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Audiophile quality variacs to decrease voltage?

I have an older 30 w.p.c. tube amp that should be run with 110-115 Volts coming into the unit. The average voltage coming from my AC lines is 124 volts, which puts the operating voltages inside the amp well above what it should be, and will cut short the life expectancy of various components and tubes in the amp. I purchased a newer model 10 amp variac to reduce the incoming voltage to the amp, but quickly found that the sound quality was noticeably reduced with the variac in line, at any voltage set between 100 and 124 volts when in use. Are there any "audiophile quality" variacs available, or some that "sound" better than others? I researched power conditioners that might have the feature of reducing output voltage, but the only solution I found were the new PS Audio Premier power plants that can do this. Unfortunately, they retail for $2,000, and my budget does not allow for such a purchase. Even at used prices, their reliability seems to be an issue from posts I have read on them. Any suggestions from others who have suceeded at reducing voltages without ill effects? Thanks for your help!
bigshutterbug
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albertporter
4,949 posts
 
Perhaps a step down transformer, designed to operate Japan electronics within the USA?

I have one made by Hammond, if you input 121 volts it delivers 105 volts at the plug. With your voltage near 125, you might hit a perfect 110-112 volts.

http://www.hammondmfg.com/179.htm

I suggest the one rated for 1500 Va to insure headroom.
eldartford
4,262 posts
 
How sure are you about the 124 volts? I would doublecheck this before buying anything. Also check the other leg of the 220 volt input to your house. Maybe the other leg is 8 percent low which means you have a neutral grounding problem. It is not unusual to see a volt difference, but 18 volts (+9 to -9) would be bad. (Does anyone know what spec the power company is obligated to maintain?)

If the 124 volts is correct that's just less than 8 percent high. Don't worry about filiaments. (Has anyone ever had a filiament burn out?) Your plate voltages will be 8 percent high but different amps run the same tubes at different plate voltages so I doubt this will be a problem.

Look at the bright side. You have a 32.4 watt amp :-)
eldartford
4,262 posts
 
Even better...it's a 35 watt amp! (E^2/R not E/R).
infinity_audio
186 posts
 
THE BEST PRODUCT FOR THIS IS A TICE TITAN / POWERBLOCK POWER CONDITIONING COMBO. IT ALLOW A ADDITION/DEDUCTION IN VOLTAGE WITH A FLICK OF A COMBINATION OF TWO SWITCHES. AT THE SAME TIME YOU GET CONDITIONED POWER. I USE IT WITH MY OLD CARY WITH GREAT RESULT.
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albertporter
4,949 posts
 
Eldartford, did you understand the posters question?

He's obviously measured 124 volts at his place and stated:
I have an older 30 w.p.c. tube amp that should be run with 110-115 Volts coming into the unit.

I take this to mean the design is from the 1950's or 60's when USA voltage was lower.

As for measuring the other leg of his 220, that's not a bad idea but running another line to access that side of the transformer would cost more than the transformer I provided a link to.

Also, I doubt the two sides of his 220 are that far apart, the other side could be higher or lower. Even if lower, probably nowhere near 110 volts he's shooting for.

Too late to advise him to not spend money, he's already purchased a Variac in hope of protecting his investment. Unfortunately Variacs are famous for turning good sound into BAD.

If I misunderstood the question I hope Bigshutterbug will post back and clarify, but that's the meaning I derived from his question.
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