Ryan
237 posts
Mar 18, 2010
10:38 AM
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So I recently purchased a used Peavey KB1 keyboard amplifier off ebay. I bought it because I wanted a clean sounding solid state amp that I could run my digitech pedal through. Well it just arrived this morning, so I grabbed a Bb harp and plugged a mic straight into the amp to see how it sounds. Unfortunately I noticed the amp made wierd noises when I hit certain notes. When I leaned into a 6 draw bend, or hit a 4 blow, the amp would make these wierd sort of buzzing noises(although it only did this on certain notes). The sounds are pretty irritating.
Am I playing too loudly? I didn't really have it cranked up that loud, so I have trouble believing that's the problem. Could this be a problem with the speaker? If so, where can I get a replacement speaker that's meant to be used in a clean sounding amp? I'm pretty bummed, I hate when you buy equipment and it ends up not working as well as you'd hoped. Thanks for any help you can offer.
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MrVerylongusername
1008 posts
Mar 18, 2010
10:43 AM
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Check the cone, are there any rips?
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congaron
692 posts
Mar 18, 2010
10:54 AM
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Use a PA speaker of the with size. They are designed to be run clean. Also make sure it's not an intermittent tweeter.
Musician's friend has replacement PA speakers. Sometimes a torn cone can be repaired too, with varying results..might be okay in this application. There's no harm in trying. If it's torn there's nothing to lose. Your city may also have a reconing shop or you may find a reconing kit online for the speaker in it.
Last Edited by on Mar 18, 2010 10:56 AM
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Ryan
238 posts
Mar 18, 2010
11:15 AM
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I just checked the cone and there were no visible rips in it. I also checked to make sure the cone wasn't rubbing up against the coil. Maybe I'm just overdriving the speaker, it was made for keyboard not harmonica afterall. Do they make 8" PA speakers? A PA speaker sounds like a good idea. I'm thinking I should maybe check with a local amp technician to make sure the speaker is actually the problem. I'd hate to spend money on a new speaker and have it turn out that it doesn't fix the problem.
Thanks.
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congaron
694 posts
Mar 18, 2010
11:19 AM
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You have a keyboard amp with an 8 inch speaker? You might need to go to peavey for a direct replacement..there are some 8 inch PA speakers, but they are pricey. The amp tech is a good idea, there are other things that can buzz..even loose cabinet parts or grills/grill cloth can buzz.
Last Edited by on Mar 18, 2010 11:20 AM
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MrVerylongusername
1010 posts
Mar 18, 2010
11:26 AM
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Does it have any other inputs so you can try another signal source? - like an RCA for a CD player for instance.
What kind of mic are you plugging in?
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LittleJoeSamson
264 posts
Mar 18, 2010
12:04 PM
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Yes, try a different mic first. Also, see how a line transformer that switches from lo-z to hi-z affects the sound.
Seems to be some kind of harmonic vibration. Check for other loose components that could cause this.
I have heard of some amps that the tube holders will vibrate and cause microphonics, but this is SS.
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Ryan
240 posts
Mar 18, 2010
12:36 PM
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I put in a different 8" speaker (it's just a cheap chinese speaker that I changed out of my tube amp), and it's seems to be a little bit better. The buzzing is still there, but it doesn't seem to be as loud or as intense. Although I suppose its possible I may be wrong as I can't really do a side by side comparison, because I have to go through a 5-10 minute process of changing the speakers.
The microphone I was using is an Akai DM-13(it's a hi-z mic), it is the only mic I have with me at the moment(I loaned my other mics to a friend). I will definately give it a try with my SM57 when I get a chance, to see if that makes a difference. I appreciate all the help.
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bluemoose
141 posts
Mar 18, 2010
1:12 PM
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Ryan, check out Weber signature speakers,
https://taweber.powweb.com/weber/
best $35 I ever spent. 8 inch AlNiCo Signature. Dump that
cheap chinese speaker in your tube amp.
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Ryan
242 posts
Mar 18, 2010
1:26 PM
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Bluemoose, I replaced the speaker in my tube amp with a weber ceramic signature 8S, which is why had the the cheap chinese speaker sitting around. I put the chinese speaker into the keyboard amp (which also had a chinese speaker already in it), not the tube amp.
I am quite happy with the weber speaker.
I considered maybe testing the weber speaker in the keyboard amp, to see if it would get rid of the buzzing, but it was a real pain getting the speaker screwed into the cab(for the tube amp). I would have to take the whole thing apart to get the speaker in and out, so I didn't feel like it was worth it.
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congaron
698 posts
Mar 18, 2010
3:20 PM
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Is it possible you are overdriving the preamp or amplifier itself? The 4 and 6 hole may be extra dynamic the way you play them and causing distortion in the actual preamp. Also, You may be mismatched. If so, if if you are using the digitech pedal into an auxiliary input it should be okay, as long as your pedal isn't overdriving it (you can adjust the output of the pedal then)...barring any other actual issues.
Last Edited by on Mar 19, 2010 6:56 AM
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boris_plotnikov
51 posts
Mar 19, 2010
3:08 AM
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Low buzzing?
It seems, you overdrive power amp. Don't worry about it.
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http://myspace.com/harmonicaboris
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