I will describe the changes:
1) Add a resistor between the base of the BD140 and the emitter of the 2N5401.
2) Add a diode in parallel with R18. Otherwise, C6 will discharge through the base-collector junction of the 2N5401 (that may be okay depending on the base current rating).
3) Add a diode in parallel with the coil of K1. It occurred to me that the circuit never turns K1 off. I would add a diode to make a possible turn-off work.
Ed
1) Add a resistor between the base of the BD140 and the emitter of the 2N5401.
2) Add a diode in parallel with R18. Otherwise, C6 will discharge through the base-collector junction of the 2N5401 (that may be okay depending on the base current rating).
3) Add a diode in parallel with the coil of K1. It occurred to me that the circuit never turns K1 off. I would add a diode to make a possible turn-off work.
Ed
I strongly recommend that you DO NOT waste any time to build my "design".
The reasons are as follows :
a) I do not consider it a design that can be build in practice. It was meant to demonstrate how the LU1014 should be used in practice.
b) You will find that, even in simulation, it is very difficult to adjust DC offset to cope with part variations such as Vgs.
c) Even if it can be adjusted, it is not optimised for stability, ability to cope with capacitive load, distortion, .....
d) The LU1014 has positive tempco, i.e. sensitive to thermal runaway. You need to know how to cope with that, not just big heatsinks.
But don't listen to me. Listen to Nelson :
https://www.diyaudio.com/community/...-watt-with-low-distortion.397378/post-7309370
https://www.diyaudio.com/community/...-watt-with-low-distortion.397378/post-7309373
https://www.diyaudio.com/community/...-watt-with-low-distortion.397378/post-7309379
If you know what you are doing, want to play with LU1014s and are prepared to blow a few parts, there are a few circuits floating around in the net.
By all means have fun with those.
Like that built by Michael, you will find out practical details like gate leakages, etc.
That is very far from a public project.
I certainly do not want my name to be associated with any of those.
You have been warned.
Patrick
PS
If you are interested in a small amp with 12V rails, one of the Alpha Testers of the Power Whammy with M2OPS is going to test his with 12V.
Only then would I consider it recommendable for the public. Not just in Spice.
https://www.diyaudio.com/community/...-and-maybe-a-power-whammy.390636/post-7309540
"I am hoping one of the Alpha testers will run a quick test.
With opamp up front, you probably won't even need to trim DC.
But we'll see."
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I have noted your Warning.
But still I want to try my design.
Even Nelson can see the difficulties.
I have now been Warned.
If we continue this circuit, I may have to suit myself.
It can probably end in disaster.
But let's try.
It might work 🙂
Well, rails should be decoupled.
Question is only how much capacitance to use.
Maybe only small value caps ....
Question is only how much capacitance to use.
Maybe only small value caps ....
Some models do have thermal outputs in the form of extra pins with voltage on them. I haven't investigated that feature but I noticed it exists. The L0 and L1 model types also vary along those lines.
This project should end here.
If some guys want to go on and test it, then fine.
But I will not take this thread any further.
Both @EUVL and @Nelson Pass are unsure this amplifier will work.
I have been Warned.
I am sorry if I have encouraged people to try this difficult amplifier.
You do like you wish.
But I can not live with having put people into believing in something so troublesome.
I will post another Amplifier which is less of a problem.
You are welcome to build that one instead.
Stefan, alias @lineup
If some guys want to go on and test it, then fine.
But I will not take this thread any further.
Both @EUVL and @Nelson Pass are unsure this amplifier will work.
I have been Warned.
I am sorry if I have encouraged people to try this difficult amplifier.
You do like you wish.
But I can not live with having put people into believing in something so troublesome.
I will post another Amplifier which is less of a problem.
You are welcome to build that one instead.
Stefan, alias @lineup
to whom it may concern:
Could you please combine the amp and protection into a single PCB board?
The dream would be to have the regulated PS also on there so there are only 1) ~~ 2) GND 3) +/- in and 4) +/- outs. Preferably with screw on and RCA terminals like the miniACA
There are two guys involved in making PCB files.
I don't know if they are willing to make PCB for you.
You could ask them: @myfirstamplifier and @Angry Fat Cat
Love
Stefan
I don't know if they are willing to make PCB for you.
You could ask them: @myfirstamplifier and @Angry Fat Cat
Love
Stefan
The base current should be 1/5 to 1/10 the collector current. 1K-2.2K is fine.
Ed
A prominent foundry that used to be called Philips have a line of "application specific" MOSFETs with "extended" safe operating area that graciously allows people to use them for linear applications without blowing up. That's not to say that other MOSFETs are unsafe, but the switching speed wars seemed to produce a lot of devices that were so prone to hot-spots, they were only rated for PWM usage. Also, SiC FETs seem to be the new big boys in town that can do both (switching and linear).
If someone does a layout with the TO247 adapter footprint, I will buy the PCBs and supply PCBs to the layout provider.
It would also be nice to support the footprint of both JFET package types as well as the MOSFET 2nd stage driver.
a. gate in the middle
b. gate on one end
I will also provide a pair of the TO247 adapters with matched LU1014 parts for the layout provider.
It would also be nice to support the footprint of both JFET package types as well as the MOSFET 2nd stage driver.
a. gate in the middle
b. gate on one end
I will also provide a pair of the TO247 adapters with matched LU1014 parts for the layout provider.
