Hi - newb here!
I have a weird problem with a pair of eBay special monoblocks I bought a couple of years back. They are silver shoebox cases using IRS2092 and IRFB4227 boards of a type I suspect folk are familiar with.
These amps have relays for activation / output, and these relays happily click and beautiful sound comes out of my esoteric Vienna Acoustics Beethoven speakers - provided I leave the case off each amp 😕
They have been like this since I got them, I had a case open to return them to the seller but the logistics of returning them to an address in the far east I can't write on a box accurately and pressures of work got in the way.
OFC for some time I just ran the amps in my rack in the study with the lid off, but enter Jackson, my wonderful two year old boy - he just loves to post CDs and anything else he can find into the open cases, in addition to terrifying me by putting his fingers in there when I'm not paying full attention (swear the child is going to be a Ninja).
tl;dr amps of an otherwise popular reference design won't activate the output relay with the lids on, is there a way to fix / diagnose this?
I have a weird problem with a pair of eBay special monoblocks I bought a couple of years back. They are silver shoebox cases using IRS2092 and IRFB4227 boards of a type I suspect folk are familiar with.
These amps have relays for activation / output, and these relays happily click and beautiful sound comes out of my esoteric Vienna Acoustics Beethoven speakers - provided I leave the case off each amp 😕
They have been like this since I got them, I had a case open to return them to the seller but the logistics of returning them to an address in the far east I can't write on a box accurately and pressures of work got in the way.
OFC for some time I just ran the amps in my rack in the study with the lid off, but enter Jackson, my wonderful two year old boy - he just loves to post CDs and anything else he can find into the open cases, in addition to terrifying me by putting his fingers in there when I'm not paying full attention (swear the child is going to be a Ninja).
tl;dr amps of an otherwise popular reference design won't activate the output relay with the lids on, is there a way to fix / diagnose this?
It's likely you create a ground short with the case. That often happens when the input and/or output plugs are connected with the ground/case. Especially the outputs have to be isolated (yes, the - too!). Ground loops with multiple ground connections should be avoided anyway.
One problem with metal cases can be the toroidal transformer.
If the bolt touches top and bottom of case it creates a shorted turn which messes up power supply.
If the bolt touches top and bottom of case it creates a shorted turn which messes up power supply.
Might as well use their pics 🙂 Finished 1000W mono Hifi Class D Audio power amplifier IRS2092 +IRFB4227 amp | eBay
Maybe a pcb mounting bolt or spacer is shorting a board trace to ground when the case is installed.
Does it do this when you just lightly set the cover on top? Probably not.
Does it do this when you just lightly set the cover on top? Probably not.
For spacers on boards I didn't made myself I usually use nylon ones. For my own or boards which do not have ground connected to every mount hole, I use brass ones because they are more rugged and stable, sometimes a requirement for a heavier board (ie. with on board heat sink and fan, big chokes etc).
Plastic washers are sometimes really a game changer, when I buy speaker terminals or RCA plugs I always get the ones which already bring isolation spacers with it. For the ones which lack these spacers/washers there is still the possibility to mount them on an isolated plate or plywood part or get plastic washers from the hardware store.
Plastic washers are sometimes really a game changer, when I buy speaker terminals or RCA plugs I always get the ones which already bring isolation spacers with it. For the ones which lack these spacers/washers there is still the possibility to mount them on an isolated plate or plywood part or get plastic washers from the hardware store.