Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

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

Question about replacement transformer for 37-660
#1

I have am looking for a replacement for the output transformer for this radio. I have a line matching transformer with 5 primaries: 500 ohm,1k,2k,4k,and 8k. Output is 4ohm or 8ohm, listed as 10 watts.
Radio schematic calls for 370 ohm and 330 ohm ct primary on transformer (has two 6f6's)
Will this work on this radio? If not, any suggestions on what will work for a replacement?
Thanks,
Bill
#2

Just remember that those "300 ohm" DC resistance numbers on schematics have nothing to do with audio impedance values. You can forget those DC numbers for this exercise.

You should be up in the 'several K' numbers for impedance on the primary. I'd go with the 4k/8k options. It will vary if you feed a 4 vs an 8 ohm speaker. An original Philco speaker of that era will be closer to 4 rather than 8 ohms. I think they lean towards the ~ 2.6 ohms neighbourhood .

The AF xfmr behaves as a 'ratio' animal to match the tubes to the speaker at AUDIO frequencies. Just try it and see. Dunno your specific transformer but you should be able to come close to spec. Lots of leeway.

-Bill
#3

Thank you for your help. I will try it at 4k.8k primary, l don't understand the impedance vs resistance on these transformers. It does have an original philco speaker, but not from this radio. Is the 330/370 ohm value in the schematic significant as far as the load on the audio tubes?
Thanks,
Bill
#4

Hi,
No, those resistances are simply noted as a troubleshooting aid so that a repairman would know what to anticipate while troubleshooting with an ohmmeter.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco Model 249 made in England
Gary - Thanks for responding!  I hadn't actually taken possession of it at the time of my post but since you said it was...fklown — 03:32 PM
Philco model 40-100
Marion; Replacing volume controls was something some service shops did in years gone by to make a little extra profit...Arran — 03:24 PM
Philco Model 249 made in England
Welcome to the Phorum, fklown!  That's one heck of a Philco 'yardstick' you've got there!  Could you possibly post a clo...GarySP — 03:19 PM
Philco model 40-100
Arran, Thank you so much for your assistance and the link to the fleabay listing! They say a picture is worth a thousan...mhamby — 01:43 PM
Philco Model 249 made in England
I wonder if anyone has any information or experience with this model.  My internet searches are coming up with nothing. ...fklown — 11:40 AM
Road Trip for a Philco 46-480
Good morning, folks! I’ve finished the cabinet and the electrical restoration, and have detailed those in their respecti...jrblasde — 10:56 AM
Studebaker/Philco AC-2687 car radio
Arran, Thanks for checking you manuals. I appreciate that. Let me know what you find. PhilPdouglaski — 08:46 AM
Studebaker/Philco AC-2687 car radio
I have some car radio service manuals, Riders I think (not to be confused with the big blue binders), so I may see if on...Arran — 01:20 AM
Philco model 40-100
Greetings; Here is an update, I found a listing on fleabay for a similar chassis to yours, and it has a photo of what...Arran — 12:58 AM
Philco model 40-100
Greetings; I think I may have found a clue as to what is missing, from a search I made, there is a rear view of the c...Arran — 12:12 AM

[-]
Who's Online
There are currently 765 online users. [Complete List]
» 3 Member(s) | 762 Guest(s)
AvatarAvatarAvatar

>