There is no doubt I have high voltage spikes, which have caused damage to 3 rectifier tubes, and blew fuses on my variac. My electric voltage runs at an average at 122 to 127.3. I would prefer not to use the variac, is there a way that I can convert my ST-120 to a ST-70?
2 posters
ST-120 to ST-70 conversion?
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
The easiest and most reliable way to convert a vta-120 to a vta-70 is to sellmusic wrote:There is no doubt I have high voltage spikes, which have caused damage to 3 rectifier tubes, and blew fuses on my variac. My electric voltage runs at an average at 122 to 127.3. I would prefer not to use the variac, is there a way that I can convert my ST-120 to a ST-70?
the vta-120 and buy a vta-70. Conversion would be expensive ( mains transformer)
and risks of failure.
Best would be to seek contact with someone that would like to exchange
his vta-70 to a vta-120.
But the trouble with high mains voltage remains even if you change to a vta-70.
Why not get a step-down transformer that reduces by 6 - 8 volts ?
I have seen participants on this fora presenting their step-downs here, they
might even build one for you !
Bob Latino- Admin
- Posts : 3277
Join date : 2008-11-26
Location : Massachusetts
music wrote:There is no doubt I have high voltage spikes, which have caused damage to 3 rectifier tubes, and blew fuses on my variac. My electric voltage runs at an average at 122 to 127.3. I would prefer not to use the variac, is there a way that I can convert my ST-120 to a ST-70?
If your line voltage varies from 122 to 127.3 VAC, then you need a variac to drop your line voltage into a safe range (116 - 121 VAC). Yes - a VTA ST-120 is more sensitive to higher line voltages than a VTA ST-70, but a the ST-70 will also have problems with your higher line voltages. Get a variac OR a power conditioner that puts out a true sine wave. The power conditioner will be a lot more expensive. The 5 amp variac at the link below will work fine with your amp ..
Variacs at Circuit Specialists
Bob