04-01-2008, 08:17 PM
The 90 has an interesting time line. Ron can confirm it, but the P-P 45 output must have been in the first series sets. Then, they "improved" it by using the latest, sensational 47 in the output. That's the one I have.
I've never heard a good answer to this, but I have a 90 console with P-P 47's in it. Someone (possibly Ron) told me that table sets never has the push-pull 47 chassis in them.
Do I have that right?
The big craze in 1931, or whatever year it was, was the use of the whoop-de-do pentode: the 47. Looking at the tube charts, what we gained with the 47 was power sensitivity, and inherent distortion (Pentodes are quite non-linear, and triodes are quite linear). They sounded OK, but ears were not critical in those days, so the "breakthrough" was acceptable. The power output of P-P 47's was comparable to P-P 45's only with added distortion.
The addition of inverse feedback would have cleaned up the 47 audio, but nobody ever would have heard it.
I've never heard a good answer to this, but I have a 90 console with P-P 47's in it. Someone (possibly Ron) told me that table sets never has the push-pull 47 chassis in them.
Do I have that right?
The big craze in 1931, or whatever year it was, was the use of the whoop-de-do pentode: the 47. Looking at the tube charts, what we gained with the 47 was power sensitivity, and inherent distortion (Pentodes are quite non-linear, and triodes are quite linear). They sounded OK, but ears were not critical in those days, so the "breakthrough" was acceptable. The power output of P-P 47's was comparable to P-P 45's only with added distortion.
The addition of inverse feedback would have cleaned up the 47 audio, but nobody ever would have heard it.
