Red LEDs not lit
Hi all,
I just happen to be in the middle of a SSLV1.1 board PSU build for a standard Pass B1 Buffer PCB (the original from Pass Labs). Target voltage is +18V single rail.
I already built one successfully for my phono pre-amp and had no issues at all. But for this one, the two red LEDs in the voltage reference area do not light up. The 4 green LEDs do. I used the calculator to get the right parts (although I don't really know the load current), used 15R/5W for R301, 2 Wima Mks 4,7 uF Caps for C303 and C301, 1K8 for R303 and a Bourns W502 5K trimmer. D301 jumpered. I used BYV28-200 diodes for D311-314 as rectifier that I had lying around (instead of the MUR120). Nichicon Gold Tune 4700uF 100V as C305 (polarity is correct)
I had no visible signs of bad soldering, so I thought it would be good to build a second board with a different set of parts to be sure there is no bad part involved (I had a second board and IRF+ set on hand). Unfortunately with the same result.
Since building a shunt regulator with Salas and teabags boards for a B1 has been done loads of times in the community, could anyone give me a hint where I went for the wrong path?
Any help appreciated,
cheers
Hi all,
I just happen to be in the middle of a SSLV1.1 board PSU build for a standard Pass B1 Buffer PCB (the original from Pass Labs). Target voltage is +18V single rail.
I already built one successfully for my phono pre-amp and had no issues at all. But for this one, the two red LEDs in the voltage reference area do not light up. The 4 green LEDs do. I used the calculator to get the right parts (although I don't really know the load current), used 15R/5W for R301, 2 Wima Mks 4,7 uF Caps for C303 and C301, 1K8 for R303 and a Bourns W502 5K trimmer. D301 jumpered. I used BYV28-200 diodes for D311-314 as rectifier that I had lying around (instead of the MUR120). Nichicon Gold Tune 4700uF 100V as C305 (polarity is correct)
I had no visible signs of bad soldering, so I thought it would be good to build a second board with a different set of parts to be sure there is no bad part involved (I had a second board and IRF+ set on hand). Unfortunately with the same result.
Since building a shunt regulator with Salas and teabags boards for a B1 has been done loads of times in the community, could anyone give me a hint where I went for the wrong path?
Any help appreciated,
cheers
Quick question to the jfets selection.
The build guide says 3-5mA range, and it also says
My question is whether the 3-5mA range is the 9V testing reading,
or it is the prorated in-circuit IDSS?
For some reason, I have quite a few (50+% of a batch of 40pcs) at over 5mA IDSS using the 9V testing method. Can these be used by any means like at Q105?
Thanks!!
The build guide says 3-5mA range, and it also says
My question is whether the 3-5mA range is the 9V testing reading,
or it is the prorated in-circuit IDSS?
For some reason, I have quite a few (50+% of a batch of 40pcs) at over 5mA IDSS using the 9V testing method. Can these be used by any means like at Q105?
Thanks!!
That's for IDSS on a battery out of circuit yes. Characterization for a parameter in other words. They can be used if you aren't planning a 40V+ reg. In an upper Vout range situation much current would make Q104 transistor hot (sinks Q105's feed, sees most of the voltage), Q102 hot by itself spanning the voltage distance to 4 LEDS potential. Still even in lower Vout range apps you should know that a strong Q103 will present higher voltage for same value voltage set trimmers and resistors. If it goes out of manageable revise resistance lower.
Thanks, Salas and Andrew.
I am about to start a 5V SSLV1.1 point-to-point wire build for JP's ES9023P Dac by
using the parts that I already have. My transformer is 9-0-9 which should work out to approx. 12.5VDC at C105. I think I am not at risk of overheating any transistors without major human mistake
I am about to start a 5V SSLV1.1 point-to-point wire build for JP's ES9023P Dac by
using the parts that I already have. My transformer is 9-0-9 which should work out to approx. 12.5VDC at C105. I think I am not at risk of overheating any transistors without major human mistake
It is up and stable upon first switch, no BOOThanks, Salas and Andrew.
I am about to start a 5V SSLV1.1 point-to-point wire build for JP's ES9023P Dac by
using the parts that I already have. My transformer is 9-0-9 which should work out to approx. 12.5VDC at C105. I think I am not at risk of overheating any transistors without major human mistake
Next is to parallel a couple resistor to R101 and R103 to hit my 250mA and 5V mark then hook up to the dac ....
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