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HG Transistor input power question.

Discussion in 'Amplifiers' started by Capt Crunch, Mar 19, 2020.

  1. Capt Crunch

    Capt Crunch Captain Crunch NJ Mobile

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    Is the input power data the same with HG2879 as the Toshiba 2879s? I am finding datasheets on the HGs but the aren't giving the max pep inputs like the 2879 does, or any input power info that I can see. Thanks in advance.


     
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  2. groundwire

    groundwire Active Member

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    I have not found any data on it either. But i know one thing for shure, hg transistors are nowhere near as robust and does not have the longevity of the old toshibas. Also i know from using them that the peak drive levels are lower as well. I hate them so much! Damn you toshiba, why
     
  3. Tokin

    Tokin 42Zero Tampa

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    Imo, half to 75% of the input of the toshiba if you want the hg to last. Dont try to volt it either. Its just cheap low quality chinese replacement junk that, like everything else chinese isn't designed to last, kinda like their food. Ever notice how you can eat a pile of Chinese food and be hungry again 30 minutes later???
    I rest my case.
     
  4. 2NC995

    2NC995 DAN

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    I baby them. 12-14 watts into my DX500. That's it.
     
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  5. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    I learned the hard way that my Stryker 955 was too much for my XForce 4 pill. It had DEI transistors and I replaced them with a matched set of HG from RFParts. Watch your operating temperature carefully. As the temperature goes up so does the gain. Then one goes pop.
     
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  6. Ranch55

    Ranch55 Well-Known Member

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    Same happened here.
    I also do not see the same gain as with the Toshiba's …….
     
  7. Shockwave

    Shockwave Sr. Member

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    If they are showing these signs of thermal runaway in a class C amplifier, this problem gets much worse when biased into class AB and would explain why these HG parts have no market anywhere outside of CB.
     
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  8. Capt Crunch

    Capt Crunch Captain Crunch NJ Mobile

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    So I am going to run these like I normally do when I had my TS500DX which was about 25 watts PEP max in, for a 4X HG2879 HD amp I bought. Still not understanding or I do and it really means nothing when they say High Drive. Thanks everyone. Here is an interesting video from BBI about HGs...
     
    #8 Capt Crunch, Mar 26, 2020
    Last edited: Mar 26, 2020
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  9. 2NC995

    2NC995 DAN

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    What amp do you have now?
     
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  10. Capt Crunch

    Capt Crunch Captain Crunch NJ Mobile

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    Carl Built 400HD.
     
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  11. 2NC995

    2NC995 DAN

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    Oh...that’s why I asked. It’s a much different beast than your DX500.
     
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  12. Capt Crunch

    Capt Crunch Captain Crunch NJ Mobile

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    Yes but wouldn't 2879s be the same as far as typical input drive no matter the name? I understand one can take more than the other from what I have seen but I believe normal drive is the same, no. Right now Im running a Galaxy DX979 with it and have a 6666 as well. My old DX500 had Toshibas in it.
     
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  13. 2NC995

    2NC995 DAN

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    I’m referring the differences in amplifier designs.

    Say, your Carlbuilt and a Texasstar. Even if they both had Toshibas, the drive requirements will be different.

    You can’t really count watts per transistor and then apply it to all amplifiers.
     
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  14. 530

    530 Well-Known Member

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    He said it takes 5 watts to kick in the relay. I don't understand that part of HDs. I mean from what Ive read all the 2879s except for the new C ones I have seen 6 typical and 10 max PEP, so how can they drive more in without blowing stuff, because I have also seen repair stuff about these amps and other big names as well blowing transistors. I know they can take more than data sheet but it doesn't seem to be that good to do from what I read. The other thing i read but i think thats a long time ago is they just buffer the power down, so still confused on this as well as I am not experienced enough to just go look at one at see what the difference is. I heard of volting and HD but how is it possible safely without blowing them.
     
    #14 530, Mar 27, 2020
    Last edited: Mar 27, 2020
  15. 2NC995

    2NC995 DAN

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    That’s something for the experts - which isn’t me!

    All I know is that there’s something substantially different with the design that allows for much higher drive in amps like Carl’s. No way you could put what he runs into a DX500 and expect it to last more an a few seconds.

    Then again, I’m happy with my DX500 chugging along with 12ish watts in, and don’t plan to run it any harder than that. If I need to see the meter swing further, I’ll buy a bigger amp.
     

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