Quick q's about the MCM plate amp

[GhettoSQ]

Hey everybody,
thanks to all who helped in the past with my ported isobaric monster. It sounds good but I've always noticed a bit of audible hum and some minor crackling sound from the amp. The hum improved when I switched outlets, leading me to believe it's a ground issue, but a ground loop isolator actually made it far worse. As for the crackle (on top of the hum), could it be the cables? I'm just using whatever cheap cables were lying around until I get the time to make some better ones.

BTW, do you guys use the preamp in/out or speaker level?

thanks (again) in advance!

[crippledchicken]

i don't know if it applys or not but, if you have a green ground wire attached to plate amp try removing that. i had to do so on a couple of different brand plate amps i've owned.

[Cal Weldon]

I use both the line level and speaker level depending on the installation. When I build the woofer into the main cabinets, I use the speaker level so I only have to run one set of wires.

When the woofer box is separate from the satellites, I use the line level because in the back of my mind, I think the line level is a better way to go. I then run the satellites direct from the amp(s).

[GhettoSQ]

crippledchicken -- where would the ground wire run? I think I recall something like that but before I take it out I should know what to look for I was thinking it might be a bad input cap?

Cal -- I have that same idea, that the line levels should be better. Perhaps from car audio tinkering, where speaker-level inputs are generally bad, but it shouldn't matter for low freq. I may switch anyway for the highpass filter involved and so my speaker selector shuts off the whole system.

[crippledchicken]

the green ground wire will probabley be screwed to the amp plate if, it does indeed have a ground wire. my last problem was, my satellite receiver. if i unplugged audio out jacks from satellite or, just unplugged power cord for sat. hum was totally gone. so, i decided to try unhooking green ground wire which was screwed to the amp plate and have been hum free since. have had to do this to a couple different amps. good luck!

[Netlist]

Never, ever unplug the mains ground wires, they are there for a reason.
That reason is to protect YOU. Don’t let your life depend on that.
If you don’t feel confident, let someone trained in the field have a look.

/Hugo

[crippledchicken]

hi, if you are refering to the green ground wire, some people do feel that way but, on something like a plate amp, i see very silm chances of actual danger to the user as many electronic components do not even have the third ground wire. now dryers, washers, ranges, power tools, and other types of appliances only a fool, would remove the ground from those items. some people use a cheater plug instead of removing the ground wire which, does the same thing, breaking the ground wire circuit. i know of many people over the years who have found this wire on plate amps and other audio components to be more of a problem than a safety factor but, if removing gives no benefit, by all means replace it. the best thing i guess for anyone reading this thread if not sure, is to do searches on this forum, as well as others on this subject and see, how many people have actually been hurt, had other problems, or been killed by removing the ground on a plate amp and make their own decision based on what they find searching. i myself have done it only! if needed for many years with no issues. cheers

[pinkmouse]

It's very hard to post your results if you are dead.

[SY]

as many electronic components do not even have the third ground wire.

This is NOT safe unless the plate amp is double insulated. It assuredly will not be. Just because you ride in a car without seatbelts and you haven't died yet is no reason to recommend to others that they stop using seat belts.

[crippledchicken]

Originally posted by pinkmouse
It's very hard to post your results if you are dead.

why of course lol! not looking for debate here the man can wire his equipment however he feels safest by all means. just trying to help him solve his problem that's all! but, if anyone knows of a large list of people who have actually died from removing a ground wire off a plate amp, i would for sure, like to see it. dangerous? could be just as lots, of things involving electricity depends on the situation and the person involved. if someone has the advice they think he needs, great! but i haven't seen anyone do anything to help him so, why don't you start, and quit wasting your time bashing me lol! i just try to help when i can. good day to all!