UcD400 Q & A

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#1,764
Hi fellows,
I had narrowed my search down to UCD400 because I've blown my tripath amp and want to reuse the casing/parts.

Malefoda said:
...

yes this is DIY, destroy it yourself. Done. (with fireworks).

...

I have the case, +/-58V, (useless 10V and 5V), a passive pre (10K because the Truepath was 50K Zin) and let's say 2/300€.
As for power my old 8ohms JBL -wich I play loud- were at pain with my 30W amp, just nice with the Tripath (let's state 120W with low THD).
...

well low Zin of the Class D Audio amps and Anaview's ones lead me to UCD400HG HxR and its matching voltage req. But do you guys think having a single linear supply powering 2 modules (27.000uF each rail) will lower sq?

Matthieu
Click to expand...

I can add a second row 2x2 +/- caps before each UCD, worth? BTW, now I wonder if having the modules near (tight space there) will cause crosstalk...
 
#1,765
Well, case in progress... BTW, still questions, I've sent them to Hypex support, don't know if they answer such questions... and image search, website search I've done for hours never gave the the answers.
So I do let them here, on my UCD400HD HxR:

* are the 2 films caps just after the input connector coupling caps for DC blocking? As I'm serious about my sources and there is no DC there, can I and should I (soundwise) bypass them?

* are the blue 22uF supply caps for the LM4562? As the HR are quite close, do you think it is already top or a better cap will better these? (no snake oil there, I have spares Rubycon ZLG caps, if it's just pointless I don't mess with your design).

Thanks for any input!
Matthieu



... still strange, g**gle image returns no example of bypassed input caps so nobody can guess wich they are...
 
#1,767
It's done, had to do with the remains of the TA3020.
What may I mesure/check prior to power it up? LS- is the common ground?
The supply wires are hanging until I am not 110% assured it will work flawlessly...
 

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#1,775
Hi fellows,

prior to close the lid of my amp, wich feature very few air vents, I've done heat measurements. As you can see the heatsinks seem to cool the aluminum T enough (55°C).
But other parts get hot, really hot, the worst being the two TO-220 devices on the very right of the boards, 100°C!
Is that normal, are these devices speced to run hot? The small device at the bottom of the T is also very hot, as a point (under?) the PCB wich is close to 70°C, seen on the top side of the PCB.
As it's winter and room temp is 19°C I'm worried for this summer and the 38°C we can have several days in the room...

Thanks,
Matthieu
 

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#1,777
I'm sorry dude, I'm afraid I can't do that.
That's a recycled case wich limits things ; can't flip the boards to the side, what's left then are large vents in the case for air flow. Don't know how to do that without butchering the top and bottom lids...
The TO-220 devices are Darlingtons wich are speced at max (internal junctions) 150°C, so to run hot. Will add a tiny heatsink anyway. And report.
 
#1,780
Hi there, I have read some, even Bruno's note, but maybe my english is not that great as I feel confused;
- do lower the gain (x10 so 20dB) by changing Rg degrade sq in any way (the CMRR thing),
- do that resistor need to be of a precise type? micromelf metal?
- is the gain the same in SE & Bal?

Thanks!
Matthieu
 
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