[R-390] 600 ohm audio

[Roy Morgan]

Late to comment also:

The original poster showed a photograph that he ALREADY HAS A VERY FINE line to voice coil transformer. 

Attached is the data sheet from a 10-watt line transformer. The 10-watt line input tap is rated at 500 ohms impedance - this is ideal for the R-390A line output to drive a normal speaker. 

Some notes:
-Stated impedance of speakers VARY GREATLY over the range of audio frequencies
-The R-390's radio maximum audio output available power is about ONE WATT (?)
-A reasonably efficient speaker gives you plenty of sound driven by a small portion of a watt. 
-Most any line to speaker transformer will "work a treat", even though original costs and quality levels varied greatly**
-Some such transformers are meant for 25 volt lines. Input impedance for them at corresponding power levels will be lower. 

**My security contractor suggests that I neither confirm nor deny that I have a pair of Altec Lansing Peerless Type 15066 line transformers rated at 8, 16 and 32 watts operating level. 
 

-------------- next part --------------
A non-text attachment was scrubbed...
Name: image2.jpeg
Type: image/jpeg
Size: 948540 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/r-390/attachments/20220219/b1f409a2/attachment-0001.jpeg>
-------------- next part --------------


Roy Morgan
K1LKY Western Mass
K1LKY68 at gmail.com

> On Feb 19, 2022, at 10:33 AM, Tisha Hayes <tisha.hayes at gmail.com> wrote:
> 
> ?(Sigh) late to the conversation but I have a few things to add;
> 
> If you are going to browse through ebay for 600 ohm to 8 ohm transformers
> they can be a little pricey.