Fan installation in Hayseed 30

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Kurzman, Feb 14, 2015.

  1. Kurzman

    Kurzman Supporting Member

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    I velcroed in a little 3" computer type fan in the back of my Hayseed 30 head. It blows right across the EL84 and the needless to say, the amp runs MUCH cooler.

    Is there any tech reason that I shouldn't do this? Would it be better to have the fan output pointed away from the tubes?

    This is probably a stupid question but I just want to be sure as I really love this amp.

    Thanks in advance.
     
  2. BluntForceTrauma

    BluntForceTrauma Member

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    I would have the fan blowing heat OUT of the chassis, not drawing air in.
     
  3. ACETECH

    ACETECH Member

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    Fans last longer if it is moving cool air. Blowing air on the tubes will make the tubes last longer. In my humble opinion, removing hot air is less efficient than blowing cool air. However the amp would need a little more cleaning to remove dust. I first saw amps with fans blowing on the tubes in 1964.
    Good luck.
     
  4. teefus

    teefus Silver Supporting Member

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    pretty sure rob doesn't recommend adding fans to his amps. i don't think he deems it necessary.
     
  5. Kurzman

    Kurzman Supporting Member

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    I've only played the amp in the garage but after about a 2.5 hour practice the stand by and power switches were pretty hot. I could still hold on to them but pretty hot and seeing as these are on the outside, I figured it was probably really hot inside the cab.

    I didn't wire the fan in. I just have it plugged in separately.

    I appreciate the info.
     
  6. Kurzman

    Kurzman Supporting Member

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    Sorry to dredge this old thread up.

    I was thinking about trying to make this a neater install than having another power cord hanging out of the back of the amp (the one connected to the fan).

    If I connected two wires from the pilot lamp terminals to the 12v fan would it work okay except for running at half speed (which I'm sure would be good enough to cool the power tubes a bit)? Would this cause any problems with the heater voltage?

    Thanks in advance.
     
  7. Structo

    Structo Member

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    Measure the voltage of the heater circuit with the fan on.

    If it is at least 6vdc then you are good to go.

    Another thought is if the fan blows on the hot tubes unevenly, it could cause problems.

    The switches getting hot tells me that the power transformer is likely at it's limit.

    I bought a cheap laser thermometer pistol ($12) so I can see how hot things actually are.
     
  8. donnyjaguar

    donnyjaguar Member

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    I have the answer. Make a voltage doubler from your filament winding. That will give you 12Vdc to get your fan going full speed. The components you'll need are two 1N4004 diodes and two 1,000uF/16V electrolytics.
    [​IMG]
     
  9. Joe F

    Joe F Member

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    I realize that youre looking to run the fan off the amp electrical - but i mounted a fan on two L brackets and clear plastidip'd the brackets. You just slide the brackets under the amp (head) and the fan blows into the back of the amp.

    For recording, if the amp is by the mic'd speaker the fan gets picked up so i prefer to keep the fan and the amp separate so i can ditch the fan.

    Less hassle when the fan dies eventually as well.
     
    Last edited: Dec 25, 2015
    teleman1 likes this.

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