switchable voltage 120/230 = switchable cycle 60/50Hz

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by cbstrat, Oct 10, 2008.

  1. cbstrat

    cbstrat Supporting Member

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    Do amps that are capable of multiple voltage inputs ie, old Marshall, Vox, compensate for the 60 to 50 cycle also? I was looking at the Carol-Ann OD line and they come with a switchable voltage 120/230. Are new amps better at this than vintage ones? This is over my head so any help would be great.
     
  2. cbstrat

    cbstrat Supporting Member

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    But, does this adjust the frequency(if that is the correct term) for 60 to 50 cycles?
     
  3. SatelliteAmps

    SatelliteAmps Member

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    No. It does not adjust frequency. Nor do most step up or step down transformers.
     
  4. mark norwine

    mark norwine Member

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    Adam is right: no conventional transformer changes frequency.

    As a general rule, any transformer that's designed to handle 60Hz will handle 60 and above.

    A transformer designed for 50Hz can handle 50 and above.

    The secret is in the wire sizing and whether or not it can handle the increased current [and resultant heat] associated with the longer duration of the sine wave (at the slower frequency).

    If you see a transformer labeled 50/60Hz, know that it's not "switching" anything. Simply put, it was designed for 50, but will handle frequencies above that (60 being the "other" frequency"). But if a transformer is labeled 60Hz, you don't really know how it will handle 50. Might be fine. Might run, but hotter. Might burn out.
     
  5. VacuumVoodoo

    VacuumVoodoo Member

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    Well, a properly designed power transformer that complies with IEC 61558 norm will/must handle 40-63Hz frequency range without over heating or dropping power transfer efficiency.
     
  6. Carol-AnnAmps

    Carol-AnnAmps Gold Supporting Member

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    Even with a correctly spec'ed PT, with an incorrectly designed power supply circuit and HT line you can end up with tonal artifacts (ghost notes, weird resonance effects where just one particular note on the guitar neck will sound like the speakers blown) at different line frequencies. Been there. done that !! I now do the math on the RC decoupling networks in the HT line on any design. Also remember that ripple can be double the supply voltage frequency if a center tapped PT secondary is used. I have no issues with any amp designs running at either frequency.

    I do always recommend a bias check is carried out on any amp that is moved from one Country voltage to another. There can be some differences.
     
    Last edited: Oct 10, 2008
  7. VacuumVoodoo

    VacuumVoodoo Member

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    Ripple is always double the AC supply frequency when you use full wave rectification. Whether it is dual half wave with CT or bridge rectifier and single HV secondary winding. Just for the sake of technical correctness.

    Yes, doing the math for all of the DC supply chain is the way to go. Usually it's the part you skip the math on that causes trouble. One of Murphys laws at work.
     
  8. cbstrat

    cbstrat Supporting Member

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    WOW! that went so far over my head. Dumbel down for me. :) does that mean that your OD amps work on both 120 and 230 with no heat or tone problems as long as they are properly biased? As a side do you have that on the ODr?
     
  9. cbstrat

    cbstrat Supporting Member

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    WOW! that went so far over my head. Dumbel down for me. :) does that mean that your OD amps work on both 120 and 230 with no heat or tone problems as long as they are properly biased? As a side do you have that on the OD2r?
     
  10. cbstrat

    cbstrat Supporting Member

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    WOW! that went so far over my head. Dumbel down for me. :) does that mean that your OD2 amps work on both 120 and 230 with no issues or tone problems as long as they are properly biased? As a side do you have that on the OD2r?
     
  11. SatelliteAmps

    SatelliteAmps Member

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    Which was drafted in 1997.....So anything made prior probably will not conform to it. Also, current transformers made to vintage spec's usually do not.
     
  12. cbstrat

    cbstrat Supporting Member

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    Is there any difference then between using a switch that changes the Pt taps and using a line matching transformer?
     
  13. Carol-AnnAmps

    Carol-AnnAmps Gold Supporting Member

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    Sorry....

    Yes they do work fine. The OD2r is not switchable, but it can be ordered in either 120 or 220.
     
  14. Carol-AnnAmps

    Carol-AnnAmps Gold Supporting Member

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    Thanks, that is correct. I was thinking half wave vs full wave.
     
  15. cbstrat

    cbstrat Supporting Member

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    Still unclear if it is the same.
     
  16. SatelliteAmps

    SatelliteAmps Member

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  17. cbstrat

    cbstrat Supporting Member

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    Thank you for a straight answer. My previous thread http://www.thegearpage.net/board/showthread.php?t=434422 has left me quite confused.

    I am American spending a lot of time in Europe and it would be much easier/cheaper to use one of the many amps I already have.
     
    Last edited: Oct 12, 2008
  18. SatelliteAmps

    SatelliteAmps Member

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    No problem. It's pretty straightforward. A lot of people have a lot of opinions about this, but in my opinion, a step down/step up transformer is the easiest and least destructive way.

    A step down and a step up transformer are the same thing. One is just wired backwards.
     

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