Channel Switching FREAKIN' CAN OF WORMS!!

[gktamps]

OK, I spent 2.5 hours searching every site I could find for ideas on how to switch my new JMP50 build inputs for either:

Channel 1
Channel 2
Channel 1 parallel Channel 2
Channel 1 cascade Channel 2

There are lots of ways to implement switching, but I've opened a can of worms, and don't know how to pick the best worm from the can.

There are so may options - passive relays, JFET, CMOS, MOSFET, and each with pros and cons. I don't have the technical chops to know which is the best way to go in this case.

I've got an unused 5V supply from my PT. I've got a spare input jack hole. I've got some space in my chassis.

Thanks for any leads, fellas.

Cheers,

Greg

[John_P_WI]

Personally, I would make it as simple as you can using a mechanical dpdt or what ever switches you need for your scheme. Determine what you like best and then think on how to improve upon it. I'll guess that you will end up using a paralleled "jumpered" and a cascaded scheme the most.

The reason I say to keep it simple is you will constantly be playing with gains and volumes to get that tone, and in using the stock tube numbers and "volumes" live or performance switching is not easily achieved. Like the rest of us, you'll end up using one setting the most then use pedals or another amp....

[gktamps]

OK, thanks for your comments, John.

I generally do like to keep it simple as you suggest, and most likely will for this build. However I would like to get a better understanding of the options, given that there are so many.

Cheers

[10thTx]

If you will go to EL34 World (Hoffman amp forum) & go into ARCHIVES, you will find an abundance of good info along with schematics and layouts for relay switching.

Look under relay switching

Hoffman sells the relay power boards, relay boards & all the parts you'll need.

Easy to do.

With respect, 10thtx

[gktamps]

Thank you, 10thTX. I'm been looking on several other forums, particularly Metro, but am not yet signed up on EL34 World, but will do so right away.

Thanks for the lead.

[Reeltarded]

Best thing is to hit Dave with the problem <Co-lassie, the bionic domestic> and wait for him to engineer the whole fix while you have coffee.

He's good like that. haha

[gktamps]

Hehe, yeah, I should offer him some coffee...

[Reeltarded]

You can't buy the coffee he drinks. It's gathered by enchanted river otters and packed out of Shangri-La on the backs of billionaire monks for their closet friends.... and enemies.

[gktamps]

Dammit!
I can get the enchanted river otters, but not the billionaire monks.
Tea?

[10thTx]

http://www.el34world.com/Forum/index.php?topic=14348.0

With respect, 10thtx

[ampgeek]

Although I love coffee and otters...I don't think that I am the Dave you mentioned earlier

Regardless, I will offer up some grist for the mill on this topic with the hope that it helps.

When faced with a relatively complex switching array, I always start with a simple sketch and a logic diagram just to see how deeply over my head I might be getting. In this case, using simple on-off switches.

From there, I stare at it for a while until I see a pattern emerge that allows the use of different switches (like...dpdt or 3pdt) and/or different logic approaches.

Here is a less than 10 minute attempt at that first step. It is unverified so please have a look and let me know if anything is grossly out of whack. I didn't study the JMP 50 schematic so it is layout agnostic for the time being.

Good luck!
Dave O.

[Colossal]

Best thing is to hit Dave with the problem <Co-lassie, the bionic domestic> and wait for him to engineer the whole fix while you have coffee.

He's good like that. haha

Eh, what'd I miss? Who's switching what now?

<sips Buddhist tea>

[gktamps]

Dave O., thank you for doing that diagram! I appreciate you spending your time. The approach of diagramming makes good sense, and I do that all the time. I think S4 would be closed for A, at a quick glance, but I get your drift.

I will follow the good advice provided so far, then try to make sense of the various types of switching set ups out there, per my OP.

Colossal Dave, my query stems from the myriad ways of performing the task, trying to figure out the best approach per my OP at the top.

Is that a little teacup Homer is frolicking in Elysian Fields with in your avatar?

Oh no, he's being chased by otters!

[M Fowler]

Dave said he is going to teach me switchola techin first and that my friends could take up the rest of the year easily.

[gktamps]

Man. We're gonna need lots of enchanted river otters. And coffee. Or monk tea.