WTB Amp-Head Dual Probe Bias Tester

Discussion in 'Amp Tech Center' started by Josey, Sep 18, 2015.

  1. Josey

    Josey Tele-Meister

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    Sorry if this is the wrong place to post, but I'm looking to purchase someone's Amp-Head Dual Probe Bias Tester or something equivalent.

    I contacted Amp-Head and they said they don't have any in stock and don't have any plans to build and sell anymore either.

    I'm looking for something with the toggle switch to easily check back and forth from current to plate voltage.

    If you have one laying around you don't use or know of another brand that won't run me more than $100 bucks or even have a link with plans on how to build one, then please shoot it my way. Thanks.
     
  2. milocj

    milocj Friend of Leo's Ad Free Member

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    I don't have one for sale, but I don't think the Weber Bias-Rite two head version is a lot more than $100. They've had impeccable customer service the one time I had a problem with one of the three I have owned, and that one was the one I had bought used, which I told them.
     
  3. Josey

    Josey Tele-Meister

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    I looked into Weber but I read where the parts they used for their bias tester kept getting fried. From what I read it wasn't necessarily operator error but merely breaking down from use. Have they fixed these issues with their testers?
     
  4. milocj

    milocj Friend of Leo's Ad Free Member

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    I don't know if it was the parts being bad or how they were being used. I do know that they accidentally got a batch of counterfeit capacitors several years ago, and even though the one of three I've owned didn't burn a capacitor, it was from that time. Mine smoked the 1 ohm resistor in the bias head that converts the reading from amperage to volts.

    The main difference I've noticed is that last time I looked they had added a warning to not play the amp while using the unit which would show the peaks and valleys of the current draw instead of the average which is what you set a fixed bias amp to. This would draw the full power of the amp through the resistor and if it wasn't a large enough capacity (big resistor in little space) it would burn out if abused.

    My first one was the old style that looked sort of like a home made box. I never had any problems with that one and gave it to a friend because I had picked up one of the newer style. When I owned the old one I had actually asked Ted senior if it was alright to play through the amp while setting the bias and he told me it was.

    I don't recall doing that with the one that broke, but that was the one from the time that it turned out they received the counterfeit capacitors. I sent an email asking them how to separate the head components so I could fix it and they said they preferred I send it to them. They ended up replacing either the whole unit or the majority of it at only the shipping cost to them.

    After that I've not had problems. I don't know whether they got bad parts, changed to a part that didn't have a high enough safety margin if somebody strummed while testing bias, or if the parts were just cheap.

    I just know that I haven't had any other problems and the first one (old style) that I gave away is still going strong.
     
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