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Topic: Problem with effects loop |
Richard Wilhelm
From:
Ventura County, California
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Posted 26 Apr 2016 8:05 am |
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I have an old Randell 100 watt tube amp 112. I'ts a big monster in a little box with a very clean sound. The effects loop does not work. On my other amp some of my effects sound better thru the loop, so it's something I want to fix. Before I send it to a tech, I would like to give it a try. The first place I will look are the 2 jacks inside, if some corrosion or anything is keeping it from connecting. Next would to be a visual inpection of the signal path from the 2 jacks as far as I can see. Is this something that is normally a easy fix? I do realize that power can still be stored in the capacitors even when unplugged, I want to keep all my fingers.
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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David Nugent
From:
Gum Spring, Va.
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Posted 26 Apr 2016 3:53 pm
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| If your amp is equipped with a footswitch jack, have you tried plugging one in? If the effects loop is governed by an on/off switch, it may be set in the off position. |
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Richard Wilhelm
From:
Ventura County, California
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Posted 26 Apr 2016 6:11 pm
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It has a foot switch that changes channel's and a jack for a foot switch for the reverb. Very much appreciate the suggestion.
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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Lane Gray
From:
Topeka, KS
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Posted 26 Apr 2016 8:12 pm
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Spray contact cleaner inside the jacksjacks of the loop, then run a plug in and out several times.
Almost all loops use switching jacks on the return jack.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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Richard Wilhelm
From:
Ventura County, California
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Posted 26 Apr 2016 9:20 pm
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Thanks Lane, when I get the amp back, I'll try that and let u know. Mucho Garcia.
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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ajm
From:
Los Angeles
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Posted 27 Apr 2016 6:29 am
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| You forgot to state the exact model number of the amp. |
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Richard Wilhelm
From:
Ventura County, California
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Posted 27 Apr 2016 9:53 am
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RGT100
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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ajm
From:
Los Angeles
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Posted 27 Apr 2016 2:04 pm
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Basically, what Lane said.
I found a schematic on the internet (I think).
This amp has 4x6L6 power tubes and 5x12xxx preamp tubes. The effects loop is not foot switchable.
You said that the loop does not work. What exactly does that mean? I assume that the amp is working without anything being plugged into the Send/Return jacks.
If you take a guitar cord and plug it into the Send jack only, do you still get guitar sound? (You should.)
If you take a guitar cord and plug it into the Return jack only, do you still get guitar sound? (You should not.)
If you take a guitar cord and plug it into the Send and Return jacks with no effects, do you get guitar sound? (You should.)
Cleaning jacks: I have also heard of wrapping some fine grit sandpaper around a pencil and inserting it into the jacks a few times. This should of course be done with power off. |
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Lane Gray
From:
Topeka, KS
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Posted 27 Apr 2016 3:19 pm
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Cleaning the switching part of the jack would require some luck, or pulling the chassis and getting at it. The switching contacts don't usually meet the plug.
See this picture
This one is closed until you insert a plug and then it opens. They're also available in normally open.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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ajm
From:
Los Angeles
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Posted 28 Apr 2016 6:43 am
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Lane is correct.
I was thinking of only the "main" jack connection, and didn't go far enough to cover a jack with a switching function.
At any rate, it will be interesting to see what you find with your amp. |
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Lane Gray
From:
Topeka, KS
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Posted 28 Apr 2016 6:51 am
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Since he says "the loop doesn't work", I assume that he means that the signal is unaffected by the devices in the loop. That makes me suspect the switching function on the return jack, because until that switch activates, the loop isn't in the circuit.
These bits are known to fail, and provides both simple answer and simple solution. You MIGHT have a larger problem, but I doubt it.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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Richard Wilhelm
From:
Ventura County, California
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Posted 28 Apr 2016 4:07 pm
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Lane and j, thanks for the support. Will be alble to look into it tomorrow. Will post back to you. How did I know that Lane would respond????
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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ajm
From:
Los Angeles
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Posted 9 May 2016 7:00 am
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| Was there any resolution to this problem? |
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Richard Wilhelm
From:
Ventura County, California
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Posted 10 May 2016 6:09 pm
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I got my amp back after an absence, and it turns out the loop does work but is too noisy to use. Plus the amp is not as good as I remember, so I didn't even try cleaning the jacks. There was a reason why I started using my solid state Fender 100w (2x12) instead. What I did benefit from, is take the Celestrian G12H100 speaker (a speaker that's been said to have not a big low end and could benefit from being in conjunction with a more bassier speaker) and put it in the Fender. A nice improvement (a sweeter high end) and seem to work well in conjunction with the Fender Special Design (Eminance Legend 1218?) as the other speaker. The Celestrian is the loader speaker I know because I had to turn everything down. When I run the Celestrian by itself (8 ohm and 4 ohm amp), it sounded very spiky and not nice. With both speakers, it sounds warm and clean, very nice. I don't think that the mismatch should make it sound so inferior but I'm not sure. My SS Fender with my passive volume pedal is benefited by the tube reverb (Peavy Valverb with a 40w preamp) is benefited with the Valverb placed before the volume pedal. I think my next amp upgrade will probally be a Fender 212 Deville with a speaker upgrade. It's tempting to play with other speakers like adding a Tone Tubby ($300 for the Nashville) or a Celestrian Cream ($300) or just add something that's just in the mids and low end like the Cannisbis Rex (about $100). I heard a 70's SF Twin Reverb with 2 of them and I thought it sounded good. Or the new Pete Anderson inspired Eminace Hempdog ($120). Thanks again for your help and I think Lane should be put on the Forum's payroll.
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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chris ivey
From:
california (deceased)
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Posted 10 May 2016 9:04 pm
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what is the main instrument you're playing through these amps you don't like the sound of?
there may be a lighter cheaper simpler better alternative. |
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Richard Wilhelm
From:
Ventura County, California
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Posted 11 May 2016 7:28 am
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Last night I played my steel and I really liked my tone. I play a Fender long scale 400 and sometimes 6 string guitar. After reading the recent thread "HELP play both a steel in regular guitar IN SAME amp", I might be right where I want to be. I will probably invest in that Hempdog speaker, it's always nice to know what's available and $120 is not a big loss. I will upgrade my Fender amp regardless, there is a little tear in the black grill cloth and that silver Fender cloth is very magical. Cheers.
_________________
"Be Kind to Animals, don't eat Them"
"If you know music, you°ll know most everything you°ll need to know" Edgar Cayce
"You're only young forever" Harpo Marx
Fender 400, Fender FM212, G&L ASAT.
Was part of a hippie-Christian store in Cotati, California (circa 1976) called THE EYE OF THE RAINBOW. May God love you. |
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