Author Topic: New member in Central IL  (Read 667 times)

ed from Baltimore

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Re: New member in Central IL
« Reply #15 on: August 19, 2019, 07:13:52 AM »
    I have seen a schematic for an older Philco with 6L6s instead of 7189. It had an electrostatic tweeter. The electrostatic was connected to the plate of the 6L6 through a high valued resistor, which provided the high driving AC voltage and the DC polarizing voltage at the same time. The voice coil winding of the output transformer went to the woofer only.

1959MagnificentMagnavox

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Re: New member in Central IL
« Reply #16 on: August 19, 2019, 07:56:00 AM »
Very nice, was talking this morning to a fellow member, and it would be nice to have a nice 40's 78 am radio player. any ideas on a good brand or model to look for?
i know Philco had some nice ones

electra225

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Re: New member in Central IL
« Reply #17 on: August 19, 2019, 10:22:02 AM »
Stromberg-Carlson, Magnavox, Zenith, RCA or something built by Wells-Gardner.  RCA had dual changers in the late 1940's.  Whatever you get, I'd take the 78-only changer out and replace it with a four-speed stereo changer bridged for mono.  I like BSR and VM for this procedure.  Easy to tune up, easy to find parts for, and common as dirt.
I don't need Google.  My wife says she knows everything.

macgolf

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Re: New member in Central IL
« Reply #18 on: August 19, 2019, 07:58:27 PM »
    I have seen a schematic for an older Philco with 6L6s instead of 7189. It had an electrostatic tweeter. The electrostatic was connected to the plate of the 6L6 through a high valued resistor, which provided the high driving AC voltage and the DC polarizing voltage at the same time. The voice coil winding of the output transformer went to the woofer only.

Interesting. I'm far too new at this to understand everything going on, with this unit. The unit has a single tube that, research showed ,was to provide the dc voltage for the stats. The unit had a 6AL5 in that spot and has since been replaced with the factory specified 6EB5 tube. When I pull the amp this weekend I hope to find a simple fix. I'll be relieved if it's not transformer related. I need to start verifying caps present vs schematic and get an order together. Thank you for information.

Mark

Motorola Minion

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Re: New member in Central IL
« Reply #19 on: August 20, 2019, 07:53:59 PM »
    I have seen a schematic for an older Philco with 6L6s instead of 7189. It had an electrostatic tweeter. The electrostatic was connected to the plate of the 6L6 through a high valued resistor, which provided the high driving AC voltage and the DC polarizing voltage at the same time. The voice coil winding of the output transformer went to the woofer only.

Interesting. I'm far too new at this to understand everything going on, with this unit. The unit has a single tube that, research showed ,was to provide the dc voltage for the stats. The unit had a 6AL5 in that spot and has since been replaced with the factory specified 6EB5 tube. When I pull the amp this weekend I hope to find a simple fix. I'll be relieved if it's not transformer related. I need to start verifying caps present vs schematic and get an order together. Thank you for information.

Mark

The 6EB5 is a rectifier tube for the dedicated supply to the electrostatic tweeters, which are in the cabinet on your model and in the satellite speakers on my smaller Philco.

I have a 1959 Philco G-1906, phono-only (VM) two-cabinet stereo Philco model with a 6L6 PP amp in each cabinet. The supply to the electrostatic tweeters may be similar to what Ed described.

Tubes - Magical - Tubes

Dave