[Collins] Transformers

[antqradio at sbcglobal.net]

Comments in Blue.


________________________________
 From: Carl <km1h at jeremy.mv.com>
To: antqradio at sbcglobal.net; Collins at mailman.qth.net 
Sent: Thursday, August 29, 2013 5:09 PM
Subject: Re: [Collins] Transformers
 

Jim,
1. Ive yet to pay more that $1.50 for a 1-2A transformer and under $10 for the bigger ones mentioned prior.
Good for you, you must go to better Hamfest then I get the chance to go to.

2. You bounce around from an AA5 to no real details but a power resistor for a set that draws 70-140W or more wont be .74.
Your right, it is $0.64 less shipping, see:
http://www.mouser.com/Passive-Components/Resistors/Wirewound-Resistors/_/N-7fx9f?P=1z0x6zbZ1z0wt4wZ1z0z819

3. Adding a 10W resistor in an already packed to the limit AA5 chassis is asking for trouble. Putting a 50W resistor in a big radio is no different.
AA5s don't use power transformers.  Why do you mention a 50 watt resistor?  Hyperbole?

4. Adding a resistor to a radio with PP AB1, AB2 or B audio will just add distortion due to the added lack of regulation plus what Jerry mentioned.
Like I have said already, I have no issue with using the Bucking Transformer, but for some lower powered applications, the series resistor will work just fine.

5. Using a resistor is the cheapskates way out (-; and reminds me of those that reform a 50-70+ year old electrolytic or leave the paper caps in since the radio "plays well".  I wonder how many 75A4's were junked with bad transformers? I still use the one I bought in 1965.
Cheapskate to some, thrifty to others; I thought that this was the Ham credo.  So you don't have a radio you like that is not much of a performer but you keep around anyway?  

While I realize that Collins receivers never had PP audio or sounded good either that doesnt mean that some of us dont have radios that sound good for ham AM, SWLing,  the BCB, or to play old fashioned phonograph records thru a radios audio section as I do. Some include a Scott 800B with PP 6550's (originaly 6L6G's), or want to rattle windows with a Philco 38-690 and 6L6G's, Scott AW 23 with four 2A3's, or one of many senior Hallicrafters and Nationals with just PP 6V6's or 6F6's.
Even my AC/DC NC-46 with PP 25L6's qualifies and sounds great thru the matching speaker.
Good for you.  I hope you are doing something to reduce the temperature in the transformer.

I do have several AA5's and a complete Zenith T/O collection but I dont use them other than as shelf queens. Im into more useable radios.  My biggest receiver-exciter is a 310F-6, a fun radio.  For some reason I enjoy the early synthesized radios.

And dont forget that your transmitters also benefit with a bucking transformer. That 32V whatever already has a history of transformer problems and keeps rewinders busy.
Well that doesn't make any sense at all.  Why would one rewind a transformer to the old line voltage spec and then have to replace it when it makes more sense to specify 125 vac instead of 110 or 117 the first time?

Transformer manufacturers used to sell bucking or boost transformers, I have and use several in the 500-2500W variety with home brew amps and modulators and built in as part of the PS as intended back when built. Some are older than me (-;
So in high power applications, it makes perfect sense to use the Bucking Transformer.

Carl
KM1H