[sdiy] A transformer question.
admin at bugbrand.co.uk
Mon Nov 3 22:18:29 CET 2008
Thanks Bob - that makes a lot of sense and, I think, gives me the
direction to figure things for the most part.
I'd already been planning to use 18v secondary outputs to feed v-regs
for 15volts (LM317/337)- I'll do some calculations to check whether it'd
be worth heading up to 24v secondaries to cover the potential 100v
situation. Making sure that the V-regs will receive happy operating
- that'd be right, right?!
Bob Weigel wrote:
> Normally the variation in 20V around 230V divides to a variation of a
> coule volts in the stepped down side... and in most circuitry that's a
> tolerable variation. And same percentage variation in the 110 to
> 120...usually ok. The 100V in Japan can cause some 'brown out'
> simulation, but some things will also work just fine with it. For
> example a Siel DK80 I'm pretty sure wouldn't like the 100V without a
> step up transformer because the headroom is too limited on the
> regulators as I recall. It'll buzz as the ripple drops below the
> regulator's headroom requirement.
> You can get step up transformers for 100V to 120V. For running
> Russian gear here I had a good sized 2X transformer so I just wired it
> up in a plastic box and made a simulation of the funny round pinned
> outlets on the top of the plastic box :-). Anytime you have to step
> DOWN there are real cheap options out there. Step up requires a more
> expensive solution. -Bob
> Tom Bugs wrote:
>> A quick question about twin primary transformers for which I've not
>> been able to find answers...
>> If there are twin 115v primaries.. (ie series for 230v and parallel
>> for 115v)
>> - should this be able to cover Euro vs UK ranges of c.220v to 240v?
>> - and would it cover US 120vAC and 110vAC in places like Cuba?
>> - how can one deal with the 100v in Japan (other than replacing the
>> trafo with a different spec one?)
>> I'd guess there's a bit more to it too - dependent on current draw,
>> trafo type & spec, etc..
>> Any help greatly appreciated!
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
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