advertisement


Buffalo II - Assembly for the Electronically Bewildered.

Status
Not open for further replies.
cutting42 said:
What I did when adjusting the Placids was to solder 6 inch wires to the underside of R3 and R8 so I could clamp the multimeter to the wires without the danger of slipping off and shorting the tracks.

Sorry Tony, might not help in this instance but may assist later.
Click to expand...

Funnily enough, I thought I'd do that very thing next time!:rolleyes:
 
As I patiently wait for the Farnell delivery with my new variable resistors, I ponder on the significance of using the Placid power supply. Although it can be adjusted to give a greater output it seems to have been designed to be happier at a lower current output.

So why use this type of power supply over something like an STR/generic rectifier setup, which seems to be quite OK up to 1 Amp or even 2 if necessary? presumably the Placid's a bit quieter?
 
Suffolk Tony said:
As I patiently wait for the Farnell delivery with my new variable resistors, I ponder on the significance of using the Placid power supply. Although it can be adjusted to give a greater output it seems to have been designed to be happier at a lower current output.

So why use this type of power supply over something like an STR/generic rectifier setup, which seems to be quite OK up to 1 Amp or even 2 if necessary? presumably the Placid's a bit quieter?
Click to expand...

Placid is quite; more importantly in this application, it has very low output impedance, while TR and STR don't.
 
Suffolk Tony said:
As I patiently wait for the Farnell delivery with my new variable resistors, I ponder on the significance of using the Placid power supply. Although it can be adjusted to give a greater output it seems to have been designed to be happier at a lower current output.

So why use this type of power supply over something like an STR/generic rectifier setup, which seems to be quite OK up to 1 Amp or even 2 if necessary? presumably the Placid's a bit quieter?
Click to expand...

I only use STRs in constant current (ish) analog circuits, they seem very pleasant on the analog output stages of my Giga dac but don't cut the mustard on the digital sections, on digital they seem poor a standard 317 with good implementation and the booster stage out performs the str here, Martins fleas were in another league but often need pass transistors as they are current shy and of course do not do dual rails.
 
Suffolk Tony said:
Hi Martin, it's a Panasonic 1000uF 35V. It it sufficient to up this to the same model 1500uF do you think?
Click to expand...

Difficult to say Tony without putting a scope on the output. Certainly going to 1500uF will help at the higher current draws. To be honest, I wouldn't sweat it, just add the Tridents, shorten your Placid to Buffalo/Legato wires, box up and enjoy!

Regards

Martin
 
OK, got the new variable resistor for VR2, installed, adjusted OK, added the load, Buff + Tridents. Adjusted Placid, delivering 5.3V. All LEDs glowing, Got no sound...

HELP! I've checked that the Tridents are in the right place (they are), double-checked all connections, now I don't know what to do. The lock LED is on but very dimly.

Do I need to jack up the power some more? I'm fumbling in the dark now. I'm tempted to remove the Tridents to check if the Buffalo's working OK; if i reinsert the ferrite beads will that bypass the Tridents or have I got to physically remove them?
 
Here's a couple Martin -

buff--tridents2.jpg


buff--tridents.jpg


I was using this temporary setup without the Tridents and it was working just fine.

I've just double-checked voltages with the Buff+Tridents connected & the Placid's delivering 5.3V and 0.38V across R8. So this should be OK?
 
Tony

I have to run our for a while today but will take a good look this evening. I did see that someone had responded to your question on the TP site asking if you had cranked up the Placid current - that's a good thing to check. You should check the bypass current on the Placid, with the Tridents you won't need as much headroom as without them, so 40mA bypass should fine. 0.38v across R8 isn't enough, thats the total current draw and should be more like 0.5v. You really should be checking the voltage across R3. Set this to 0.04v (40mA bypass) If this doesn't work, carefully check the output voltages of the Tridents with an multimeter. (Have steady hands with both tests!)

Regards
 
Thanks for your help Martin; I'll have another look in the morning. Can't think what else it could be.
 
