Cabinet clearance for Audio Acoustics LS16 tube pre-amp?

Thinking about this more....probably too much...a couple of things occurred to me.

First, I suspect that the owner's manual for the LS16 is talking about a completely enclosed rack or cabinet when it talks about a fan being desirable if the back is closed. That seems to imply a rack/cabinet enclosed on all four sides. Maybe not. It isn't clear.

Second, looking through pictures of user's systems here at Audiogon there are a fair many that have components, including tubed, in closed back shelves. There are tons that have components in open audio racks but that are right up against a wall which is pretty much the same as a closed back and that have other components right next to them on either side.

However, my current plan, #103 (b), is to put the pre-amp on top out in the open. I've also decided to skip the false wall for cables to go behind. While it might look better it will making moving or adding components a nightmare. It would also give less rear clearance which would decrease airflow around the components.

@cleeds Thank you for the info. I do appreciate it.

"I’m not sure why you consider the information I’ve offered here “petulant” "
Maybe this just rubbed me the wrong way:

"It’s just that you don’t like the advice offered."

I did not think that it was the correct assessment or a necessary one. Again, maybe its just me.

n80

I checked out the link to the fans cleeds provided. Interesting. They do make a front exhaust model which would be the only one that would work for me ...

Same here, except I use the rear-exhaust version.

Sound level is reported as 24 dB.

My listening chair is about 14 feet from the AC Infinity unit and I never hear it.

While I’m not a major audio tweaker I do wonder what folks with power conditioners and Noise Harvesters in all their outlets would say about putting an electric motor physically on top of their pre-amp? Maybe no issues at all.

I have no issues with noise from the AC Infinity unit. I do plug it into a separate outlet, along with things like the Littllite that I use over the turntable. All my other equipment goes into a power conditioner.

I’m not sure why you consider the information I’ve offered here “petulant” but I’m providing it anyway for the possible benefit to others.

One way to get an idea of how hot it gets is make a box out of scrap wood about the size of the opening you want the preamp to fit in, set it over the preamp and run it for a few hours and see how hot it gets. That's the way I was thinking about the fan. Use a  small flush mount in the back blowing the air  outwards , get one with a thermostat I doubt it would run that often. 

I checked out the link to the fans cleeds provided. Interesting. They do make a front exhaust model which would be the only one that would work for me but it would suite the purpose.

Sound level is reported as 24 dB.

While I’m not a major audio tweaker I do wonder what folks with power conditioners and Noise Harvesters in all their outlets would say about putting an electric motor physically on top of their pre-amp? Maybe no issues at all. I just don’t have any idea.

As mentioned I could put a fan in the false wall on the back. Initially I did not think it would have enough air flow but if it blew outward (into the room) over the top of the pre that might work since I could provide entrance for upward airflow drawing cool air from the bottom of the shelf unit.

It came as an email notice.

The other problem I have with putting the pre-amp on top is that the top shelf will have to have substantial openings for all the cables to go down through and the Transparent RCA  and balanced cables have 'bricks' on them requiring even more room for cables. Such openings would be fairly ugly and as mentioned this unit is supposed to be 'part of the decor'. I like things nice looking but this is my wife's room too.

If the pre goes on top it will be sitting next to the TT.  Was hoping to have the TT as the only thing on the top. That way it would only require a small desk type grommet for the RCA and power cables.

Designing this unit is really difficult. If all I needed to do was make something to hold audio equipment in the most effective way this would not be that hard.

That it is part of a built-in system that has to fit the room and the built-in bookshelves that will go beside it adds another level.

That it has to look good and fit with the molding and trim of the room adds yet another.

At this point my plan (which changes every 10 minutes) is to have the pre-amp on the next to highest shelf. It will have nothing within 10 inches either side of it. It will have 3 inches clearance above it and it will be on blocks giving it 2 inches of clearance below it. It will have six inches clearance behind it. The shelf below it will have vent holes. There will be no heat producing components anywhere below it.

I deleted my post I noticed cleeds already linked to the company that makes the airplates used in av cabinets I was thinking could be used in a false wall. They are flush mount you can  google , airplate, to see the flush mount fans. 

djones51, yes I can build a false wall in the back and intended to from the beginning. Will put flush mount power strips there. At each shelf level there will be openings in the false wall for cables allowing some additional air flow.

And yes, I can mount a fan there. It would not have a very good exhaust path though because these low shelves will have high shelves going up either side which will preclude side vents. Vent openings on the top shelf would be unsightly and this is part of a set of bookshelves which are intended to be an attractive part of the decor. My "music" room is not really my room or entirely a music room as it doubles as a TV room and den.

