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Audio Rack Clearance for Tube Amp

Discussion in 'Tube Audio' started by bigjazzboy, Aug 8, 2018.

  1. bigjazzboy

    bigjazzboy New Member

    Messages:
    31
    Hey all,

    So, some background. My current setup is all spread across a large oak dresser’s top, so there’s pretty much limitless ventilation for my amp. However, I’m going to be moving out of my parents’ house to my first apartment in the near future, and the dresser won’t be coming with me. Given limited space, I think some kind of rack system would be a great help. That brings me to my question:

    Do most rack units, in y’all’s experience, provide enough clearance for a tube amp’s ventilation? To be clear—my amp would be on a lower, enclosed by a top and bottom shelf, because my turntable needs the top space to be useable.

    Of course, I know this will vary unit to unit, amp to amp, but I’m just looking for a general idea.

    Maybe, a better question—how much clearance does a tube amp generally need? A wide margin? Not much?

    In fact, please throw some suggestions for units my way. My budget—I should be clear—is somewhere in the $100-200 range.

    Thanks!
     

     

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  2. Legrace

    Legrace Active Member

    Messages:
    119
    Location:
    Ontario, Canada
    Supplemental cooling may prove necessary. I found myself in a similar situation where the acquisition of new gear forced my tube amps off a top shelf and onto lower shelves. Where they were getting scary hot. The heat was radiating off the adjacent surfaces back onto the amps causing them to get hotter and hotter. Hotter they got the more heat radiated back in a viscous cycle.

    I could tell I had to do something. What solved it for me was addition of forced cooling. Installed a 120 mm computer fan behind each amp. Put them to their lowest setting, 900 rpm I think, at which point they are noiseless. At this setting airflow output is reduced to a mere whisper, but all it took. Transformers now remain just slightly warm to the touch, even with amps being left on all day. If you do go this route seek out a quality low noise fan; good brand in this regard is Noctua.

    cooling fan_1.JPG
     
  3. 6DZ7

    6DZ7 Super Member

    Messages:
    2,143
    I think the best guidance would be to use the same volume of space most console stereos used. Most I've seen have about 12" above the power tubes overall probably 2-3 cubic ft. of space total. And have a perforated deck for upflow and perforated back cover for outflow. I wouldn't want much less than that for a cabinet.
     
  4. savatage1973

    savatage1973 Addicted Member

    Messages:
    6,008
    Location:
    NW Pennsylvania snow belt
    Forced air cooling is certainly an option--and there are lots of inexpensive computer fans out there that can run on a wall-wart and move a lot of air volume quietly.

    But, if you don't want to go that route, just make sure you have a fair amount of clearance on ALL sides of the unit in the cabinet--like 3-4" vertical, at least an inch or two per side, and an open back to the cabinet space. In an apartment, I doubt you are looking to drive it like you stole it all night long, so just a decent amount of breathing room.
     
  5. bigjazzboy

    bigjazzboy New Member

    Messages:
    31
    All very helpful ideas! I definitely appreciate them. Once I get closer to full on furniture shopping time, I’ll bear them in mind. Definitely true that I won’t be driving it all that hard, haha. Thank you!
     
  6. linuxslate

    linuxslate Member

    Messages:
    62
    Location:
    Central Florida, USA
    On a related note...

    How about using a tube amp in high ambient temperatures?

    I have a converted organ amp chassis that I would like to try to use as a DJ amp.

    An upcoming event is outdoors in Florida summer heat. The event is being held in the morning to avoid the worst of the heat of the day, but that also means the ambient temperature will be increasing as the amp runs. The amp will be in free air on a table, and under a canopy tent. There will also be a breeze off the ocean -- the event is just across A1A from the beach. The weather calls for 90 Deg F, (32C)

    Load is two (one per channel) Monitor/DJ speakers (on stands). Indoor testing seems to indicate that it has the needed horse power, but I will probably be running it at much more than room listening levels for >3 hours.

    This is meant to be a stress test. I realize that something else (transportation damage, salt air, table being knocked over...) could happen, too.

    I'm taking my regular (beach sand) rack mounted amp, and I will switch to it if for any reason the tube amp seems to be having difficulty.

    Which will have heat stroke first -- DJ or amp?
     

     

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  7. mkane

    mkane AK Subscriber Subscriber

    Messages:
    6,218
    Location:
    103 miles N. of S.F.
    Some like it hot.
     
  8. peterh

    peterh AK Subscriber Subscriber

    Messages:
    1,852
    Location:
    Gothenburg,Sweden
    Installing a tubeamp below a record player in any configuration should be avoided.
    Try to find a place "high up" ( a shelf on the wall) where the amp won't heat anything else,
    this will avoid fans that might make noice and might not always work. Passive cooling
    is better.
     
