what's push-pull /Dynakit st-70

leftwinger57

Hi guys, It's been a while since i FIXED fix my computer tunes to my main avr in different rooms. I was railed on for not stateing what started the thread . So as quickly as one could type here goes,I ran 2 50ft RCAs to my Yamaha RX-V665 to computer. After getting the rite splitter I was getting an annoying gnd hum which would never do. Most said it was the lenght and picking a gnd somewhere. After chaning out to another style splitter and by accident unplugged my HDMI OUT of the Yamaha, and all was right w/ the world. No hum, or background noise whatsoever,and the thing is that HDMI out is used for on screenadjustments which I very rarely change.So now all of you are brought up to date and now for todays question.
I've seen the term push-pull amps w/ mostly older tube types like Marantz8s or Dynakit ST-70S. So why is this terminology used and could it be easily explained.The next thing trolling around the bay is the Dynakit-ST-70S are getting some good money for something less than A mac 240 and even on Audiogon there are some that are modded out like hot rods. How good if seen at a garage would it be if worked to pick up. Is it that good of a simple design.
Sorry for the lenght but I wanted to be squared away w/ all the thread followers......LW

cnh

With parallel “push-pull” amplification, the receiver’s transistors alternately “push” and “pull” the current. In pairs, one output device (i.e. a transistor) will amplify the positive half of the waveform, while another output device will amplify the negative half of the waveform. Push-pull amplification has the advantage of efficiency, but can be affected by occasional instances of distortion.

A short description from Onkyo. The basic principle of push/pull is that there is alternating duty as described above. Most A/B amps (if I'm not mistaken--and if I am I KNOW someone will correct me) have this kind of architecture.


cnh