Peavey 6505 MH 4 ohm mod?

Discussion in 'Other Amps' started by Ryan Morris, Feb 3, 2020.

  1. Ryan Morris

    Ryan Morris New Member

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    I'm looking into buying a Peavey 6505 MH but I noticed that the amp can only be run at 16 or 8 ohms. Does anyone know if there's an easy mod to make it work at 4 ohms?

    For example, I had a JCM 900 head, switchable from 8 to 16 ohms, However, you can go into the amp and resolder a connection on the transformer so it can run at 4ohms, like the JCM 900 combos do. Is there a way to do that with the Peavey 6505 MH?
     
  2. pedecamp

    pedecamp Well-Known Member

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    Youd be better off asking this question in the workbench section, and even better off at the Peavey website.

    This is an amp that fell short of being a great amp, I found that you could only dial in 1 channel at a time, if this is all you need then this is a great amp, but if you want to use this amp as a channel switcher thats where it falls short, plus its got lots of great features that would only be useful with a channel switching amp so not so useful as a single channel amp. Depending on your needs Id get something else like the DSL20HR.

    You have a 4 ohm cabinet? Probably easier to rewire the cab to change it from parallel to series, a pair of 8 ohm speakers wired in parallel is 4 ohms, change the wiring to series then the speakers will give you 16 ohms.
     
    Last edited: Feb 3, 2020
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  3. mickeydg5

    mickeydg5 Well-Known Member

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    If it is like the other 6505 the schematics show only the two output taps.
    Anyone have a schematic for the 6505MH?
     
  4. ampmadscientist

    ampmadscientist Well-Known Member

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    Peavey is cool about giving you schematics 601 483 5365.
    When I started as a PV service center in 1970s since then they have always provided parts and drawings without fail (let's hope so).
     
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  5. Gunner64

    Gunner64 Well-Known Member Premium Member

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    I do know that the 6505mh has some heat issues, at least mine did and will overheat after an hour of moderate volume and go into protection running in the 16 ohm postion, I would hesitate running it at 4, if it's even possible.
     
  6. Gunner64

    Gunner64 Well-Known Member Premium Member

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    I have called them in the past and they are excellent in this regard. Even if you are not an authorized service center they bend over backwards to get you what you need.
     
  7. ampmadscientist

    ampmadscientist Well-Known Member

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    Dude, the bench techs will get on the phone and help you if you ask.
     
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  8. MickeyJ

    MickeyJ Well-Known Member

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    To the Op, i'd check and see if this is the case with yours, if it is, i wouldn't be trying to get it to run on 4 ohms, I'd be listing this for sale and buying a real amp.
     
  9. Gunner64

    Gunner64 Well-Known Member Premium Member

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    And he's gone...
     
  10. Ryan Morris

    Ryan Morris New Member

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    I don't have one yet, I've been considering buying one and I wanted to see if a 4 ohm tap was possible before buying one.
     
  11. Ryan Morris

    Ryan Morris New Member

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    To everyone, I appreciate the insight into the possible overheating issues! I've never played one, only seen YouTube demos, and to me it sounds almost exactly like its bigger cousin, but overheating is something you don't find out about until you've stress tested it, which most YouTube demos don't do.
     
  12. Ryan Morris

    Ryan Morris New Member

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    I'll definitely try and get in touch with Peavey about it, thanks!
     
  13. Gunner64

    Gunner64 Well-Known Member Premium Member

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    I really liked how it sounded. I gave it to my brother and he is actually the one who is having overheating issues with the head I'm refering to.

    Upon googling it sure enough there are issues. After talking with my brother, who called Peavey, there apparently is a problem with a thermisistor in the protection circuit. Apparently they went a little tight with the tolerence of this part, and it goes into protection prematurely. I do believe they recommended a fix, which has to do with upping the value of the thermisitor iirc.
     
  14. Northwinds

    Northwinds New Member

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    This is the first time I ever heard of a 6505 mini head! I have the USA made 2x12 original combo which is the same as the 5150 still and it is a 2 channel amp with 3 button foot switch. Is this MH true to the original 5150 design? I heard changes were made shortly after all production went overseas. I admit I am not in the loop on amps like I used to be
     
  15. Adieu

    Adieu Well-Known Member

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    Why? Any 2x12 or 4x12 that's 4 ohm cab easily be rewired to 16 ohm

    It's easier and safer to mod the cab
     
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  16. Evil Z06

    Evil Z06 Active Member

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    The earlier ones had some overheating issues but not the later ones.....I can run mine all day and no problems
     
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  17. ampmadscientist

    ampmadscientist Well-Known Member

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    True, but also cool if it has another tap on the tranny maybe?
     
  18. Ryan Morris

    Ryan Morris New Member

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    I have 2 8ohm 2x12 cabs and I'd like to be able to run them both at the same time. I could rewire them to have 32ohms each, but then I HAVE to use both of them.
     
  19. solarburnDSL50

    solarburnDSL50 Well-Known Member

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    Who gives 2 fux about Peavey when Farah Fawcett smiles? No one.

    Best avatar evar.
     

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