DC output protection:
Sorry to intrude, but, what do you think about this kit:
http://www.ampslab.com/dcpro.htm
Can we predict sonic impact? I this relé good enough?
BTW, they have also an inrush limiter kit. I use it in my amp and it works OK. It is not that pricy but we have to buy a trafo. I'm using a low quality 15VA EI trafo and it seems silent to me (save one of four channels next to Tx that I can't get right: small hum)
See:
http://www.ampslab.com/inrush.htm
Probably, this kind of delay circuit is better for class A amps?
Thanks to the wise...
Mauricio
Sorry to intrude, but, what do you think about this kit:
http://www.ampslab.com/dcpro.htm
Can we predict sonic impact? I this relé good enough?
BTW, they have also an inrush limiter kit. I use it in my amp and it works OK. It is not that pricy but we have to buy a trafo. I'm using a low quality 15VA EI trafo and it seems silent to me (save one of four channels next to Tx that I can't get right: small hum)
See:
http://www.ampslab.com/inrush.htm
Probably, this kind of delay circuit is better for class A amps?
Thanks to the wise...
Mauricio
OK, another question, this one goes out to Bruno and Jan-Peter, but also to the rest of you.
How do the UcD's sound near or at clipping levels? Is it the same like conventional designs or does it sound different?
Does it clip softer or harder than a class AB?
Can I monitor near clipping somehow? Will the voltage over the rails drop? (Couldn't make it drop more than 0.5V at high volume, my ears were hurting and I was scared for my N804's lol)
My multimeter isn't "fast" though...
Thanks,
Yves
How do the UcD's sound near or at clipping levels? Is it the same like conventional designs or does it sound different?
Does it clip softer or harder than a class AB?
Can I monitor near clipping somehow? Will the voltage over the rails drop? (Couldn't make it drop more than 0.5V at high volume, my ears were hurting and I was scared for my N804's lol)
My multimeter isn't "fast" though...
Thanks,
Yves
Yves:
In my setup I've never heard them clip.
I'm sure your ears will clip before the modules
Please note that when listening to high volume music the little muscles on your midlle-ear contract and protect your timpany and inner-ear from injury (to a level), actually diminishing dinamic contrast and detail.
The modules are so dinamic and natural sounding that I don't have the need to increase the volume too much to get a facsimil of reality.
Regards
Mauricio
In my setup I've never heard them clip.
I'm sure your ears will clip before the modules
Please note that when listening to high volume music the little muscles on your midlle-ear contract and protect your timpany and inner-ear from injury (to a level), actually diminishing dinamic contrast and detail.
The modules are so dinamic and natural sounding that I don't have the need to increase the volume too much to get a facsimil of reality.
Regards
Mauricio
Yves Smolders said:
Whilst slightly interesting this does seem to be one of those slightly irrelevant questions in real usage. I guess what I mean is that IMHO any two really good amps should sound the same (wire with gain). If they don't it's down to imperfections in either.
[To be honest though my opinion is that there is far more to gain elsewhere in the audio chain than simply fiddling with amps. Build better speakers and research accoustic treatment in the room for example...]
So, don't make the amps clip at all is the best suggestion. Any two good amps should clip the same though, ie reach peak output levels, input signal increases, but output signal does not and so you square off the top of the signal
However, what I observe with the digital amps I have built is that with too small powersupplies that they must clip much earlier than in theory (or rather they probably "sag"). To me this sounded like a nice amp at low vol levels or at high vol levels with "simple" music, and as the volume level went up it sounded "harsh" as though there was far too much treble.
My conclusion is that if the power supply is not stiff and beefy enough that you get significant distortion in the digital amp (possibly due to the voltage sag adding a high freq tone modulated to the output signal?) This is probably the answer that you are looking for?
Basically, if you are going to run the amps hard I think you need to put in very beefy power supplies or else these will become the limiting factor. Personally though I would consider using multiple amps if possible!
Good luck!
Don't worry, I don't need to run my amps anywhere *near* to clipping.
I was just wondering, because the whole amplification is totally different to class AB, how it *would* get when stressed.
Class AB starts to distort way before actually clipping, so you know you're going way to load.
I'm afraid that (but am not sure) that class D goes into clipping very abruptly, with no "early warning" until it is too late?
When my enclosure is finished I want to take it to a local high-end dealer - he's a very conservative guy when it comes to audio and would like to see his reaction to the amp. Maybe I'll need to turn it up higher over there... some really difficult to drive speakers over there... (N802D, maggies, top of the line KEFs, Wilson Watt Puppies...)
