Cooling MC275 w/ case fans

[nsgarch]

In response to many inquiries, here's my cool MC275 :yes: I use 80mm 12VDC rollerbearing case fans (Vantec SF8025L) wired parallel to a RadioShack 9VDC wall transformer. They're inaudible from 16" away. The cage stays at room temp. and even the power and output transformers are barely warm to the touch.

I may start making sets of these (just for our group) if enough people don't want to do it themselves :nono: Of course this fan system will work with any tube amp that has a cage to set them on.

 

[dshoaf]

I've done similar but having them blow up from below with the amps mounted on a screen I rigged up to make room for the fans. The biggest long-term problem I had to deal with was the buildup of dust - depending on the environmemnt you're in.

The good thing about using forced air is that you can filter it before it enters the pressurized side - usually with a filter at the input to the fan. What I'd really like to do is to build a wooden platform for each of my amps that would pass air up and, if possible, through the chassis using a sealed chamber in the platform so that I could control the dust issue better.

I also tried boxer fans blowing sideways/across the amps to maximize the airflow around the output tubes. Did this specifically with a set of MC-30s with the outputs between the 2 transformers. Same problem of dust buildup on the tubes and transformer cans.

I've not been fortunate enough to have any of the cages to experiment with.

Just my experiences. BTW, your fan setup has a really nice presentation - balanced and well dressed.

Cheers,

David

 

[thisOne]

Do these suck or blow?

(I mean this as a legitimate question...)

Also, I thought these sounded best at their optimum operating temperature. Does this mean that the amp does not sound as good (or sounds different) if it is cooler than it would normally be?

(I mean this, too as a legitimate question...)

Thanks

 

[nsgarch]

The airflow is from inside to outside.

Do these suck or blow?
(I mean this as a legitimate question...)

I understand They blow upward, drawing air thru the front of the cage as well as from under the chassis (and up thru the tube chimneys.) BTW, I feel it's better to exhaust the hot air from the device rather than to blow air at the glass tubes for obvious reasons. Also, by doing it this way, the velocity of the air entering the amp (at so many different places) is much too low to pick up any dust.

It's heat buildup that destroys equipment. So by using exaust fans, the tubes, trannies, etc. operate at the same temperature as they would without fans, except the heat they throw off is removed immediately, instead of its building and building until convection begins to remove it. And convection isn't always enough in certain locations,

The only company I know of that blows air right at the tubes is Audio Research and I can tell you from experience it's not the way to go in my opinion

 

[masterlu]

Retrofit these for Audio applications. They work great & so does the ambient temp/speed control.

https://www.marinedepot.com/ps_View...ighting_Accessories_Cooling_Fans~vendor~.html

 

[dj_AmTraX]

I like the heat that tubes produce, saves on gas heating bill.

 

[speedracer]

why not just leave the cage off ?

 

[Yamaha B-2]

Yeah.......why bother? The amp is designed to run with a cage and no forced ventilation so why add it? Not talking silicon and thermal-run-away here.

 

[chathamdad]

I have the same fan setup on my Mac1500 and my Fisher 800B. At the very least you are increasing tube life by dissipating heat. I agree that pulling air across is better than blowing air onto the tubes; it just seems like sped-up natural convection.

 

[nsgarch]

1. Besides McIntosh protecting itself from liability litigation, a couple of reasons to leave the cage in place would be little fingers:finger: and little pawsawprint: in the living environment :yes:.

2. If you really do want to use your audio amp as a space heater, adding fans is just the ticket :thmbsp:

3. Sure Yammi, they'll run without mechanical cooling, but they'll run stronger and longer with it. In my summer environment, 75 deg. F and 9% humidity aren't exactly a recipe for great convection cooling

4. Leave it to Ivan to ferret out the most expensive (even with a discount!) fans on the planet!

Tubes are pretty in the winter, like a fireplace, so I'll probably be storing the cage and fans for a few months. It's nice to have the choice :yes:

 

[Mr. Orange]

why not just leave the cage off ?

Yeah.......why bother? The amp is designed to run with a cage and no forced ventilation so why add it? Not talking silicon and thermal-run-away here.

I would tend to agree. :yes: Besides that the 275 is the only amp where you can actually see the tubes. Why would you want to run them with the cover on? This is the one design aspect I don't like about Mac tube gear, they hide the tubes. This is one reason I use a Cary because of the open style design. :thmbsp: Half the joy of running tubes is that lovely orange glow to go along with that beautiful sound.

