DIYbanter - View Single Post

Tom Biasi[_3_]

On 12/3/2018 12:15 PM, wrote:
On Sun, 2 Dec 2018 19:38:33 -0500, Tom Biasi
wrote:

On 12/2/2018 3:46 PM, wrote:
On Sat, 1 Dec 2018 20:45:41 -0500, Tom Biasi
wrote:

On 12/1/2018 3:47 PM, wrote:
To All,
I need to power an amp that draws just under 1.5 amps at 110 volts.
I measured the current it draws when powered from my variac. The
voltage to the amp should be within 5% according to the documentation.
The voltage in my house measures 122 volts to 126 volts, varying
during the day. So bucking 12 volts should be fine.
I am looking at a 120 volt to 12 volt center tapped 5 amp rated
xmfr at PartsExpress. The VA of the xmfr is not listed in the
description. I want to connect this xmfr in buck configuration. Since
I will be bucking 12 volts at approx 1.5 amps this equals 18 VA. At
least that's how I remember how to calculate VA from connecting big
buck xmfrs to one of my machines several years ago. I think the 12
volts at 5 amps secondary means that the xmfr is 60 VA. But I'm not
sure because it is center tapped. It shouldn't make any difference,
right? If I used the center tap and just bucked 6 volts then the VA
rating would be 30, wouldn't it?
Thanks,
Eric

If all the 110 volts does is make DC why can't you just clamp the DC?
It's a tube amp. Seems easier to just feed it the correct voltage.
Eric

I'm just curious as to what product has that spec. 110 VAC on an old
amplifier means line voltage in North America. The 5% is odd to me.
Nobsound. Who knows why the spec but I don't want to burn up expensive
tubes prematurely.
Eric

Do you have a model number?