Thanks very much to Ian and all who helped me with my first amp project. Thought I should report back that I have breadboarded one channel and am blown away by the clarity and quietness of this design.
I used a very simple CRC power supply (GZ34 - 50uf - 680R - 220uf) I threw in a large resistor value as I was only testing one channel and I was worried about too much voltage going around the circuit.
I have recorded my voltages and schematic in the attached jpeg. The only difference being that I omitted the 470R's and the 1k pot from the cathode section of the phase inverter. I have built the CCS and attached it directly to the cathodes. Could anyone tell me why the 470R and 1k pot was used in the original schematic?
I am tring to understand the phase inverter, i beleive it to be a long tailed pair?
I have read up lots on this but would love some clarification on my understanding. Am I right in thinking that electrons exist across the two cathodes which are joined together. If the signal presented on the grid is positive then it will encourage conductance towards its anode, however, if the grid signal is negative then it will repel electrons and they will subsequently be pulled to the anode of the other tube?
So why do we feed the cathodes with a CCS from a negative supply?
hmm, i bet i got it wrong but would love a mickey mouse explanation if anyone is willing to offer one?
Also, can anyone see any problems with the voltages I'm reading? will these drop significantly when I connect the other channel to the psu? I'm using a 270 - 0 -270V transformer that I pulled from an old heathkit s99 amp along with the OPT's
cheers Stuart
I used a very simple CRC power supply (GZ34 - 50uf - 680R - 220uf) I threw in a large resistor value as I was only testing one channel and I was worried about too much voltage going around the circuit.
I have recorded my voltages and schematic in the attached jpeg. The only difference being that I omitted the 470R's and the 1k pot from the cathode section of the phase inverter. I have built the CCS and attached it directly to the cathodes. Could anyone tell me why the 470R and 1k pot was used in the original schematic?
I am tring to understand the phase inverter, i beleive it to be a long tailed pair?
I have read up lots on this but would love some clarification on my understanding. Am I right in thinking that electrons exist across the two cathodes which are joined together. If the signal presented on the grid is positive then it will encourage conductance towards its anode, however, if the grid signal is negative then it will repel electrons and they will subsequently be pulled to the anode of the other tube?
So why do we feed the cathodes with a CCS from a negative supply?
hmm, i bet i got it wrong but would love a mickey mouse explanation if anyone is willing to offer one?
Also, can anyone see any problems with the voltages I'm reading? will these drop significantly when I connect the other channel to the psu? I'm using a 270 - 0 -270V transformer that I pulled from an old heathkit s99 amp along with the OPT's
cheers Stuart