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

38-38 conversion to AC?
#1

I recently acquired a Philco 38-38 at an auction. It is almost in perfect shape. Is it possible to convert this to run on AC? If so where can this be done?
Thanks in advanced
Greg
#2

I just got a 38 38t I think I Will convert mine to ac using the circuit for a 38 23t.

vinzer
#3

Geez I thought I had a lot of time on my hands.
Think it would be simpler to build a p/s to emulate the batteries. Well at least for the hv and filament supply the bias batteries would last a very long time.
Or you may want to consider building a battery pack that would power it. In this you can eliminate all of the interference from the ac mains. I have 39-80 (battery farm set) it plays quite well from batteries. Like supersized transistor radio.
The 1938 model use the older 2v tubes so a resistor in series is in order to drop 3v worth of battery power down to two. The '39 models use 1.5v tubes so D cell work fine.

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
#4

I built one for another battery radio but it  had room for batteries so I put it inside the radio but cannot do that on this one has no room for it . does  look to hard to change to ac.

Vinzer
#5

I did that exact same thing a couple of years ago. Find a suitable power transformer and use schematic for model 38-9.
#6

I think I will use a 38 23 schematic no power transformer needed

Vinzer
#7

I did it now what do I call its not a 38-38 any more no quite a 38-23?
#8

38-38 Renegade?

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#9

Sounds good to me.
#10

Well I got to feeling bad about making a Franken Philco still had original parts changed it back to original and made a power supply.
#11

That was probably the smart move, in my opinion, I've seen a few attempts where someone tried to convert a battery operated tube set into an AC set, with AC tubes, and they never seemed to produce a functional set afterward, they seem to get just so far, and then loose the handle. On the other hand I have seen a number of sets where someone retained the original battery tubes, and circuits, and constructed either an outboard power supply/battery eliminator to operate it from the AC power line, or built an inboard power supply in an empty area of the chassis, and almost all of those were successful. The nice thing about battery sets is that whilst the voltages and currents required are different from lets say a transistor radio, you can throw together a very good power supply using inexpensive off the shelf or salvaged parts.
Regards
Arran




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
462ron
Oh that sucks. It’s something easily overlooked. Hopefully it’s nothing more than a resistor! Ron462ron — 08:08 AM
Philco 46-480 Electronic Restoration
Just confirmed that you are correct. It’s the function generator. I connected the signal output probe to one of the inpu...jrblasde — 07:52 AM
Philco 46-480 Electronic Restoration
Ouch, you may be right. Yes, it is solid state. It’s the signal output of my oscilloscope. May be time to crack that ...jrblasde — 07:27 AM
462ron
If you didn’t put a DC blocking cap between the signal generator probe and the plate of the 1st IF it’s possible you ble...462ron — 07:07 AM
My Philco 37-116 Restore
Hi DConnant, The reason why C127 is isolated from ground is because sets of this vintage did not have the center tap...MrFixr55 — 01:07 AM
Philco 46-480 Electronic Restoration
The shield is on the 6H6. It was, in fact, a missing jumper to connect the main chassis ground to the RF chassis grou...jrblasde — 10:58 PM
Zenith H725
When dealing with noise on power lines, time to get my Jackery 240 out. Talk about clean can hold a portable am radio ne...David — 08:52 PM
Zenith H725
Arran - I bet you're right probably vinyl, there was no rubber smell when desoldering it, which you often get with the o...EdHolland — 08:23 PM
Zenith H725
Ed; It was very likely vinyl covered wire given the vintage of the set, there was some rubber/gutta percha wire used ...Arran — 06:34 PM
Zenith H725
I think the problem is traced - to noise on the AC line. It sounded so local, that it seemed certain it was generated wi...EdHolland — 05:51 PM

[-]
Who's Online
There are currently 919 online users. [Complete List]
» 1 Member(s) | 918 Guest(s)
Avatar

>