Placid-BP Bipolar Shunt Regulated Power Supply

[avr300]

Measure between tp_out+ and tp_shunt+
Do the same between tp_out- and tp_shunt-

Post the result.

 

[nvduybom]

Thank avr300, with 10VAC input I measured gnd - tp_out += 12.9vdc, gnd - tp_shunt+= 12.9vdc, tp_out- and tp_shunt- is the same . No current load on R2A and R2B.

 

[avr300]

What happen when you turn the current limiting potentiometer(s).

 

[nvduybom]

I am try to change the current load by VR1A, but VDC of TP_VIN = TP_CCS+ , no current load on R1A .

 

[avr300]

Lets move this to the support site at

Twisted Pear Audio Support

Go create a case, I'll help you there.

 

[nvduybom]

Great thank avr300, the problem was solved by my friend, the cause by VR2A, but I don't know why the line negative fail, same .

About the case vol dc down 15 VDC to 1 VDC by I mistake GND with - when connect to Legato.

Now, my board work well .

 

[picovolt]

HD problems, new build, no adjustment at VR2

Built HD and HD PBP at the same time; just tested them. BP is working just as expected, but the HD is not working correctly. All LEDs lit, checked all 550 and 560 transistors (for orientation and solder joints), resistors, solder joints on everything. Twice.

These are most basic measurements, and I can provide photos and more measurements as required.

V in 10.85V AC
DC in 13.45V (TP GND1 & TP VIN)
V out is about 4.05 cold, then lowers to 3.9ish; turning VR2 has no effect at all on V out.
TP V REF is 3.87V which is correct I think.
CSS measures 0.00

Any suggestions where to look?

Edit: cross-posted here:http://www.twistedpearaudio.com/forum/yaf_postsm20135_Placid-HD-not-adjusting.aspx#post20135

 

[orangeart]

I have an application where I need 35-37 volts out, I have a spare placid, can it be modded to take out put this kind of voltage and if so how much head room would it need?

Stefan

 

[Russ White]

Not to discourage you, but I would not recommend it unless you understand the circuit well enough to make the changes yourself. If it not the HD version it is not really possible with serious rework.

 

[pixelpusher]

Built HD and HD PBP at the same time; just tested them. BP is working just as expected, but the HD is not working correctly. All LEDs lit, checked all 550 and 560 transistors (for orientation and solder joints), resistors, solder joints on everything. Twice.

These are most basic measurements, and I can provide photos and more measurements as required.

V in 10.85V AC
DC in 13.45V (TP GND1 & TP VIN)
V out is about 4.05 cold, then lowers to 3.9ish; turning VR2 has no effect at all on V out.
TP V REF is 3.87V which is correct I think.
CSS measures 0.00

Any suggestions where to look?

Look at your soldering. I recently had the same issue. I checked, double and triple checked my soldering and could not find fault. I reflowed the solder three times and checked it under magnification. I finally sucked all that solder off. It was some boutique "audiophile" solder that a friend gave me. I re-soldered all parts with my good old eutectic solder and no problems now.

 

[Salar]

Can I solder the Placids Parts from both sides?

Can I solder the Placids parts from both sides?
I have already built a Dac and as far as I remember
all solder joints of the older Placids were accessible from top and bottom.

The reason for asking:
I can use the large heatsinks of the cabinet for the Placids, but the
Bipolar HD connected this heatsink, the power transistors mounted from above and facing outwards takes too much space.
But I could place the Placid HD Board upside down,
the trannies now bent inwards.
It will be tricky to solder them because they must be attached to the heatsink before.
All large parts (besides the resistors) must soldered from the bottom
of the pcb.
Is this possible?
My approach sounds complicated.
I could place the transistors the way I need them without messing around with the board using some extra wire,
But the transistors connection now hade to be crossed
and I do not want to care about heat resistant insulation of the wires.

Next question:
The 35V/1000µF Panasonic Caps will be discontinued in 2015. What will be their replacements?
All the best,
Salar

 

[BrianDonegan]

All the holes are through-plated, so yes, you can solder from the either side.

Typcially, to mount the transistors to the case or large heatsink, simply bend the pins forward to a 90degree angle and mount under the board (it was designed with this in mind). The tips of the transistors should reach the board and you solder them from the top.

Since this is too wide for your heatsink, yes, you could mount parts on the bottom of the board. Just be very careful about getting the pins right for the small-signal transistors and voltage references.

 

[BrianDonegan]

The 35V/1000µF Panasonic Caps will be discontinued in 2015. What will be their replacements?

The replacement will most likely be the Cornell-Dubilier 381LX103M035A022.

I have a large stock of the Panasonic caps, however, so it will be some time before I switch over in the kits.

 

[Russ White]

Some of you will be interested in this:

http://www.diyaudio.com/forums/twis...-2-1-lesson-teamwork-passion.html#post4115080

 

[Audiohifi]

Placid-BP Bipolar Shunt Regulated Power Supply PCB 2.1.2

May I know is the above PCB still available?