ART amplifiers voltage change

[gbel]

Hi all,

Does anyone know how to make a voltage conversion to the ART monoblock amps (275 watts version) from 120 to 230 volts?

Thanks in advance

[AnotherJohnson]

You might PM Roberto. He has probably done this.

Steve Javaherian at High Performance Stereo also has this knowledge.

[gbel]

Thanks, I will check with Roberto.

[SolderSlinger]

As an FYI - CJ products have dual primary power transformers. Connect primaries in parallel for 120V, or in series for 240V. If you download the schematic folder from this website, open the folder labeled "Wiring Diagram Speaker Output". Then open pdf file "Premier 11 12 783p1 - 783p19 Voltage Conv". It shows connections foe 100V, 120V, 220V, and 240V. One thing to consider is connection to the switch contacts. I haven't changed voltage in an ART, so I'm guessing that if you look at the switch there are two sets on contacts. For 120V the contacts are wired in parallel. While it's functionally correct to connect the primaries in series, it's not safe. It leaves 1 phase always connected to the transformer. International agencies require both phases are switched. You should follow that example for safety consideration. Earlier amps like Premier 4 and 5 already had extra wire routed to the switch with a 3 point solder strip near the power cord exit/entrance to facilitate easy voltage changes.

Just out of curiosity, are you in the USA and have you experienced hum if each amp is plugged into different outlets? Site member AnotherJohnson had a pair of LP275M amps that hum when plugged into separate outlets. The only way to eliminate the hum is to plug them into the same outlet or a common power strip. I bought the amps from him and have the same issue. I know that a lot of CJ owners struggle with AC line noise. Before buying the LP275M amps from AnotherJohnson, I've never had issues with CJ amps. The LP275M amps definitely like sharing the same ground connection. I have wondered if converting to 240V operation would cure the problem. At this point, I do not have the time to route two 240V feeds to my listening room. And it's only speculation on my part, so it's hard to justify taking the time to convert to 240V.

[gbel]

I live in Europe and looking for a pair of used ART monos to buy, so in case I find a good deal in the USA I need to know how to convert voltage..

[roberto]

Hola gbel,

All Conrad Johnson products are made with the possibility to have the voltage conversion. It is a very easy task, but it should be made by a tech or if you have a soldering skills, you are able to do it. It is marked in the print circuit board how to make the connections. All CJ power transformer has double primary wounds, so in parallel connection is for AC 110V -120V and in series is for 220-240V.

Happy listening!

[SolderSlinger]

Hello gbel,

If your plan is to buy a pair of ART Mono amps in the USA, consider sending them to Conrad Johnson for an inspection and the 240V conversion.

Best regards,