Since about Friday, I've been getting numerous reports that my box is got this sizzling sound in it. I've got a 2 pill Fatboy mobile(2879's),Galaxy 2517, 35 amp Pyle power supply. I noticed that when I key up the amperage draw meter is at 20 amps, then it creeps on up. Another thing I've noticed is that when I first start talking it barely does it, then the sizzling sound gets worse as I keep talking. When I go barefooted, people say it's clear as a bell. I bought this box used, it had a blown transistor so the tech replaced it. The pill that wasn't blown tested as almost brand new. PLEASE HELP!!!
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Sizzling sound in 2 pill Fatboy
- Thread starter 007_man
- Start date
If there was smoke then things might be simpler, if you post pictures he may be able to diagnose the problem faster.
UPDATE: I won't be able to post pics of inside the box. But I did take the top off the amp. Around the pills, there was brownish coke looking liquid around them. What causes this? Just the pills breaking down? Just breaking in? But no I don't have another box to hook up. I remember a few months ago, I had a Silver Eagle 350 amp do the same sizzling sound on the same exact power supply, BUT it didn't last as long as this time. It soon stopped after a while and I didn't change anything on the radio.
The brown stuff you're seeing is most likely dried resin from the solder used to solder the transistors to the board and is of no real concern but you may try to remove it with alcohol if it bothers you being there.
If you're having the same issue with more than one amp on that power supply I would look at that power supply, the only thing I could think of in an amp that might make a noise might be the switch over relay which might make a buzzing or chattering noise if dirty.
Can you elaborate a little on the nature of this "sizzling" noise and how it manifests? From what I can tell, you could mean one of three different things:
1) "When I transmit, I can hear a sizzling sound coming from inside the amplifier."
2) "When I transmit, people tell me there's a sizzling sound in my transmitted audio (even when I'm not talking -- i.e. I just hold the key down, and you can hear a sizzling/crackling sound)."
3) "When I transmit, people tell me my audio sounds "sizzly," i.e. my voice is distorted such that it seems very grainy and/or crunchy."
Is it one of those things? Is it a combination of those things? Is it something completely different? Inquiring minds want to know.
If it's number 3, I think it means the amp is being driven with too much input power, pushing it into non-linear operation. This can cause a lot of clipping and distortion. It may get worse as you talk more because the transistors get hotter and the non-linearity becomes even worse.
If it's 1 or 2, then it could be a problem with the power supply. The regulator might be failing and causing the voltage to climb too high. (You should be able to confirm this with a voltmeter.) Or there might be some kind of noise or hash on the supply voltage that's being translated into noise on your transmitted signal. You didn't say if you're running the radio off the same power supply. If you are and things are fine with the amp off, then either it's not the power supply or it's a problem that only manifests when the amp loads it down.
From what I can tell googling around, the Pyle 35 amp power supply looks like a decent quality unit so I'm not inclined to blame it.
My money says that either the amp is being over-driven, or else there are still some failed or intermittent parts left behind from when that 2879 blew up. (But that's just an armchair engineer's opinion. )
-Bill
1) "When I transmit, I can hear a sizzling sound coming from inside the amplifier."
2) "When I transmit, people tell me there's a sizzling sound in my transmitted audio (even when I'm not talking -- i.e. I just hold the key down, and you can hear a sizzling/crackling sound)."
3) "When I transmit, people tell me my audio sounds "sizzly," i.e. my voice is distorted such that it seems very grainy and/or crunchy."
Is it one of those things? Is it a combination of those things? Is it something completely different? Inquiring minds want to know.
If it's number 3, I think it means the amp is being driven with too much input power, pushing it into non-linear operation. This can cause a lot of clipping and distortion. It may get worse as you talk more because the transistors get hotter and the non-linearity becomes even worse.
If it's 1 or 2, then it could be a problem with the power supply. The regulator might be failing and causing the voltage to climb too high. (You should be able to confirm this with a voltmeter.) Or there might be some kind of noise or hash on the supply voltage that's being translated into noise on your transmitted signal. You didn't say if you're running the radio off the same power supply. If you are and things are fine with the amp off, then either it's not the power supply or it's a problem that only manifests when the amp loads it down.
From what I can tell googling around, the Pyle 35 amp power supply looks like a decent quality unit so I'm not inclined to blame it.
My money says that either the amp is being over-driven, or else there are still some failed or intermittent parts left behind from when that 2879 blew up. (But that's just an armchair engineer's opinion.
)-Bill
No I can't hear sizzling coming from my box. People tell me that they can sometimes hear it while I throw a dead key, other times it sizzles when I modulate. The 2517 is plugged in the wall. The only thing that's running off the power supply is the Fatboy, and my meter light. Yes, people tell me that my voice sounds gravelly. I lowered the deadkey to a watt and a half. My buddies tell me it helped a little but still is in there. Ever since I've had this box ( early December 2011) I've ran a 2 and half watt dead key. I haven't had problems until last week. So I don't know. Thanks for the help guys. Please keep sending the suggestions!
try installing a bonding wire from the case of the amp to the case of the power supply, be sure it has good metallic contact to both units and give that a shot.
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
Are you 100% certain the sound isn't originating in your radio and just being reproduced by the amps? It would be odd to get the same "sizzling" sound from two different amplifiers.
Rule out the radio and mic first by taking the amps out of line and listening to your tx audio on another receiver.
Connect the amp to a car battery, see what the results are, if the sizzling sound can still be heard.
If it can still be heard, take the top cover off the amp so you can see the board, turn lights off and key the amplifier(hopefully into a dummy load) observe the amp and see if you can see any thing shorting to ground.
RF is a funny thing, the output matching network, transformer, caps etc etc would be suspect to failure as the sizzling sound goes.
good luck.
If it can still be heard, take the top cover off the amp so you can see the board, turn lights off and key the amplifier(hopefully into a dummy load) observe the amp and see if you can see any thing shorting to ground.
RF is a funny thing, the output matching network, transformer, caps etc etc would be suspect to failure as the sizzling sound goes.
good luck.
There is a sizzling noise transmitted and you sound gravelly??? If you want help, these descriptions won't help.
The sizzling sound is there when I key up, then when I modulate my voice sounds gravelly and staticy.