I have a large high end subwoofer based on a 15" driver in a ported design. The amplifier is broken but I have better amplifiers from other subs so will substitute one of those into it.
the replacement amplifier is a slightly different size to the original.
The original amplifier sat in a plastic box (effectively a shallow, square bucket) which kept the amplifier sealed away from pressure changes/vibrations inside the main enclosure.
The replacement amplifier will not fit in this box.
How important is it to seal the amplifier from the subwoofer itself? Will the amplifier be damaged if it is not sealed?
I can make a new internal box to seal the amplifier away. The advantage will be that the volumetric diaplacement will be similar, the disadvantage will be that it will become very difficult to access the bass driver from the rear. Also it will take time to build.
the replacement amplifier is a slightly different size to the original.
The original amplifier sat in a plastic box (effectively a shallow, square bucket) which kept the amplifier sealed away from pressure changes/vibrations inside the main enclosure.
The replacement amplifier will not fit in this box.
How important is it to seal the amplifier from the subwoofer itself? Will the amplifier be damaged if it is not sealed?
I can make a new internal box to seal the amplifier away. The advantage will be that the volumetric diaplacement will be similar, the disadvantage will be that it will become very difficult to access the bass driver from the rear. Also it will take time to build.
1) As long as the amplifier provides an airtight seal over the hole it fits in, it is unimportant to seal it from the sub.
2) No, sound waves surround an amplifier whether inside or outside the enclosure.
Make sure the manufacturer used enough Hot glue, most use some sort of adhesive to hold down all loose "things". If your enclosure makes enough air velocity to create a breeze (most pro subs do) then you will want to make sure it doesn't have wires buzzing on you. This should however slightly help with cooling 🙂.
So there's a deffinate consensus that the vibrations present with an non sealed vs sealed amplifier enclosure will provide no risk to the amplifier itself then? If that's the case I won't bother sealing it, too much work 😉
Vibration can fatigue solder connections over the long haul. Years ago Yamaha P2250 and 150 series pro amps were manufactured with poor quality solder which was wave soldered to thin. When these breaks occured the amps typically would emit a very powerful elephant trumpet. Very bad when a NBA game is being played. Solution was to replace outputs (if neccessary), but the major PITA was complete dissasembly and rework every solder connection, reassemble. That should take a few hours 😉
I have put the 470uf's across the rail now.
But when I build the next one I will put it on the scope before I insert the 470uf's.
But when I build the next one I will put it on the scope before I insert the 470uf's.
I am sorry I have to dig out this thread. So finally from the electrical point of view is it ok to place amplifier in common enclosure with loudspeaker?
This is small sealed subwoofer with class D amplifier working up to 70 Hz. Maximum peak to peak pressure variation due to excursion will reach 1/15 th of atmospheric pressure. Amplifier is mounted to large 5 mm aluminium plate which will have contact with the outside for proper cooling. All elements on the PCB are secured with silicone. Most part of the internal volume will be filled with damping material, there will be sheet of steel over amplifier to prevent it from being jammed with damping material.
This is small sealed subwoofer with class D amplifier working up to 70 Hz. Maximum peak to peak pressure variation due to excursion will reach 1/15 th of atmospheric pressure. Amplifier is mounted to large 5 mm aluminium plate which will have contact with the outside for proper cooling. All elements on the PCB are secured with silicone. Most part of the internal volume will be filled with damping material, there will be sheet of steel over amplifier to prevent it from being jammed with damping material.
The only two possible adverse conditions of doing so:
1. Possible vibrations could induce a piezoelectric effect on capacitors. Same is true with passive crossovers, but to a lesser effect.
2. Vibrations could cause poor solder connections to weaken and or break and anything loosely socketed could cause partial or full disconnection.
Allow me to add that atm I'm building a 3.5way active system using two MiniDSP 2x4HD's that are built into the speakers base, which also houses two stereo 1U rackmount Class D amps. Amps have XLR inputs and Speakon output connections, typical pro equipment stuff, not hifi. The sub part incorporates dual pairs of 6.5" subs in a transmissionline force cancellation configuration, front and rear pairs are controlled independently. No speaker wires exposed, each speaker is fed a single 24/192 Toslink, 25' each.
1. Possible vibrations could induce a piezoelectric effect on capacitors. Same is true with passive crossovers, but to a lesser effect.
2. Vibrations could cause poor solder connections to weaken and or break and anything loosely socketed could cause partial or full disconnection.
Allow me to add that atm I'm building a 3.5way active system using two MiniDSP 2x4HD's that are built into the speakers base, which also houses two stereo 1U rackmount Class D amps. Amps have XLR inputs and Speakon output connections, typical pro equipment stuff, not hifi. The sub part incorporates dual pairs of 6.5" subs in a transmissionline force cancellation configuration, front and rear pairs are controlled independently. No speaker wires exposed, each speaker is fed a single 24/192 Toslink, 25' each.
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