Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Sven on January 03, 2025, 01:21:39 pm
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Hi,
I wanted to get some opinions on using my amp with different mains voltages to decide what I should do. I want to use my amp in the UK, Germany and the US.
The amp stays in every country for a while and it's not constantly moving so connections can be made inside the amp but a switch would be nicer I think.
I just put a new power transformer (Pacific PAM-PT-40-18RZ) into my deluxe reverb which has two primary windings with multiple taps that have to be connected in parallel or series to create a primary for different voltages. Primary winding diagram attached.
Everything would be slightly easier if it was a PT with one primary winding and different taps for the voltages but it isn't.
I want to use the amp plugged straight into the wall without a transformer or conditioner.
The UK and Germany both use 230V, most of the US is 120V so I really only need a switch to switch between those two voltages.
And again, it would be easier if it was 240V and 120V (or 230V and 115V) for a switch but it isn't.
So my options are:
- Solder the primary normal for one voltage and when moving the amp redo the connections.
- Figure out a solution using a switch. Seems to me at the moment I'd have to use at least two switches to combine the primaries for the two different voltages? Am I missing an easy way to do this?
- Has anyone done something in between? Maybe using quick connects or so inside the amp? So I'd still open the amp to do the switch but without soldering and minimal change to the wiring?
Right now I'm leaning towards just wiring it for one voltage, heat shrink and tidy the other wires and then redo the wiring whenever the amp moves country. I'd probably open the amp anyway to set the bias for every wall voltage.
Would be great if anyone has any thoughts on this!
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The UK and Germany both use 230V, most of the US is 120V so I really only need a switch to switch between those two voltages.
And again, it would be easier if it was 240V and 120V (or 230V and 115V) for a switch but it isn't.
The UK is 240V (it's 'officially' 230V, but what comes out of the wall is 240V wherever you go). German walls are apparantly more variable, between 230 and 240V depending on location, so I would just stick to the 240V option; better that your amp voltages are sometimes a few percent lower than higher. Then all you need is a DPDT switch -you can buy ones that have the voltage labels on (https://cpc.farnell.com/arcolectric-bulgin-limited/t22208eaag/switch-voltage-selector-snap-in/dp/SW04242), and have to be flipped with a tool, to minimise mistakes. Loads of international appliances are made that way.
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That's exactly the kind of opinions I was looking for, Thanks!
I think a 120/240 switch will probably the best option. I'll probably use a round Schurter one.