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37-690
#24

Yes, it will be really interesting to hear it when done. What you have now appears to be the ultimate pre negative feedback PP triode audio amp. Those LS transformers were guaranteed to be flat between 20 Hz to 20 KHz to within 1 dB.

It looks like some of the electrolytics may have also been replaced with the more modern twist-prong FP types at some time.

You might get some idea of when the work was done by looking at the date codes of the 6A5G's. They appear to be late 30's or 40's manufacture. The codes are located on the base to the right of the PHILCO logo.


Messages In This Thread
37-690 - by thirtiesradio - 11-21-2013, 08:07 PM
RE: 37-690 - by codefox1 - 11-21-2013, 08:18 PM
RE: 37-690 - by KCMike - 11-21-2013, 08:24 PM
RE: 37-690 - by Skip - 11-21-2013, 09:02 PM
RE: 37-690 - by thirtiesradio - 11-21-2013, 09:40 PM
RE: 37-690 - by Skip - 11-21-2013, 11:31 PM
RE: 37-690 - by Jayce - 11-21-2013, 11:59 PM
RE: 37-690 - by thirtiesradio - 11-22-2013, 12:53 AM
RE: 37-690 - by ipwizard - 11-22-2013, 01:58 AM
RE: 37-690 - by Gene Pederson - 11-22-2013, 10:43 AM
RE: 37-690 - by sam - 11-22-2013, 11:42 AM
RE: 37-690 - by thirtiesradio - 11-22-2013, 01:21 PM
RE: 37-690 - by Bill Kinghorn - 11-22-2013, 02:17 PM
RE: 37-690 - by thirtiesradio - 11-22-2013, 07:16 PM
RE: 37-690 - by Bob Andersen - 11-22-2013, 08:09 PM
RE: 37-690 - by thirtiesradio - 11-24-2013, 02:14 AM
RE: 37-690 - by y2kbruce - 11-24-2013, 10:45 AM
RE: 37-690 - by thirtiesradio - 11-24-2013, 01:40 PM
RE: 37-690 - by Bob Andersen - 11-24-2013, 04:24 PM
RE: 37-690 - by thirtiesradio - 11-29-2013, 12:02 AM
RE: 37-690 - by thirtiesradio - 11-29-2013, 01:04 AM
RE: 37-690 - by Mondial - 11-29-2013, 11:52 AM
RE: 37-690 - by thirtiesradio - 11-29-2013, 02:37 PM
RE: 37-690 - by Mondial - 11-29-2013, 04:17 PM
RE: 37-690 - by thirtiesradio - 11-29-2013, 06:56 PM
RE: 37-690 - by Mondial - 11-29-2013, 10:45 PM
RE: 37-690 - by thirtiesradio - 11-29-2013, 11:40 PM
RE: 37-690 - by Mondial - 11-30-2013, 11:08 AM
RE: 37-690 - by thirtiesradio - 12-01-2013, 04:53 PM



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