How hot is too hot?

[Cornman]

Using the built in shelfing shown in photo, do you think I could replace my solid state mac with a pair of VRD's or mac 275? Or would it be too hot? Room temperature is kept at about 73F. The cary tube pre-amp seen in photo seems to run at or just below 100F measured just an inch above the hottest tube. Cooler will extend the life of course but at what point do you begin to hasten the demise?

Cornman

[CECAA850]

If you had a heat issue to deal with, what's preventing you from putting a slot at the rear of all the shelves to allow the heat to rise? Just an observation, I don't have an answer to your question!!

[CaptnBob]

Both the 275 and the VRDs are taller than the 2505 in the picture, so you've got a bit less room for ventilation. As mentioned above, cutting some slots in the upper shelf might help.

My big concern is weight. I don't know about the VRDs, but the 275 is well over seventy pounds. Are you sure the shelf can support that much?

Bob "still has the scars from catching a Teac 4010GSL when the bookcase it was in energetically disassembled" A.

[cjgeraci]

Bob, the VRDs are over 60 pounds. Now, I can also personally vouch for that. (You have an open invitation to hear the "revised" system).

My concerns are weight and heating up (and bubbling) the surrounding paint moreso than damage to the amps. But, if the shelf will support it, I'd say go for it.......

But, I would put them on the top shelf instead of the second one. Otherwise, that top shelf is going to be glowing after awhile.

Carl.

[NOSValves]

Are far as heat you will have no real issue with VRD's on that shelf as long as you keep them placed toward the front of the rack. All the heat producing tubes are on the front portion of the amps so the heat will just naturally rise out the front of your rack. In an ideal world it would be nice if the back was open also but I'm not worried that heat will be an issue. Not sure if the shelving will have issue with the weight of the amps or not depends on how rigid it is you could just add a support board along the front lower edge running the width if the weight ended up being an issue.

Craig

[cjgeraci]

See, you should buy a pair of VRDs.

Carl.

[Allan Songer]

Or one of the new NOS Valves Stereo amps running 350B tubes! SWEEEEET!

[Travis In Austin]

Using the built in shelfing shown in photo, do you think I could replace my solid state mac with a pair of VRD's or mac 275? Or would it be too hot? Room temperature is kept at about 73F. The cary tube pre-amp seen in photo seems to run at or just below 100F measured just an inch above the hottest tube. Cooler will extend the life of course but at what point do you begin to hasten the demise?

Cornman

Cornman,

I can bring my VRD's over and put them on that shelf, you can have a listen and see what you think about the "heat" or lack thereof. However, you better test that self for 60 lbs before I come over because I don't know what I would do if the thing came crashing down, not to mention what damage it would do to your stuff underneath. What type of floor is at the bottom of those shelves? You might want to consider taking the CD's and putting them on higher shelves, putting the AMPS on amp stands on the floor, then running the ICs from the VRD's up to the preamp which would also go on a lower shelf.

Travis

[thebes]

Those are adjustable shelves with the standard rail and metal pins. Lose a rack of cd's and the totchkies (sp) on top. Put one VRD per shelf and have a true wall of sound (double the eye-candy factor). Try for at least 3" clearance between top of tubes.

Just be sure that all screw holes on the rails are filled and that they go directly into studs and make sure the metal supports are firmly in place and level after you shift the shelves.

Actually lose all of the cd shelving. Buy a couple of wooden wine cases (about $5 a case, more if wine still in box) at your local liquor emporium and mount them on the wall of the nearest closet and use that for your cd's. These are perfect size for cd's and since they are edge on on it's easy to read the title instead of flipping through them to get to what you want. If the closet door opens instead of slides, you can mount them on the door.

[NOSValves]

Thebes,

I'm kind of dissapointed I was sure when I seen you had posted to this thread that some mention of the twins would be found in your post in reference to heat........ Man are you getting old on me?

Craig

[mas]

The attached ventilation cheat sheet will give you everything you need to handle just about any configuration.

[tigerwoodKhorns]

Go to the home depot and get some 1" x 3/4" wood. Put is along the sides that hold teh shelf and put long drywal screws in the hold it. Put three strips along teh bottom of the shelf. You want the 1" portion going up and down and the 3/4" portion vertical.

I added grante shelves to a similar cabinet and used 1/4" steel angle iron. Welded up some rectangles and securred it with drywall screws. Very strong and supports the granite with no problem.

[Spongeworthy]

I think you have some good advice on the VRDs or NOS Valves Stereo Amp. I have been running VRDs for a few weeks with several preamps and they are some sweet, sweet amps. They shine with everything I throw at them. Big fan.

[WMcD]

Nice work btw.

