[Amps] Expert 1k amp

[peter chadwick]

Steve,
How much filtering is there to meet EU regs on noise put on the mains, and is there any power factor correction circuitry?
73
Peter G3RZP





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Message Received: Mar 07 2013, 08:50 AM
From: "Steve Thompson" 
To: amps at contesting.com
Cc: 
Subject: [Amps] Expert 1k amp

Yesterday I did some minor repairs to a friend's amp - resoldering 
joints on the current sensing resistor. Looking at the circuits 
later I noticed that the main supply voltage is regulated by 
having SCRs in place of diodes rectifying the transformer 
secondary and the main smoothing capacitor is 47000uF.

My friend tells me the amp runs over 40A at full tilt, which means 
something like 8.5V ripple on the supply (7V at 60Hz). That 
strikes me as quite high and I'd expect to see some difference in 
amplifier gain/output if I was running such an amp off a regulated 
supply and altered the voltage that much. Has anyone measured one? 
Is any 100/120Hz audible on a carrier?

Steve
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