Rebel-30 cold solder input jack

[Soundchasm]

Hello,
Just want to post to save anyone else a future headache. It's just my luck, but the replacement for my first Rebel-30 head developed a problem, or had it all along and I finally noticed.

I had a lot of static and low level signal as the amp warmed up. I didn't notice it for a while because I usually let it stay on standby for 10 minutes before switching to "play". Switching to "play" after 30 seconds or so alerted me that I had a problem. It would start out severe, and slowly vanish. It was frightening powering up at a gig. Even the drummer heard this...

Over time, I discovered that putting a finger on the input jack would make it behave normally.

Short story is that the surface mount input jack must have had some cold solder joints. As the amp warmed, the problem disappeared. Took it to my tech (didn't have time for warranty shipping), and it's 45 minutes to get the circuit board free, 60 seconds with an iron, and about 30 minutes to button back up, and it's fixed.

Since it's a surface mount input jack, it's inevitable that these amps will fall into two categories, those that had this problem, and those that are going to. Still, I like the amp, my bandmates like it, and I intend to use it.
Thanks,
Greg

 

[bruce egnater]

Oh my. Very sorry about the trouble. Did your tech notice anything while in there that would help us to make better stuff? Always looking for suggestions. FYI, the term "surface mount" is not really quite accurate. It is a circuit board mounted jack but does have pins that solder into the 2 sided, FR4 glass epoxy, plated through board. Surface mount does refer to another type of construction where the parts are soldered only to the top of the board and not through the holes. Regardless, I'm glad your friend was able to fix it.

 

[Soundchasm]

Apologies for miss-characterizing the jack and I appreciate the clarification. There is a difference between what I wrote and what you've made!

I can't help but express some worry because my first unit exhibited the same "really bad guitar cable" symptoms, but I never literally put my finger on it like I did with this exchange unit.

I wish I could talk tech like the best of them, but I am a novice in that department. I do know that better design and better components make a superior product. Having said that, my tech and I agreed that the Rebel-30 is a feature-rich amp, and a bunch of the goodies that I enjoy on it are available due to the circuit boards utilized. The through-board mounted input jack has got to be the weakest link, and probably ought to be addressed first in any troubleshooting.

My dilemma was that I had so much time in shopping, then exchanging, and then discovering the second issue right after I retubed. That really threw me off the scent and spent a lot of hours eliminating vacuum tubes from the equation.

As a novice, I almost wondered if a stand-off on that corner of the circuit board might mitigate any input jack mishaps and mechanically reinforce it.

To end on a high note, the direct out is VERY good and allowing me to make some extremely precise vacuum tube assessments. I'm using the M13 loop feature to play the exact riff and record via direct out to a new track with every tube I try. Pretty cool.
Thanks,
Greg

 

[Soundchasm]

Here's the two bits from Mike Safreed, my amp tech. This guy makes me loud and proud. It was a pleasure to watch him patiently eviscerate and repair my amp.

Greg,

Since you've already joined the thread, how about you passing along to Bruce that the quickest fix for the jack, and eventually the pots that are mounted in a similar manner, would be to use a THIN lock washer under each nut. I noticed that the nut on the input jack was not tight, which when the guitar cable is plugged in or out, allows the jack to flex against the soldered connections. This will also eventually happen on the control pots when you are adjusting the volume/tone/etc. This problem is common to nearly all amps built in this manner. I repair several Fender amps each week with the "bad jack" problem. Same goes for Peavey, and, like I said, nearly every brand that uses board-mounted jacks/pots. It's a love-hate relationship with me. I hate to have to tear into these amps - they are not really easy to work on - but I love that it keeps me in business.

Had the jack not been the problem in this particular amp, I think I would have had to seriously look at the soldering on the tube sockets. Since the problem with the amp seemed to go away as the amp "heated up", I would have looked at tube-related problems next. That noise that was initially heard upon power-up is usually related to a preamp tube that simply needs to heat up a little - the tube isn't necessarily "bad", but simply needs a little heat in it to start operating correctly. The same type of problem can be displayed in amps with this type of construction when a tube socket has a faulty solder connection. The heat from the tube sometimes cause the faulty joint to literally close up and make a solid connection. When the amp is cold, the materials in the connection area shrink and create an "open" connection point. This is a problem that causes a lot of tech persons to chase their tail. It also helps sell a lot of tubes.

I am sure that if current amp construction techniques were available to Leo Fender back in the 50's and early 60's, he would have used them. There wouldn't have been any hand-wired Fender amps. But, I have to admit, hand-wired amps are easier to work on, but they have some limitations and their own set of problems, like lead dress and the resulting oscillation issues. Once you get a PC board-based amp properly designed, that is never a problem. So, I'm not bigoted to the point that I summarily dismiss PC board-based amps as inferior. As a technician and amp designer/builder, I simply have to learn the weaknesses in their individual designs and figure out how to keep them up and running...

On a very positive note, the Egnater Rebel 30 is an amp that I would seriously consider buying, and since my primary is source of income these days is derived from building and selling new amps, that's saying something... I don't build an amp that overdrives like the Rebel 30. My amps are for players that like a clean sound - very Fenderesque. But, I'd put that Rebel 30 up against my Marshall 50 watt head for that overdriven tone any day. Cool amp!

Mike Safreed
Owner
S&S Amplification