I was packing a few things in the garage today and found an 8" speaker with "62 swan" written on it..
This is the right speaker for the chassis... The other is for the silvertone 45. duh!
Yeah..it does.
We spent half the day standing outside in the snow, burning a bonfire, drinking vodka with traditional russian snacking, canned fish and bread, and talking to a fiend in Russia over Skype.
Came home just now.
Well...it works well, other than at the very maximum of volume it oscillates.
Not unusual for a TRF though in tethrodes Miller effect is not as pronounced....
Maybe I should put it to rest now.
When at Kirk's will solder the cord to it.
(02-08-2015, 11:06 PM)morzh Wrote: Well...it works well, other than at the very maximum of volume it oscillates.
Not unusual for a TRF though in tethrodes Miller effect is not as pronounced....
Maybe I should put it to rest now.
When at Kirk's will solder the cord to it.
Mike;
I think that oscillation is in part due to the audio output stage, I've noticed that sets with push pull #45s do it as well, I think it's just the inherent instability one gets from triodes, which was why they developed screen grids, pentodes, and then beam power types. This Jackson Bell was what they called a "Midget Set" back in it's day, it was intended to be a lower cost, mass market set, not unlike a Philco 20 but obviously cruder. I would like to get my Philco 96 going just to compare, it has a proper AGC circuit rather then a funky control attempting to vary the cathode bias and antenna input in the front end.
Regards
Arran
(This post was last modified: 02-09-2015, 12:30 AM by Arran.)
Kirk, we both possess some arcane knowledge and skills, you yourself do things that I would be afraid to take on.
As for the 45.....I have to take another look, it may or may not be even worth it..... will see.
When I unplug the RF part (these things, TRF with 3 RF stages and a tunable detector are like those Duesenbergs, capable of switching off some cylinders and work on a lower power) the oscillation stops, and the volume reg still works since all three have the Ks biased by the same volume pot.
Which, BTW, while I was writing this, gave me an idea to try another capacitor on cathodes...oh wait, did that already....but maybe a bigger one.
They are all connected with a longish wire that goes to that divider and them the cap is connected at one of the three tubes.....methinks, actually at the 1st RF panel.
In this sch it is shown (and is what Kirk put in the chassis; I take it he put in the same values that were there before) as 0.1uF, and another one has it as 0.2uF (should not be critical if increased, it is the lower value that is more important.)
I tried to increase that 250 Ohm resistor that separates Ks from GND when the col is at its max, to 300 Ohm, as in the other version, did not help. The volume pot comes within 12 Ohm from the max when it starts whining.
As I said, I am not gonna bust my tail trying to quell that but will give it a half-hearted try once more, just to see what it will do.
You can see the beautiful chassis I gave to mike also..
HEY! I just remembered. I did a full cleaning, de-rusting, recapping, and de-mousing on that chassis. I even provided new unchewed coil tubes. You got it easy Mike!
Remember the tubes may not be in the right sockets
Kirk
Times I have been electrocuted in 2021
As of 1/01/2021
AC: 4 DC: 1
Last year: 6
(This post was last modified: 02-09-2015, 09:11 PM by OldRestorer.)
and it was the smoke smell; wet, drunk and fishy was OK.
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