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
Correct model 84 Ac plug an cord type
From what I read Philco went to using brown rubber power cords in 1936, so cloth was used in the 1935 and earlier models...Arran — 11:25 PM
Correct model 84 Ac plug an cord type
Hi Bruce, I have not worked on an 84, but in general, power cords for almost any radio prior to 1938 was cloth covered...MrFixr55 — 08:34 PM
Restoring Philco 38-14
OK, well, so after staring at the sch again, I realized the problem had to be the #12/12A padder. I put a scope on the o...morzh — 08:15 PM
Correct model 84 Ac plug an cord type
Hello Bruce, I mostly use brown far as my cloth powercords go ! Here is the plug that I have used bakelite Acorn style...radiorich — 08:05 PM
Correct model 84 Ac plug an cord type
Looking for as correct as can find the right Ac plug an the correct colored cloth line. Ive seen many old photos but mos...Bruce — 04:13 PM
Restoring Philco 38-14
Rod Two Y-caps make sense if you use them from L/N to the chassis; this is only makes sense in the transformer radios...morzh — 10:11 AM
Restoring Philco 38-14
Mike, I'm curious about a specific use of he Y cap. Lately I've seen a single cap across the power transformer primary. ...RodB — 09:01 AM
Restoring Philco 38-14
hello morzh , That sounds like a plan ! Sincerely Richardradiorich — 07:45 AM
Restoring Philco 38-14
Richard, It helped some, but I still had the whining when engaging the rear power strip (I did not realize it was fro...morzh — 07:07 AM
Restoring Philco 38-14
Hello morzh, Yes , that dreaded hum in my room where i do alighment I have my cable modem and router plus desktop plus ...radiorich — 11:25 PM

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

>