There is a desire to make a powerful amplifier exclusively on JFET.
Without negative feedback.
Tested circuit at low power is already available.
There is now a powerful MOSFET output scheme.
The next step - a powerful circuit Si-C JFET.
Related topic:
JFET-only Headphone Amp "Circlotron КП903B".
Without negative feedback.
Tested circuit at low power is already available.
There is now a powerful MOSFET output scheme.
The next step - a powerful circuit Si-C JFET.
Related topic:
JFET-only Headphone Amp "Circlotron КП903B".
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Wide question. It works very stably.
Even at low rest currents (50 mA) there is no "stair".
In addition, the small JFET transistors in this switching circuit turned out to be very resistant to breakdown voltage.
Which allows you to increase the supply voltage.
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Sorry, the work of the circlotron amp is well known.
The first cascade is nothing unusual.
The driver cascade is a "ladder". Transistors can be three, four or more.
Linearity allows you to get rid of negative feedback
Here's another close related topic nearby:
Current feedback Mosfet Circlotron
The first cascade is nothing unusual.
The driver cascade is a "ladder". Transistors can be three, four or more.
Linearity allows you to get rid of negative feedback
Here's another close related topic nearby:
Current feedback Mosfet Circlotron
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When the amplifier was operating at medium power for one hour, the output stage current increased from 100 mA to 160 mA. It was on a small radiator. Now I'll see how it will be on large radiators and later I will write the result.
The preliminary part is very stable. When the amplifier is turned on, the shutters are +3.85 V, and when warming up, it is +3.81 V. This is very good.
I set the current to 213 mA. The amplifier worked at an average power of 2 hours. The current has become - 219 mA. It is on large radiators. And this is without a temperature sensor on the radiators. Great circuit !!!
Hi, Seb!!!🙂
VT1 must have a saturation drain current of 15-20 mA.
Yura applied J113 (18 mA).
VT2 must be found with saturation drain current: 1.5 - 3 mA.
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Hi!
Any low-power n-channel JFET with an initial current greater than 8-10 mA can be used as VT1. As BT2 - with an initial current of 1.5-5 mA.
It is important that the voltage is drain-source VT2 was on the verge of crossing the triode to pentode characteristics. As outlined in the figure.
The same goes for relationships VT3-VT4 and VT5-VT6. In both shoulders to equal or close.
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HI thanks 🙂
which is good is that I already have paired 2SJ103Y and 2SJ103bl
VT1 : J113
VT2 : maybe 2SK30GR ??
VT3 VT5 : 2SJ103Y
VT5 VT6 : 2SJ103BL
which is good is that I already have paired 2SJ103Y and 2SJ103bl
VT1 : J113
VT2 : maybe 2SK30GR ??
VT3 VT5 : 2SJ103Y
VT5 VT6 : 2SJ103BL
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Dear Svjatoslav!
great name!
emiter/source resistors are suspected for sound quality degeneration, please refer this great thread: Emitter resistor in HexFet OPS
but I think that mostly in gnfb amps, not open looped like yours.
Do you think that ommiting 0.1 Ohm res (I know that they are very small valued) is possible in your circuit?
Would you do the test what will be idle current change after shorting them?
Slava!
Hi Pawel!
In the circlotron and so half the load under the source.
0.1 Ohm there will do nothing wrong. However, there is a great current sensor and fuse.
Testing fo the spectr, by blocking resistors 0,1 Ohm is quite possible.
In the circlotron and so half the load under the source.
0.1 Ohm there will do nothing wrong. However, there is a great current sensor and fuse.
Testing fo the spectr, by blocking resistors 0,1 Ohm is quite possible.