[R-390] Subject: Re: R-390 Audio Transformer

[Steve Hobensack]

Mike,
My TCS rx uses C and 0.62 watts for primary and c & 16 ohms to the speaker voice coil found experimentally. I don't remember the connections on the R-390 because I use the filament transformer. You can find it experimentally by listening for best/loudest sound by ear or you can use a Simpson 260 VOM on A/C. Put the R-390 on calibrate with a 1000 cps tone output, look for max volts on the speaker.
Steve N8YE 

> Message: 4
> Date: Sat, 21 Apr 2012 07:36:18 -0700 (PDT)
> From: Michael OBrien <mikobrien at yahoo.com>
> Subject: Re: [R-390] R-390 Audio Transformer
> To: Steve Hobensack <stevehobensack at hotmail.com>
> Cc: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> Message-ID:
> <1335018978.67779.YahooMailNeo at web130206.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
> 
> Hi Steve
> I have 1 or 2 of the RS 70v line transformers Do you remember what taps to use?
> Mike
> 
> 
> 
> ________________________________
> From: Steve Hobensack <stevehobensack at hotmail.com>
> To: r390 reflector <r-390 at mailman.qth.net> 
> Sent: Saturday, April 21, 2012 10:17 AM
> Subject: Re: [R-390] R-390 Audio Transformer
> 
> 
> An 18 volt filament transformer will do the same thing as the more expensive audio transformer. 120 to 18v is the ratio for maximum power transfer that I found experimentally.? Radio shack used to sell them. I don't know if they still do. I don't know about the frequency response though. I also compared it to a multi-tapped 70 volt line to voice coil transformer, and my ear couldn't tell the difference.
> Steve N8YE