Conference napalm::commusic_v1

    
    Keeping the back open should be enough, unless you are planning
    on driving the amp to >100W continuous power... 
    
    I have found that most equipment is quite happy with no fan, so
    long as you ventilate properly, and the amps are not overdriven.
    
    Most single-rack-height stuff doesn't generate a lot of heat anyway,
    I mean, how much is 7-15W dissipation? The amps, however, can get
    quite warm, but again, that's only if you are really driving them.
    
    For your studio, try it without a fan first. If you really think
    that it needs one, get a "whisper fan" and mount it in back of the
    power amp so that it blows air across the heatsinks. If you are
    gigging with the equipment, the power amps are probably in a separate
    rack anyway, and then you should put a squirrel cage fan in the
    bottom, and you still don't need anything for the fx rack.
    
    I took my whisper fan out of my stereo 8 years ago, the stereo has
    gotten bigger but it still occupies the same rack. No heat-related
    failures yet. My studio rack has an open back. The amp is not in
    it, it has it's own space. I don't overload anything in either
    location. The only heat problems come from the combined power
    dissipation of 23 separate power supplies, but I have an air
    conditioner for that.
    
    Hope this helps.
    
    /pjh

    ...and, obviously, you want to mount the equipment so that 
    none of the vents are blocked.
    
    I left an open rack space above my MKS-30 to help it keep
    it's cool. No probs yet...
    
    Edd

    
    This is kind of a side note, maybe should deserve its own, but....
    
    I just started using a preamp with a Peavey M2600 power amp.  I
    am running the power amp full blast, and one thing that concerns
    me is the DDT compression thing. Peavey says the DDT circuit engages
    just before power amp clipping, which is cool,  however, my DDT
    lights on both channels are constantly coming on, and sometimes
    staying on until I stop playing.  Question, is this dangerous to
    continue in this fashion, should I cut back the level coming out
    of the preamp and/or cut back on the power amp volumes??
    
    Buck who doesn't wanna smoke up a new power amp in ignorance.

    I've got the same circuitry in my Peavey XR-1200 board...
    
    The manual says to *expect* the lights to be on most of the time...
    
    Edd

    
    
    re .3
    
    Whats this?  First Mr. Marshall himself puts in an ad
    to sell a '71 super lead head, then he says he's using
    a Peavey????  Is nothing sacred anymore?? 
    
    ;^) ;^) ;^) ;^)
    
    ralph
     

    I had 3 SRV-2000s and an SDE-2500 mounted in the same 4 space
    rack and they get too hot to touch after an hour or two.  So much
    for the idea that single rack space non-power-amp 15 watt dissipators
    don't raise any cooling problems.  
       
    len.
    

    My _soldering iron_ is fifteen watts. 
    
    You have the equivalent of four soldering irons.
    
    And you wonder why they're too hot to touch?
    	
    	:-)
    
    	-Bill
    

    That's not really an appropriate comparison, as all fifteen watts
    are concentrated in the tip.  And I didn't say I was surprised at
    all, I said it clearly put the lie to the notion that single unit
    high non-power-amp components didn't merit concern about cooling.
    I wish you'd read what I write rather than what you can argue with.
    
    len.
    
     

	Yeah, len, people sure like to argue with you.  Maybe it's your cologne.

--mike--

    
    re: .-2 len or whomever
    
      Well, I can't speak for your equipment. Mine, however, when
    ventilated, doesn't get "too hot to touch". Must be the reason we
    have multiple opinions. 15W dissipation spread out over a small
    heatsink as opposed to a 100 in� metal plate might make a difference
    too. 
    
      Let's just say "if it gets too hot then use a fan", which, although
    it's kind of obvious, may be a proper response.
    
    /pjh_who_is_getting_sick_of_arguing.
    

    
    	But it's more fun to argue!
    
        :-)
    
    -----
    
    	On a more serious note: the heat has to go somewhere- either
    be dissipated to the surrounding air or raise the temperature of
    the matter in the rack.  
    
    	-Bill
    	

    
>    	On a more serious note: the heat has to go somewhere- either
>    be dissipated to the surrounding air or raise the temperature of
>    the matter in the rack.  
    

    That's the point. If you're ventilating properly you shouldn't have
    heat problems. Again, it might seem obvious, but if you leave the
    back open and the "hot" units separated by �" or one rack hole if
    you can, then you probably wouldn't need a fan. Otherwise, use a
    fan. I don't use one, I don't need one, I might be an exception,
    but my rack has an open back too.
    
    Caveat Emptor.
    
    /pjh

    OK, if I decide that I *do* want to add a fan, what is the best
    way of doing it?  For example, how can I avoid (if that's possible)
    the problems of a fan bringing in dust'n'dirt?  Is there some standard,
    "known-to-work-fine" location for the fan (as I asked in .0)?  Should
    the fan "blow onto" the rack, or "pull air out"?  I have no gear
    with fans, so don't know (even my Macintosh has no fan, nor any
    amp I have) ... are there racks with fan "built in"?  
    
    The cover to my LA210 at work has a fan built-in; that fan is covered
    with dust!                                                           

    		-Jim

    
    Short of installing a filter...
    
    You can install the fan in one of two basic configurations. Either
    drawing air through the box, or blowing air across the hot components.
    
    You really aren't going to avoid dust 'n dirt unless you live in
    a clean room. It's a way of life, and fans help bring more of it
    to you. A vacuum cleaner works wonders sometimes.
    
    top or bottom depends on where the heat source is. Also, if you
    are going to draw air into the unit (i.e. airflow pointing outward),
    you must seal the box so that air is drawn in only at the places
    you want it to be. You would need a more powerful fan for that also
    (= more noise). 
    
    Try Eli Heffron's in Cambridge, they used to sell lots of old rack
    fans/muffin fans/whisper fans. Many had rack-space-wide mounting
    assemblies. I dunno if he sells them anymore, but they used to be
    there.
    
    /pjh

  See also KEYBOARD mag Sept 88 for an article on racks/fans/etc.

Chad

    Having the air intake as high up as possible will generally keep
    things cleaner.   Even a few inches will help a lot.  Floor-level
    air is much dirtier than knee-level air.
    
    Note that this goes against "conventional wisdom" of heat rising;
    you have to pump the warm air downwards with the fan.
    
    An old car air filter will work wonders; my old film-drying cabinet
    used an old FIAT air filter to provide clean air (and used a muffin
    fan to pump it).  It was also a "down-pumper", it sucked the
    air thru the air filter into a box with a 300 watt light bulb (the
    heat source) and then blew it down over the hanging film. It worked 
    wonderfully. 
          
    	-Bill

    	Alot of manufacturers who make cooling or muffin fans have 
    filters available that screw on to the frame of the fan. The 
    types of filters I have seen come in both paper and foam formats.
    The foam filters can be removed and washed if they become too
    dirty, the paper filters are just replaced when needed.
    
    DonH

    
    re: .5
    
    I'm just selling my Marshall cuz you did Ralph.

    
    
    re .18
    
    Geez, I wish I had the cash for the Marshall....I've been toying
    with dumping the Boogie and my pagan ways, and looking for an
    old super lead again.  I miss that sound I had before the old
    marshall died.....