315]https://www.youtube.com/watch?v=_Dvwd8Hyh-Y[/BBvideo]

[Tadpui]

Oh look, someone already makes a fancy version. 8 amps x 8 cabs. Only $1500.
https://www.ampete-engineering.com/product/88s-studio/

Here's a 5x5 for $750.
http://www.krusekontrol.com/kruse_ampca ... her/unit_5

I saw this same product in Pete Thorn's recent studio tour and I immediately came to this thread to mention it, then I realized that you'd already found them a while back. The price sucks, but damn they've got some great features.

[Greg_L]

I saw this same product in Pete Thorn's recent studio tour and I immediately came to this thread to mention it, then I realized that you'd already found them a while back. The price sucks, but damn they've got some great features.

Yeah at those prices I will happily keep on getting my ass up to manually move a speaker cable around.