Old amps in far off lands - need help from pros!

greenblob · Joined: 10 Jan 2006 Posts: 6 Location: Australia

Hello all,

Got a problem (hopefully a simple one) that ive been trying to figure out.
Hopefully this is relevant to this forum. Apologies in advance if not.

Relocating from Australia to America in a few weeks. Was wondering what i can do in relation to power supply to run my amps over there.
I have an old 1960's 40w amp head (Playmaster 116). Its a point to point hand build job. My other amps all have universal voltage dials (resistors) built in so they will be ok. The only real options i can see for the Playmaster is to buy an Inverter to raise the voltage from 110v to 240v. Or a nasty idea of changing the Power transformer (prefer to leave it orig)

Will the differing supply frequency (Aus 50Hz - U.S 60Hz) hurt the amp?
How many watts will a 40W amp draw (40w?!)
If i buy an inverter, how big should i go? (higher VA ratings get pretty bulky fast!)

Im sure some of you guys have played in different countrys, dragging your fav bit of gear with you. Ive been looking through the old forums but havnt had much luck.
Any help would be greatly appreciated
thanks

1bassleft · Posted: Sat May 20, 2006 3:33 am Post subject:

Hi Greenblob, and welcome to Guitarsite Smile

Sorry, but it is a problem and not all that simple. I just sorted out the opposite; an American amp that had to be stepped down from my UK 240V to the expected 110 (ish)V. That was pretty easy, especially as it's only a 8W, single 6V6. A step-up isn't quite so elegant. As you say, you can end up carrying something the size of a camping-gaz cylinder Crying or Very sad

I think (but I'm not an exp, I'll have to check it up) that the cycles won't be a problem. Your filter caps should be able to handle 50 or 60Hz without a hitch. Even if they were replaced, I think a lot of horse is talked about original filter caps. It's the humping 110V up to 240V that gives you the headache. Again, there is some good news in that replacing (even if temporarily) the power transformer is nowhere near as tone-altering as changing the output transformer.

A valve amp draws in a lot more than it puts out, so you'll need a step-up that's good for about 100AV, I would think. Your options are either a suitable PT with selectable V (like the Partridge 50W pulled from an old Selmer etc) as a replacement or a modern from somebody like Weber, or the butane-cylinder-sized step-up. If it were me, I'd go for the step-up and live with carting the lump around. Keep the thread alive and I'll have another thunk in the meantime.

greenblob · Joined: 10 Jan 2006 Posts: 6 Location: Australia

Thanks for the reply 1bassleft,
I've had a chat with a older friend who plays quite a bit with electronics. He has assured me that (as you correctly said) the 50Hz to 60Hz change will be no issue at all.
For the supply voltage, he agreed that an inverter would be the easiest, but was unsure what VA rating would be appropriate (he didnt even want to hazard a guess - i understood his reasons, unknown load).
Any ideas for ways of figuring out a max current draw of the amp?
Obviously, an inverter rated slightly above the current draw (plus 15%?)would be better so as to keep the weight and size down.

I'm guessing this senario is relatively common. What do guitarists do when touring with their favorite vintage amp? Some one must have had this issue! Still alittle scared to rush out and buy an inverter for a few hundred bucks (hopefully!) only to find its not going to do the job.
Once again thanks for your ongoing help.

USGold · Got Rhythm Joined: 28 Mar 2006 Posts: 92

Maybe you'll find some help there:

http://www.mouser.com/index.cfm?handler=data.listcategory&N=601

1bassleft · Posted: Wed May 24, 2006 1:04 am Post subject:

Blob, I'm posting this thread to my mate, Terry, in Cali. He's all-knowing on this front, having zapped himself several times forwards and backwards on 110V and 240V amps. Watch this space. In the meantime, DO NOT buy some $$$ benchtop V-transformer kit. That won't be necessary for your job. Also, bear in mind that the apparatus you need will be much cheaper to buy in the US than it would in Aus. Yanks tour; they have the technology... but they can buy it cheap from the Chinese Laughing

1bassleft · Posted: Wed May 24, 2006 2:32 am Post subject:

Terry suggests this:

Quote:

http://www.voltageconverters.com/voltage_converters.html?source=overture
about 14 bucks its a stand alone so it wouldnt be a
big hassle to tote around.t

Hope this helps,
1BL

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