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Topic: Amp won't work unless I jumper the effects loop |
Tim Whitlock
From:
Colorado, USA
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Posted 24 Dec 2019 2:55 pm |
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| My Evans FET 500 crapped out recently - very low power - however if I run a cable to close the effects loop the amp works fine. What problem is this symptomatic of? |
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Ian Rae
From:
Redditch, England
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Posted 24 Dec 2019 3:39 pm
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Dirty contact in the jacks you're jumpering across.
If you can get in there and clean them it should solve the problem.
_________________
Make sleeping dogs tell the truth!
Homebuilt keyless U12 7x5, Excel keyless U12 8x8, Williams keyless U12 7x8, Telonics rack and 15" cabs |
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Jon Light
From:
Saugerties, NY
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Posted 24 Dec 2019 4:00 pm
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The red arrow shows the point in the 'send' shorting jack that, without a plug in it, should be making contact and allow everything to flow thru. Inserting the plug opens this contact point and allows the signal to be diverted thru the plug. If that point is dirty or loses tension to hold itself firmly closed, you'll get what you've got. Ideally a spritz of DeOxit and some in & out with a plug should get you good. Much better would be opening it up to get access to the innards of the jack and cleaning it directly. Some fine grit wet-dry paper with Deoxit or even just some alcohol ought to do the trick. Needle nose pliers and a gentle touch can retension it if that is the problem (but you can also mangle a jack doing this).
There is nothing wrong with using a short jumper cable as a semi-permanent solution so if that suits you better than messing with the jack....no problem.
In the scheme of things, this is a wonderfully simple problem.
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Larry Dering
From:
Missouri, USA
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Posted 24 Dec 2019 6:09 pm
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| Jon, you have the best diagrams and descriptions. Enjoy reading your replies. |
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David Higginbotham
From:
Lake Charles, Louisiana, USA
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Posted 24 Dec 2019 6:29 pm
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As I mentioned in your other thread, patching through the effects loop with a cable remedies the problem if you don’t want to go through the trouble of a proper fix such as John’s excellent diagram shows. (John’s always of great help with these matters as well as many others!🙂)
This is a common problem in the older Evans amps as I’ve had many of them as my main amp for years in the past. They are wonderful sounding, especially Darrell Stephens models, and I’ve used the patch cord as a fix many times. It works and it’s easy! 🤠ðŸ‘ðŸ»
Dave |
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Ken Fox
From:
Nashville GA USA
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Posted 25 Dec 2019 9:47 am Jack
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A safer way to adjust the contact:
Insert a 1/4†male plug into the jack. That will open the contact. Then insert a flat blade screwdriver between the 1/4†male plug and the jack contact. You then twist the the screwdriver to bend the contact a bit closer to the other contact point |
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Jon Light
From:
Saugerties, NY
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Posted 25 Dec 2019 9:56 am Re: Jack
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| Ken Fox wrote: |
A safer way to adjust the contact:
Insert a 1/4†male plug into the jack. That will open the contact. Then insert a flat blade screwdriver between the 1/4†male plug and the jack contact. You then twist the the screwdriver to bend the contact a bit closer to the other contact point |
1000X better than the needlenose suggestion. Thanks for that, Ken. |
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Ken Fox
From:
Nashville GA USA
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Posted 25 Dec 2019 10:42 am
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| I used needle nose pliers for years One day I thought, there got to be an easier way. Well, I got lucky and came up with that |
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Jon Light
From:
Saugerties, NY
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Posted 25 Dec 2019 11:00 am
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The potential to get that tang out of shape with pliers (and never get it back in shape) is.....real. (Not that I'd know  ) |
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Ken Fox
From:
Nashville GA USA
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Posted 25 Dec 2019 1:17 pm
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| You are right there. Done it myself. The good thing about my new way of doing it is your only putting the most tension on the contact piece. If you push it too far and the contact stays closed then must remove the 1/4â€plug and press both pieces back the other way and then repeat the adjustment process |
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Tim Whitlock
From:
Colorado, USA
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Posted 26 Dec 2019 8:58 am
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| Jon Light wrote: |
The red arrow shows the point in the 'send' shorting jack that, without a plug in it, should be making contact and allow everything to flow thru. Inserting the plug opens this contact point and allows the signal to be diverted thru the plug. If that point is dirty or loses tension to hold itself firmly closed, you'll get what you've got. Ideally a spritz of DeOxit and some in & out with a plug should get you good. Much better would be opening it up to get access to the innards of the jack and cleaning it directly. Some fine grit wet-dry paper with Deoxit or even just some alcohol ought to do the trick. Needle nose pliers and a gentle touch can retension it if that is the problem (but you can also mangle a jack doing this).
There is nothing wrong with using a short jumper cable as a semi-permanent solution so if that suits you better than messing with the jack....no problem.
In the scheme of things, this is a wonderfully simple problem.
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Thanks for the picture Jon. This explains the issue perfectly! |
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Tim Whitlock
From:
Colorado, USA
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Posted 26 Dec 2019 9:00 am
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| Thanks for the information everyone. I'll try the electronic cleaner for starters and then see about pulling the chassis to clean/adjust the contact points. So happy to know I don't have to take it in for repairs! |
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Tim Whitlock
From:
Colorado, USA
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Posted 27 Dec 2019 11:20 am
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| The electronics cleaner solved the problem! At least for now the amp is back to its original clean loudness. I'll keep a short patch cord in the back just in case. Thanks again! |
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Willie Sims
From:
PADUCAH, KY, USA
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Posted 30 Dec 2019 2:06 pm
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| TIM ,IF YOU PULL THE CHASIS YOU SHOULD CLEAN THE POWER AND OUTPUT MODULES LIKE I SUGESTED IN MY OTHER POST.EASEY TO DO,MAY PREVENT TROUBLE LATER. |
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