The owner's manual says it recommends a fan if the cabinet has a closed back. It says this is in case of "long periods of time in hot ambient air". They do not say what they mean by "hot". We keep the house at no more than 78 degrees in the summer time. Usually 76. 

I am prepared to put the unit on top if need be. I wish I had measured operating temps while the unit was running in the summer. Then I could compare them with the unit on a shelf and move it if temps were to run higher.

Given the vagueness of the manufacturer's 'advice' (which is the whole reason I asked the question to begin with) I'm not sure. They don't give much to go on. As I've documented. "Reasonable airflow".  "An exhaust fan". 1"? 2"? 8"? CFM?

And I've gotten advice from knowledgeable people that seems less vague than the manufacturer. And reasonable too. And all without being petulant. 

n80

And for the record I've gotten conflicting advice here. Right?

Quite so. Some of it was consistent with the maunufacturer's recommendation. Some was not.  Who do you trust?

@cleeds : " I think ARC gave you all the information you or anyone would need. It’s just that you don’t like the advice offered."

Thanks for the analysis.

And for the record I've gotten conflicting advice here. Right?

n80

... Madrigal gives specific numbers in terms of spacing as do some other manufacturers. In that regard I don't see why it is unreasonable to expect that sort of info ...

I think ARC gave you all the information you or anyone would need. It's just that you don't like the advice offered.

... the last thing most of us want in our music rooms is a fan humming along and producing all sorts of noise in the power source.

Producing noise in the power source? That needn't be a problem.
If you'd like a really quiet, effective and inexpensive fan, it's tough to top one of these.

Yes, I quoted that above. Does "desirable" mean that it will burn your house down with out a fan, short out the unit irreparably, shorten tube life, roast marshmallows over it?

And again, Madrigal gives specific numbers in terms of spacing as do some other manufacturers. In that regard I don't see why it is unreasonable to expect that sort of info about a unit in which we are typically very fussy about everything else. Knowing where to put it is something most users will be confronted with.

And the last thing most of us want in our music rooms is a fan humming along and producing all sorts of noise in the power source.

n80 

I find it irritating that Audio Research did not give more specifics in regard to placement.

How much information did you expect ARC to provide? From the LS16 user manual:
"In a cabinet or rack-mount installation which has an enclosed back, an exhaust fan is desirable ..."

I can put it on the top shelf, with nothing above it. I don't want to but I can.

 I find it irritating that Audio Research did not give more specifics in regard to placement. I'd be willing to measure temps if I needed to for equipment this expensive (when new).

Again, in my design it technically would not be 'enclosed'.

donvito

All these consoles from the 50’s and 60’s that your granddaddy owned were all tube. Many are still working today with no problem! I doubt an enclosed preamp with its small tubes would be something to worry about!

Enclosing a vacuum tube component is not a good idea - even a preamp. Three or four inch clearance above the component is not sufficient, imo. Those old consoles - if you examine them carefully - typically have good accommodation for ventilation. They are not as "enclosed" as they appear at first glance.

All these consoles from the 50’s and 60’s that your granddaddy owned were all tube. Many are still working today with no problem! I doubt an enclosed preamp with its small tubes would be something to worry about!
https://www.pinterest.com/retromodradio/vintage-stereo-consoles/

Cabinet is probably not the best term for what I'm building. It is shelves. Open in the front. No doors. There will be 3-4" clearance above the unit. Vent holes below it and a good 8 inches of clear space on either side of it.

Putting tubes in a cabinet is a very bad idea.Good luck though.

The amp manual recommends 2'-3" of clearance. I'll allow for more for both components. And even though these shelves will be closed in the back and on the ends there will be lots of space around each component. The LS-16 pre amp does have grill on top and bottom so it can draw air up and through. As mentioned, the shelf below both of them will have vent holes.

The key to these devices is often in the power specs.

45 Watts. A lot more than a solid state pre, but not unreasonably.

I'd say 4" ideal, 2" minimum, since it has to have enough air to go in and out the same way.

Thanks. My shelves will be open front and there will be vent holes under the amp and pre-amp as well.

I think the pre gets great air flow sitting on top the way it is now but I'm also sure it gets a fair share of dust (and dog hair) too.

Don’t worry about it. I have all my tube gear in cabinets and never a problem. Take a look at my system. Those tube amps have been sitting there for years without any problem. And they sure get a lot hotter than your AR preamp!!

Don't know why I wrote "Audio Acoustics" in the title. It is an Audio Research of course.