[R-390] R-390 Non-A...have a question

[rbethman]

Walt,

This link simply goes to a "box". This asks for email address then Password.

Regards,
Bob - N0DGN

On 3/16/2014 4:39 PM, KR4HV wrote:
> John & Roger, here is a link to my file on Box.com that may help someone. It
> is a chart that details some parameters of common public address line to
> voice coil transformers.  They will work well in this application. If you
> are an audio purist you can even buy very high quality Hi-Fi ones for high
> $$ vs the $4-10 ones I use.  Hi! Hi!
>
> Copy and paste in browser(a .pdf file)
> https://app.box.com/files/0/f/554495476/1/f_5314152110
>
> Both this PDF and an Excel file are on box and open to all to download if
> you like.
>
> Enjoy your R390A!
>
>
> Regards,
>
> Walt
> KR4HV
> kr4hv at numail.org
>
> "There is no excuse for doing a job poorly.  Just do it right.  If you don't
> know how, engage someone that does"  WM
>
> "It is now more difficult to obtain a driver's license in most states than
> to obtain an Amateur Radio license. Citizen’s Band déjà vu."WM
>
> "Why would one celebrate an eight year old obtaining an Amateur Extra Class
> license? Isn’t it very demeaning to that license class, the examination, the
> entire licensing process and Amateur Radio? Think about it."WM
>
>
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Roger Ruszkowski
> Sent: Sunday, March 16, 2014 2:58 PM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] R-390 Non-A...have a question
>
>
> John,
>
> You have to remember the Audio out is 600 ohms and only a 1/2 watt at best.
>
> There is no indication in your post that you have used a 600 ohm speaker or
> that you are running a transformer (70 volt  speaker transformer) between
> the output and your speaker.
>
> How much power out are you getting.
>
> Your AC volt meter may have a DB scale on it or you can read AC volts and
> convert  the value to watts. you are looking for about 15 to 17 volts AC
> across a 600 ohm resistor ( two each 1200 ohm in parallel makes a nice 1/2
> or 1 watt load resistor).
>
> You may have poor audio output. But you only get a 1/2 watt and if you are
> not matching the 600 ohm output to the speakers the level will be very low.
>
> Radio shack use to have matching transformers mostly used for taping several
> speakers in an area to a single PA amplifier. they come under several names
> and in different power ratings. As you only have a 1/2 watt to work with any
> 4 or 5 watt size will work. Some pair of taps on the primary and some pair
> of taps on the secondary will match the 600 ohms to a 4 or 8 ohm speaker or
> set of head phones and provide good listening level audio. If you need more
> than the 1/2 watt then use the line out audio into a PA amplifier and
> speakers.
>
> Roger AI4NI
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>