Need help with step-down transformers!!

[justanotherguitarist]

Hey everyone. This is my first post on here (long time reader though) and need some help regarding step-down transformers.

I'm in Australia but have just bought a US Mesa Roadster (don't have it yet just preparing for when i gets here) but have only just been told that this can be a mistake as step down transformers will kill the sound quality, so the $2000-something dollars i spent to achieve awesome tone (Roadster) will be ripped apart by a necessary $200 piece of equipment (transformer). I think the basic idea is that the transformer won't produce a perfect (or close perfect as needed) sine wave such that the audio signal is already degraded before it even reaches the amplifier! This is fine for your run of the mill US powered toasters or whatever, just not for good quality audio gear.

Does anyone have any info regarding this (hopefully to dismiss my claims as myth!!!). If theres anyone in Australia who can give some advice that'd be sweet, or who knows a decent supplier/manufacturer making step-down transformers for this kind of sensitive audio gear!

Thanks in advance

 

[simonich]

I don't have any experience with a situation similar to yours. But there are products on the market that I think would cover you on this one. Here is one voltage regulator example from Furman. Covers both 120V and 240V inputs for worldwide use. I have no idea on a price for such an item over there.

http://www.furmansound.com/product.php?div=01&id=AR-PRO

I have not used the product. But I would hope a voltage regulator (which will put out a good wave form) is noticeably better than a step down transformer.

 

[msi]

What do you think changes with you step the power down? The electricity coming out of the wall is still electricity. The amplitude of the ac current has been reduced. That is all. If there was to be any change it would be from the frequency of the AC current being different in Australia from America. But the amplifier filters all ac current out of the amp. Once the power gets through the power supply all the amp sees is how many volts of DC power the amp was designed for. The amp doesn't care what frequency the AC voltage is, just how much there is. I don't see any reason why a step down transformer would matter. IMHO it's audiophile hocus pocus.

 

[justanotherguitarist]

I thought of putting one of the many furman products between the transformer and the amp, but realised i would need one with US style plugs to match the amp. The one you suggested is looks like a pretty sweet unit. All i'd need is converter plugs (something like $4ea) but that unit looks damn expensive, which would be magnified by the damn aussie prices. I'll check out how much the furman gear retails for here soon.

In regards to the third post, i hope it is "audiophile hocus pocus"!! haha. To compare what i'm thinking with what you said, think of the clipping stage in preamp tubes resulting in pre-amp distortion, its the same electricity/current etc running through the tubes yet the waveform is modified (ie clipping of the top however-much-percentage of the waveform, say 5%, results in a changing of the waveform). This is the kind of thing that was suggested to me, that it produces a somewhat distorted sinewave. I'm not really knowledable in this area, although having studied some uni physics helps a bit, but i think the idea kinda freaked me out as it has some potential to be true. Cheers for the advice, i'll probably look into a some Furman gear.

Otherwise I'll just see what i can get and hope its good enough. I think I'll post a thread in a few weeks once i've got the amp and tested it with a SD transformer, in case anyone else in Aus or anywhere else has heard similar things.

 

[voodoo_child]

All of my Boogies are US-voltage, running with a step-down (voltage is 220-240V over here). I know dozens of guys doing the same. No problem. As mentioned above, electricity is electricity, once the transformer is high-quality and not introducing any extra noise, it shouldnt make any real difference.

 

[simonich]

I guess we should separate problems. One problem is the quality of the transformed power. I agree the transformer itself shouldn't significantly distort the incoming signal form, assuming it's a reasonable quality transformer. Should be no problem.

The second problem is noise on the source electricity. If it is noisy, even a quality transformer will pass the noise. The amp filter caps will get most of it, but maybe not all. If this is an issue, a power conditioner or voltage regulator would help I think.

Either way, I'd try with a stepdown before paying the extra $ for a voltage regulator.

 

[msi]

The amplifier reduces the alternating current coming from the wall to a steady DC current. That is the electricity that goes to the tubes, not any ac current from the wall. As long as you have a decent 110-120VAC going into the amp you should be fine. I don't think it's a bright idea though to rely on a step down transformer for other reasons. You might know that you have to use the transformer but some other douche might not. If you only going to use the amp in one place, and your the only one who will use it that shouldn't be a problem. But we all have that one douche friend who thinks he knows what he's doing.......

 

[simonich]

The amplifier reduces the alternating current coming from the wall to a steady DC current. That is the electricity that goes to the tubes, not any ac current from the wall. As long as you have a decent 110-120VAC going into the amp you should be fine. (chopped)

Yes, clearly, but the resulting DC isn't always perfectly smooth and constant. The AC is rectified first, but is still "lumpy" at that point. The massive filter caps smooth the lumpiness to provide as flat a DC as possible, but they are not perfect. Some noise can get through (depends on the values of the RC and the resulting freq response). That's why people at clubs sometimes have issues with noisy items plugged into the same AC circuit as their amp (lights, neon, etc). Typical issues will be a "hum", or a more substantial effect if the voltage is too low (or the amplitude varies a lot).

 

[Shep]

dude, Just get a GOOD Transformer and it well be just as good as running them at 240v.. i think even better becasue 240v the amp run hotter... i have a mk IV at 110 and a C+ and 240..and i am thinking i might run the c+ at 110..