NOOB. Double a.c. 12v?

Discussion in 'General Electronics Chat' started by mattfletcher9292, Mar 8, 2016.

  1. mattfletcher9292

    Thread Starter New Member

    Mar 8, 2016
    So, I've got an amp from China that requiresa double a.c. 12v input but Im struggling to find something that will power it...
    Live in the uk. A link to an example of what I need would be great.
    Thanks for any help guys!
  2. mattfletcher9292

    Thread Starter New Member

    Mar 8, 2016
    Photo 8)
  3. dl324

    Distinguished Member

    Mar 30, 2015
  4. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    You want a 12-0-12v transformer, but how much power is the amplifier rated at, will determine the VA rating..
  5. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    If you are looking for a single plug-in device like a wall wart, you won't find one as a standard off-the-shelf product. You could use two separate 12V to 18V wall warts, because the input almost certainly will accept a dual-DC input. But the "right" way is a single transformer with a center-tapped secondary (or two identical secondaries), a line cord, an inline fuse, etc.

  6. Tonyr1084

    Well-Known Member

    Sep 24, 2015
    All I can do is state the obvious (about your photo): The transformer is a 220 VAC primary, Center tapped 24 VAC secondary. By center tapped that means the center of the secondary coil is tapped so you get 12 volts AC from either side to the center tap - or 24 volts across the two leads.

    Transformers come in different ratings as well as different ratios and configurations. Without knowing the amp's requirements we can't help you or answer your question.
  7. ian field

    AAC Fanatic!

    Oct 27, 2012
    Used to be fashionable to manufacture transformers with 2 identical primaries and 2 identical secondaries.

    The primary could be linked series or parallel for 230 or 117V.

    The secondaries could be V-0 V-0 (no links), V-0-V or just V-0 at double the current.
  8. Tonyr1084

    Well-Known Member

    Sep 24, 2015
    Boy it's not easy to find a transformer. You think someone would design a web page where you input your requirements and it will tell you what you need.

    I found a transformer that can be used;

    However, I don't know if this meets your power requirements.

    This transformer has a double independent primary. Each individual primary is rated for 110 VAC. By jumping the two inner most wires (one red, one black) you turn it into a 220 primary. On the output side you will have your 12 Vac - 0 V - 12 Vac configuration.

    HOWEVER: I don't know if a 3 amp transformer will be sufficient to drive your amplifier. It COULD overload the transformer. 3 amps at 12 volts is 36 watts (per side). But you've given us nothing on what you need for power requirements. Volts is not Power. Is there ANY information you can give us on how much power the amp requires? It might even help if we knew how many watts OUTPUT it is supposed to be capable of delivering.

    Comment on IAN FIELD's post: This transformer is almost exactly what he's describing. The only difference is the secondary is not a double secondary, it's a single center tapped secondary.
    Last edited: Mar 8, 2016
  9. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    You could also find a torroidal transformer speced somehting like 24 VA, 2x120 VAC Pri; 2 x 12 VAC at 1A secondary.
    VA is almost Watts in this case. That transformer would be suitable for 240 and 120 Mains and the Center tao you have to do yourself.
    Likely they will be rated for 50/60 Hz. 50 Hz works beter on 60 Z than the other way around. Generally the transformers could be marked 50/60 Hz.