In Reply to: Re: Build ideas for Allen Wright PP-1C Push Pull Power Amp posted by Burney on April 16, 2007 at 22:27:14:
Yep, it sure is. You get about half the gain from an LTP splitter than you would get from a differential stage with balanced input.What guarantees good signal balance is the CCS in the tail. It forces the total current of the two halves to be the same at all times. So, if the current through the first half goes down by, say, 0.5 mA then the current in the second half must go up by 0.5 mA. If the plate load resistors are equal then the voltage signals at the plates must also be equal (but 180 degrees out of phase). Note that the CCS doesn't guarantee good DC balance, just good AC balance. For that reason, it's quite common to see two equal resistors between the cathodes and the tail - usually a few hundred ohms - to even out the quiescent currents.
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Follow Ups
- Re: Build ideas for Allen Wright PP-1C Push Pull Power Amp - Ray Moth 01:58:59 04/17/07 (3)
- Re: Build ideas for Allen Wright PP-1C Push Pull Power Amp - Burney 06:49:22 04/18/07 (2)
- Yes, but make the pot as small as possible - 100k is too big IMO. (nt) - Allen Wright 10:03:37 04/18/07 (1)
- Thanks! The guru has finally blessed this thread... - Burney 13:48:18 04/18/07 (0)