# Champ clone issues



## blam (Feb 18, 2011)

*champ/princeton clone input jack issues*

Hey guys

Maybe one of you can help me with a problem I having. 

I have a valve train 205 tallboy which is basically a champ with tone circuit added. 

The issue is my hi input. Sometimes it cuts out. Some times it has very little volume ( my strumming will drown it out)

Sometimes it's perfectly fine. 

The Lo input seems to be unaffected. 


The inputs of this amp are weird. They are not your standard 1/4" input. Any ideas? Is the input jack dead? Should I replace them? Or could it be a tube or other issue?

Thanks.

Here are the inputs. The guitar is sitting in the Li input in these photos


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## loudtubeamps (Feb 2, 2012)

good pics.
hard to tell but it looks like the top input lead going to the 68k resistor is being grounded out with the 1 meg ohm resistor lead?? 
I believe the top yellow lead should be wired to the bottom(other end) of the 1 meg resistor.
here are some references


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## loudtubeamps (Feb 2, 2012)

also........if the jacks are not directly grounded to the chassis......if they have any plastic or fibre washers insulating them from the chassis, then after you move the top yellow lead down to the next lug(other end of the 1 meg resistor).....
connect a short lead from the black lead (ground) on the bottom jack to the lug on the top jack where your yellow lead was.
(We'll call it the top of the 1 meg r)
cheers, d


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## blam (Feb 18, 2011)

Thanks, i will guve that a try when i get a moment 

is there any reason the current wiring suddenly stopped working? This is the way the amp was from factory and it worked fine up until now.


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## epis (Feb 25, 2012)

loudtubeamps said:


> connect a short lead from the black lead (ground) on the bottom jack to the lug on the top jack where your yellow lead was.


I would do this anyway, it's not gonna hurt, and you are right 100% about everything, I'm wandering how did it work before ?


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## washburned (Oct 13, 2006)

Before you start rewiring check and make sure you have good contact on both jacks at the tip, ground and where the tip/ring connection is made. I believe that this is wired to use the tip/ring connection on the unused jack when the other jack is in use.


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## blam (Feb 18, 2011)

Well. Too late for that, but there was indeed good connections to the input tip. 

I requires it as per loudtubeamps recommended and it works fine now. Thanks loudtubeamps!!

The Lo channel was acting up after the fix though (worked fine before) and it turns out that tab that grounds out the jack when not in use was still touching when I plugged a guitar in. 

I'll play it some more tomorrow to confirm its working right as I only got about 2 minutes with it before I had to leave the house.


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## blam (Feb 18, 2011)

Alright, I had some time with the amp. Both channels are working now, however they seem to both sound the same. (the low channel should have more headroom and less gain)

As well, this is not a champ clone, but a narrow panel Princeton 5F2 if that makes a difference. 

Any ideas on this one?


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## epis (Feb 25, 2012)

The switch in lower jack is open all the time, or dirty.


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## blam (Feb 18, 2011)

You mean the grounding tab? Check to make sure it's contacting when nothing is plugged in?

New pics


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## epis (Feb 25, 2012)

blam said:


> You mean the grounding tab? Check to make sure it's contacting when nothing is plugged in?


Yes, exactly.


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## blam (Feb 18, 2011)

Epis,

I plugged my guitar into the hi input, played whilst poking at the grounding tab on the Lo side. no effect.

I then did the same with the guitar plugged into Lo and poking at Hi...static, and changes in volume. I then gator clipped the tab to the tip prong and VOILA.

my Lo input is noticeably quieter with much less gain. 

Is it now safe to assume my input is faulty and I should replace it? 

Thanks for all your help.


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## washburned (Oct 13, 2006)

Looks like they use the switches in the jacks to complete/disable the other jack's circuit. Make sure the contacts are clean and making solid contact when no jack plugged in.


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## greco (Jul 15, 2007)

Blam...this is an excellent thread with great pics and very helpful information.

Thanks...especially for the pics !!

Would you consider changing the thread title to indicate that it is primarily about input jacks ?
It would certainly help in the future for searches and as a very thorough reference thread.

Cheers

Dave


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## blam (Feb 18, 2011)

Washburned, yup. as per the post above yours, I narrowed it down to the Hi jack being faulty. the tab that grounds out the tip doesn't make good contact when there is nothing plugged in so I'm getting the Hi channel tones regardless of where I am plugged in. I've got a new jack coming and she'll be good to go in no time. Will be replacing the resistor as well while I'm in there.

Dave, I don't think I can edit the title unfortunately. Makes me rather upset to find they made this error from factory. I guess handwired, USA made isn't always what it is cracked up to be.


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## washburned (Oct 13, 2006)

blam said:


> Washburned, yup. as per the post above yours, I narrowed it down to the Hi jack being faulty. the tab that grounds out the tip doesn't make good contact when there is nothing plugged in so I'm getting the Hi channel tones regardless of where I am plugged in. I've got a new jack coming and she'll be good to go in no time. Will be replacing the resistor as well while I'm in there.
> 
> Dave, I don't think I can edit the title unfortunately. Makes me rather upset to find they made this error from factory. I guess handwired, USA made isn't always what it is cracked up to be.



Usually when you see Switchcraft on a jack you can have confidence it will work. I would bet yours is the exception to the rule.


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## blam (Feb 18, 2011)

haha.

yes. the tab seems to be totally fubar'd when I plug in a guitar it diconnects are required, when I pull it out, it looks like its touching, but obviously not making great contact.

I tried to bend it back so it would make better contact but no luck there.


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## epis (Feb 25, 2012)

blam said:


> Epis,
> 
> I plugged my guitar into the hi input, played whilst poking at the grounding tab on the Lo side. no effect.
> 
> ...


You're welcome, what I do usually, I use 1000 grade sandpaper, or piece of some rough surface paper ( my favorite is loudspeaker cone material ) to clean the contacts.
I cut it in thin stripes and just drag in between closed contacts. Your jacks are good, probably just slightly oxidized. After cleaning apply some contact cleaner or liquid wrench silicone spray. Cheers, Damir


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## blam (Feb 18, 2011)

Well look at that. That fixed it. I keep an input plugged in all the time. Usually the hi jack. Probably why it oxidized. 

Thanks so much.


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## greco (Jul 15, 2007)

blam said:


> Dave, I don't think I can edit the title unfortunately.


IIRC, I think you can edit the thread title if you go to the first post and click "edit post" and then "advanced"

Cheers

Dave


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## washburned (Oct 13, 2006)

blam said:


> Well look at that. That fixed it. I keep an input plugged in all the time. Usually the hi jack. Probably why it oxidized.
> 
> Thanks so much.


I wondered earlier if you did that. Hindsight is 20/20.


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## blam (Feb 18, 2011)

I guess I should get into the habit of leaving it unplugged. Lol


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