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220V amplifier in 110V country... oops!

mike7877

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So I've been looking for an Arcam A18 forever, and one finally came up on eBay that shipped to Canada.
I was so excited to find it, that during the entire ordering process (plus the time it took to cross the ocean and a couple cities to my house), the fact that it was from the UK didn't register as the issue it is!
..lol...

Bit of info on the amplifier

- It's Bri-ish
- 350W maximum power consumption
- rated 50WPC into 8 ohms, 70 into 4 (continuous)
- TTT (toroid-type transformer)

Anyone looking for a 50/8 or 70/4 amplifier and who doesn't mind the used market - if you come across a great example of an A18? Jaaaack potttt!
(just sayin'...)


Anyway, back to my mistake...
When I attached a 3 prong power cord and plugged my A18 into the mains, the VF display glowed everrrr-so-lightly green for a tenth of a second.
... that was it! No relay noise - no,... NOTHIN!

I thought I got ripped off with a borken amplifier. I stewed for about 5 seconds, until I realised the greedy thing came from England and needed more volts.

I've got a couple variable transformers, one 300VA, one 2,000VA - when connected in series, they can turn 116V into 180V. While this is enough to run the A18, I'm not sure about its power rating while doing so (if I were to guess, I'd say probably 30 watts. 35 tops {not from testing}).

Since I want allllll of the beautiful watts the A18 can provide, without tying up my variable transformers needed for their intended purposes (2,000VA's job is to correct voltage droop on 200ft 14ga extension cord for 7+ amp power tools outside, 300VA's job is to enable supplemental suction on my push-vac), I've been thinking that I should get a dedicated 110-220V converter.


Below is a picture of a UMI converter (apparently it's a good brand). They use toroids.

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They come in many sizes, for many prices. Since I thought I was done paying for the A18 when I ordered it on eBay, I'd like to spend as little as necessary on this. Since all UMI converters should be the same build quality, the only difference between options is power rating, and, of course, price.

300W model is $70
500W model is $90
800W model is $130
1200W is $150
1600W is $170
1800W is $200
2000W is $200
2400W is $230 - $15, or $215

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So technically the 300W model should do just fine, because even at just 50% efficiency, running 70WPC would only draw 280W from the wall... But 280W is too much, because 70W RMS is 140W maximum, and music music's average power is only 10-15% maximum power, 20% in extremely bass heavy/consistent songs, so

28 + 28 = 56

56 * 2 (for worst-case 50% efficiency) = 112W average power for bass heavy music at 0.1dB below clipping with 4 ohm speakers

for 8 ohms, take 112W * 5 / 7, or only 80W average power


Something I forgot to mention is all the models mentioned above (300W, 500W, ...2400W) have a continuous rating of 80% of their rating. Don't ask me why they didn't just say 240W, 400W, 640W, 960W, 1280W, 1440W, 1600W, 1920W... IMO they're more marketable numbers - especially beside each other. Seem more sophisticated lmao

The speakers A18 will be driving most often have a minimum impedance between 6-7 ohms. The least considerate speakers he'll be forced to interact with: LSiM 703... They're a bit rude - they're between 3 and 4 ohms from 88 to 220Hz, with the average being about 3.65, and the bottom of the valley at 120Hz.


So I'm leaning toward the 300W (240W) model for $70...

Normally, the highest average power will be 80W. Since usually aim for 3dB below clipping to avoid clipping, the highest average power will be 40W. Since I don't often listen to consistently bassy and bass-heavy music, 40W turns into 30W.

30W when listening at louder levels. Whatever a watt over idle consumption is, is what it'll be drawing 90% of the time +
Call it 70W when I hook up my 3-way bookshelves.


The reason I'm considering options all the way up to 2400W is, when you plug a device into the grid, impedance is Low (capital L: LOW)

I'm not sure what the impedance is going to be of this 300W converter... I know it's going to be significantly lower than a similar weight EI transformer.