I was just wondering, because the whole amplification is totally different to class AB, how it *would* get when stressed.
Class AB starts to distort way before actually clipping, so you know you're going way to load.
I'm afraid that (but am not sure) that class D goes into clipping very abruptly, with no "early warning" until it is too late?
When my enclosure is finished I want to take it to a local high-end dealer - he's a very conservative guy when it comes to audio and would like to see his reaction to the amp. Maybe I'll need to turn it up higher over there... some really difficult to drive speakers over there... (N802D, maggies, top of the line KEFs, Wilson Watt Puppies...)
Hmm... Well I am no expert, but a good amp is a good amp. It *should* behave like a wire with gain until it runs out of steam when it clips abruptly. I see no intrinsic reason to think class AB would behave differently?
Of course realistic amps are not perfect and so there may be some differences in practice...?
Of course realistic amps are not perfect and so there may be some differences in practice...?
SSassen said:
Hi Sander,
SOmewhere in the UcD180 thread, someone posted a figure.
It is simple. The UcD modules have a + and - input for the input signals. Assuming you have RCA input. You connect the input signal for one module to the + input and the other module to the - input. You connect the speaker between the output of one modul and the other module. Speakers are not connected to GND anymore. Jan-Peter also advised to connect a small capacitor of 47nF (must be A 160V type or more) between the outputs so that both modules oscillate at the same frequency.
If you have XLR input, then you can connect the + input signal to the + input of one module and the - input signal to the + input of the other module.
Also at the lcaudio website, you can download some application notes of the zappulse modules. In that application note, it is also described how to make a bridged setup. You can do exactly the same thing with UcD, just add the capacitor between the two outputs to synchronize the two UcD modules. For the ZAPpulse, this type of synchronization does not work since they take the feedback signal before the output LC filter.
Best regards
Gertjan
on/off switch
I have received my UcD 400s now and maybe I will build it this weekend. However, I have a question. In the connection diagram of UcD 400, there is a switch between "on" and "supply ground". I think it should be the on/standby switch - closed means on and open means standby. Am I right? The problem is I don't see anybody in this forum connects this switch in his project. I wonder how they deal with this switch. Always on?
I have received my UcD 400s now and maybe I will build it this weekend.
However, I have a question. In the connection diagram of UcD 400, there is a switch between "on" and "supply ground". I think it should be the on/standby switch - closed means on and open means standby. Am I right? The problem is I don't see anybody in this forum connects this switch in his project. I wonder how they deal with this switch. Always on?
)
XMAN:
I use this on/off option through a toggle switch (in fact I would use everything that Jan-Peter and Bruno advise; not very tweaky at this point).
This should be safer for the modules: put them on when PSupply is stable; longer 1/2 life of components.
I feel the amps perform at its potential after 15-30 mins on (sooner than my class A amps) so I don't feel the need to put them on all the time.
Regards
Mauricio
I use this on/off option through a toggle switch
(in fact I would use everything that Jan-Peter and Bruno advise; not very tweaky at this point).This should be safer for the modules: put them on when PSupply is stable; longer 1/2 life of components.
I feel the amps perform at its potential after 15-30 mins on (sooner than my class A amps) so I don't feel the need to put them on all the time.
Regards
Mauricio
Re: on/off switch
The switch connects your ground point to the /ON pin. My front panel switch acts as a mute for all three channels of my UcD modules.
xman737 said:In the connection diagram of UcD 400, there is a switch between "on" and "supply ground". I think it should be the on/standby switch - closed means on and open means standby. Am I right? The problem is I don't see anybody in this forum connects this switch in his project. I wonder how they deal with this switch. Always on?
The switch connects your ground point to the /ON pin. My front panel switch acts as a mute for all three channels of my UcD modules.
An externally hosted image should be here but it was not working when we last tested it.
With shipping et al it would cost more than 200 / module in Canada. Probably 300 after you get stiffed at customs + the brokerage fee. I'd imagine it would hit close to that mark in the US as well.
50 modules... must be a reseller.
A toggle is one idea but how about an electronic delayed switch or relay? Jan-Peter posted something that would do the job early on in the UCD180 thread, not very complex.
What if you leave the toggle on and power it up for instance? I dont' think you'd see smoke or anything but wouldn't it be nicer not to have to worry about it?
Regards
Chris
Just taking an educated guess, but I would say that there's nothing in it between the two amps. Both will have a small loss of a couple of volts max under the rail voltage. 43V into 8 ohms will give you 231W, into 4 ohms it doubles to 462W, but will more likely be nearer the 458W mark due to the extra losses caused by the heavier current draw.