Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco newspaper articles 1940
#1

Here is a copy of a newspaper page from 1940 I ran across, describing the latest features of the 1941 Philco models.

Although it seems like all the writing was done by Philco's marketing department, there are some technical details among the hype. The advantages of the XXL (triode) mixer are discussed, along with the benefit of two IF stages, and the intermodulation problems sometimes caused by an RF amplifier stage. The beam of light phono pickup is also mentioned.

A little hard to read but interesting nonetheless.

http://fultonhistory.com/newspaper%2010/...200628.pdf
#2

I love this kind of stuff, thanks for sharing.

Paul

Tubetalk1
#3

Yes, thanks
#4

Yep, just like the Philco PR dept. sent them. But that's okay. We wouldn't know it if they hadn't done it.Icon_razz
#5

Using twin triodes as a mixer and oscillator seems to work quite well, though I don't have any sets that use the XXL tubes I do have two AC/DC sets that use an XXD/14AF7. What I can't understand is why they decided to use a triode as a mixer, maybe another patent royalty dodge? I also can't figure out why they used a silly designation for a tube like XXL or XXD, that must have been the marketing department's idea just to make them sound mysterious then just calling them 7A4s or 14AF7s.
Regards
Arran
#6

There is some legitimate technical basis for using a triode as a mixer. In general, the lower the number of grids in a tube, the lower the internally generated noise, called partition noise.

RCA did some research in the late 30's and found that multigrid tubes like hexodes and pentagrid tubes were the noisiest, followed by pentodes, and triodes being the quietest. So using a triode as the converter results in the lowest internally generated noise level. It is interesting that while RCA did the research, Philco actually put it into practice in their 1940's sets.

As to the XXL name, it seems that it was pure marketing. This way
Philco could claim that they were the only one using this particular "special" tube. Anyone could use a 7A4, but no one else had the "XXL".

http://www.radiomuseum.org/forumdata/use...e_TEXT.pdf
#7

I thought the XXL's were for big guys like me!Icon_lol

Paul

Tubetalk1




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 38-2 Automatic Tuning
Hi Richard, I enjoy it to some extent. I do that type of work out in barn (modern) during the summer on nice days when I...dconant — 03:13 PM
Philco 38-2 Automatic Tuning
hello dconant , my set is the tabletop one and it also needs refinished someone put plant or something on top and the f...radiorich — 02:56 PM
Philco 38-2 Automatic Tuning
Well, you could take a look at most features of those radios, and other than some very few of them, they all are selling...morzh — 02:20 PM
SABA 400 Automatic Stereo 11
I actually got to hear the SABA play today when I took my Westinghouse AM-FM up to be worked on and also now know a pric...Jayce — 02:08 PM
Philco 38-2 Automatic Tuning
Seems more like a selling point to me. I too have have a Philco with the Cone-Centric tuning. Hopefully I will get the ...dconant — 12:17 PM
Philco 38-2 Automatic Tuning
I found out, I never use it in my 37-116 and 38-690. I made sure it works, but this was it: I always hand tune.morzh — 10:55 AM
Philco 38-2 Automatic Tuning
Does it wash your windows? Then it would be useful and worth fixing. Music and window washing.RodB — 10:00 AM
Philco 38-2 Automatic Tuning
You press the lever (crank) and you rotate the dial into the desired position. Also, while pressed, the contact that it...morzh — 09:50 AM
Philco 91 Speaker Replacement
I do not have much experience with speakers, but acetone sounds right. It does not affect paper but does dissolve about ...morzh — 09:48 AM
Philco 38-2 Automatic Tuning
Hello Dconant, In my collection I have a model 38-7T which Philco called their famous "Cone-Centric" dial me...radiorich — 08:14 AM

[-]
Who's Online
There are currently 1705 online users. [Complete List]
» 1 Member(s) | 1704 Guest(s)
Avatar

>