Voltage Regulator

[ezra1]

I have some Vintage Amps and would like to run them at 110 volts instead of 120 volts.
Any recommendations ?

 

[Old Garage-Bander]

I'm not sure I understand your concern.
Any amp designed to work on the US power grid will work regardless of 110 or 120.
You are essentially splitting hairs of the power grid tolerance and the equipment designed to be used in the US.

Now if your concern is about an amp with a 2 prong plug vs a 3 prong. That also is not a concern for the operation of the amp in terms of voltages. You may wish to consider having a new, grounded power cord installed by someone qualified to do so. But the 110 vs 120 volts is not an ussue.

The power grid is backwards compatible with older gear.

 

[Flippy]

I'm not sure I understand your concern.
Any amp designed to work on the US power grid will work regardless of 110 or 120.
You are essentially splitting hairs of the power grid tolerance and the equipment designed to be used in the US.

Now if your concern is about an amp with a 2 prong plug vs a 3 prong. That also is not a concern for the operation of the amp in terms of voltages. You may wish to consider having a new, grounded power cord installed by someone qualified to do so. But the 110 vs 120 volts is not an ussue.

The power grid is backwards compatible with older gear.

Some folks claim that old amps, especially tube amps, sound differently when supplied a lower voltage. I don't know a thing about that, but that's what some people say.

EDIT: This guy talks about this right at the 7 minute mark

 

[ezra1]

I think the older amps sound better at 110v.
That is just my opinion.

 

[Old Garage-Bander]

I think the older amps sound better at 110v.
That is just my opinion.

I certainly won't dispute that there may possibly be some sonic differences, even though negligible, I suspect.
That is more a factor of brute force power supplies that while they removed ripple weren't all that good at keeping a constant voltage with varying inputs. That's why I asked why you were concerned about it. As there was no mention in the first post.

The point is that unless you have a variac to control the AC voltage down from "120" to "110", the actual voltage at the wall is a crapshoot. It could be lower than 110, it could be more than 120. Always has been that way since we were looking for an outlook to plug in our amps.

-edit- I like the idea of isolated power. Just me... transformers are cool. But the guy in the video is limiting himself by using only a transformer.
IMHO, anyone who is concerned about how the A.C. voltage levels on the power grid being too high for their sonic taste, should have variac with a voltmeter so you can adjust and monitor the voltage feeding your amp. Transformers and variac capable of handing the currents involved will be very pricey. If that's what it takes to achieve the tone you want and you are willing to pay the price, then by all means, go for it. Just be aware that you are messing with those things not intended to be messed with. In other words... Boys and Girls, consult an electrician, otherwise do not try this at home.

 

[beans-on-toast]

Here is a nice variable transformer. You would need a voltmeter to set it.

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I use this one:

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[Old Garage-Bander]

Here is a nice variable transformer. You would need a voltmeter to set it.

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Will it fit on your pedal board?

What's the right amount of AC for metal?

 

[beans-on-toast]

Will it fit on your pedal board?

What's the right amount of AC for metal?

I prefer not to operate it with my foot, so it doesn't go on the pedal board.

With Marshalls in Europe, 234 VAC is apparently optimal. But Angus Young (AC/DC) insists on 236 VAC, less is too spongy. Otherwise, it depends on the amp. I find that the voltage does matter if you are pushing the amp hard.

Of course, whatever the line voltage chosen, if it is a fixed bias amp, the bias should be set for optimal performance. Then the amp whould always be operated at that voltage. If it is a cathode biased amp, rebiasing is not necessary.

 

[agedhorse]

I think the older amps sound better at 110v.
That is just my opinion.

There are just as many who feel that amps sound better at 120V too.

 

[ezra1]

I am an Industrial Electrican by trade.
I spent about 11 years repairing old tube amps until I got burnt out dealing with the public.
Back then I had a variac with an ampmeter on it.
Wish I still had it now.
I was just wondering if there was anything new out there that would do the job.
If I got another Variac,I could use my Fluke to make certain that I got 110 volts.

 

[Old Garage-Bander]

I am an Industrial Electrican by trade.
I spent about 11 years repairing old tube amps until I got burnt out dealing with the public.
Back then I had a variac with an ampmeter on it.
Wish I still had it now.
I was just wondering if there was anything new out there that would do the job.
If I got another Variac,I could use my Fluke to make certain that I got 110 volts.

How was a variac not the first thing that came to mind?
eBay?

 

[ezra1]

I can't find one like I used to have, hence asking for advice.
The one posted by Beans looks good.

 

[BassmanPaul]

My variac came out of a lighting system console. It's rated at 20A. it's big and heavy and gets used only once in a while.

 

[beans-on-toast]

You can find good used US made variable transformers for way more affordable prices.

I've also seen some pretty bad, made in China, ones. I doubt that they had legal regulatory approval. When it comes to a tool like this, you want quality.

The most affordable option would be a bucking circuit. It will reduce whatever the the line voltage is by a fixed amount.

 

[Slevage]

Variac or Powerstat.

Both trade brands for a variable auto transformer.

 

[beans-on-toast]

There are voltage regulators that some bands carry. You dial in the desired voltage and the unit delivers what is specified.

Here is one example:

The PCR-LE is the newest product.

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[Drgonzonm]

This is my opinion, At one time radio shack had a two amp 120 to 12v step down with a center tap. This transformer can be adapted to give zero, six or twelve voltage drop from the wall. Forums that specialize in tube amps can lead you to the design.
I do not think that reissues should have their voltages dropped.
Before I would drop the voltages I would review the the schematic. Then I would match the power transformer, to the schematic.

Got to do some home work.
El34world has schematics there are other sites

 

[Wasnex]

There are just as many who feel that amps sound better at 120V too.

I think it depends on the amp. Generally I believe most Fender, Marshall, and Hiwatt amps work fine on 120 volts 60 hz, but it can be fun to brown them out a little.

Now vintage Orange, Matamp and Vox may be a different story. I think the power transformers in these amps go a little agro on 60 hz. I know it's an issue with my JMI era Vox AC 30 and 76 Matamp GT120.

 

[Old Garage-Bander]

This is my opinion, At one time radio shack had a two amp 120 to 12v step down with a center tap. This transformer can be adapted to give zero, six or twelve voltage drop from the wall. Forums that specialize in tube amps can lead you to the design.
I do not think that reissues should have their voltages dropped.
Before I would drop the voltages I would review the the schematic. Then I would match the power transformer, to the schematic.

Got to do some home work.
El34world has schematics there are other sites

Done that exact thing myself to create a poor man's isolation transformer.
Those RS transformers won't handle a lot of current.
It also doesn't get 120 volts down to 110.
But the OP will know that because he's an electrician.

 

[agedhorse]

There are commercial buck-boost transformers that will better and more safely handle the current.

Note that current calculations are done differently on auto-transformers and buck-boost transformers. Worth reviewing the math, I have to for the rare occasion that I need one.