This amp isn't cheap, the flagship Polks in 2013 cost $2500 CAD, have semi-exotic drivers (underhung woofer) - same with the 8 ohms that will normally be driven by the A18. Though the music isn't bass heavy/focused, and the speakers aren't large/extend low, I'd like the amplifier to perform as well as possible - like it's plugged into the wall of some bloke's house across the pond.

If that takes a 2400W toroid, that's what I'll get. But if the 300W'er will do, I'm perfectly happy to use that. Money: I don't mind spending it, but I hate wasting it!





(note: the SA-10 and A19, Progression: A18 > A19 > SA10, are not similar in sound or design to the A18.
Arcam was bought up between A18 and A19, and whatever happened during the takeover, was bad (in my opinion...)
After learning the A18 was out of production, I bought myself an A19 for $1300CAD +tax (how bad could it be? it looks identical, it's the same brand...)
Less than two sad, sorry, years later, I sold the thing for just $400 :/
(tl;dr)lolol
 
Alternatively, you can hire an electrician to wire 2 phases to a receptacle next to the amp and use it in 220ish volts with no transformer.
 
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Don't think "average" power you need to buy the transformer for "peak" power and leave some headroom. I would not go less than the 800 watt model.
 
Some A18's were dual voltage. Maybe your Arcam's internal transformer can accommodate your house voltage, if a qualified technician changed voltage taps? Ask Arcam.

Wouldn't there be a switch on the back if this was the case? Or did they just skip that step and left the 110v tap untapped (pun lol).
 
Alternatively, you can hire an electrician to wire 2 phases to a receptacle next to the amp amp and use it in 220ish volts with no transformer.

Interesting proposition... how would that be done, leaving neutral alone and using the two lives?
 
I would check with Arcam. There's good chance that they use a "universal" transformer that can be re-wired by a technician. It's often more economical to purchase & stock one part than two, especially something expensive like a transformer that might be custom made.
 
Typically there are 220 volt outlets for electric stoves and for tumble dryers in American homes. The electrician would tap this circuit most likely. Yes, phase to phase measures 220 volts and phase to neutral measures 120-ish volts.
 
Don't think "average" power you need to buy the transformer for "peak" power and leave some headroom. I would not go less than the 800 watt model.

About 8 years ago I had a Cambridge Audio CXA-60 which was rated for a bit more power (60W into 8, 90 into 4?). Back then, I believed that run-in of solid-state audio electronics had an audible effect on sound quality, so I had purchased four ~2 ohm (I think they were 1.9 or 1.8, can't remember) 10 watt ceramic resistors for the purpose of running in the power-amp section. I used the resistors to create two 4 ohm pairs, and hooked one to each channel. I had calibrated the peaks of the kick on an album to reach ~10V below the rails and average about 15 watts. When I pressed "play", funny thing - I could hear the song everrrr so quietly coming from the amplifier! Lol. Anyway - later that night, I was eating supper in my kitchen. My kitchen has a ceiling fan with lights over the table, and the table sits closest to the living room. The light sockets were small and I couldn't find proper energy efficient bulbs, so I had incandescents in. The way electrical was done, the kitchen's ceiling box the fan was mounted to was the last after half of the outlets in the living room. So... as I was eating, I noticed that the lights were dimming - rhythmically. I thought "that's weird!" and kept eating. After a couple minutes I realised - that's from the amp! Sure enough, I went over to it, placed my ear near the ventillation, and the tempo matched the lights dimming! To verify, I turned up the volume maybe 3dB, and the dimming became more intense! This amp also used a toroid (capable of higher current). Because of this property, the bulk storage caps in amps that use them can be about half what an EI would need. Since the A18 has the same design, voltage drop at the mains is something to avoid
 
Typically there are 220 volt outlets for electric stoves and for tumble dryers in American homes. The electrician would tap this circuit most likely. Yes, phase to phase measures 220 volts and phase to neutral measures 120-ish volts.

