Small multi-UcD for active speaker setup, what to do?

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No, I don't like wood very much (at least not for speakers or amps) ;)

It simply has to fit in one box.

Amps in the speakers is not an option:

1. No room there
2. I'd have to use three long volume controlled (so most of the time very small signal) wires to transport the signals to the amps. No way that's going to work well.
3. It makes it less generic
 
tinitus said:
OK, lets screw it down to this

One box

ONE heavy duty supply for both bas channels

TWO smaller supply for midrange/tweeter - one for each channel


Yes, very good idea and use UcD400 for the lows and UcD180 for mid and high. And drive the two woofers amps for left and right out of phase so that the supply gets loaded symmetrically.

Gertjan
 
I think I'll opt for a big 1 KVA 32V transformer for all six amps, and seperate PSU's for all the amps. 2x10.000 uF slitfoil for each of the mid and high amps, and 4x10.000 uF slitfoils for each of the low end amps. All with seperate rectifiers.

I guess this is the best compromise between space needed, value for money and full mono vs combined setup?
 
4real said:
I think I'll opt for a big 1 KVA 32V transformer for all six amps, and seperate PSU's for all the amps. 2x10.000 uF slitfoil for each of the mid and high amps, and 4x10.000 uF slitfoils for each of the low end amps. All with seperate rectifiers.

I guess this is the best compromise between space needed, value for money and full mono vs combined setup?


Better make sure you use a softstart circuit as I'm pretty sure your lights would go out when you power up that 1kVA transformer with a total of 16x10.000uF caps if I counted correctly. With that large amounts of caps, you will be drawing large peak currents from the mains which is I think the reason why Bruno has advised against excessive use of power supply caps. Anyway, if that fits all in that one case, you can try it and let us know the result, just keep some space open for the softstart.

Groeten

Gertjan
 
Thanks for the conserns :) There wil definantly be a softstart of course, as wel as a DC detection, and a DC filter on the mains, since I don't like it when the transformer starts humming if someone turn on the hair driyer or something like that. But I don't think I'm using an excessive amount of PSU caps. If there were 6 individual amps in boxes, no-one would complain I guess ;)
 
4real said:
Thanks for the conserns :) There wil definantly be a softstart of course, as wel as a DC detection, and a DC filter on the mains, since I don't like it when the transformer starts humming if someone turn on the hair driyer or something like that. But I don't think I'm using an excessive amount of PSU caps. If there were 6 individual amps in boxes, no-one would complain I guess ;)


You could use smaller, and possibly better quality, caps for the highs and mids as they have to deliver less power. Anyway, I should not say too much as I plan to use quite bizar amounts of caps myself as well :)

Gertjan
 
4real said:
What better caps then. The Slitfoils appear te be the best solution according to the expers, despite the high ERS rating. Well, T-net caps might be better, but are not available in <10.000uF and are far to expensive.


Well, good question, do not have a clear answer, I was thinking of using for example a number of Panasonic FC caps 100V 680uF in parallel. The smaller caps likely have better high frequency properties and a number of them in parallel will give you a very low series resistance and inductance which would help to get rid off any remaining high frequency ripply that maybe present on the power supply rails (the modules themselves will put some HF signal on the rails, although quite small in case of UcD).

Gertjan
 
tinitus said:
will small caps be more stressed than big ones, under power-up with this huge trafo - or will they draw less current because they are small ?


They will just draw less current during charge up. The amount of charge stored in them, and thus the current that is needed to charge them at startup, is proportional to the capacitance value.

Gertjan
 
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