Phil Starr Posted February 10 Share Posted February 10 I believe you may be over thinking this. These Peavey's are pretty robust and repairable if they do go wrong. Leaving this amp open circuit won't cause a problem, that is for valve amp power stages and the odds of a momentary short from a jack causing damage with an amp turned down and with no signal going through the amp is miniscule. The real risk is the one you have identified, to your speakers. I've had a quick look at the circuit and it looks like there is a triac circuit which might be a pop suppressant. You've also got a split rail power supply and the two smoothing caps may be charging up at different rates giving a DC offset on switch on so there may be a problem there, i've had to replace these before. You'd see the cones jump and then slowly return if that was the case. It could be all sorts of other things including the mains switch. The mains switch would probably have some signs of arcing if it was that and yes you can use a capacitor/resistor circuit to supress that. I wouldn't advise anyone to start playing round with mains or the power supply caps unless they really know what they are doing. The power supply caps can store a significant charge for quite a long time and 150V DC is going to give you a much more significant shock than the mains. There is a small risk of death. Unless you can read the circuit diagram and are confident working with potentially lethal voltages your choice is simple either put up with turning the amp down on switch on and then connecting the speaker or take the amp to a trusted repairer. 2 Quote Link to comment Share on other sites More sharing options...
petetexas Posted February 10 Author Share Posted February 10 Thank you all for your input . Pete 1 Quote Link to comment Share on other sites More sharing options...
nekomatic Posted February 10 Share Posted February 10 What @Phil Starr said, but just for reference since this was discussed: any capacitor you do connect across the mains should be a ‘Class X’ type, which is rated for that purpose, not just any old cap. You can get the cap+resistor combo in one package, sometimes called a ‘snubber’, e.g. https://cpc.farnell.com/ampohm-wound-products/fe-sp-cr23-100-100/contact-suppressor-0-1uf-100r/dp/FT00711 2 Quote Link to comment Share on other sites More sharing options...
petetexas Posted February 11 Author Share Posted February 11 I have ordered one of these............ 1 Quote Link to comment Share on other sites More sharing options...
petetexas Posted February 14 Author Share Posted February 14 Hi , Put the above suppressor across the switch contacts ............ Switch on is quieter , and switch off is almost silent ! Pete 2 Quote Link to comment Share on other sites More sharing options...
petetexas Posted March 12 Author Share Posted March 12 (edited) Is there any milage in putting a soft start circuit ( the type used for electric drills , circular saws etc , that limits the initial switch on voltage , and gradually increases it ) in the switch on cables in the amp ? Dont know if this can be done , not enough knowledge , just a suggestion . Edited March 12 by petetexas Quote Link to comment Share on other sites More sharing options...
Bigguy2017 Posted March 12 Share Posted March 12 2 hours ago, petetexas said: Is there any milage in putting a soft start circuit ( the type used for electric drills , circular saws etc , that limits the initial switch on voltage , and gradually increases it ) in the switch on cables in the amp ? Dont know if this can be done , not enough knowledge , just a suggestion . An NTC Thermistor in the supply line will do that Quote Link to comment Share on other sites More sharing options...
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