Here is the last 200W-CFA-VMOSFET zip file with .asc and models files.
Damir
Hi Damir,
I may be wrong but I believe there is an error in this asc from your post #775 200W MOSFET CFA amp. C33 which goes between the two 15v rails, appears to shorted to the + input of the LT1022.
I had connected the cap like this in the modded version of the 100W CFA and could not adjust the DC offset after much poking around I realised what the problem was.
When I ran the sim with the input shorted and load open to check the bias and offset, I got -847.7544mV DC offset. Removing the short as per your 100W CFA attached allowed me to make/ test the adjustment.
As I say I may be wrong and will defer to your knowledge.
Attachments
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Shorted Cap at Servo.JPG58.2 KB · Views: 1,191
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Shorted Cap at Servo Sch.JPG187.3 KB · Views: 1,127
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Not Shorted Cap at Servo.JPG51.9 KB · Views: 1,166
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100 CFA- CM-VMOSFET-dado-1 Low PPM-sch.jpg208.7 KB · Views: 1,160
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200W-VMOSFET-efVAS-mc-RC-150-0_47u-OIC-DCservo- VDMOS ksubthres models-Vbe_blue.asc24 KB · Views: 280
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Hi, happy new year everyone
By accident I stumbled accross a "funny" stability issue using different well known mosfet models.
I created a new thread to not highjack this one or turn it into a model discussion.
Simulation stability with different models - Dado's 200W CFA
Regards
Jørgen
By accident I stumbled accross a "funny" stability issue using different well known mosfet models.
I created a new thread to not highjack this one or turn it into a model discussion.
Simulation stability with different models - Dado's 200W CFA
Regards
Jørgen
I would like to offer gerbers for my 100W CFA and corresponding Power Supply.
I hope more people will build this amp.
I hope more people will build this amp.
Attachments
Probably, but first I would like to see if any interest to build 100W version.and whether you will also share up to 200W MOSFET CFA gerbers
Hi Damir,
The 100W circuit uses BC550 and BC560 transistors. The BC560 is not easily available/obsolete now.
Looking at the specs, would the use of BC549 and BC559 be ok. The BC549/BC559 has a Vceo = 30V, as compared to the BC560 Vceo = 45V.
I notice there is a 15V zener diode limiting the rail voltage where the BC550/BC560 transisors are used.
My thinking the BC549/BC559 pairing should be ok in the transistor positions of Q15/Q17, Q11/Q12, Q16/Q19 and Q3/Q4.
This would allow the use of the lower noise BC549/BC559 transistors, similar to the BC550/BC560.
kind regards
steve
The 100W circuit uses BC550 and BC560 transistors. The BC560 is not easily available/obsolete now.
Looking at the specs, would the use of BC549 and BC559 be ok. The BC549/BC559 has a Vceo = 30V, as compared to the BC560 Vceo = 45V.
I notice there is a 15V zener diode limiting the rail voltage where the BC550/BC560 transisors are used.
My thinking the BC549/BC559 pairing should be ok in the transistor positions of Q15/Q17, Q11/Q12, Q16/Q19 and Q3/Q4.
This would allow the use of the lower noise BC549/BC559 transistors, similar to the BC550/BC560.
kind regards
steve
Last edited:
Hi Steve,Hi Damir,
2SC2240/2SA970, may these be replaced with KSC1845FA/KSA992FA
Kind regards
steve
Yes.
Yes, instead of BC550C/560CHi Damir,
Thanks for the quick reply.
Was I also correct with the substitution of BC549/BC559?
I have a bunch of bc550/560bta transistors.Hi Damir,
The 100W circuit uses BC550 and BC560 transistors. The BC560 is not easily available/obsolete now.
Looking at the specs, would the use of BC549 and BC559 be ok. The BC549/BC559 has a Vceo = 30V, as compared to the BC560 Vceo = 45V.
I notice there is a 15V zener diode limiting the rail voltage where the BC550/BC560 transisors are used.
My thinking the BC549/BC559 pairing should be ok in the transistor positions of Q15/Q17, Q11/Q12, Q16/Q19 and Q3/Q4.
This would allow the use of the lower noise BC549/BC559 transistors, similar to the BC550/BC560.
kind regards
steve
https://www.diyaudio.com/community/threads/some-components-for-sale.314633/
It’s hard to resist such a good offer. I just ordered pcb and plan to build it along side Astx’s amp.Any fruits born from offered gerbers?
Good, show your progress here.It’s hard to resist such a good offer. I just ordered pcb and plan to build it along side Astx’s amp.
Thank you very much!I would like to offer gerbers for my 100W CFA and corresponding Power Supply.
I hope more people will build this amp.
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