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Output impedance and DC offset on BII (with IVY-III)
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I'm considering a minimalistic integrated digital amplifier (ultra high performance of course .......) using the BII (dual mono) together with a set of Hypex UcD's bypassing their buffer/gain stage. I don't need the gain - not so sure about the buffer.....). To make this work would requires the BII to deliver very, very close to zero DC offset and being capable of driving a 1k8 input impedance load efficiently. Is this feasible? Maybe my questions are more relevant on the analog (IVY) part of the forum. Thanks, Nic Edited by user Tuesday, February 23, 2010 3:29:13 PM(UTC)
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IVY's output impedance is in the mOhms, so you should be fine.
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NicMac wrote:What about DC offset? It is pretty much non-existent. :) The measured DC offset is < 0.1mv on the prototype at the balanced outputs and < 0.3mv at the SE outputs. :) Hope that helps. Cheers! Russ
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On the output impedance. It will be about 21ohms unless you jumper the output resistors which in your case is just fine. If you jumper the output resistors it will be as Brian says, in the milliohms. In either case it will drive your power amp with ease. I would actually probably leave the output resistor just to ensure there are no issues with any input capacitance at the power amp.
Best of luck! Sounds like a fun project!
Cheers!
Russ
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I have have for a couple of weeks been running my Buffalo 32S with a set of Hypex Ucd180ST modules (with bypassed buffer stage and no coupling caps).
This simplistic solution sounds like a dream and I can strongly recommend it !!!
I have compared the bypassed UcD180ST directly with a set of UcD180HG HxR (which cost three times as much) and the cheapest solution is definitely the best!
Try this while waiting for the Sympatico...
Nic
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You must have very efficient speakers. I think the input buffer provides a gain of 5 or 6. My speakers are 90 db and sometimes I listen at -0db
I have a pair of ucd180hg (not the hrx) but I may use Placid to power the input stage.
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No - not particularly. My speakers are 92 db (http://pagesperso-orange.fr/apertura/FR/altra.html) and I never listen at max volume. Family etc.
You can recover the gain on the IVY and/or by getting the UcD400ST's. In any case I really recommend this combination...
I guess the better sound is caused by having only two gain stages and no decoupling caps in the signal path.
The Placid's are great but as I'm bypassing the buffer/gain stage this is not really relevant.
I am using a regulated high-current supply for the UcD's anyway.
Cheers,
Nic
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Russ White wrote: I would actually probably leave the output resistor just to ensure there are no issues with any input capacitance at the power amp.
Best of luck! Sounds like a fun project!
Cheers!
Russ Russ, Would the use of a lower value output resistor (like 2R2) be a valid compromise between a jumper and the 22R provided. I will have only about 30 cm of XLR cable between the IVYIII and the hypex amp (without decoupling caps). I admit that I can't hear much (if any) difference between jumpering and the 22R output resistor so I'm just probing for an "intermediate" solution....... Thanks, Nic
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22R is already a very low value. I would just use that. If you like you could go down to say 4.7R without harm.
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Output impedance and DC offset on BII (with IVY-III)
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