Still no joy I'm afraid. I followed these instructions from a guy on the TP forum - .38V is not enough. Your Buffalo/Tridents are starved. The Placid needs to shunt current above and beyond what the Buffalo with the Tridents is pulling. This is measured across R3. Please see the Placid schematic. If I'm not mistaken Buffalo pulls ~350mA, Tridents another ~100mA. Your Placid needs to be adjusted to pull another ~50mA or so above the load for proper operation. The voltage across R8 is measuring the total current. 1 ohm resistors at R3 and R8 make the current calculations easy (I=E/R). With Placid disconnected, adjust CCS pot until you measure .5V across R8, double check output voltage, 5.3V. Reconnect Buffalo and adjust the CCS pot until you have .05V or so accross R3, measure carefully as not to short anything."

It all measures as he suggests, all alight although this time neither the mute or lock LEDs are on.

I'll try to measure the voltage across the Tridents & see what readings I get.
 
Thought I'd try & disconnect one of the Tridents - the one on the extension which doesn't require unsoldering, & re-bridge the relevant link. No difference but I notice the mute and lock LEDs behave erratically. If I cycle the power sometimes none come on, once both came on quite brightly, then just the lock one, dimly.

Heavens!
 
I wonder if your Buffalo is now functionong fine and something else is going on. Can you check your digital inputs? - Are you feeding directly into the Buffalo or through the MUX?

1) Check your digital connections - can you hook up you digital input to another DAC to check?
2) Bypass the MUX and try
3) Check and tighten all your screw terminal connections on all the boards, give them a tug (powered down) to make sure they are secure.


Can you post another image with all the connections in place

Thanks
 
ISTM most likely that you don't have enough voltage. Assuming everything is wired and generally connected correctly. What is the output voltage of the Placid no load, and then with the Buffalo connected?

Is there any possibility you have the wrong Trident in the wrong place (right Trident, wrong place, you know what I mean)? I've not got around to Tridency yet, so no direct experience.

Paul
 
Feed directly into the Buffalo, and it works fine with my old Gigaworks DAC. I tried reinstalling the TOSlink module, no luck. All connections checked, soldering rechecked.

Tridents definitely in the right place. Placid voltage no load = 5.3V. With load=5.3V. All voltages on the Placid are as per my post above.

I've had to give up for the day now (I'm not very popular with SWMBO...)

I'll post another photo later on Martin.
 
Ah-Ha! Measuring the Tridents revealed DVCC & VDD_XO were in the right position and delivering 3.3V but although VDD's LEDs are illuminated it wasn't producing any output!

I've just removed it, reinstalled the ferrite bead and, by golly, the Buffalo works! Whew!

(I'm also posting on the TP forum by the way - there do seem to be a fair few issues with the Tridents)

There's nothing obviously wrong with the faulty Trident so I guess I'll send it back to TP? I've also left the Placid set to its higher output - is this OK please?
 
Suffolk Tony said:
Ah-Ha! Measuring the Tridents revealed DVCC & VDD_XO were in the right position and delivering 3.3V but although VDD's LEDs are illuminated it wasn't producing any output!

I've just removed it, reinstalled the ferrite bead and, by golly, the Buffalo works! Whew!

(I'm also posting on the TP forum by the way - there do seem to be a fair few issues with the Tridents)

There's nothing obviously wrong with the faulty Trident so I guess I'll send it back to TP? I've also left the Placid set to its higher output - is this OK please?
Click to expand...

Tony,

Leaving the Placid current won't cause any harm. Glad you found the problem.

Regards
 
All's well now; I checked the Trident (it was the 1.2V one) & discovered there was no output even off the board . I looked at it carefully with a high-powered loupe but again there was nothing obvious. I then ran the soldering iron over the bits I'd soldered, cleaned round, rechecked and bingo!

I've still got the bits mounted on a ply board the same size as the case. I'm just enjoying listening to it whilst it runs in & then I'll pop it in its case with the components positioned as you folks have advised.

buff--tridents-working.jpg


No doubt it'll sound even better when properly wired and enclosed but it sounds pretty damn good now! Adding the extra Trident seems to have made a greater difference to the sound quality than adding two.

I'll order another Placid when they're back in stock to power the MUX 4:1 & TOSlink module but there's no rush.

Thanks again for all the great help folks!:)
 
Great news Tony :)

I think that everybody here is waiting for some more detailed comparison with your CDP 555 ;)

PS I know, that this is you test setup, but try to keep the cables beetwen ps and pcbs as short, as possible.
 
Status
Not open for further replies.


advertisement


Back
Top