jnorem
94 posts
Mar 07, 2014
6:28 PM
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I've found the sweet spot on my 68 Fender Super Reverb amp. Normal, input 2, 7,3,4.
But playing it tonight I was hearing intermittent spikes which I'm interpreting as a speaker issue, since I've recently taken the amp to a tech for a complete tune-up, and I've had my old Astatic repaired. So it isn't either of those, and anyway it definitely sounds like a busted speaker cone.
But which one, and how many? How would I know, how would I determine which one of the speaker cones is busted, if that's even possible.
Is there a way of finding out which of the four speakers is busted?
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Call me J
Last Edited by jnorem on Mar 07, 2014 6:28 PM
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HawkeyeKane
2350 posts
Mar 07, 2014
6:39 PM
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Yeah, there's at least one way. Have your tech pull them one at a time, and run a load on each one with an amp corresponding to the power and impedance of them. That's a surefire way.
Are you certain it couldn't be a cabinet resonance issue?
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Hawkeye Kane
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jnorem
96 posts
Mar 07, 2014
6:53 PM
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I have no idea what a cabinet resonance issue sounds like, Hawk. But the amp was sounding real good, loud and tight and just a bit dirty.
I shall google cabinet resonance.
Also, the guy who worked on my amp doesn't work on speakers. I've found a place that does, but I hate the idea of going there without being able to tell them exactly and precisely what it is I need done.
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Call me J
Last Edited by jnorem on Mar 07, 2014 6:55 PM
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jnorem
97 posts
Mar 07, 2014
7:29 PM
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I googled cabinet resonance. It's not that, and I really had to do some searching to find what cabinet resonance is about.
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Call me J
Last Edited by jnorem on Mar 07, 2014 7:29 PM
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Barley Nectar
313 posts
Mar 08, 2014
8:38 AM
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Take the amp back to your tech and play it. Use the same setup as when you experienced the trouble. Many things can cause this. The problem could be cabinet buzz, speaker problem, tube problem, circuit problem, bad cord, screwed up mic, see what I mean. Your tech will be able to help pinpoint the trouble...BN
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dougharps
573 posts
Mar 08, 2014
8:50 AM
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@jnorem
Could you describe the "intermittent spikes" in more detail?
Does this happen on specific notes or bends, or just randomly, unrelated to what you play? Is it when you are playing loud?
I had a recurring issue of sudden louder short momentary "scratchy" noise when I was pushing the amp. It is a small push/pull amp with a tone stack similar to a Fender stack, with Bass, Treble, Volume, and Gain. My friendly amp builder/guru checked for microphonic tubes, but that wasn't it. It wasn't a grounding issue, either. I tried different mics and cables, but that wasn't it. I tried different speakers, but that wasn't it.
Then I noticed that if I pushed or pulled or wiggled one tone pot the sound would occur, even without playing. My amp guru identified the problem as a tone pot that was shorting to wide open under vibration caused by loud volume playing, especially on loud bass notes.
This bad pot was causing what I could have called "spikes". He was surprised by this being the problem with a pot that should have been ok, but after he replaced it, the problem went away.
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Doug S.
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5F6H
1753 posts
Mar 08, 2014
9:00 AM
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Your amp will be fine running on 3 speakers, one by one disconnect one speaker at a time & test to eliminate the culprit.
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Rick Davis
3042 posts
Mar 08, 2014
9:10 AM
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What doug said: Be more specific about "intermittent spikes." Is it a certain note that rings louder sometimes?
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-Little Rick Davis
The Memphis Mini harp amp
The Blues Harp Amps Blog
The Mile High Blues Society
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jnorem
98 posts
Mar 08, 2014
11:05 AM
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It seems to be random. I'm playing, just playing lines, and suddenly a short sort of "chzt!" sound will be heard.
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Call me J
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