Can a GT703G germanium transistor be used to replace an AD150?
Under some circumstances it may be possible to replace the AD150 with gt703g. The max voltage and consumption are nearly the same, except the max power dissipation (30 W vs. 15 W). In power push pull stages it's necessary to use a pair of equal types and to adjust carefully the quiescent current about 20...30 minutes.
My main question here, is the "transitional frequency" of 10,000 hz of the GT703G and 450 khz of the AD150 Would this create any problems or distortion?
the gt703g can be used for "simple" amplifiers or power switches with a f t of less than 10 kc - and isn't recommended for full audio range amplifications, such as medium / high class hi-fi stereo amplifiers / units. For latter reasons a AD150 or similar type should be used. Some offers I have seen on E*ay these days. Another option may be the SFT213 or 2N1536 instead.
So what you are saying , if I understand correctly, is that the GT703G is
not able to amplify sound frequencies over 10,000 Hz?
You mentioned in post #3 the f t of 10,000 kc - I myself don't have datasheets with this limitation. The f t value says, that an amplification factor of 1 (!) at this frequency will be guaranteed. The less the frequency is, the more amplication will be possible, up to the named values (beta/hfe). If the limit of 50,000 kc of gt703 is true (I don't remember the source...) then this transistor may be used in stereo amplifiers, too.
Thank you for this information / confirmation - so my response to post #5 is: YES