Twisted Pear Buffalo Sabre DAC - Page 65

My world revolves around macs, iphone using remote via itunes = bliss, I haven’t got a problem with the functionality.

It’s seems like APE and Buff32 conflict, the DAC’s re-clocking the data somehow and tripping up. If I can’t get around the problem I just keep doing optical directly out of the mac.

Low current dual powersupply question

for the common mode choke, L1 / L2

I see a dot on the circuit board indicating orientation. But I looked at the data sheet and I wasnt able to find anything to do with how to orient L1 and L2, plus there are no markers on the thing to make a reference from.

A choke (inductor) is non-polar, like resistors.
Just solder it on its place on the PCB and you are fine.

ah ok i had thought so but the dot just confused me

thanks a bunch

well I wish i had thought about that before I desoldered one because it wasnt orientated correctly. there is actually a small dot on the side of the inductor, like a tiny raised dot in the plastic, which I only noticed after looking very closely after being confused at the purpose of the dot myself and so I think I may have damaged one inductor desoldering it. one of the conmtacts came off the coil when removing it, but I was able to solder it back on with minimum effort; its a tiny bit mis-shapen, but appears to be fine and stoill fits on its contacts just fine. Soldering it back on the 'right' way was a total PITA, because the board was fully populated. havent fired it up yet to see if it works.

Brian, any chance you could pop one in the mail for me?? do you have any spare. of course i'll sort you out for shipping and whatever the part costs. making an order specifically for that from overseas will be very costly. everything else went swimmingly and i'm just waiting on my case before I fire it up. its taking a while, so i'm very tempted to mount it on a bread board in the meantime to test.

is there a check routine that I can go through to see whether it is OK or not?? or is firing it up and testing for voltage the only way?? sorry for the noob question, as I said this is my first project like this and these are the first power supplies I have made; other than the onboard one on the gamma1. i'm cautious, because it involves power and I certainly dont want to connect it to the B32 to test.

Well my guess a check would be to test teh g and V- and V+ pads with a meter and see if your getting the correct desired voltage as you would have to do with a sigma22 psu.

I will let u know more when i build mine.

qusp, as boinger stated check the psu’s first before connecting up the Buff32, adjusting the trim pots to their respected voltages - if you manage correct readings then your ok to power up the Buff.
Are you using the Avel Lindberg trannies? Remember to solder and heat shrink the purple and grey primaries for 230v.

yeah well sure, but was just wondering if there was a way to test with just a meter without powering them up; if the inductor is dead I guess it just wont do anything, rather than burning out the caps or something?? would just mean an open circuit??

of course!! I was not talking about connecting up to the B32 to test, but rather connecting up the LCBPS to test. i'm actually using the terminal blocks for everything except the outputs, as I know how much I like to fiddle and using them will enable that easily, without multiple soldering and resoldering of the pads. Then once i've settled on a favourite configuration with hook-up wire etc; i'll just solder to the underside. plus it means less lead in the signal path yeah i'm using the avel trannies (2 x 25v and 1 x 15v because they ran out), was actually about to look up the data sheet on them, since they dont have it all marked on the side. you mean together for 230 and the outputs are what black (V-) and red (V+) and orange (V-) and yellow (V+) correct??


like I said first time with anything like this and its pretty serious stuff i'm gonna have to go buy myself a new meter too, the one i've been surviving on since the move disappeared one; doesnt have alligator clips, just a couple of spikes that I would have to hold onto ^^

I knew you’d do that, I expected nothing less

FOR 240V OPERATION AVEL LINDBERG TRANFORMERS ARE WIRED:

Connect the grey wire to the violet wire and insulate/heatshrink it.

The secondaries output AC, so they aren't positive or negative, but you do have to make sure you connect them in the proper order so that the phase is not messed up.
You simply connect the secondary wires to the terminal block in the following order: Black, red, orange, yellow

It doesn't matter whether it's from left to right or vice versa.

Well qusp, I think your desoldering work was needless. It doesn't matter which way you solder the common mode chokes. Russ comments about it over at the TPA forum.

Concerning testing - a look in the schematics cannot harm. You'll see that the chokes are in series with the main lines. If the inductor lost contact to it's pad, then it would simply mean open circuit and no voltage.

hehe am I THAT predictable ;D


**** hey; shows you how long it is since I worked with AC, totally vagued on no polarity for alternating current in my post LOL; my work is almost entirely to do with DC voltage; my knowledge in this area is very specific, but i'm growing it all the time. I also probably do too much thinking out loud on here and pose too many rhetorical questions; which brings me to this vv

hehe I see you quoted an earlier version of my post. do you get this thread funneled through to your email immediately or something??

as I said above; more thinking out loud with that 'question' than anything; I should probably do less of that, or go back and edit afterwards. it just helps me to process it myself to put things down in writing. thanks for the response though. I had thought everything was cool as well, but then noticed the dots after I had finished the first board. seeing as inductors are basically similar to resistors gut said cool; but noticed each inductor has a small raised dot on one side, so my OCD took over and I had to desolder it

thanks for the help guys, I dont just rely on you guys to do it for me, but as I said it helps me to work through stuff externally; so I tend to google, think things through, but also write down a train of thought on here in case my logic is floored.

must have got in before you edited, funnily enough my email is the latest quote - go figure I’m picking up my cut panels today, a quick check and there off for laser engraving, I’m crossing my fingers all my measurements line up...

Wow you move quick!
I've wiring everything up before I dismantle the three panels for engraving.
Ass backwards I know but I want to make sure everything actually works lol...

whats the inrush current like on this baby?? do I really need a soft start circuit? i'm thunking in the long term yes, to prolong the life of the parts, but short term is it totally necessary?? I mean these are pretty small trannies, so I would imagine the resistance in the windings itself would halt it pretty quickly. or am I out of my depth again ??

No.