Model 20

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Model 20

Mondial
Phorum Expert

Posts: 1,114
Threads: 14
Joined: Feb 2013
City: Irvington, NY

01-08-2014, 10:13 PM

Yes it is a bit confusing since the measurements are not referenced to chassis ground. With heater-cathode tubes there is not much difference, but with the directly heated filament of the 71A, the self bias resistor throws off the reading.

As to the speaker problem, are you sure the spider is stiff or is the voice coil rubbing on the pole pieces? I have a 20 speaker that wont move at all because of this.

You could try removing the screw in the center of the spider so it is free to move and see if the cone movement is still restricted.

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Messages In This Thread

Model 20 - by gregb - 01-07-2014, 12:06 PM

RE: Model 20 - by Mondial - 01-07-2014, 04:46 PM

RE: Model 20 - by gregb - 01-07-2014, 05:24 PM

RE: Model 20 - by gregb - 01-08-2014, 07:08 PM

RE: Model 20 - by Mondial - 01-08-2014, 10:13 PM

RE: Model 20 - by gregb - 01-08-2014, 10:55 PM

RE: Model 20 - by gregb - 01-08-2014, 11:46 PM

RE: Model 20 - by morzh - 01-09-2014, 12:05 AM

RE: Model 20 - by morzh - 01-09-2014, 12:09 AM

RE: Model 20 - by gregb - 01-09-2014, 12:18 AM

RE: Model 20 - by morzh - 01-09-2014, 12:17 PM

RE: Model 20 - by gregb - 01-09-2014, 02:15 PM

RE: Model 20 - by morzh - 01-09-2014, 03:33 PM

RE: Model 20 - by gregb - 01-09-2014, 03:44 PM

RE: Model 20 - by gregb - 01-09-2014, 03:46 PM

RE: Model 20 - by morzh - 01-09-2014, 07:04 PM

RE: Model 20 - by gregb - 01-11-2014, 12:57 AM

RE: Model 20 - by morzh - 01-11-2014, 11:30 AM

RE: Model 20 - by BrendaAnnD - 01-11-2014, 06:07 PM

RE: Model 20 - by morzh - 01-11-2014, 06:51 PM

RE: Model 20 - by gregb - 01-11-2014, 09:40 PM

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