I have installed the IRFP240 and is working fine but but the last 3 transistors close to output (the 2 sk170 and bipolar) are running very hot, almost impossible to touch. Maybe not all three of them are hot but is hard to say as they are very close on the pcb.
The negative rail seem to be much hotter than the other one. On the three 68ohm paraleled resistors i have 3.8v on the negative and 2v on the positive side.
The negative rail seem to be much hotter than the other one. On the three 68ohm paraleled resistors i have 3.8v on the negative and 2v on the positive side.
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I guess you have shorted one of the transistors. Are the IRF's isolated from chassis?
I wonder if the IRF's are shorted, and or bipolars.
Do you have any extra?
I wonder if the IRF's are shorted, and or bipolars.
Do you have any extra?
I have some spare transistors. The IRF's are totally isolated from chassis as i dont have a chassis yet 🙂
Both regs are working but now i see one went a bit up to 12 v even if in the first minutes they where very close with less than 0,5v difference.
Both regs are working but now i see one went a bit up to 12 v even if in the first minutes they where very close with less than 0,5v difference.
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No sinking for the IRF's as they are slightly warm. I don't know to answer to the question regarding current. The strange thing is that acros leds i have a bigger voltage than theoretically they stabilize.
Across three leds string (ccs) i have 7.8v
The 100ohm resistors are also hot.
Across three leds string (ccs) i have 7.8v
The 100ohm resistors are also hot.
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There is a Jfet connected to that 100 Ohm on your version right? Which board version and a photo would help too.
For my build i have followed first posts of this thread: http://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer-2.html
Across Jfet close to 100ohm i have a voltage of 0.7V so seems to be ok i would say.
Across Jfet close to 100ohm i have a voltage of 0.7V so seems to be ok i would say.
Salas thanks for your inspiration, i've found the problem and like always was an human error in the pcb design. Now my buffer sings very very nice and makes a nice team with the Simplistic Riaa 😉
After building and testing the DCB1 with plain resistors i want to buy some better quality resistors (mainly for buffer part) and i ask you what to choose (preferably from Mouser ).
What about CF1/4CT52R221G KOA Speer Carbon Film Resistors - Through Hole
or these
RN55C2200BRE6 Vishay/Dale Metal Film Resistors - Through Hole
If you have some other sugestion i'm open to something else.
What about CF1/4CT52R221G KOA Speer Carbon Film Resistors - Through Hole
or these
RN55C2200BRE6 Vishay/Dale Metal Film Resistors - Through Hole
If you have some other sugestion i'm open to something else.
metal film, 1%, 25 or 50ppm/C, all copper connections (non iron, Fe) are very good.
0.1% and 15ppm are not worth paying the extra for unless the circuit specifically requires those.
0.1% and 15ppm are not worth paying the extra for unless the circuit specifically requires those.
I used DALE 1% Metal Films in the signal path.
There was much more improvement to made with the caps.
I used Siemens 1.0uF MKP caps at the input and Oblligato 10uF PIOs at the output.
Again, the difference is subtle and definite snake oil territory.
You wont fit these caps on a Mesmorize board though. I used a homebrew clone of the original B1 board.
The resistors at the bottom right of the board are not in the signal path so I just used good quality 1% metal films there.
I can't find the original photo so I'll post it again - Apologies to the Moderators.
I eventually used the Mesmorise board as a Salas shunt reg with my homebrew Pass B1 boards.
There was much more improvement to made with the caps.
I used Siemens 1.0uF MKP caps at the input and Oblligato 10uF PIOs at the output.
Again, the difference is subtle and definite snake oil territory.
You wont fit these caps on a Mesmorize board though. I used a homebrew clone of the original B1 board.
The resistors at the bottom right of the board are not in the signal path so I just used good quality 1% metal films there.
I can't find the original photo so I'll post it again - Apologies to the Moderators.
I eventually used the Mesmorise board as a Salas shunt reg with my homebrew Pass B1 boards.
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Forgot to ask you if worth to buy some BL grade transistors if i have matched GR transistors with Idss around 5.5
I used these
eBay - The UK's Online Marketplace
Whether you will notice any difference is up to you.
eBay - The UK's Online Marketplace
Whether you will notice any difference is up to you.
Guys I am waiting for some mesmerize boards I got from the diyaudio store and I am currently planning on the rest of the parts.
What I was wondering is if there is a way to get two outputs from the board, so that I can drive 4 monoblock amps (dual - dual mono setup driving woofers and mid-twitters separately)
Thanks a lot
Dimitri
What I was wondering is if there is a way to get two outputs from the board, so that I can drive 4 monoblock amps (dual - dual mono setup driving woofers and mid-twitters separately)
Thanks a lot
Dimitri