Internal Jumper

Get support and show off your MetroAmp JTM 45 kit builds.

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lgehrig4
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Internal Jumper

Post by lgehrig4 » Mon Feb 18, 2013 9:37 pm

I read a few thread on this but it appears there are different ways of doing this so I wanted to tell you specifically I'm looking to do.

1. I'm not looking for high/low inputs. Just want to end up using 1 input jack.
2. I want the end result to be like I used a Y-cord plugged into both high inputs. When I jumper using a short cable I notice a small decrease in volume and I remember reading that there is a drop because you are involving the lower inputs.
3. When one of the volumes is completely off I would like the amp to work as though I was plugged into the high input of the channel that I am using just as if it wasn't internally jumpered.

For reference I have a Mojave Scorpion and had a Peacemaker. I pretty much want it to work like those amps. Are ther any diagrams that you can refer me to? I built my JTM45 but my no means am a tech.

Thanks!
Jeff

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toner
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Re: Internal Jumper

Post by toner » Mon Feb 18, 2013 11:17 pm

This is probably the closest you'll get without adding a switch:
http://forum.metroamp.com/viewtopic.php ... 41#p332841" onclick="window.open(this.href);return false;

In the above diagram, the low input acts the same as if you used a Y-cable plugged into both high inputs.

I don't think any non-switching solution will exactly satisfy your number 3 requirement because of the slight input impedance change and voltage divider formed by the volume pot that is turned all the way down. However, it's probably so close that there wouldn't be an audible difference.

For those who may be interested, the diagram below is exactly like using a jumper cable from the bright low input to the normal high input while plugged into the bright high input:

http://forum.metroamp.com/viewtopic.php ... 46#p361146" onclick="window.open(this.href);return false;

lgehrig4
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Re: Internal Jumper

Post by lgehrig4 » Mon Feb 18, 2013 11:52 pm

Thank you for answering this and my other question about the .68 cap!

lgehrig4
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Re: Internal Jumper

Post by lgehrig4 » Sat Feb 23, 2013 4:00 pm

Hooked it up today. Works as described, but I used both high inputs instead of a high/low. Same result, but probably would have be easier the other way.

Based on all the mods I've done I think I have too much gain now. Saturated more than I've like so now I have to backing out or adjusting my previous mods. This internal jumper does exactly what I so thats a start.

Tinners1983
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Re: Internal Jumper

Post by Tinners1983 » Wed Feb 08, 2017 8:41 am

Hi Sorry to drag this up, but the links no longer work (old website)

Any chance you could fill me in on this? I only want to use 1 input and use both volumes...

cheers

Matt

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