08-02-2015, 09:14 AM
Well it's not really the fact that it doesn't have push pull audio output ( the 20 does). If you ever hooked up a pm spkr across the output transformer of the 20 but you'll hear a big difference. Sound really good. Those brown "pie pan" spkrs have a very stiff spider and cone this limits the low frequency response.
The 70 and 90 use a thing called a Power Detector. It has a fairly high output enough the drive the 47 but also generates a high lever of distortion. I suppose you could replace the the 24A with a 2A6 and rewire it as a diode detector/triode 1st audio and add avc then you'd have something. You could also lose that dual gang volume control that is difficult to find a replacement.
Single ended audio output can sound very good it's all in the design.
Terry
The 70 and 90 use a thing called a Power Detector. It has a fairly high output enough the drive the 47 but also generates a high lever of distortion. I suppose you could replace the the 24A with a 2A6 and rewire it as a diode detector/triode 1st audio and add avc then you'd have something. You could also lose that dual gang volume control that is difficult to find a replacement.
Single ended audio output can sound very good it's all in the design.
Terry