I'd agree that adjusting the shelf spacing to give a bit more headroom can help a bit with convection currents. You might cut an inch or so off the shelf at the back (or drill a number of one-inch holes) so that there is chimney effect with airflow up though the back, across the semibox formed by the shelf, and then out the front at the top.

Overall, I think you're okay. This is based on my experience with tube equipment as a young lad. Consider that TV sets were almost completely enclosed with only a few vents and the CRT and the tubes put out a lot of heat . .. making the interior very warm. There there were the myriad of transmitters, receivers, and the like which were also almost totally enclosed.

Also, it is true that heat is the enemy of electronics. It is widely thought that heat cycles are the worst of it. And transistors are particularly sensitive. Tubes are going to be hot even if not enclosed. So that leaves the caps, resistors, inductors and the like which might be in a chassis.

It seems to me that we have to look at the design of amp contemplated with the tubes exposed to air, and the rest of the components in a metal chassis below. (Isn't that correct?) My thought is that all components except the tubes are somewhat insulated from heat in the chassis. So their life should not be affected too much. Your question, if I understand.

There is something to consider about placement on the shelves. The tube components should be at the top so that their convection currents do not heat up the solid state components like the CD player.

My guess is that you could set things up and then place a thermometer over the tubes just at the overhanging self. If it is 120 F degrees or less, that might be a decent marker. It is desert type heat and about the limit for human tolerance. On the other hand, this is probably about what one finds in an attic or a closed car on a hot day and is okay for paint, wiring, etc. It should not be a fire hazard.

While somewhat flippant, let me ask whether anyone has set up a pinwheel or Sterling engine over their tube amps to monitor heat and watch things go around? Smile.

Gil

[mas]

I frankly don't understand why the class A and tube folks haven't implemented a co-generation program. Aren't there tax breaks for this?

[thebes]

Thebes,

I'm kind of dissapointed I was sure when I seen you had posted to this thread that some mention of the twins would be found in your post in reference to heat........ Man are you getting old on me?

Craig

Not to old just sore.

I've had very recent experience with the downfalls (sic) of shelving. I'm thinking of it as the "Great Shelving Escapade".

It started innocently enough. Numerous ongoing requests from Forum members for pictures of The Twins had been passed along by me to the gals usually to be greeted with various expressions of disdain or outright disgust.

Employing various angles and stratagems in this fruitless endeavor I had finally worn them down to a grudging acceptance of an inevitability.

I finally hit on the ultimate ploy, the Queen of England's impending visit.

The Twins have something approaching a fetish for dressing up in various costumes, the latest in fashion, haute couture and anything associated with massive outlays of my cash at the various local fashion emporiums. There was to be a lottery to choose 100 commoners to meet the Queen down in Richmond and I conned (er, persuaded) them that an appropriate patriotic picture would enhance their chances for winning.

Since the English are known for their eccentricity I soon had Tawny decked out in in tight shorts, moderate heels accenting her lovely legs and wearing a tee-shirt showing the British Lion. Tickles had soccer cleats, thigh-high white cotton socks, black shorts and a rugby JJersey one of her Uncles from Bristol had given her.

Perched on top of their heads were some garish bonnets very similar to what the Queen wears.

I convinced them that they would look fabulous with their legs demurely crossed sitting atop the Cornwalls but the camera angle was all wrong. Eyeing the shelving behind the speakers I suggested we drape a flag of England on the wall, and have their very fashionable 105 lbs apiece perched up there. We would crown the whole tableu with them making a demure "Princess Di-Wave".

Well up they went.

And

Down they went.

It seems my calculations were in error. As it now stands (sic) I'm perched in some sort of cage-likedevice over the glowing tubes of my Bogen monoblocks. They've refined my calculation's over the hours by gradually lowering and raising me above the tubes. Yup, I would say that 3" is just about he right clearance.

[thebes]

double

[NOSValves]

Thebes,

Man what a relief I was worried about you.......

[Cornman]

So great, sounds like this can definitely be done. Reinforcing the shelfing, adequate spacing, and perhaps adding some ventilation, with holes through the back wall that go into a closet area. Had even considered fans but was trying to avoid the harmonic possibilities.

Gil, I'm not just smiling, I'm still grinning from ear to ear over your pinwheel question - and I thought I was the only one that had such silly notions.

Travis, thanks for the gracious offer to bring over the VRDs - nothing better than auditioning in your own environment and system, and no we will not put them on the shelves, but out on a safe table. For I could not live with the crash either.

Alen, we are still waiting with great anticipation for your review of the NOS 350B amp. And MAS - I agree, we tubies need a tax break or some kind of relief.

Thebes, you lucky dog, if only I had some twins to test my shelves.

Thanks again to all,

Cornman