Ok, recently got 3 ucd400 modules and they absolutly sound wonderful. I've got alot of work to do with the power supply side to improve things though. My question I suppose is power output. As wonderful as these sound to my ears they do not seem as loud as the Adcom GFA 5500 amp @ 200watts into 8ohms that I came from. Maybe 200 watts of distortion just seems louder. My transformer is 1000va 40vac gives me 60 volt rails. My speakers are 4ohm. Don't get me wrong the ucd's do play loud just wondering about this power output thing.
dave
dave
snoot said:
Hi Dave,
This is something I have experienced as well so far with every class D amp I have had. (ZAPpulse, UcD, Tripath based Marantz). They seem to sound less loud, as a result, you crack up the volume far higher than with a non Class-D amp. I think the main reason is that with the Class D amps, the output signal stays cleaner (less distortion at high levels) and thus it does not sound "hard" and it feels OK to cranck up the volume.
Best regards
Gertjan
Yeah, loud is such a dirty word!! When it gets loud, you ran out of clean power.
Something that's very thrilling with these amps is their high dynamic range /ultra low noise floor, and the gobs of clean power available.
With the right recording that takes advantage of that (far and few in between), it can be near mind blowing.
Something that's very thrilling with these amps is their high dynamic range /ultra low noise floor, and the gobs of clean power available.
With the right recording that takes advantage of that (far and few in between), it can be near mind blowing.
Hello,
Few quick comments on the Version 6.1 of UCD400AD.
What a thrill they are to experience!!
While it has the sonic signature of the AD8620 (love it or hate it), the response across the frequency range is extremely flat going by ear alone. It is not at all guilty of a "thin" sound, rather the bass is insanely clean, and it doesn't take much getting used to. The power and low end grunt is all there.
The clarity in microdetail is also very good, near flawless, very clean and level.
No single aspect of the sound is "stuck to the speaker", soundstage is deep, wide, musical, and holographic.
All I did was remove the AC coupling caps and they're otherwise bone stock. I find them of such a high caliber that there's very nearly a strong want to not modify them further, of course ... one can only be so strong.
Few quick comments on the Version 6.1 of UCD400AD.
What a thrill they are to experience!!
While it has the sonic signature of the AD8620 (love it or hate it), the response across the frequency range is extremely flat going by ear alone. It is not at all guilty of a "thin" sound, rather the bass is insanely clean, and it doesn't take much getting used to. The power and low end grunt is all there.
The clarity in microdetail is also very good, near flawless, very clean and level.
No single aspect of the sound is "stuck to the speaker", soundstage is deep, wide, musical, and holographic.
All I did was remove the AC coupling caps and they're otherwise bone stock. I find them of such a high caliber that there's very nearly a strong want to not modify them further, of course ... one can only be so strong.
Hi Yves,
No, I didn't have a previous version of the 400 at all, which is why I was extremely careful in my wording to try and not compare it to my version 4.1 of UCD180. No solide conclusions between the two can be drawn given the number of revisions they've both been through.
All I can truly say is .... wow, I like it, and I thought I'd share it
I'd agree with you, the AC coupling caps are an obvious bottleneck to good performance, and I didn't even try the modules with them in place.
Any possible tweak that leaves them as is would seem somewhat futile.
Just set your multimeter on the lowest DC scale and measure across the outputs of your preamp with them unplugged.
They should be below 1.2mv DC. With the newer modules you can likely go even more since able to adjust it about +-150mV or so, but that should be adjusted while plugged into the preamp, and after it's warmed up. Switching inputs after it's been adjusted may change the offset so keep an eye out for that.
Even if you have too much offset to allow DC coupling, at least use some better film caps in their place.
As far as turn on and turn off goes, whenever the modules are ON so should the preamp be. Otherwise you're likely to hear them "settle" to their DC bias.
For example if I turn off my computer prior to the modules, I'll hear a hell of a click as the relay disables the outputs of my soundcard audiodock. So you really only need be concerned with the steady state DC, and follow a proper start up/shutdown procedure, where the modules are the last to turn on, and the first to turn off.
No, I didn't have a previous version of the 400 at all, which is why I was extremely careful in my wording to try and not compare it to my version 4.1 of UCD180. No solide conclusions between the two can be drawn given the number of revisions they've both been through.
All I can truly say is .... wow, I like it, and I thought I'd share it
I'd agree with you, the AC coupling caps are an obvious bottleneck to good performance, and I didn't even try the modules with them in place.
Any possible tweak that leaves them as is would seem somewhat futile.
Just set your multimeter on the lowest DC scale and measure across the outputs of your preamp with them unplugged.
They should be below 1.2mv DC. With the newer modules you can likely go even more since able to adjust it about +-150mV or so, but that should be adjusted while plugged into the preamp, and after it's warmed up. Switching inputs after it's been adjusted may change the offset so keep an eye out for that.
Even if you have too much offset to allow DC coupling, at least use some better film caps in their place.
As far as turn on and turn off goes, whenever the modules are ON so should the preamp be. Otherwise you're likely to hear them "settle" to their DC bias.
For example if I turn off my computer prior to the modules, I'll hear a hell of a click as the relay disables the outputs of my soundcard audiodock. So you really only need be concerned with the steady state DC, and follow a proper start up/shutdown procedure, where the modules are the last to turn on, and the first to turn off.
On my UcD180 placed with the T on the table and looking at the back, in the lower left, etched metallic letters say V4 and under the V4 06/07/2005. I did not see the V4 originally because the silk screen covers the "V" with "R10"
At the same place on myUcD400 (lower back of the T when the top of the T is placed on the table) it says (in upside down etched metallic traces) "UcD400 V6.1 Bottom".
At the same place on myUcD400 (lower back of the T when the top of the T is placed on the table) it says (in upside down etched metallic traces) "UcD400 V6.1 Bottom".
Well, keep in mind it is ultra clean power, so it's actually not at all tireing to listen to, and far from deafening. I never have it "blasted" for very long either, so it's not hard on the ears.
Usually I appreciate comfortable levels, which for me seems to be more than 10W though, and more if the fridge is running, more if the fan is on.. neighbours have never complained?
Usually I appreciate comfortable levels, which for me seems to be more than 10W though, and more if the fridge is running, more if the fan is on.. neighbours have never complained?