From the schematics I have seen, the MC275 has only one primary winding with a tap for 125V as well as the basic 117V. So it seems like you will need an external stepdown transformer to get from 220 to 115. Either an isolation or an autotransformer will do the job. I'm not sure if Sweden is 50 or 60 Hertz mains frequence. And I'm not sure how the MC275 (original one?) will react to 50 Hertz. The power transformer may just run a little hotter. It's a shame that McIntosh could not have provided "this" basic information. http://www.pmillett.com/file_downloads/McIntosh/MC75_sch.pdf
It would seem that many of the power tools in European use were built with the North American market in mind.
Mats, before you buy anything, look at the amp's power trafo, closely. It may have dual primaries wired in parallel. If that's the case, you are in luck and all that's necessary is to rearrange the primary setup to wired in series, instead of wired in parallel. If only a single, "115" V. primary is present, you will need a step down autotransformer. Something like Allied Electronics' 500 VA model 6K171VCP should do nicely. Shipping from North America to Europe makes little sense, but you should be able to find something similar from a reasonably local source.
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Do check your customs and duty regulations before you buy!
I was thinking about buying in the states as well at some point but everything above $20 value attracts 30% duty plus 17.5% VAT here and that makes it no cheaper than buying in a local shop.
On ebay here I can get a new 3.3kVA step-down transformer for less than £45.
Most touring musicians from the US I see here use them for their big Ampeg bass amps. A friend of mine has a european spec SWR (converted to 220V by the factory) which kept dying on him until he re-converted it to 110V and started using one of those yellow transformers.
The 110V thing is a safety regulation by the way.
I was thinking about buying in the states as well at some point but everything above $20 value attracts 30% duty plus 17.5% VAT here and that makes it no cheaper than buying in a local shop.
On ebay here I can get a new 3.3kVA step-down transformer for less than £45.
Most touring musicians from the US I see here use them for their big Ampeg bass amps. A friend of mine has a european spec SWR (converted to 220V by the factory) which kept dying on him until he re-converted it to 110V and started using one of those yellow transformers.
The 110V thing is a safety regulation by the way.
Yeah, I have a number of European friends who clued me in on this requirement long ago..(Some visitors asked me to take them to the local Home Depot - when I asked about the power issue they told me about the 120V tool requirement) I can't imagine 240V power tools in use on construction sites, frankly I find 120V tools are scary enough.. I always make sure mine are plugged into GFIs when I am using them outdoors, and if possible will do so indoors as well. For that extra measure of safety in such situations I would probably use an isolation step down transformer.. For home use heavy duty battery powered tools really are much safer..
Incidentally you should probably buy the biggest step down auto-transformer you can for this amplifier that will not trip the circuit breaker (or blow fuse) in your panel. Since the MC-275 output stage operates quite near to class B the current demand drawn from the AC line varies quite a lot with signal level and a slightly undersized step-down transformer can result in quite poor mains voltage regulation which will be reflect in the performance of the power amplifier as well.
I grew up overseas and encountered these sorts of issues and worse with auto-transformers. Northern Italy in the 1970s had mains voltages varying from 140V to 240V (mostly 50Hz, but some 25Hz hydro as well apparently) depending on where you lived and small auto-transformers were consequently ubiquitous there, despite this they unfortunately were not too reliable. (Open windings were the quite common consequence of a minor overload..)
With Kevin's remarks in mind, perhaps Allied's 1 KVA 6K173VCP or another vendor's equivalent is in order. A MC275's mains draw should be roughly the same as that of a H/K Cit. 2. A properly set up "Duece" (CL150 inrush current limiters) works with a 6 A. fast blow fuse in the post. A 1 KVA autoformer should handle a continuous 120 V./8 A. easily enough.
Believe it or not I would probably recommend 2KVA for Citation II or a MC-275 - generally I found the transformers performed best when loaded to less than 50% of their rating.. My dad used a 1KVA autotransformer to power a stereo system that required less than 3A total, we had no problems. Note that a fully loaded autotransformer may experience an output voltage drop of up to 7 - 10% depending on who made it, (how conservative the design) factor in some drop in the mains wiring as well and you can see where this is going.. Note that they can get very hot/noisy in operation as well at a high % of their rated load current. (Remember the load currents are non-sinusoidal and generate additional heating in the core and windings relative to the average power consumed) Go large!
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You can connect two power trans in series............
Some power trafos come with dual primaries. You wire them in parallel for "120" V. zones and you wire them in series for "240" V. zones.
My understanding is this is the USA version of the amplifier and has only a single primary.. Plus being a stereo amplifier there will only be one of them.
In the event you have a situation with two separate identical 120V amplifiers their power transformers should NOT ever be connected in series because you cannot guarantee that the load currents are identical and hence the supply voltage will not divide equally across their primaries. You must use a step down transformer!
In the event you have a situation with two separate identical 120V amplifiers their power transformers should NOT ever be connected in series because you cannot guarantee that the load currents are identical and hence the supply voltage will not divide equally across their primaries. You must use a step down transformer!
i had same problem... found this -
http://akdatabase.org/AKview/albums/userpics/10004/MA6900 Voltage Conversion.pdf
also schematic:
http://akdatabase.org/AKview/albums/userpics/10004/MA6900 Service.pdf
looking at other model amps schematic - looks like is same transformer, so it would only need changing "jumpers" on main wire terminal located on the bottom of the amp
hope it helps
http://akdatabase.org/AKview/albums/userpics/10004/MA6900 Voltage Conversion.pdf
also schematic:
http://akdatabase.org/AKview/albums/userpics/10004/MA6900 Service.pdf
looking at other model amps schematic - looks like is same transformer, so it would only need changing "jumpers" on main wire terminal located on the bottom of the amp
hope it helps
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