  9. Bill Ferris

    Bill Ferris Super Member

    Messages:
    1,667
    Location:
    NE. FL.
    You will find that the amplifier power requirements for outside gigs are much greater than a inside gig (no " room gain", as it`s sometimes referred), so you might find your converted organ tube amplifier easily running out of breath trying to achieve the required SPL, and stressed thermally, especially it decades old power transformer..

    If the amplifier should end up capable of performing your task, the use of a small personal desk fan blowing on it might be helpful.

    BTW. And salt air is never good for electronics, or ferrous metals, I know, as I`ve lived in FL. often near the coast, all my life(nearly 64 years), and forty + of them repairing both SS & tube audio equipment.

    Just some of my thoughts Sir. from my experience, FWIW.

    Good luck with the gig.

    Kind regards, OKB
     
    KlipschFan61 likes this.
  10. KlipschFan61

    KlipschFan61 Smooth Jazzer

    Messages:
    863
    Location:
    Manchester, NH
    I use this for all of my tube stuff. The bottom shelf is tall enough to keep the amp in the air flow.

    [​IMG]
     
    Bill Ferris likes this.
  11. punkzter

    punkzter Brad

    Messages:
    460
    Location:
    Central Pennsylvania
    Given your budget, you might consider some of the diy rack options out there. I built a Flexy for my system and am very happy with it.
     
    Last edited: Aug 10, 2018

     

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  12. savatage1973

    savatage1973 Addicted Member

    Messages:
    6,008
    Location:
    NW Pennsylvania snow belt
    All this discussion about heat (and I don't want de-rail this thread--I'll start another), but most electronic components are rated at either 85C or 105C. I will concur that proper ventilation is/should be required, but just because something (especially tubes) run a little warm is not the "end all/be all" factor. I'll propose the theory of "over-cooling" and then duck--tubes have a "heater" for a reason--just sayin'
     
    darkblue94 likes this.
  13. mkane

    mkane AK Subscriber Subscriber

    Messages:
    6,218
    Location:
    103 miles N. of S.F.
    Just make sure you get a stereo L pad or you will need 2
     
  14. E-Stat

    E-Stat AK Subscriber Subscriber

    Messages:
    6,247
    When all else fails, you might consult your owner's manual or amp manufacturer. :)

    VTL recommends 9" clearance above and to the sides.
     
    darkblue94 and Bill Ferris like this.
  15. linuxslate

    linuxslate Member

    Messages:
    62
    Location:
    Central Florida, USA
    I never did hook up the tube amp at my DJ gig.

    Set-up took longer than expected. A fight with a new canopy tent, then connecting bare-ended speaker wires (I decided to wait for the next hamfest to buy more dual banana plugs.)

    So the quickest way to get up and running was the solid state Fisher in my home-made rack case.

    It turns out Bill F was right. The event was a car show, and to get the sound 2 parking lot rows down, it took some horse power. The Fisher is rated at 100W per channel RMS, and that is old-fashioned 100W from a manufacturer that I trust. It did fine.

    I think the tube amp is relegated to "intimate" indoor events.
     
    Bill Ferris likes this.
  16. Bill Ferris

    Bill Ferris Super Member

    Messages:
    1,667
    Location:
    NE. FL.
    No surprise Sir.
    I learned the hard way back in the early seventies helping my HS friends rock bands anemic budget based underpowered PA equipment , that whatever power that you have that you you think is enough, is often usually is not "enough".

    As soon as you attempt to setup a PA/music playback system and use it outside, then minimal of 2 to 4 times amplifier power will be required to do the job without stressing the amps, speakers, or both, while trying for a clean well balanced sound that the public will appreciate, not including your reputation whilst attempting.

    Background ambient noise is a important factor too, to contend with, on top of the open space sound absorbing battle your faced with..
    Of course, your target goal loudness(SPL) determined(light background music with voice over, etc.) and what you have available in horse power(clean watts delivered ) ..
    I when I could, provided more watts than I thought I might need, but sometimes I had more output watts available than there was available from the 120 volt power circuits provided for my PA`s requirements for the gig !!
    It can be frustrating , to say the least.

    The last time I used a tube amp in a PA environment, was a club/bar for around a month @6 nights a week, at a indoors gig with a local rock band using my ARC D76A tube amp in a bi-amplified EV Eliminator system, driving the very efficient EV Mid/HF horns in 1978, with a Phase Linear 400 doing it`s stuff for the bottom end.
    In that case, even with all the South FL.(Miami UM. student partying noisy crowd, it was able to hold it`s own, with lovely smooth tube upper frequencies delivered to the crowd, and my ears, because of the low demands placed upon it`s ability, and my selectivity in it`s use.
    But that "Tuber" was rated at minimum of 75 watts RMS per channel and certified by me on my bench, to be so, and used by me in a mid to light duty PA environment..

    Take care Sir.
    I`m glad the gig went over well for you.

    Kind regards, OKB
     

     

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