Help with fan noise

[BECOST]

Hello

I have an old carver pm-350 that a fella (with a reputable outfit) did some work on.
My problem:
He replaced the old fan with a new one and wired it so it runs perpetually.
I didn't feel like "locking horns" with anyone that day and so I took the amp on home.
My question:
How simple (indeed, how) is it for me to put in a quieter fan - especially if it's going to run all the time - or even reverse modification so it only runs when temp demands it?

Thanks for any help

 

[sKiZo]

What did he use ... standard computer type muffin fan? If so, you can get all different sizes that have a thermal switch built in so they can either be set up as variable speed or just kick on when needed.

Also looks like plenty of room on the back panel to cut a hole for mounting. Little more work, but less resistance = less noise. Larger fans tend to be quieter as well, and mounting a bigger one horizontally will move a lot of air as well.

My last HTPC was particularly noise, so I went with the nuclear option ... cut ventilation holes in the top of the case and dropped a laptop cooler on top ... bit overkill for you I imagine ... <G>

 

[whoaru99]

Hello

I have an old carver pm-350 that a fella (with a reputable outfit) did some work on.
My problem:
He replaced the old fan with a new one and wired it so it runs perpetually.
I didn't feel like "locking horns" with anyone that day and so I took the amp on home.
My question:
How simple (indeed, how) is it for me to put in a quieter fan - especially if it's going to run all the time - or even reverse modification so it only runs when temp demands it?

Thanks for any help

I replaced the fans in the QSC amps I use in my HT/main system. Ordered some Panaflo fans from Digikey. The originals were the high volume/high velocity fans but they are also available in medium and low. I put in the low version. With a stack of 4 of these amps I can't hear any fan noise at all beyond one or two feet. That's with nothing playing, just at ambient noise level.

 

[elnaldo]

Down here, a guy sells an "intelli fan" board, that manages the fan while monitoring temperature and sound levels, so it tries to speed up the fan when the music plays louder, and stop on the quiet passages. Of course, temperature overrides this, so in case the temp goes too high, it will run at full speed regardless of the music level.

I'm sure it's a chinese board, so you can search the web for this. I'll try to find it and link a pict to the board.

 

[sKiZo]

Wonder if I can get one of those that will turn off my furnace and aquarium as well? <G>

Sounds interesting ... nothing worse than working hard on getting a low noise floor on your music, then having some silly fan kick on at the least appropriate times ...

 

[N8Nagel]

first of all go ahead and crack it open so we can see what the fan is

if it is a standard PC type fan, I've had good luck quieting stuff down with Noctua fans. I have used them on several Tripp-Lite UPS units to make living room friendly power conditioners for cheap, with a thermostatic fan control "Noise Magic NMT-3" from Frozen CPU.

Not familiar with the original Carver design is why I am asking these questions. I may be leading you down the whole wrong path...

 

[whoaru99]

A simple mod to a lower velocity fan is good place to start. No need for unnecessarily complex solutions out of the hole.

Edit: From a picture I saw, the fan looks like a hobby motor and open fan blade mounted to the board.

Looks like there might be room to install a "muffin" fan instead.

 

[savatage1973]

Carver PM series amps use an AC powered fan that will run variable speed during normal operation. Under overload or overdriven conditions they will scream like a jet taking off. And yes, they look like a little hobby motor with a plastic blade on the end, bolted to the board. Typical computer fans are DC and do run much quieter, and there are mods to do the conversion over on the Carver forums websites.

 

[Bratwurst7s]

I've had good luck quieting stuff down with Noctua fans.

+1 on the Noctua fans. Quiet and good quality, fluid bearings also, last a long time.

Cheers,
James

 

[elnaldo]

Wonder if I can get one of those that will turn off my furnace and aquarium as well? <G>

Sounds interesting ... nothing worse than working hard on getting a low noise floor on your music, then having some silly fan kick on at the least appropriate times ...

This is a pict from the auction site where it's published (NO AFFILIATION)

http://mla-s1-p.mlstatic.com/modulo...2-x-100-w-rms-5120-MLA4183451445_042013-F.jpg

I can't find info on international sites, perhaps is a local development... I'll ask the seller. Seems interesting...
It can manage 2 fans, monitoring temperature and signal level. Under 60ºC, it stays off, and start when it reachs more than 60º, moving the fan proportionally to the sound level. In case the temp keeps raising, at 80ºC the fans start to rotate at fast speed (not proportional to sound level), but only if some music is playing, stopping on low level passages. In case of temp going up to 95ºC, it disconnects the speakers, forcing the amp to work without load. INFO PROVIDED AT THE SITE (NO AFFILIATION)

 

[elnaldo]

The seller said it's optimized for the amplifier he sells, and there isn't any adjustment point to adapt it to another circuit... But I leave this "idea" to some DIY tech... a circuit that monitors temperature and signal level, moving a fan...