Just wanted to give a last report in. My amp is finally back to 100% and rockin' and rollin' again!
When we got into the amp this time it turned out to be a pretty easy fix. There were more than a few loose connectors in the amp and one of the ground connectors was just barely hanging on. It looked at a glance like it was connected but turned out to be almost completely loose.
Upon inspecting all of the connectors about 40% of them were slightly loose with a couple others being almost as loose as the ground. We pushed them all firmly back into place and fired the amp back up and it's dead quiet again and sounds great! We didn't mess with the wiring before, mainly just tested solder joints and used contact cleaner and the like, I have no idea how all of that got loose?! I can only guess that the 7,000 or more miles the amp traveled on the road maybe rattled them all slightly loose over time? It was in a fairly nice padded road case back then but was also in a trailer so maybe road jitter over time loosened the connections? They aren't the kind with the clip that snaps on the end so I guess that is the most likely cause for so many to be loose, just a guess though.
Either way thanks everyone for your assistance along the way! I appreciate the time and efforts of everyone on this and for helping steer us down the right paths of what to check and do. Also thanks to ampgeek for the specs on the new amp testing device. It'll be nice to have some testing equipment handy for if/when one of the amps develops a problem down the road!
Clean channel distorting, unsure of cause
Moderators: pompeiisneaks, Colossal
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Ravenant211
- Posts: 17
- Joined: Sat Feb 18, 2012 8:42 pm
Re: Clean channel distorting, unsure of cause
My pleasure!
Glad to hear its back in tip-top shape.
Rock-on,
Dave O.
Glad to hear its back in tip-top shape.
Rock-on,
Dave O.
strange speaker overload
This seems to be a possibly relevant thread...my problem is a distortion versus pickup issue....please shift my post to a more appropriate thread if you like.
I’ve had a good read around this site and picked up many useful tips. So I thought I’d throw in my recent experience with strange noises....and possibly get some useful suggestions from electronic experts on here who’ll easily know a lot more than me.
The equipment. Well, my son’s, which I try to keep going with the simple fixes like socket probs, and I do like bass speaker design issues. I don’t know much technical stuff about the actual electronics of the amps.
Best bass guitar...a Kramer 450.. Maybe of significance, the main pick-up is what may be 8 pole? Maybe someone recognizes such a description.
Spare guitar....a squire precision bass.
Main amp....a 200W bass tube amp...a musician/specialist rebuilds old valve amps in very nice polished wood housings, so possibly an old Marshall, Vox or some other. It’s worked well for 3 years now.
Spare amp....Warwick 200W solid state bass amp.
Single 15” 400W....but displacement de-rated to 200W in this cab for bass as the E string is detuned to C.
4x10....200W each....displacement de-rated to 75W each in this cab.
Both cabs recently re-speakered.
Now to the point. My son used the Kramer, tube amp and 15” for several rehearsals after re-speakering recently and a couple of loudish gigs. No problem.
Last week, at a rehearsal he said there was a weird noise after about 20 minutes, like speaker farting, and had to play with minimum attack to get through. Gentle thumb work instead of pick. He was using the tube amp, 15” and, significantly this time, the squire.
We checked the speaker back in the garage, albeit at neighbourly volumes, and it seemed fine.
So, we went today to the studio with all the gear. We tried all combinations of guitars/amps/speakers for an hour....no problem. Then, we stuck with the tube amp/15”/squire. The noise started on low notes after about 15 minutes. The gain and master set at maybe a quarter. A bit like a woody rattle, and a maybe one and a half to two times as fast as putting your lips together softly and blowing brrrrrr. Best simulation I can think of.
We changed to the 4x10.....same noise. A puzzle. Looking at the cones, it really appeared there was the music related movement overlaid with this response. Gentler thumb play at the same volume didn’t produce this. But we’re fairly sure it isn’t a bad string or fret rattle, cos it takes about 15 minutes to start.
Ok, my son swapped to the Kramer with tube amp. No problem! And carried on for another couple of hours ok. The studio people came to tell him to turn it down cos he was giving it two hours of welly to try to recreate the problem he’d had with the squire, but couldn’t.
Fortunately the speakers survived this, I’m guessing that while it clearly makes an unplayable noise, the farty rattle doesn’t appear to be driven at full amplifier energy. Purely a guess.
So my question is.....is there some way in which the tube amp or the squire warms up after say 15 minutes or so, and then this specific combination starts to create what appears to be over-excursion? Any thoughts appreciated. Thanks
I’ve had a good read around this site and picked up many useful tips. So I thought I’d throw in my recent experience with strange noises....and possibly get some useful suggestions from electronic experts on here who’ll easily know a lot more than me.
The equipment. Well, my son’s, which I try to keep going with the simple fixes like socket probs, and I do like bass speaker design issues. I don’t know much technical stuff about the actual electronics of the amps.
Best bass guitar...a Kramer 450.. Maybe of significance, the main pick-up is what may be 8 pole? Maybe someone recognizes such a description.
Spare guitar....a squire precision bass.
Main amp....a 200W bass tube amp...a musician/specialist rebuilds old valve amps in very nice polished wood housings, so possibly an old Marshall, Vox or some other. It’s worked well for 3 years now.
