LSi25 plate amp question

When I’m running my LSi 25s, the plate amp gets really, REALLY hot, even when it is just switched to on, or I am using it at low volumes. Is this normal? No other plate amplifier that I have dealt with gets this hot, at least as far as I can remember. I will give you guys a exact temperature later, but I’d say it’s probably around 100-110* F. The other amp doesn’t work so I can’t compare it to what is happening to this one. It seems like it would be bad for the amplifier to be this hot all the time, but maybe I’m wrong. Also, this is the temperature on the heat sink, not in the amplifier. It usually is still slightly warm when it is set to auto and it has turned itself off, however when I switch it to off, it becomes cold again (obviously, if it’s doing nothing, it’s not getting hot). Anyway, is this normal, and if not, is it something I can fix?

Thanks again for your help,
Micah
Not Tom, or Trey, or Jim
Main setup:
Speakers are one of three, Mission Freedom 770 IV’s, Polk LSi25’s, or Polk SDA-CRS (stock XO, SL2000’s, Blade/Blade model). Electronics are as follows: for the LSi’s and SDA’s, a Technics SU-v75 acting as a phono preamp, into a Yamaha RX-v665, into a Crown XLi800 power amplifier. For the Missions, I have a Lafayette LR-1100. Turntable is a Technics SL-3200, with a Shure M97xE. Cables are generic/soon to be replaced garbage.
An old post I found on AK, from 2013.
I've always thought the goal of high end audio was not to have your neighbors bang on the wall and say, 'Turn that darn music down' but to have your neighbors bang on the wall and say, 'Tell your friends to go home and you can practice later this week'.

Comments

  • tonybtonyb Posts: 29,544
    Doesn't seem all that hot to me, but the speakers are old so I'd imagine sooner rather than later you'll be needing new ones or rebuilding the old, if your that handy.

    Make sure the rear of the speaker isn't up against a wall also, give it some room to breath.
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  • KennethSwaugerKennethSwauger Moderator Posts: 6,580
    Hello Micah,
    It is possible the amp's bias is set too high causing the higher temperature. This is similar to having a car's engine idling too high. Usually as long as you can place your hand on the input plate without discomfort there's no case for concern. On most amps there's an adjustment potentiometer and a place to measure in setting the bias. Since you have one amp not working you might contact Polk to see what service is available. They are at 1-800-377-7655 assuming you live in the U.S.
    "And the house you live in will never fall down
    If you pity the stranger who stands at your gate" G.Lightfoot
  • mlistens03mlistens03 Posts: 1,788
    I have contacted Polk regarding the broken amp, and I am going to send it to them (or possibly a 3rd party person, but probably Polk,) to get it fixed, I just haven’t gotten around to it yet. As for the other amp, how do I adjust its bias? Is there a switch inside? And how do I measure it?

    Thanks again for your help,
    Micah
    Not Tom, or Trey, or Jim
    Main setup:
    Speakers are one of three, Mission Freedom 770 IV’s, Polk LSi25’s, or Polk SDA-CRS (stock XO, SL2000’s, Blade/Blade model). Electronics are as follows: for the LSi’s and SDA’s, a Technics SU-v75 acting as a phono preamp, into a Yamaha RX-v665, into a Crown XLi800 power amplifier. For the Missions, I have a Lafayette LR-1100. Turntable is a Technics SL-3200, with a Shure M97xE. Cables are generic/soon to be replaced garbage.
    An old post I found on AK, from 2013.
    I've always thought the goal of high end audio was not to have your neighbors bang on the wall and say, 'Turn that darn music down' but to have your neighbors bang on the wall and say, 'Tell your friends to go home and you can practice later this week'.
  • mlistens03mlistens03 Posts: 1,788
    edited February 22
    Tony, it’s not up against the wall, The heat sink is about 4-5 inches from the wall, and the speaker is pointing towards me (probably around 75 degree angle, but I have no idea, that is just a rough estimate).
    Not Tom, or Trey, or Jim
    Main setup:
    Speakers are one of three, Mission Freedom 770 IV’s, Polk LSi25’s, or Polk SDA-CRS (stock XO, SL2000’s, Blade/Blade model). Electronics are as follows: for the LSi’s and SDA’s, a Technics SU-v75 acting as a phono preamp, into a Yamaha RX-v665, into a Crown XLi800 power amplifier. For the Missions, I have a Lafayette LR-1100. Turntable is a Technics SL-3200, with a Shure M97xE. Cables are generic/soon to be replaced garbage.
    An old post I found on AK, from 2013.
    I've always thought the goal of high end audio was not to have your neighbors bang on the wall and say, 'Turn that darn music down' but to have your neighbors bang on the wall and say, 'Tell your friends to go home and you can practice later this week'.
  • KennethSwaugerKennethSwauger Moderator Posts: 6,580
    "how do I adjust its bias? Is there a switch inside? And how do I measure it?"

    Let me contact my friend, at Polk, and see what he knows.
    "And the house you live in will never fall down
    If you pity the stranger who stands at your gate" G.Lightfoot
  • KennethSwaugerKennethSwauger Moderator Posts: 6,580
    They are checking to see.
    "And the house you live in will never fall down
    If you pity the stranger who stands at your gate" G.Lightfoot
  • mlistens03mlistens03 Posts: 1,788
    Ok, thanks!
    Not Tom, or Trey, or Jim
    Main setup:
    Speakers are one of three, Mission Freedom 770 IV’s, Polk LSi25’s, or Polk SDA-CRS (stock XO, SL2000’s, Blade/Blade model). Electronics are as follows: for the LSi’s and SDA’s, a Technics SU-v75 acting as a phono preamp, into a Yamaha RX-v665, into a Crown XLi800 power amplifier. For the Missions, I have a Lafayette LR-1100. Turntable is a Technics SL-3200, with a Shure M97xE. Cables are generic/soon to be replaced garbage.
    An old post I found on AK, from 2013.
    I've always thought the goal of high end audio was not to have your neighbors bang on the wall and say, 'Turn that darn music down' but to have your neighbors bang on the wall and say, 'Tell your friends to go home and you can practice later this week'.
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