#1
its either tubes or caps. this is the early version that has a tube PI.

i haven't taken it apart yet, but i am thinking its caps.

symptoms:
1. there is a light hum accompanied by a crackling.
2. it has got progressively worse the last few days.
3. it increases in volume the longer the amp is on.
4. the louder the volume the louder the hum.
5. it is present with or without a cable, and in all four jacks

here is what i did:
1. did the pencil test. no microphonic tubes.
2. tried different guitars, cables, etc.

what i am going to do in a few minutes:
1. [once it cools down] i am going to go through the whole thing with contact cleaner, jacks and tube sockets.
2. swap the PI.

then go from there. thanks!
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
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Quote by andersondb7
youre just being a jerk man.



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Resentments and Rambling from a Guitar Junkie
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#2
OK. i cleaned all of the sockets and the jacks.

i haven't swapped the tubes yet.

the odd thing is that if i have the amp on (cable or not) i hit the top and i get a LOUD sharp quack/smack noise.

methinks filter caps?
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#3
Hum is usually the filter caps.
I'd do a tube swap before getting new caps though. much cheaper and no waiting.

Hitting the top of an amp can make all sorts of funny noises. Even if nothing is wrong with the amp, depending on how hard you hit it.
Do the usual stuff. You should know what that is by now
Check solder joints (particularly where wires are soldered), pots, grounds, wiring.
Last edited by CodeMonk at Jun 23, 2016,
#4
i am just going to do the caps. i have read too many stories of caps taking out transformers, etc. its an older amp, and i don't think they have been done.

what do you recommend? sprague atom? where would be the best place to get them?
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#5
Bump!
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#6
I like F&T.
Measure the frequency of the hum. If it's 120Hz, it's the caps.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#7
Quote by trashedlostfdup
i am just going to do the caps. i have read too many stories of caps taking out transformers, etc. its an older amp, and i don't think they have been done.

what do you recommend? sprague atom? where would be the best place to get them?


Yeah, last amp I repaired was a Mesa, and the filter caps were hosed.
Didn't take out the transformer, but took out a bunch of other parts, and vaporized about 1/2 inch of trace on the PCB.

Like cath suggested : https://www.tubesandmore.com/products/capacitors?filters=Brand%3DF%26T
I got those at the top and so far they are working.
The amp is gigged with regularly and it hasn't come back, so I would say that F&T is good.

Look around there for some of your other caps needs as well.
Mouser for other cap values.
Thats what I usually do.

Quote by Cathbard
I like F&T.
Measure the frequency of the hum. If it's 120Hz, it's the caps.

He's in the states, not Oz.
60hz
Last edited by CodeMonk at Jun 25, 2016,
#8
I know he's over there. It's full wave rectified so it's 120Hz.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#9
It still could be the caps but I had similar symptoms with one of my Fender amps. It was a failed JJ preamp tube that was only 3 months old. Replaced the tube and she was golden. Process of elimination. Do you have a shop nearby with a tube tester?
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
Last edited by Cajundaddy at Jun 25, 2016,
#10
Quote by Cathbard
I know he's over there. It's full wave rectified so it's 120Hz.


I was probably thinking of something else.
Still kinda brain dead ATM, just woke up.
What is it, amps get halved when voltage double? I'm not really awake yet. Good thing I don't have any repair jobs in (no, actually, its bad that I don't have any repair jobs in ).
I just have weeds to kill and a fucking hedge to trim. God, I hate this place.
#11
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#12
thanks rob and cath.

i am just going to do the caps even if it isn't them. easy and relatively quick job. which is good for me because if they were to take something along with them down the chain, i would not be as comfortable doing it myself.

i will get it apart in a few days.

would there be a difference between sprague and f&t to justify the cost difference? if not, i will surely go f&t, i was thinking sprague though partially because that is what i used on my 18w and 5f1 builds.

thanks.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#13
Quote by Cajundaddy
It still could be the caps but I had similar symptoms with one of my Fender amps. It was a failed JJ preamp tube that was only 3 months old. Replaced the tube and she was golden. Process of elimination. Do you have a shop nearby with a tube tester?


i will roll another set of tubes through, after all who knows.

thanks!
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#14
There's no real difference between Sprague and F&T.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#15
Cathbard

i will get them ordered up in the next bit and will let you know how it goes.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/