I think I know what you mean. The oscillations you can get from the bases becoming negative impedances and reacting against the potentially inductive impedance of the pre-driver.
The only thing I can think of right now is doing AC sweeps to plot these impedances and then determine how they would interact.
LKA looks like the resident expert on triples, you can ask him how he how looks at the problem and let me know.
The only thing I can think of right now is doing AC sweeps to plot these impedances and then determine how they would interact.
LKA looks like the resident expert on triples, you can ask him how he how looks at the problem and let me know.
Hello Sandro,
Here is a functioning output stage which I suspect has parasitic oscillation. Could you show how you would do the AC sweep your talking about.
As usual I am interested in you feedback on the circuit.
Regards
Here is a functioning output stage which I suspect has parasitic oscillation. Could you show how you would do the AC sweep your talking about.
As usual I am interested in you feedback on the circuit.
Regards
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Hi Rick, actually my comment was incomplete 🙂. It should have been:
- Given the second stage I have in mind [not showed cased yet), will start with 2 and see if having 3 buys as anything.
For the standard second stage, an emitter follower cascaded with a common emitter, a triple OPS will give you better distortion. Bob showed this result with the BC-1.
This is specially true if you degenerate the common emitter in the second stage which is a bad idea for distortion. I find degeneration in the second stage more a "must do" for current limiting purposes, or if you have to reduce the BW of the minor loop to stabilize it and you run out of ways to do it. Sam Groner, to my knowledge, has the best write up on why degenerating the second stage is a bad idea.
Anyway, I hope this clarifies it.
- Given the second stage I have in mind [not showed cased yet), will start with 2 and see if having 3 buys as anything.
For the standard second stage, an emitter follower cascaded with a common emitter, a triple OPS will give you better distortion. Bob showed this result with the BC-1.
This is specially true if you degenerate the common emitter in the second stage which is a bad idea for distortion. I find degeneration in the second stage more a "must do" for current limiting purposes, or if you have to reduce the BW of the minor loop to stabilize it and you run out of ways to do it. Sam Groner, to my knowledge, has the best write up on why degenerating the second stage is a bad idea.
Anyway, I hope this clarifies it.
Hi Arthur, what makes you think there is an oscillation?
Regarding the circuit, looks interesting. I like the scheme you are using to bias the second stage. Did you come up with it?
Regarding the circuit, looks interesting. I like the scheme you are using to bias the second stage. Did you come up with it?
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Pheonix will you post your design for others to build or keep it to yourself like you always do after getting all this help from Sandro and the DIYAUDIO community? Or is this for your retail mates in the shop?
By the way which one of these is Edmond's design?
elektra - Melbourne Hi Fi
Because you are not a DIY'er Arthur, you are a manufacturer. If you incorporate Sandro's or anyone else's work here work in your commercial product I think it is only fair you should remunerate them instead of enriching your mates in the shop. 🙁
Thanks Stinius, will take a look.
From Ed, I read his Super TIS design, very nice design. This is under his "Where TMC really shines" article. Was going to read the rest of his site, but then I got busy with other stuff. Let me try again.
From Ed, I read his Super TIS design, very nice design. This is under his "Where TMC really shines" article. Was going to read the rest of his site, but then I got busy with other stuff. Let me try again.
Hi sandro
Thank you very much for sharing your knowledge .
Your work is enlightening to say the least.
I have been studying your test bench on the honeybadger and would like to use it in other designs... would you care to explain how to use the same bench but with a different power amp schematic ?
Best ricardo
Thank you very much for sharing your knowledge .
Your work is enlightening to say the least.
I have been studying your test bench on the honeybadger and would like to use it in other designs... would you care to explain how to use the same bench but with a different power amp schematic ?
Best ricardo
First, you need to remove any sources and stimuli from the schematic of the new power amp and add pins.
Then you need to create a symbol, hopefully identical to the one I made for the HB.
Finally just replace the HB symbol with the new one in the test bench.
I believe the instance name needs to be XT.
I have been wanting to make a video on how to make symbols for quite some time, just have not had the chance.
Best, Sandro
Then you need to create a symbol, hopefully identical to the one I made for the HB.
Finally just replace the HB symbol with the new one in the test bench.
I believe the instance name needs to be XT.
I have been wanting to make a video on how to make symbols for quite some time, just have not had the chance.
Best, Sandro
Hi guys, project is progress, but sort of in hiatus... I started working in start-up and that is draining all my time. I am hoping once things stabilize a bit, I'll have more time to get back to doing more videos.
Thanks for your patience!
Best, SAndro
Thanks for your patience!
Best, SAndro
Posts with personal attacks have been removed. Personal attacks are not allowed on this forum. Please read the rules, including the notes.diyAudio Rules
We also take a very dim view of arguments brought over from other places. That is not welcome here.
Granted. But what are the rules about using other peoples designs on here either in part or whole and commercializing them without permission or proper consideration for compensation ?
For example diyer-X presents a schematic that he has simulated or built and then Commercial Operator-Y then modifies the design for the purpose of commercializing it and then never presents the modified design again on the forum for the diyaudio community to benefit from ??
Alternatively, Commercial Operator-Y re-posts a design from diyer-X and asks the diyer community for their input. Takes advantage of the input and then commercializes the design without ever presenting it again for the benefit of the diyaudio community ?
cheers
For example diyer-X presents a schematic that he has simulated or built and then Commercial Operator-Y then modifies the design for the purpose of commercializing it and then never presents the modified design again on the forum for the diyaudio community to benefit from ??
Alternatively, Commercial Operator-Y re-posts a design from diyer-X and asks the diyer community for their input. Takes advantage of the input and then commercializes the design without ever presenting it again for the benefit of the diyaudio community ?
cheers