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

Hammond Output Transformer Feedback Loop Workaround
#1

Hello,

I'm replacing a Philco output transformer on a 39-40. I'm wondering how to work with the center tap connection on the primary or where the center tap used to be as well the feedback center tap on the secondary. I did read an earlier post about taking the high side of the secondary for the feedback. I was little uncertain about going about it. Can anyone help me out. Thanks.
#2

The center tap on the primary side isn't going to do you any good for feedback as there is no audio present at that point just HV. The feedback loop will have to be connected to the secondary. I would just experiment with the different taps till you find something you like. I'm assuming that the transformer has a multi tap secondary. If it oscillates (squeals) reverse the connections. That's called positive regeneration what you want negative feedback or negative regeneration.
Good luck!
Terry

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco Battery-WWII vintage
My younger sister went to SUNY Plattsburg NY, (BS, MS, RN) in the late 1970sabout 10 min from the Northern NY / Canada b...MrFixr55 — 07:59 AM
Philco Battery-WWII vintage
Hello Bob, What Amazing find! Sincerely Richardradiorich — 10:19 PM
Testing a speaker and output transformer Trutone A2-G
Hi Murf, Do this: Monitor between ground and one plate of the rectifier while playing the radio.  Do the same with ...MrFixr55 — 09:51 PM
Philco Battery-WWII vintage
Mike; I take it that Soviet cars did not come equipped with block heaters, hence the hot oil change? Where I lived in...Arran — 08:42 PM
Philco 42-345 Restoration/Repair
The more the better. (Within reasonable limits.) 2-5 times more is no problem in this case.Vlad95 — 03:50 PM
Philco 42-345 Restoration/Repair
Thanks, RodB and Vlad95, I was mainly trying to figure out this capacitor to locate a replacement, Vlad thank you for...osanders0311 — 03:44 PM
Testing a speaker and output transformer Trutone A2-G
Would an output transformer if weak, cause the problems I am seeing with lower B+ voltage? murfmurf — 01:22 PM
Testing a speaker and output transformer Trutone A2-G
Hello murf! I merged the threads. Please do not start new threads regarding the same radio. Take care, - GaryGarySP — 10:21 PM
Philco 42-345 Restoration/Repair
Regarding picture 5 on page 1 of this thread this capacitor is #40 on scematics diagram - 4mF+4mF. Black wire is "-...Vlad95 — 09:01 PM
Philco 42-345 Restoration/Repair
That's a dual 4 MFD, red and green are both 4mfd and black is common negative. You should be able to see them in the pow...RodB — 08:58 PM

[-]
Who's Online
There are currently 328 online users. [Complete List]
» 3 Member(s) | 325 Guest(s)
AvatarAvatarAvatar

>