Since the plug is 3 prong (and so, by definition, polarized), is it possible that there's no right way to hook it up?

In the basement I put a closet with fittings for washer and dryer, and that closet is in the hallway. The closest room off that hallway is the room I have the system in, so it would be pretty easy for me to run an extension cord... I have the nicest 25 foot 12/3 extension cord you've ever seen (no, really lol) I could run from it... Go to home depot, buy an end that fits in a dryer receptacle, a self contained electrical box, an outlet, and cover - wire it up, and plug that extension cord into it
 
When I moved from Europe to the US in the 90s I could convert my Arcam gear. It was as described above. The power transformer had a tap for 110 VAC and the conversion was easy. I sold the units here in the US years ago. If that's the case with your amp then that would be the preferable solution for me.
 
When I moved from Europe to the US in the 90s I could convert my Arcam gear. It was as described above. The power transformer had a tap for 110 VAC and the conversion was easy. I sold the units here in the US years ago. If that's the case with your amp then that would be the preferable solution for me.

I'll open 'er up tonight and take a look. The least complicated option is always best! (especially when it's free...)

After tax, the dryer transformation is probably $25, the optimal transformer $250. Opening a chassis and moving a wire? 15 minutes and $0.00
 
Your house has 220V. Have an electrician wire a drop. Make sure you have it done right, this amp isn't worth a safety hazard.
Or get a step-up transformer. It will have to be fairly large.
Both of these options seem to be a sizeable fraction of the cost of this amp and totally not worth it. I would sell it and start over. A 220V amp in a 110V world is a bit of a boat anchor in life. There are so many amps that will sound great, and many have more power which is actually an advantage.
 
Interesting proposition... how would that be done, leaving neutral alone and using the two lives?
Yes, phase + phase and no neutral.

More here.
 
Not recommended but interesting. Not a Meza presenter but very detailed after all. FYI Actually the problem with 220V conversion could be wire gauge in the wall but an audio amp isn't a cloths dryer. Anyway:
 
As stated above, in the US a 240VAC plug is hot-hot-ground. A 120VAC plug is hot-neutral-ground. Equipment that expects neutral (i.e. zero potential, but separated from 'ground' for safety reasons) on that certain leg, if you wire hot to it, you're likely to blow it up; amateur electricians do this all the time wiring regular 110VAC circuits backwards.

If this model has an internal transformer, moving the taps or replacing the transformer seem like a far better idea. But again I'd let the manufacturer make that call, even if it is expensive.

Euro power would also be 50hz vice 60hz, which is generally not an issue with something like an amplifier but I wouldn't make that call for sure.

There are reasons these aren't easy-peasy conversions and why people aren't just regularly snapping up overseas bargains and running them on laundry dryer circuits.
 
As stated above, in the US a 240VAC plug is hot-hot-ground. A 120VAC plug is hot-neutral-ground. Equipment that expects neutral (i.e. zero potential, but separated from 'ground' for safety reasons) on that certain leg, if you wire hot to it, you're likely to blow it up; amateur electricians do this all the time wiring regular 110VAC circuits backwards.

If this model has an internal transformer, moving the taps or replacing the transformer seem like a far better idea. But again I'd let the manufacturer make that call, even if it is expensive.

Euro power would also be 50hz vice 60hz, which is generally not an issue with something like an amplifier but I wouldn't make that call for sure.

There are reasons these aren't easy-peasy conversions and why people aren't just regularly snapping up overseas bargains and running them on laundry dryer circuits.
Agreed. This is a mis-purchase.
I can somewhat understand if OP is looking for some unicorn piece of audio heritage, like this:
But this is a dime a dozen amp.
 
Agreed. This is a mis-purchase.
I can somewhat understand if OP is looking for some unicorn piece of audio heritage, like this:
But this is a dime a dozen amp.

They're not too common... I was looking (albeit on and off) for years! When I finally found one that shipped to Canada, I snapped it up, completely forgetting it may not run on 120V
 
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