 

[Shane]

I would tend to agree. :yes: Besides that the 275 is the only amp where you can actually see the tubes. Why would you want to run them with the cover on? This is the one design aspect I don't like about Mac tube gear, they hide the tubes. This is one reason I use a Cary because of the open style design. :thmbsp: Half the joy of running tubes is that lovely orange glow to go along with that beautiful sound.

Err, don't think so. My MC2102's have nice big windows in the front to see the tubes and I don't use the cage as it sounds better!!.

believe it or not. I would suggest to try your tube amp and see if you hear a difference with and without the cage on. me I here a bit more air, space and feeedom with the cages off.

 

[howiebrou]

Err, don't think so. My MC2102's have nice big windows in the front to see the tubes and I don't use the cage as it sounds better!!.

believe it or not. I would suggest to try your tube amp and see if you hear a difference with and without the cage on. me I here a bit more air, space and feeedom with the cages off.

You can clearly see the tubes in my Mc2000 and that is if you are lying on the floor. Standing up they are even more visible although the 275 tubes are more exposed :yes:

Nsgarch, would it be possible to install the fans under the cage :scratch2: Just that the sight of fans reminds me of PCs and not high end tube amps. Perhaps raising up the cage with an extension? :scratch2:

 

[Shane]

You are right Howie - All Mac tube amps you can clearly see the tubes.

Do you notice any difference in sound with and without the cages??

 

[howiebrou]

You are right Howie - All Mac tube amps you can clearly see the tubes.

Do you notice any difference in sound with and without the cages??

I have never even comtemplated on putting the cage on because IMO it's seriously ugly! Its still wrapped up in the box and has not seen the light of day :nono: I doubt it would improve the sound, just cause a possible deterioration.:scratch2:

howie

 

[Shane]

I have never even comtemplated on putting the cage on because IMO it's seriously ugly! Its still wrapped up in the box and has not seen the light of day :nono: I doubt it would improve the sound, just cause a possible deterioration.:scratch2:

howie

smart move and spot on Howie :thmbsp:

 

[nsgarch]

1. Well, some of you may simply not need the protection of a cage -- but don't expect your insurance to cover you if a guest burns themselves on an exposed tube.
2. Duh! Of course the amps sound better with the cage off -- and guess what? They sound even better with the cage on, and assisted cooling!
3. I don't think Mac's cages are ugly, but it wouldn't hurt to make the mesh more open so one can see the tubes and have protection. A number of products just use 'roll bars' to protect the tubes (not quite enough protection IMO) and the most expensive amps of all, WAVAC, uses a tempered glass fence around the tube area. So for a mere $150K a side, you can have your cake and eat it!

I love Howie's "amp hutch"! Although, if that's a real fireplace, you might want to have a barrier of some kind installed at the bottom of the chimney (or maybe an exhaust fan at the top :thmbsp Unfortunately there's no room under the cage top to get fans in there. But the ambient air is pretty cool on a stone hearth. Even setting a fan on the floor each side of or behind the amp, will assist the natural convection.

If I lived in a cooler climate, I'd probably run fanless (and cageless), but if you live in the desert or need the protection of a cage, you should consider using fans.

 

[Little Nellie]

You can clearly see the tubes in my Mc2000 and that is if you are lying on the floor. Standing up they are even more visible although the 275 tubes are more exposed :yes:

I think Howie found the best place for the amp. I would put a rotating rack up on top to toast some marshmellow. Perfect for the holiday.

LN

 

[howiebrou]

1. Well, some of you may simply not need the protection of a cage -- but don't expect your insurance to cover you if a guest burns themselves on an exposed tube.
I love Howie's "amp hutch"! Although, if that's a real fireplace, you might want to have a barrier of some kind installed at the bottom of the chimney (or maybe an exhaust fan at the top :thmbsp

Actually there is normally a fire grate in front of the amp for mutt protection :yes:

I have sort of blocked up the chimney as well so that St. Nicholas doesn't burn his arse on Christmas Eve

 

[nsgarch]

Actually there is normally a fire grate in front of the amp for mutt protection :yes:I have sort of blocked up the chimney as well so that St. Nicholas doesn't burn his arse on Christmas Eve

That's really sweet! It looks like you have your bases covered :yes: It's amazing how much dirt can come down chimneys though if they don't have a tight-fitting damper.