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Philco 86 Voltages - Printable Version

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RE: Philco 86 Voltages - radiorich - 02-09-2023

Hello Tiddat,
I Agree you will have enough volume and if it's not to late to say welcome aboard !
Rob, for sure having pushpull output really does make an improvement .

Sincerely Richard

RE: Philco 86 Voltages - Tiddat33 - 02-12-2023

Now that I have everything back together and the RC bridge bypassing my bad transformer primary, I have to keep the volume turned all the way down so my local AM station doesn’t drive me out of the room!

Now I want to add a polarized plug and rewire the power switch to make it a little safer. Please correct me if I’m wrong……

If I move the power switch (#27) into the hot line between the plug and switch #28, and connect the neutral to capacitor #33 and the other side of the transformer…. This should eliminate a hot chassis whether I jumper LOC to GRD or not… or am I missing something?

RE: Philco 86 Voltages - RodB - 02-13-2023

Hi Tiddat,

There won't be a hot chassis with a power transformer in the radio. You should replace capacitor 33 with a safety capacitor and leave everything the way it is. But if it makes you feel more comfortable using the polarized plug then do it the way you describe. I believe connecting LOC to gnd might reduce noise.

So, read up on the hot chassis situation. You'll find that it occurs in transformer less radios because the tube heaters are wired in series to the power cord and one end is either directly or indirectly connected to the chassis. In the days of nonpolarized plugs 115 volts might be on the chassis. For a shocking experience, pick up the radio and touch the chassis screw.

RE: Philco 86 Voltages - Tiddat33 - 02-13-2023

Hi RodB,

Thanks for the info…. Apparently I misread something somewhere pouring over a bunch of older threads. I’ve already recapped, including a safety capacitor at #33, and it sounds great…. Just looking do some more cleanup before putting it all back together in the cabinet.

Thanks again!!!

RE: Philco 86 Voltages - Ron Ramirez - 02-13-2023

The LOC terminal is the lead which connects to one side of the AC line through a capacitor. Do not connect this terminal to ground.

The LOC terminal will be most effective if the AC end of capacitor (33) is connected to the hot side of the line - not the neutral side of the line.

It is not recommended to use the LOC terminal as an antenna these days due to the proximity of AC to this terminal. Philco provided this in their early days of radio manufacturing in an effort to eliminate the need for an external antenna. However, for model 86 or similar Philcos, there is nothing better to use than a good, long, longwire antenna which is preferably erected outside with suitable lightning protection.

In any event, yes indeed, capacitor (33) should be an X1-Y2 rated safety capacitor.

RE: Philco 86 Voltages - RodB - 02-13-2023

Well I figured there was a good reason LOC wasn't used in later models. Thanks Ron.

RE: Philco 86 Voltages - Ron Ramirez - 02-14-2023

I failed to mention this:

Philco provided the LOC terminal to use as a temporary or "local" antenna (LOC = local).

Note that Philco only provided the LOC terminal in their 1928 model line of radios (511 Series), as well as some of their 1929 models (86, 87, 95).

RE: Philco 86 Voltages - Arran - 02-14-2023

It's been my experience with these late 1920s and early 30s TRF radios have no lack of gain, particularly with screen grid RF tubes, they can suffer from lack of selectivity but usually not too bad with the cascading tuned stages.
Regards
Arran

RE: Philco 86 Voltages - Ron Ramirez - 02-14-2023

I agree with Arran. In fact I'll go a bit further and say that, based upon my prior experience many years ago, many of the three dial radios of the mid-1920s also have plenty of gain.

I recall a Freshman Masterpiece three dialer I once owned which was an amazing performer - and its audio transformers, all of which were bad, I had converted to resistance coupling. This was one of the first sets, if not the first, I had ever tried that trick on and I was very pleased with the results.

RE: Philco 86 Voltages - RodB - 02-14-2023

Yes Aaron, the AK L chassis I just finished has a Local/Distant toggle switch that puts B+ on the first rf screen grid. Better have your hand on the volume control. Man, what a boost!