Dual Voltage Ampeg SVT2Pro

[Blade3dge]

I was taking a look at the back panel of the SVT2Pro on musicians friend:

Ampeg SVT-2 Pro Series Amp Head: Shop Bass & Other Musical Instruments | Musician's Friend

The back panel actually lists multiple voltages for the SVT2Pro, on any other product I would naturally assume this to mean that it will run off any voltage, just plug it in and let 'er rip. On a $2000 amp, I'm slightly more skeptical; especially upon considering the amount of times the question has been asked. So could one of the more educated TBers out there answer my question... What exactly does it mean and if I were to purchase an SVT2Pro would it run off 240v?

Thankyou

[coreyfyfe]

As far as I know, it's setup with the taps on the power transformer so that it's a quick and easy change over to run on 120V or 240V. It's set at the factory for the given market it will be shipped to, but if you were to say, sell a US amp to someone in the UK, they would change the fuse and switch the mains connections and be good to go. How involved of a process that is I'm not sure.

[Blade3dge]

Originally Posted by coreyfyfe

As far as I know, it's setup with the taps on the power transformer so that it's a quick and easy change over to run on 120V or 240V. It's set at the factory for the given market it will be shipped to, but if you were to say, sell a US amp to someone in the UK, they would change the fuse and switch the mains connections and be good to go. How involved of a process that is I'm not sure.

Strange then that it lists all voltages with no indication which one it is set to :S seems like a sure way to cause confusion and maybe cause a few lawsuits from people claiming "it's written right there in black and white next to the input".
Anybody more certain on this? Or if it is in fact correct that it does need to be swapped over anybody out there understand the process? Thanks.

[coreyfyfe]

From one of the former ampeg engineers:

Originally Posted by Jerrold Tiers

ANY of the more recent SLM "SVT" series amps has the 'export type" transformer in it regardless of whether it was a US or an export unit. I assume that Loud has continued this, but I don't know that.

So, yes, it can be rewired, but depending on how often the change is needed, it could be more practical to keep it wired for the "more used" voltage, and adapt with a transformer. That's a 3 minute plug-in solution.

We actually did make some units with switches, but the switch gets complicated with UL and CE requirements. They want it to be tested to be safe if you set it for the lower voltage and plug into the higher....... Otherwise you have to make the switch accessible only with a "tool"......

And with the SVT, there are two transformers, plus a fan, that need to be switched. So no 120/240V switch.

[Blade3dge]

Damn and I suppose then it wouldnt be unreasonable to assume that switching the voltage would void the warranty, CURSE YOU AMPEG!

[JimmyM]

Up until a few years ago, there was no such thing as switchable voltage in amps. It's a very recent thing, and amps with iron power transformers will almost always need to be rewired for alternate voltages. But it's better than the early days when the only solution was to replace the power transformer entirely, so you have that going for you.

I'm guessing you're a younger guy who hasn't got a lot of experience with amps, correct?

[coreyfyfe]

Originally Posted by Blade3dge

Damn and I suppose then it wouldnt be unreasonable to assume that switching the voltage would void the warranty, CURSE YOU AMPEG!

Not necessarily. If it's done by a tech that is an ampeg "authorized repair center" then it would likely be fine. I say likely because you never really know unless you contact them directly.

I'm assuming you've purchased a newer amp set up for the wrong voltage?

[SurferJoe46]

Then there's the actual 'plug' end of the power cord to give a big hint where the unit is set up for in the first place.

If it has a US-style plug on it, then it prolly is 117-130VAC 60~

That's the goes-inta-thingy, not the thingy-it-goes-inta part on the back of the amp head if it is modular in the first place like a computer is now. .

Gonna be BIG I think:::

[Blade3dge]

Originally Posted by JimmyM

Up until a few years ago, there was no such thing as switchable voltage in amps. It's a very recent thing, and amps with iron power transformers will almost always need to be rewired for alternate voltages. But it's better than the early days when the only solution was to replace the power transformer entirely, so you have that going for you.

I'm guessing you're a younger guy who hasn't got a lot of experience with amps, correct?

Younger, yes. But my expectations of switching voltages comes from experiences with other electrical appliances where 90% of everything comes with a dual voltage option and the general rule for my customers is that "simple products normally aren't everything else (except for guitar amps) generally is"... Then I sell then stepdown transformers

[Blade3dge]

Originally Posted by coreyfyfe

Not necessarily. If it's done by a tech that is an ampeg "authorized repair center" then it would likely be fine. I say likely because you never really know unless you contact them directly.

I'm assuming you've purchased a newer amp set up for the wrong voltage?

You raise a good point, I will have to look in to this.

[rodl2005]

I had my tech swap the tap on the transformer so my SVT II could run at 240v. Was pretty simple, but it was a 2nd hand '91 model

[nashvillebill]

Originally Posted by JimmyM

Up until a few years ago, there was no such thing as switchable voltage in amps. It's a very recent thing, and amps with iron power transformers will almost always need to be rewired for alternate voltages. But it's better than the early days when the only solution was to replace the power transformer entirely, so you have that going for you.

I'm guessing you're a younger guy who hasn't got a lot of experience with amps, correct?

Err...I have a Grundig tube radio from the mid '50's and it has a switchable 110 or 220 voltage selector. Hardly a recent concept!

edit: and as far as guitar amps, the 1987 Marshall schematic shows a selectable voltage switch.

[Blade3dge]

In hindsight used local models only come with a 1 months warranty which suggests that anything from America is probably going to have equal or superior coverage anyway... Interesting...

[Jerrold Tiers]

You'll see fewer switchable units these days....

The safety agencies (UL, VDE, Semko) want to have the unit remain totally safe even if you set it for 120V and plug it into 264VAC (240V maximum high line voltage).

Nobody much wants to deal with the problems that produces, so internal switches, and re-wiring is more popular. And units (like 8PRO) that take ANY voltage from 100V to 240 with NO switching.

[JimmyM]

Originally Posted by nashvillebill

Err...I have a Grundig tube radio from the mid '50's and it has a switchable 110 or 220 voltage selector. Hardly a recent concept!

edit: and as far as guitar amps, the 1987 Marshall schematic shows a selectable voltage switch.

My mom and dad have an old Grundig tube radio from the 50's as well. Next time I'm over there, I'll have to take a look at it. Never saw one in a bass or guitar amp until recently, though, Marshall notwithstanding.

[Jerrold Tiers]

Marshall has had switches, usually with a bunch of voltages from 100 to 240, and we even made a few units with 120/240 switches.

If you needed a "tool" like a screwdriver, to reset them, you could avoid the issues, so we usually put a screwed-down cover over the switch.

more recently, we wanted to allow 100/120/220/230/240, and that doesn't all fit on a single switch, unless the transformer is made like a Marshall , which is a bit inefficient on transformer usage, since the Marshall switch has only ONE wire switched, meaning that at 120V a considerable amount of winding is unused.

[Sifl]

My Sound City 150 bass amp from '74 has a voltage selector. 105/115/225/235

Pull out the knob and line it up to the desired voltage.