- Single End
- Class A
- No global Feedback
- 2 Stages with J113 and IRFP240
- Max 4-5 Watt
Here is the simplified idea.
And the actually fully working circuit.
It can deliver more than 5 Watt into 8 Ohm.
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The unity gain output stage regulates voltage, so it may not have the low-thd sweetness of having the CCS on top in a current-drive configuration. Also, will the gain be high enough?
I will make a version with CCS on top, too.
Thanks for your analys and comment.
With IRFP9240 on top and output.
I have a working circuit in my SPICE.
It can deliver more than 5 Watt. With acceptable distortion.
If anybody is interested I post my circuit.
It can deliver more than 5 Watt. With acceptable distortion.
If anybody is interested I post my circuit.
As you might have understood - I'm on the hunt for some proper driving of my 16 ohm 18sound compression drivers 🙂 so I'm listening!
I also have a flat with electrical element heating so a bit a class A will not hurt 😉
Would this be suitable - anything better? Suggestion?
//
I also have a flat with electrical element heating so a bit a class A will not hurt 😉
Would this be suitable - anything better? Suggestion?
//
I have designed for only 8 Ohm.
But I can make some investigation how to use 16 Ohms speaker.
It is a lighter load then 8 Ohm, so is no problems.
But I can make some investigation how to use 16 Ohms speaker.
It is a lighter load then 8 Ohm, so is no problems.
In practice might need turn on surge protection.
Although the good old Quad 303 manages to turn on without any problems - and that runs from a 67V unipolar supply with an output capacitor.
Although the good old Quad 303 manages to turn on without any problems - and that runs from a 67V unipolar supply with an output capacitor.
Mike Rothacher has done a nice job on similar setups on his L'amp and Mofo series. TLDR is try a much simpler setup with a depletion mosfet for the CCS. And my favorite, use a choke in its place to reduce heatsink needs and improve efficiency
Look here , it is a version of the Zen amplifier by Nelson pass. The Aleph I would describe as a controlled current source.
For a mu amp example, this is something I cooked up some time ago:
The bottom mosfet gets the output signal of the top mosfet into its gate through C5. So now the bottom mosfet becomes kind of a controlled current sink.
They used to call this a totempole arrangement I think, nowadays mu amp is more hip.
Nice! I'll have to get those circuits onto a simulator for a closer look. I'm basically looking at varying the output impedance vs frequency, e.g. by having a controlled current at high frequency, pulling against a muted voltage source. Whereas at low frequencies, the voltage source gets a stronger input signal and the CCS side has reduced impedance so it also runs as a voltage source.
I can do it with 'servo' style feedback, but I want to be able to use different filters that aren't constrained to a low phase shift for negative feedback.
I can do it with 'servo' style feedback, but I want to be able to use different filters that aren't constrained to a low phase shift for negative feedback.