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Re: [Amps] Buck-Boost Transformer Selection

To: "Joe Subich, W4TV" <>, "" <>
Subject: Re: [Amps] Buck-Boost Transformer Selection
From: Steven Katz <>
Date: Wed, 25 Jun 2014 20:08:12 +0000
List-post: <">>
I don't know why anyone would want to reduce the line voltage for use with the 

It's a switchmode power supply with "universal input," and will become more 
efficient at higher line voltages.  The VP-1000 manual states on page 2 
"capable of operation from 100 to 240V at 50 or 60 Hz," which is very typical 
of switchmode power supplies such as those in our computers.  The IEC standard 
tests such equipment at +/- 5% of whatever the specified rating is, which would 
be 95V to 252Vrms.

I wouldn't do anything except plug it in and use it.


-----Original Message-----
From: Amps [] On Behalf Of Joe Subich, W4TV
Sent: Wednesday, June 25, 2014 1:00 PM
Subject: Re: [Amps] Buck-Boost Transformer Selection

The issue is that the Quadra was designed for the Japanese market in an era 
where the common input power level was 100/200 V and typical maximum voltages 
were 220V.  As such a 240 V maximum input voltage is entirely acceptable ... 
particularly considering that the 240 V spec even covers 110/220V that was 
common in North America at the time.

The VP-1000 (Power Supply) manual specifies 14A at 200/220/234V input.
I would be looking for a 250 to 220 V boost/buck transformer rated for 15A to 
be safe.  Solid state amplifiers of this generation tend to have somewhat lower 
efficiencies than modern tube amplifiers - around
40 to 50%.  At 1000W output the amplifier is specified for 48 A at 48V
(2300 W) input - consistent with the rated 14A input.


    ... Joe, W4TV

On 2014-06-25 3:25 PM, Bill Turner wrote:
> ORIGINAL MESSAGE:          (may be snipped)
> On 6/25/2014 12:18 PM, Adrian Flynn wrote:
>> If you monitor the line voltage closely you will find that the "Power 
>> Companies" are slowly raising the *Normal Line Voltage* to /*125 
>> volts per leg and 250 volts* *for both legs!*/
> Nevertheless, I would ask the power company to fix it. If they refuse, 
> then go from there.
> 73, Bill W6WRT
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