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

[KR4HV]

I'll see what I did wrong.  In the meanwhile I'll send it to anyone that
wants the pdf or excell file.  Same info on both.

-----Original Message-----
From: rbethman [mailto:rbethman at comcast.net] 
Sent: Sunday, March 16, 2014 4:47 PM
To: r-390 at mailman.qth.net; kr4hv at numail.org
Subject: Re: [R-390] R-390 Non-A...have a question

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
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