# Help Diagnosing Issue please



## davetcan (Feb 27, 2006)

Guys, my Fryette Memphis 30 has started fading in and out for lack of a better description. When I bought it the low input already exhibited this problem but the high input was just fine and has been that way until now. It's now doing exactly the same thing. Any thoughts? I haven't tried swapping out tubes yet and if you think that would help where should I start  I did try tube swapping on the low input about a year ago with no success. I did ping Steve Fryette back then but his only comment was that it didn't make sense ;-) here's the tube layout.

I'll throw some de-oxit on a jack just to make sure it's not something stupid like dust/dirt 

V1 Input Gain Stage 1.
12AX7 Tung-Sol Gain stage 4 for DRIVE channel in BOOST mode only.
12AX7WB Sovtek Use in place of Tung-Sol for less mid saturation and deeper low end.


V2 Gain Stage 2 for CLEAN channel. 12AX7A/7025 China Gain Stage 2 for DRIVE channel.


V3 Gain Stage 3 for DRIVE channel. 12AX7A/7025 China Tone Control Driver for DRIVE channel.


V4 Gain Stage 3 for CLEAN channel. 12AX7A/7025 China Tone Control Driver for CLEAN channel.


V5 (shielded tube) Reverb Driver (Parallel Triodes) 12AT7 China For stock “ambient” reverb response.
12AX7A/7025 China For traditional jangle/surf reverb response.


V6 (shielded tube) Phase Inverter for power amp. 12AX7A/7025 China For stock smooth and easily saturated power amp response.
12AT7 China For tighter response, lower gain and increased headroom.


V7 – V10 Power Tubes.
EL84 Sovtek
EL84 EH


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## keto (May 23, 2006)

EL84's are (speaking in relative terms) pretty high wear/high maintenance, as far as power tubes go. I'd throw a new set in before anything else. Or ship it to me, and I'll work on it for you


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## Lincoln (Jun 2, 2008)

worn out input jacks making bad contact? Try giving your cord a wiggle and you'll see instantly if that's it.


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## davetcan (Feb 27, 2006)

Lol, no !!!!

My first thought was the EL84's but that wouldn't explain it when the low input was the only one exhibiting this problem. At least I don't think it would.




keto said:


> el84's are (speaking in relative terms) pretty high wear/high maintenance, as far as power tubes go. I'd throw a new set in before anything else. Or ship it to me, and i'll work on it for you :d


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## davetcan (Feb 27, 2006)

Pretty sure it's not that but it's worth a shot 



Lincoln said:


> worn out input jacks making bad contact? Try giving your cord a wiggle and you'll see instantly if that's it.


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## nonreverb (Sep 19, 2006)

"fading in and out" is usually a filament problem. You might have a preamp tube with a intermittant filament. It could be a bad socket pin or, bad solder somewhere in the heater circuit.


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## davetcan (Feb 27, 2006)

Why don't you live in London  

I'll mess with the tubes a bit. Is it likely to be any one of them in particular ?



nonreverb said:


> "fading in and out" is usually a filament problem. You might have a preamp tube with a intermittant filament. It could be a bad socket pin or, bad solder somewhere in the heater circuit.


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## GuitarsCanada (Dec 30, 2005)

Had the same issue on my Johnson. It was the socket pin

http://www.guitarscanada.com/showth...-and-out-(Guitar-Amp)&highlight=volume+fading


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## davetcan (Feb 27, 2006)

Well I'm ashamed to admit it might be a false alarm. I sprayed the cable with contact cleaner and then stuck it in and out a few times and so far after 15 minutes of playing all is good. I did also replace the reverb tube (I was going to work my way from right to left) but i really doubt that was the problem. Looks like the culprit could be dust. I have had it sitting for awhile uncovered and unplayed while I've been messing with my new Koch Studiotone so maybe it's getting back at me ;-p

I'll pick this up again if the problem resurfaces. Thanks all.


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## davetcan (Feb 27, 2006)

I had exactly the same issue on my Boogie LSS loop as yours, that's why i was thinking about the contact cleaner. Boogie actually recommended that fix before looking for bigger problems 




GuitarsCanada said:


> Had the same issue on my Johnson. It was the socket pin
> 
> http://www.guitarscanada.com/showth...-and-out-(Guitar-Amp)&highlight=volume+fading


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## ampsplus (May 7, 2010)

Always check to see if the effects loop is a series type, and if the jack contacts are going. It is easy to diagnose; take a short patch cable and connect the send to the return. I have seen this type of problem time after time, and the loop is generally the problem. This applies only to series loops, many makers use them.


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