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Post by patchworkcat on Jun 8, 2007 13:35:35 GMT -5
Sorry to start another PC30 thread but i have a different concern. Simply put the power transformer on my Peavey Classic 30 hums enough to be nuisance in practice. It seems to be a loose winding. The sound comes from the amplifier, not the speaker.
i heard that you can dip the transformer in varnish overnight to fix this. Is that a sane idea? How much would it cost to get a new power transformer? i am in the UK. Also, is there any way to cut the noise down acoustically?
It's probably worth fixing. The amp sounds very nicel. i have had a few mods done, like a master volume control and switched components on the preamp stage, they work very well.
cheers
patchwork cat
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Post by dd842 on Jun 8, 2007 14:24:53 GMT -5
Sorry to start another PC30 thread but i have a different concern. No need to apologize for starting stuff around here. We like it!  Welcome! to the forums here at Guitar Nuts 2, patchworkcat  Possibly it could work ... it sounds like the same concept as potting a pickup. But wait for a few people with a little more experience with amps to chime in before you do anything. Regarding your transformer question, we have an excellent resource list of suppliers here: guitarnuts2.proboards45.com/index.cgi?board=reference&action=display&thread=1129956856Hopefully you can find a local supplier to get an idea of price (and shipping etc.). By the way, I am not sure what you mean by cutting the noise down "acoustically" ... but that's likely my fault, not yours  Sorry I can't be of a little more help, but I hope that helps a bit - others will usually come along and provide additional information or address any unanswered questions. Welcome aboard! Dan |
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Post by sumgai on Jun 8, 2007 16:22:53 GMT -5
pwcat, Welcome to the NutzHouse! (Even if it has been 22 months since you joined! ) Where power is concerned, doing anything to a coil is asking for trouble. You can dip a pickup into a potting compound, and probably not botch it very badly, but if you try that with a transformer that carries gobs of current, then you better make sure your fire insurance premiums are all paid up! Power transformers are designed with tightly-toleranced air gaps in mind. They allow room for the core to expand and contract with heat buildup, and help to distribute that heat evenly. If you 'fill in' those gaps, you're asking heat to transfer to unexpected and undesirable places, causing no end of stress to the transformer's internal parts. And that's before we start talking about the permeability of the core, which will be distorted if the air gaps are filled. Now you're generating eddy currents, which translate to more wasted power, which we see as heat. The list goes on, but the danger doesn't ever decrease. The moral of the story is, don't do it, period. I can't recommend loudly enough that playing with power components like this is a Romper Room No-No of the highest order! You'll be far better off spending the money on an upgrade transformer before you burn the original, and a bunch of other components besides. HTH sumgai |
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Post by UnklMickey on Jun 8, 2007 17:08:39 GMT -5
Power transformers are designed with tightly-toleranced air gaps in mind. They allow room for the core to expand and contract with heat buildup, and help to distribute that heat evenly. If you 'fill in' those gaps, you're asking heat to transfer to unexpected and undesirable places, causing no end of stress to the transformer's internal parts. And that's before we start talking about the permeability of the core, which will be distorted if the air gaps are filled. Now you're generating eddy currents, which translate to more wasted power, which we see as heat. The reason for the gaps in transformers is to prevent eddy currents. If the material used to fill the gaps is non-conductive, it won't affect the eddy currents. I doubt it is the laminations themselves that are causing the noise. It's more likely the bell-ends, or the mounting bolts are loose. I've seen this all too many times. Insure that the bolts are tight, then if necessary, you can use pieces urethane foam to damp the bell-ends, if the transformers don't run too hot. There is a chance that the laminations themselves are responsible for the noise, but it is a small chance. good luck, Unk |
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Post by patchworkcat on Jun 8, 2007 18:39:54 GMT -5
The reason for the gaps in transformers is to prevent eddy currents. If the material used to fill the gaps is non-conductive, it won't affect the eddy currents. I doubt it is the laminations themselves that are causing the noise. It's more likely the bell-ends, or the mounting bolts are loose. I've seen this all too many times. Insure that the bolts are tight, then if necessary, you can use pieces urethane foam to damp the bell-ends, if the transformers don't run too hot. There is a chance that the laminations themselves are responsible for the noise, but it is a small chance. good luck, Unk Thanks Unk, that's interesting. It's worth some checking over, tightening and insulation. i guess i have to try and get inside without hurting anything. To do what you mention, that is. The amp sounds very nice but it's made on the cheap with those little PCBs. A local guy did some of the BlueGuitar mods for me, but he's gone now. |
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