#1
Ok have a JCA20 and recently it just started acting odd. First let me say that I have added a Choke and the BITMO "SURFA" mod and swapped tubes for some JJEL84 and JJ12AX7's.

So here is what is happening....I no longer have any sustain....but rather now it sounds dead and I get a steady wah-wah-wah-wah-wah until the distortion and wah sound turn to feedback. It stards slow and speeds up. No pedals.....

Have tried swapping tubes around but no change

theDogger
#2
Does it really go wah-wah-wah-wah? Like a wah pedal? Or is it more like a put-put-put-put?
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!
#3
It is more like a WAH pedal. It steadily increase in speed!


theDogger
Last edited by theDogger at Sep 20, 2010,
#4
That's really weird. Honestly, I have no idea what it could be.

Checked if any components are toasted inside? Tube sockets are clean?
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!
#6
Quote by end_citizen
I'm not familiar with the "SURFA" mod. What did you change in this mod?


It's "Sufra" according to their website. http://www.bitmomodkits.com/servlet/the-108/BITMO-SUFRA-JET-CITY/Detail

The tl;dr version--2 switches. First switch bypasses part of the tone stack to add clean headroom. 2nd switch is tubescreamer type boost.

Sounds to me like the TS screwed something up.
Last edited by Seref at Sep 20, 2010,
#7
Quote by Seref
It's "Sufra" according to their website. http://www.bitmomodkits.com/servlet/the-108/BITMO-SUFRA-JET-CITY/Detail

Sounds to me like the TS screwed something up.


Yeah, I agree with you.

I did find that on their site, but it doesn't go into any detail about what they are doing (lest they be copied, I presume).
#8
Wait, did it start acting up directly after the mods? I was under the impression this is not the case.
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!
#9
I recommend undoing all the mods to see if it fixes it. Bring it back to stock. If it's not ****ed up then you know that you just installed the mods wrong.
#10
No it has been working fine for over a month with the mods in place.....just happened a couple days ago?
Choke mod


The "SURFA" mods does the following...



What are you referring to
Sounds to me like the TS screwed something up.
Last edited by theDogger at Sep 20, 2010,
#11
Could be a bad solder point, either from the factory or from the mods. Maybe got warped and now has a bad connection.

Could be tubes.

Could be a lot of things. The only way to know for sure that it's not the mods is to undo the mods, try it, then put them back on.
#12
You could try reflowing all solder joints.
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!
#13
I have check all the solder points and they are good on the mods that have done. What about a bad filter Caps?

theDogger
Last edited by theDogger at Sep 22, 2010,
#14
You mean a bad filter cap? You could try swapping them.
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!
#16
^post on the harmony central mod thread for the 20h
Quote by envoykrawkwar7


edge11
that was an epic win
best thing ive read all day

[feel free to sig this statement]

Gear:
Esp Ltd Ninja 600
Esp Ltd F-50
les paul elite
5watt jcm800 clone
Roland jc-55
Crate V33
Jca20H
Ibanez tubescreamer ts9
Keeley ds-1
#17
well after spending the night trouble shooting I found the issue and I would never have expected a bad guitar cable to act this way.

Swapped cables and all is good now..


theDogger
#18
I know the feeling.
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!