guide to the v1.2
Reflektor Notes: https://www.diyaudio.com/forums/power...ml#post2724088 post 4287
B1 with Shunt https://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer-2.html#post1854512
https://www.diyaudio.com/forums/power...ml#post2223856
schematics #1983 https://www.diyaudio.com/forums/power...ml#post2103465
Transformer R-Core EBAyhttps://www.ebay.com/itm/110V-50W-R-c...item4ab0dbf733
V1.2R schematics
https://www.diyaudio.com/forums/power...lator-320.html
board design starts 2384
Sense wire: Use RG58 on all your shunts for sense wiring
bipolar +_ version https://www.diyaudio.com/forums/power...ml#post2205564
negative 35 volt #2432
heat sink:
Depends on how much current you spend on specific load VS what is left in the reg times voltages across mosfets. There is no specific answer. Some generality would be that a 1C/W common sink should do it.
Originally Posted by Salas
I think its nice up to where we addressed it from first draft. I don't know more about PCB tricks so no new comment from me. If someone spots something wrong, please comment.
I want to say something about the two 3K3 resistors in the CCS part. Those form a voltage divider so to bias the transistor cascode and feed its LED. Since they are referenced to Vout, there is a scale depending on what voltage region we use the reg, so to always have proper mA through the LED.
For 5Vout use 470R (use Vref 15K instead 27K, use trimmer 3K3 instead 1K, use 2K2 instead 4K3 R6, also when with JFET cascode)
For 10Vout use 1K (use Vref 15K instead 27K, also when with JFET cascode)
For 15Vout use 2K2
For 25Vout use 3K3
For 35Vout use 3K3
For 45Vout use 4K7
Final setup..... 10uF Audyn-cap MKP // .1uF Vishay MKP1837 on the output zobel (both channels). might try 4.7uf mkp //.047uf mkp
Coax or twisted, the ground side is attached on sense pcb ground and at load ground. Pcb sense connections meet force connections only at the load.
Only position the Jpwr and R12p, C3p near Q4p in layout. Also use as system ground point the C3p's ground point.
Its not that hard to consider a better Tempco region in a JFET Norton Vref's type CCS. A 4mA IDSS K170GR shows -0.5V pinch off (-Vp) on its datasheet. Vgs(0Tc) will be (by that formula I mentoned) 0.5-0.63=-0.13V. Its Ids-Vgs curves show 1.8mA Ids at Vgs0TC.
IdZero=(0.63/0.5)squared*1.8=2.857mA. A proper source resistor for that would be Rs(0TC)=0.13V/2.857mA=45.5R. Our Norton ref resistor for say 90V B+ to voltage stages of the amp will need be (90-vbe)/2.857=31.29K. Practically you stick a 33K 1W and a 100R Rs trimmer in Kean's CCT and you play midway travel near Zero TC. The large impedance can be cleaned easily for self noise by a 2u2 MKP with no real ESR to keep noise bugging up high in frequency. The residual 33K resistor noise is 23.4nVrtHz. That was it.
Attached Thumbnails
You got to know the IDSS of the JFET used first of all Ken. It will be roughly 70% what it is for 9V test when in position for a K170BL. So you project a Vref resistor (Vout-0.6)/IK170. If you can use a bigger film cap across the resistor than before is better, due to its lower now. Its OK for all versions. 1W up resistor(s) for your Vo.
Start of V1.2R
https://www.diyaudio.com/forums/power...lator-313.html
Electro Cap Panasonic EE series ultra low ESR
B1 with Shunt https://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer-2.html#post1854512
https://www.diyaudio.com/forums/power...ml#post2223856
schematics #1983 https://www.diyaudio.com/forums/power...ml#post2103465
Transformer R-Core EBAyhttps://www.ebay.com/itm/110V-50W-R-c...item4ab0dbf733
V1.2R schematics
https://www.diyaudio.com/forums/power...lator-320.html
board design starts 2384
Sense wire: Use RG58 on all your shunts for sense wiring
bipolar +_ version https://www.diyaudio.com/forums/power...ml#post2205564
negative 35 volt #2432
heat sink:
Depends on how much current you spend on specific load VS what is left in the reg times voltages across mosfets. There is no specific answer. Some generality would be that a 1C/W common sink should do it.
Originally Posted by Salas
I think its nice up to where we addressed it from first draft. I don't know more about PCB tricks so no new comment from me. If someone spots something wrong, please comment.
I want to say something about the two 3K3 resistors in the CCS part. Those form a voltage divider so to bias the transistor cascode and feed its LED. Since they are referenced to Vout, there is a scale depending on what voltage region we use the reg, so to always have proper mA through the LED.
For 5Vout use 470R (use Vref 15K instead 27K, use trimmer 3K3 instead 1K, use 2K2 instead 4K3 R6, also when with JFET cascode)
For 10Vout use 1K (use Vref 15K instead 27K, also when with JFET cascode)
For 15Vout use 2K2
For 25Vout use 3K3
For 35Vout use 3K3
For 45Vout use 4K7
Final setup..... 10uF Audyn-cap MKP // .1uF Vishay MKP1837 on the output zobel (both channels). might try 4.7uf mkp //.047uf mkp
Coax or twisted, the ground side is attached on sense pcb ground and at load ground. Pcb sense connections meet force connections only at the load.
Only position the Jpwr and R12p, C3p near Q4p in layout. Also use as system ground point the C3p's ground point.
Its not that hard to consider a better Tempco region in a JFET Norton Vref's type CCS. A 4mA IDSS K170GR shows -0.5V pinch off (-Vp) on its datasheet. Vgs(0Tc) will be (by that formula I mentoned) 0.5-0.63=-0.13V. Its Ids-Vgs curves show 1.8mA Ids at Vgs0TC.
IdZero=(0.63/0.5)squared*1.8=2.857mA. A proper source resistor for that would be Rs(0TC)=0.13V/2.857mA=45.5R. Our Norton ref resistor for say 90V B+ to voltage stages of the amp will need be (90-vbe)/2.857=31.29K. Practically you stick a 33K 1W and a 100R Rs trimmer in Kean's CCT and you play midway travel near Zero TC. The large impedance can be cleaned easily for self noise by a 2u2 MKP with no real ESR to keep noise bugging up high in frequency. The residual 33K resistor noise is 23.4nVrtHz. That was it.
Attached Thumbnails
You got to know the IDSS of the JFET used first of all Ken. It will be roughly 70% what it is for 9V test when in position for a K170BL. So you project a Vref resistor (Vout-0.6)/IK170. If you can use a bigger film cap across the resistor than before is better, due to its lower now. Its OK for all versions. 1W up resistor(s) for your Vo.
Start of V1.2R
https://www.diyaudio.com/forums/power...lator-313.html
Electro Cap Panasonic EE series ultra low ESR
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