So I've been looking for an Arcam A18 for
ever, 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.
View attachment 345415
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
there's an internal switch?!