Spare amp....Warwick 200W solid state bass amp.
Single 15” 400W....but displacement de-rated to 200W in this cab for bass as the E string is detuned to C.
4x10....200W each....displacement de-rated to 75W each in this cab.
Both cabs recently re-speakered.
Now to the point. My son used the Kramer, tube amp and 15” for several rehearsals after re-speakering recently and a couple of loudish gigs. No problem.
Last week, at a rehearsal he said there was a weird noise after about 20 minutes, like speaker farting, and had to play with minimum attack to get through. Gentle thumb work instead of pick. He was using the tube amp, 15” and, significantly this time, the squire.
We checked the speaker back in the garage, albeit at neighbourly volumes, and it seemed fine.
So, we went today to the studio with all the gear. We tried all combinations of guitars/amps/speakers for an hour....no problem. Then, we stuck with the tube amp/15”/squire. The noise started on low notes after about 15 minutes. The gain and master set at maybe a quarter. A bit like a woody rattle, and a maybe one and a half to two times as fast as putting your lips together softly and blowing brrrrrr. Best simulation I can think of.
We changed to the 4x10.....same noise. A puzzle. Looking at the cones, it really appeared there was the music related movement overlaid with this response. Gentler thumb play at the same volume didn’t produce this. But we’re fairly sure it isn’t a bad string or fret rattle, cos it takes about 15 minutes to start.
Ok, my son swapped to the Kramer with tube amp. No problem! And carried on for another couple of hours ok. The studio people came to tell him to turn it down cos he was giving it two hours of welly to try to recreate the problem he’d had with the squire, but couldn’t.
Fortunately the speakers survived this, I’m guessing that while it clearly makes an unplayable noise, the farty rattle doesn’t appear to be driven at full amplifier energy. Purely a guess.
So my question is.....is there some way in which the tube amp or the squire warms up after say 15 minutes or so, and then this specific combination starts to create what appears to be over-excursion? Any thoughts appreciated. Thanks
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martin manning
- Posts: 14308
- Joined: Sun Jul 06, 2008 12:43 am
- Location: 39°06' N 84°30' W
Re: Clean channel distorting, unsure of cause
This might be better as a new thread, but...
It's entirely possible that once the tube amp is up to its normal operating temperature (soaked-in, so to speak), some component is changing in value or that some electrical effect due to thermal expansion arises. The fact that it shows itself with one guitar and not the other is puzzling, but perhaps there is some harmonic content in the Squire's signal that is not present in the Kramer's.
Can you check the operating conditions of the output tubes, i.e. plate and screen voltages and bias (idle) current? I'd do that at start-up and then again after an hour or so of idling (if you want to do it quietly) or after playing it long enough for the problem to appear. How old are the output tubes? Is it possible that they are failing? Do you have another set that you can install, bias and try? What are they, BTW, and what other tube types are in there?
It's entirely possible that once the tube amp is up to its normal operating temperature (soaked-in, so to speak), some component is changing in value or that some electrical effect due to thermal expansion arises. The fact that it shows itself with one guitar and not the other is puzzling, but perhaps there is some harmonic content in the Squire's signal that is not present in the Kramer's.
Can you check the operating conditions of the output tubes, i.e. plate and screen voltages and bias (idle) current? I'd do that at start-up and then again after an hour or so of idling (if you want to do it quietly) or after playing it long enough for the problem to appear. How old are the output tubes? Is it possible that they are failing? Do you have another set that you can install, bias and try? What are they, BTW, and what other tube types are in there?
Re: Clean channel distorting, unsure of cause
trthebees,
Please start a new thread for your amp.
Please start a new thread for your amp.
Tom
Don't let that smoke out!
Don't let that smoke out!
strange speaker noise
Thanks for the replies..Sorry I've taken a while to respond but I've just started a new work contract away from home with long hours.
I regret that I know very little about electronic detail, and would have to do an awful lot of learning to catch up. It's....oh dear....40 years since college when we did electrical and electronics as part of my mechanical engineering course. And the course included valves then!
The valves in this amp are KT88....and there's 4 of them.
I have to admit I'd feel a bit awkward moving this to a new thread when I'm not sure I can contribute much follow-up detail. I'll perhaps leave that to the admin on here if they feel it's worthwhile.
Thanks
I regret that I know very little about electronic detail, and would have to do an awful lot of learning to catch up. It's....oh dear....40 years since college when we did electrical and electronics as part of my mechanical engineering course. And the course included valves then!
The valves in this amp are KT88....and there's 4 of them.
I have to admit I'd feel a bit awkward moving this to a new thread when I'm not sure I can contribute much follow-up detail. I'll perhaps leave that to the admin on here if they feel it's worthwhile.
Thanks
Re: Clean channel distorting, unsure of cause
Don't worry about it, we are here to help.
Just start a new thread with the amp in the title and tell us what is going on with it.
Start a new thread so you aren't lost to the four winds.
Just start a new thread with the amp in the title and tell us what is going on with it.
Start a new thread so you aren't lost to the four winds.
Tom
Don't let that smoke out!
Don't let that smoke out!