Ampeg SVT II Pro

Discussion in 'Amps and Cabs [BG]' started by i_got_a_mohawk, Feb 9, 2005.

  1. Im considering getting one of these from the US and importing it to the UK, if i have a decent power transformer that problem is solved

    What i want to know is, is there much danger in using one of these? ive read a fair few horror stories about the SVT II Pro's being totally unreliable and, thats kinda putting me off buying one!
  2. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Do you mean an SVT-II or do you mean an SVT-2PRO?

    Most SVT-II units were made with universal 120/240V 50/60 Hz transformers, so such a unit should be convertible directly to 240V 50Hz.

    Ther may be some that cannot be converted....but over 90% of the ones made should convert.

    A few units (some SVT-2PRO are among them, IIRC) were made during a time when some "brilliant minds" declared that all export countries used 230V. Those units were made with only the 230V option for export versions.

    Naturally, on mains of 220V, internal voltage was a little low, which reduced power somewhat. And, at 240V internal voltages were a bit high, increasing power and strin on the unit. They could get a bit too far over normal voltages if there were mains voltages at or near the the high limit (normally 264V).
    That might account for some of the stories.

    The "brilliant minds" were got out of the picture, and more recent units have for many years had full 240V capability for UK, Aus, etc, where the problems had occurred at high mains voltages.

    If you buy an ebay unit, there is no telling what version you have. Older units didn't have the serial # tracking that exists now, and I can't verify them from a serial number.

    NOTE: Many OLD US Ampeg units, such as vintage 1970s, will NOT convert to 240V 50Hz, because they have 117V only. Also, they are 60Hz transformers, and probably won't last too long on 50Hz, so an adapter transformer won't help uless you run at 20% lower voltage and accept lower performance.

    For those, you pretty much have to have an export type, or you have to replace the old transformer.

    In an SVT, or derivative unit, there are two transformers to rewire or replace. The main power transformer, and the filament transformer.

    If the unit can be converted, the power transformers will have black, white, blue, brown, gray and maybe violet or blue/white stripe wires on the primary.

    If there are only black and white wires, it's not convertible for 240V.

    I'm going to throw in a disclaimer on this: I may have forgotten and left something out, so any particular unit purchased might not be as I described.
  3. Ok, in my mind a decent step down transformer 240v to 120v outwith the amp (basically a box that i plug the amp into then plug that box into the wall) would work fine, but ill go talk to a friend of mine, hes been a sparky for 25 years so he should know

    The one im looking at getting of EBay at the minute has the Blue and Red SVT II pro logo, it is the pro model, not the svt II standard altho i know that was also floating around at the same time, looking at the back plate there seems to be a voltage changer, but i think its only got 2 possitions and i cant tell what they are damn it!

    But the problems ive heard about were often to do with extreme over heating, actually melting the solder then that dripping onto the board and shorting everything, aswell as other problems that i think were just to the owner not caring for the amp, so they are technically sound and i should have no problems if i look after it (unless its knackered when i get it obviously)

    Also, would it be possible to replace the banana (I think they are called) jacks with speakons ? Im not too bothered as ill probably just use the 1/4's, but just outta curiosity
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