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A generic rectifier/smoothing PCB

flashgo said:
So that's a grand total of 85x140 needed to fit a Hacker 6-Cap with necessary accoutrements. The board will overhang the DIN connector a bit, but that's OK since there's only 10mm of output connections on that end.
Click to expand...

The version that I just knocked together comes in at 80x180, which is too big it would seem. The current version (pics to follow) is a bit of a tight squeeze at the output end, leaving no room for optimization there.

The diode end will have to be compressed somewhat, but that means we'll lose the space for the option of 3-pin to220 diodes such as the mbr20200ct that's popular wig some bodgers. The remainder of the holes will be designed for to220 diodes like the msr1560. Axials will fit if stood on end... I'll see if I can make dedicated holes for them, but no promises!

This should all be a bit clearer when I add pictures tomorrow. Any comments so far?
 
Do we really think there's any audible difference between using resistors and inductors on these for pre-amp use? Teddy regs located between Hacker's board and pre-amp/phono in all cases.
 
i haven't tried, and I guess there's only one way to find out..... Let us know when you're done :D
 
Will do. My phonostage box has dual traffo and boards with dual outputs on, so hot swapping will be fast and simple.

Could be interesting.
 
I'm going just slightly mad, I must be 'cos I can't see what I've done wrong, read on.

Using one of Carl's excellent lower power PSU PCBs I've built a couple of single rail, +ive supplies. As a had a few hanging around I decided to use a couple of three pin diodes (Qspeeds http://www.qspeed.com/content/lqa20t300c) instead of four separate diodes. I've also installed 3 R47 3W resistors to provide a RCRCRC filter.

I've even read Carl's manual and wired LR1 to the 0V of C2.

The transformer (25v) has its secondaries in parallel wired to the AC tabs on the PCB. I'm getting about 28VAC out of the secondaries.

I can't see anything wrong, but at the end of the board, between Vout2 and 0V, there's no voltage.

My finger of blame is pointing at the diodes.

IMG_1847.jpg



Anyone any ideas?

PS I'm not using the 0V connectors on the AC side. Transformer secondaries connected across the AC/AC tabs.
 
It was the diodes. No idea why they shouldn't work as fitted.

Anyhow, swapped out the three pins for 4 four pin diodes and all if fine....weird though.
 
Can you work out what you did / they did wrong as aren't these the diodes we are buying with the new board run?

I mean ignoring specifics of spec, isnt a diode a diode :confused:
 
trancera said:
Can you work out what you did / they did wrong as aren't these the diodes we are buying with the new board run?

I mean ignoring specifics of spec, isnt a diode a diode :confused:
Click to expand...

I would have thought so too.

I double checked that the diode layout of the LQA20T300Cs and that of the MBR20200CT were the same. I was working on the theory that the MBR20200CTs would be more commonly used.

The only thing that could be amiss is that the PCB is marked incorrectly. Having just checking one of the three pinned diodes needs rotating.
 
Yes , I cant imagine they would make the diode pins different from standards.

Are you saying you think you ran one diode into another (therefore making sure nothing can pass at all in any direction) ?
 
chiily said:
I would have thought so too.

I double checked that the diode layout of the LQA20T300Cs and that of the MBR20200CT were the same. I was working on the theory that the MBR20200CTs would be more commonly used.

The only thing that could be amiss is that the PCB is marked incorrectly. Having just checking one of the three pinned diodes needs rotating.
Click to expand...

Hi,

Two things appear to be wrong: the first is that you don't need to fit two diodes when you're using 3-pin types such as the LQA20T300C or the MBR20200CT. The layout of both devices is identical, and you only need to fit one diode into position D2. They're also symmetrical around the centre pin, and as such rotating them makes no difference to their operation.

Second, you don't need a wire link on the other power rail. For a single rail using a LQA20T300C hooked up to a centre-tapped transformer, you just need a single LQA20T300C in D2, the 3 caps in C3/C5/C7, and wire links or resistors or inductors in LR2/LR4/LR6, and... that's it :)

Let me know how you get on.

Edit: looking closely at your picture, I can see that the wire link from LR1 to C2 directly shorts the output of D1 to 0V. That's your problem right there.

trancera said:
Can you work out what you did / they did wrong as aren't these the diodes we are buying with the new board run?
Click to expand...

Nope, Chiily was using 3-pin types (http://www.qspeed.com/sites/default/files/37-LQA16T300-rev_1.6_May,_2009.pdf), and the ones we're getting for the new board run are 2-pin types (http://www.qspeed.com/sites/default/files/37-LQA16T300-rev_1.6_May,_2009.pdf).

Cheers,
Carl
 
Olivier, I can send you one or more right away, but it'll take ~ 1 week in the post from America. $5.50 including S&H.
 
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