I need verification of this SS circuit

[GERPUD]

Hi,
To test my comprehension of transistor and amplifier classes, I made this schematic.
Would it work? Is there error?

Q1 Phase splitter
(Q2 Q3, AB class) Bridged with (Q4 Q5, AB class)
No gain

Thanks!

[JMFahey]

Yes, in a very crude way, or as a classroom basic concept example it would work.

2 details:

1) you will need the driver being fed +/-56V , not mere +28/0 V ,so both collector and emitter can swingb required 56V peak to peak ... what each speaker terminal can swing (ignoring losses).

2) it will need 40V RMS drive

[GERPUD]

Thanks you for the reply!

Correct me if i'm wrong:
It could work if input swings 14V, it will needs 28V differential at first stage, and only 28V differential used (on 56V) at the second stage.
With a 8ohm speaker, it will be able to push 24.5W and will need a 49VA-40Vrms transformer in order to work. So half PT will be wasted.

Is there other potential practical problems?

[JMFahey]

Thanks you for the reply!

Correct me if i'm wrong:
It could work if input swings 14V, it will needs 28V differential at first stage, and only 28V differential used (on 56V) at the second stage.
With a 8ohm speaker, it will be able to push 24.5W and will need a 49VA-40Vrms transformer in order to work. So half PT will be wasted.

Is there other potential practical problems?

1) each output will swing from +28 to -28V ; being unity gain they must be driven the same amount.

So you need +/-28V drive on top , same on driver transistor collector.

Same happens on the bottom half so you will also need to swing +/- 28V , so I correct my earlier estimation: now you need +/-56V rails for the driver transistor, er 112V end to end.

2) drive signal must still swing +/- 28V or 20V RMS

3) theorical power output will be 40*40V/8 ohms, or 1600/8=200W RMS .

It will "eat" some 300VA from the power supply, hard to get from a 49 VA transformer.

All this is a theorical analysis, ignoring losses, current gain, diode drops, etc.

[LOUDthud]

PNP transistors are drawn wrong. The collector should go to -28V, emitter to output.

Q1 won't work as a phase inverter in this case because it cannot deliver the required voltage swing on both outputs unless it is operating from a 112V supply. As drawn you can only get 14V peak to peak on each output, you need 56V.

Very doubtful that you will be able to drive the output to full voltage swing with any kind of speaker load. With capacitor coupling you will need too much current flowing in R5, R6, R7 and R8. They will need to be 10W or more each. With Darlington output transistors, much less drive will be required and R5-R8 can be one or two watts.