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: 2 Guest(s)
[-]
Recent Posts
An attempt to remove the Field Coil from a G speaker
Gary I in fact did, on a 38-14, I think, where I had a speaker with the dead coil. Well...it kinda worked. Kinda, be...morzh — 10:38 PM
An attempt to remove the Field Coil from a G speaker
Mike, what ever happened to that plan you had to try using a rare earth magnet to magnetize the pole? This looks like a...GarySP — 10:25 PM
RCA T62 is playing.....
Beautiful set.morzh — 09:07 PM
An attempt to remove the Field Coil from a G speaker
Well....here it is. The green stuff. Unfortunately, probably penetrates deep. I opened the top layer and saw that: ...morzh — 08:58 PM
Philco 91 Restore Code ??
:clap: :clap: :clap: :clap: Really nice workmanship!!! Top of the chassis looks great. Sorry about the long winded e...MrFixr55 — 08:09 PM
Philco 40-120C Restoration
Thank you for your reply. I will check voltages on the other tubes, look at resistor 23 and cap 25, etc. If all else fai...bluecap — 07:58 PM
RCA T62 is playing.....
Nice looking set great save. DavidDavid — 07:48 PM
Philco 89 indicator light.
Hello Jim, I have done several 89s. The trick is to move the drum in or out on it's shaft. You will need to loosen a set...dconant — 07:36 PM
An attempt to remove the Field Coil from a G speaker
MrFixr Yes, it is my plan to go with 45rpm spider if I go that far. No, the pole was not left-handed as I unscrewed ...morzh — 07:14 PM
Philco 40-120C Restoration
Change the tube. Check the tube's bias network. Are any other tubes experience the drop or just this?` Is resistor 23 OK...morzh — 07:09 PM

[-]
Who's Online
There are currently no members online.

>