Yves Smolders said:
This isn't clear to me, if I have multiamp system where should I connect the speakers ground? do you have a link to JP advise
Patriz
Yves Smolders said:
Thanks everyone. I haven't seen JP's schematic. Does anyone have a link before I take a few days searching through this mammoth thread?
patriz said:
You should connect both speaker connections to the UcD module only because of the issue mentioned earlier. This is in contrast to most class-b amps where you return speaker ground to the cap bank star point, i.e. you do NOT connect speaker to star point with UcD.
chrisb03 said:
I think the link was not all that long ago, maybe you only need to trace back 3-5 pages.
richie00boy said:
I haven't been able to find, is it in this thread? Was the link posted by JP? I did a search on JP's post with no luck.
Yves Smolders said:
Yves, If your talking about the LCAudio softstart then I would be careful doing this, as this will draw more current through the bank (row) of resistors feeding the relay. Also, the relay on the softstart acts as a voltage divider to bring the voltage down to around 110vdc.
The JP's mute circuit.
And the PCB is here: http://audio.cyberkata.org/UcD180/UCD_PSU.pdf
T1 = 2N2222A
R1 = 100K
C1 = 220 nF
And the PCB is here: http://audio.cyberkata.org/UcD180/UCD_PSU.pdf
T1 = 2N2222A
R1 = 100K
C1 = 220 nF
Thanks stef1777, I appreciate it. A stupid question, I suppose AC1 and AC2 are just connected to each power rail?
Sorry if I catch this thread a bit late.
I assume that circuit is for powering off the module as soon as the PSU mains are disconnected (to avoid waiting for the capacitors to discharge, etc).
What happens to UcD module if the PSU is let to discharge naturally and there is no control on the /ON pin? Does it make some click or behave erratically when the rail voltages drop to an unacceptable level? If not, what is the utility of this circuit?
Thanks!
I assume that circuit is for powering off the module as soon as the PSU mains are disconnected (to avoid waiting for the capacitors to discharge, etc).
What happens to UcD module if the PSU is let to discharge naturally and there is no control on the /ON pin? Does it make some click or behave erratically when the rail voltages drop to an unacceptable level? If not, what is the utility of this circuit?
Thanks!
if you don't disconnect /on from ground, the caps will be drained by the ucd modules and you'll hear some nasty distortion when the voltage drops. (gggggggssssssssshhhhhh-screech)
I hear the distortion on my ucd400 modules but on the ucd180's I can't hear it.
I suppose you can tie the /on pins from different modules together to one of these circuits. Am i wrong?
I hear the distortion on my ucd400 modules but on the ucd180's I can't hear it.
I suppose you can tie the /on pins from different modules together to one of these circuits. Am i wrong?
You can save connect all /on lines with each other.
The UcD400 is running in the most cases on a much higher voltage so the risk of noises by turning off is higher. Every amplifier do has this problem, the best is to use an AC detection to get a nice sharp on / off signal.
Jan-Peter
stef1777 said:
My UCD180s are very silent, hardly any pop. I can hear the whining sound but only when I put my ear in the tweeter (directly driven without filter by the UCD) and even then, the room has to be very silent. Try ZAPpulse 2.2SE then you have fun. Seems it has been solved/suppressed in the 2.3SE though. Probably by automatically shutting it off when the power rails become too low.
Gertjan
Mmmm. I don't like that 
It seems that turning the module off when there is not enough voltage to run properly is the sensible way to go.
Another question about UcD180/Ucd400: what if a shortcircuit is made when the amp is playing (loud)? Is the module protected onboard or does it rely on an external fast acting turn-off?
Best regards,
Pierre
It seems that turning the module off when there is not enough voltage to run properly is the sensible way to go. Another question about UcD180/Ucd400: what if a shortcircuit is made when the amp is playing (loud)? Is the module protected onboard or does it rely on an external fast acting turn-off?
Best regards,
Pierre
UCD180 and electrostatics
This question is for Jan-Peter:
I´m considering the purchase of two modules UPC180, however
I'm not sure if these modules are able to drive electrostatic
speakers without being destroyed.
I haven´t seen any reference to this subject on this particular
forum, but I´ve heard stories of incompatibilities of these class
D amplifiers with this type of speakers.
My intention of buying those is going to be decisive on the compatibility of the two.
Let me add that the capacity of the ESL is about 1,200 pf and
they have an impedance transformer in between so the total
capacitance is the combination of the two.
The reason of my question is because I destroyed one of those
Sonic Impact little amplifiers when I connected them to the ESL.
Another doubt that I have is, is it necessary to buy the modules
with the input buffer to be used with a tube preamplifier on
account of an impedance match? My preamp is cathode follower
so it has a very low impedance.
Could you please offer some insight on this?
This question is for Jan-Peter:
I´m considering the purchase of two modules UPC180, however
I'm not sure if these modules are able to drive electrostatic
speakers without being destroyed.
I haven´t seen any reference to this subject on this particular
forum, but I´ve heard stories of incompatibilities of these class
D amplifiers with this type of speakers.
My intention of buying those is going to be decisive on the compatibility of the two.
Let me add that the capacity of the ESL is about 1,200 pf and
they have an impedance transformer in between so the total
capacitance is the combination of the two.
The reason of my question is because I destroyed one of those
Sonic Impact little amplifiers when I connected them to the ESL.
Another doubt that I have is, is it necessary to buy the modules
with the input buffer to be used with a tube preamplifier on
account of an impedance match? My preamp is cathode follower
so it has a very low impedance.
Could you please offer some insight on this?
Just to be sure this sinks in:
When the modules are in standby (/ON disconnected from ground) the UCD's still seem to drain the CAPS dry. You just need some circuit to disconnect the /ON pin.
I don't get the voltage divider/110V thing with the relay though 😀
When the modules are in standby (/ON disconnected from ground) the UCD's still seem to drain the CAPS dry. You just need some circuit to disconnect the /ON pin.
I don't get the voltage divider/110V thing with the relay though 😀
The UcD module has no problem to drive a capacitive load, don't forget the outputfilter in the module has 680nF.
So some 100nF extra will not be a problem.
The only possible problem could be the DC offset voltage, the DC outputvoltage of the UcD is 50mV maximum. Typical it's around 20mV.
How low is the DC resistance of your ESL step-up transformer?
Modules is protected agains shortcircuit.
The current consumption in standby mode will be +/-10mA +VCC / -VCC.
Regards,
Jan-Peter
