Hi,
Thanks alot for deciding to share that paper with us Jan-Peter. It seems to sum up about five different threads and (almost)everything ever stated about the UCD.
It was very interesting to read.
Regards
Chris
Thanks alot for deciding to share that paper with us Jan-Peter. It seems to sum up about five different threads and (almost)everything ever stated about the UCD.
It was very interesting to read.
Regards
Chris
Great Jan Peter!
I'll probably order some more🙂
a question about bridging the UcD180...
Is this the proper way to do it???
What about Signal ground and signal in -...
Regards
/Stefan
I'll probably order some more🙂
a question about bridging the UcD180...
Is this the proper way to do it???
What about Signal ground and signal in -...
An externally hosted image should be here but it was not working when we last tested it.
Regards
/Stefan
OA51 said:
Hello Stefan,
Why not connect both the + input signal to the + input of one module (the first one) and the - input of the other module and the - input signal to the - input of one module (the first one) and the + input of the other module. That will give you effectively 6dB more input signal and you will drive both modules with a symmetric signal. If you have too much gain that way, you may want to make the signal weaker before you put it in the modules. That will reduce the noise level in case your noise level is determined by the preamp (in my case noise is preamp limited).
I would do it that way (I also consider bridging), don`t think there is anything against it.
You also need a small capacitor between the two + outputs that go to the speaker. I think 47nF is enough (read that somewhere in one of the UcD threads). This will make sure both modules run at the same frequency.
Best regards
Gertjan
Hi,
Yeah recommended value for a coupling cap is 47n it's mentioned several times in this thread someplace.
I trust you would also connect the active low "/on" lines together as well? Seems like you'd want them both turning on at the same time in this case.
Regards
Yeah recommended value for a coupling cap is 47n it's mentioned several times in this thread someplace.
I trust you would also connect the active low "/on" lines together as well? Seems like you'd want them both turning on at the same time in this case.
Regards
I've seen this floating on the net:
Measurements
Is this accurate or not?
There seems to be quite a roll-off in high frequency response... Between -1db and -2db at 15khz and higher??
Measurements
Is this accurate or not?
There seems to be quite a roll-off in high frequency response... Between -1db and -2db at 15khz and higher??
Hello Yves,
please, look here!
This and the following posts describe a little bit the conditions. Please do not rely on that measurements, only as an example. I do not have the right equipment until now (other soundcard, cables...).
The UcD modules seem to be much better than this test.
Should I add some comments to avoid misunderstandings?
Regards, Timo
please, look here!
This and the following posts describe a little bit the conditions. Please do not rely on that measurements, only as an example. I do not have the right equipment until now (other soundcard, cables...).
The UcD modules seem to be much better than this test.
Should I add some comments to avoid misunderstandings?
Regards, Timo
@Tiki,
Thans for the reply. I just got a little scared but, no problem,
I posted this too quicky, sorry
If you want you can elaborate on the test, but I'll read the thread first!
Thans for the reply. I just got a little scared but, no problem,
I posted this too quicky, sorry
If you want you can elaborate on the test, but I'll read the thread first!
Hi,
I would like to replace the 5532 by 8620 on my modules
Does anybody know the type of the package used for the D1 and D2 zener's ? or do you know a reference of 12v zener diode which can be mount ?
Thanks in advance for your help.
PA
PS: to future users: my full range drivers now sounds as good as i wish...
I would like to replace the 5532 by 8620 on my modules
Does anybody know the type of the package used for the D1 and D2 zener's ? or do you know a reference of 12v zener diode which can be mount ?
Thanks in advance for your help.
PA
PS: to future users: my full range drivers now sounds as good as i wish...
Short question:
why is there a minimum PSU voltage for 'optimal' soundquality? That's what is says on the info sheet that is supplied with the amp (30V-45V). What if you don't need more and want a lower power amp that is stable into difficult loads without breaking the bank for PSU parts?
Hans.
why is there a minimum PSU voltage for 'optimal' soundquality? That's what is says on the info sheet that is supplied with the amp (30V-45V). What if you don't need more and want a lower power amp that is stable into difficult loads without breaking the bank for PSU parts?
Hans.
Several possible causes come to my mind:
First the aux. supplies onboard for the modulator, drivers, etc, may not be very well designed and work well only in a very limited range of supplies.
Second, as the supplies vary, the gain of the power stage changes, and so the characteristics of the feedback loop, that is optimized for a given voltage. If you move too away from that point, the feedback gain is reduced and hence distortion increases, or it is increased too much and the amp is no longer estable. (going to the extremes, of course).
Best regards,
Pierre
First the aux. supplies onboard for the modulator, drivers, etc, may not be very well designed and work well only in a very limited range of supplies.
Second, as the supplies vary, the gain of the power stage changes, and so the characteristics of the feedback loop, that is optimized for a given voltage. If you move too away from that point, the feedback gain is reduced and hence distortion increases, or it is increased too much and the amp is no longer estable. (going to the extremes, of course).
Best regards,
Pierre
The voltageregulators who creates the stabilized voltage for the opamp in the extra gain stage needs a minimum input voltage. Because of this we recommend a minimum voltage. However the amplifier does work already at 20V. But who wants to use the amp on such a low voltage?
No this is not true, it's a self oscillator Class-D and not an open loop Class-D. In an open loop Class-D the gain of the powerstage is related with the voltage of the triangle and the powervoltage.
Don't forget that the PSRR of the UcD is >65dB😉
Regards,
Jan-Peter
I was wondering about the efficiency of class D vs class AB in receivers.
Fact: A hypex module is almost 30% more effective (in the worst case) than a class AB design.
Fact: Most commercial receivers are "underpowered" - some do well at 2 channel audio (power-wise) but can't live up to their expectations at 5 or 7 channels driven, because of the power supply that is too small. (small transformer, but somewhat ok caps, so it can handle peaks but has no continuous power)
So, if in your plain-vanilla "5*100W" receiver, the AB stages get removed and replaced by UcD180's/400's (if the voltage on the rails is right) you would get:
A) Better sound due to class D design at low power.
B) higher continuous power rating, because class D is more efficient and is less of a burden on the small transformer - net result is like you would replace the transformer with a larger one when remaining in class AB.
C) A nice cool receiver with oversized heatsinks for the UcD's where the output stages don't slowly kill the rest of the circuitry with high temperatures.
Is this a correct assumption, or would the 30-50% improvement in efficiency go unnoticed? I think even worst case, you'd gain a few (2 or 3) db's vs the AB amps before clipping, that is a world of difference for an amp?
Caps shouldn't be a large problem. For example, my old (and ready to be replaced) Yamaha receiver is "5*120W" (right...) and has 22.000uf caps. 6250 should do for 1 channel fully driven at 8 ohms, so as a result in worst case you have 2/3 of what they really need. I think this is already much better than how the japanese engineers calculate their requirements...
Too bad it's so hard to find the VA specs of receivers. Can this be easily derived from the claimed power consumption on the back of the receiver?
Fact: A hypex module is almost 30% more effective (in the worst case) than a class AB design.
Fact: Most commercial receivers are "underpowered" - some do well at 2 channel audio (power-wise) but can't live up to their expectations at 5 or 7 channels driven, because of the power supply that is too small. (small transformer, but somewhat ok caps, so it can handle peaks but has no continuous power)
So, if in your plain-vanilla "5*100W" receiver, the AB stages get removed and replaced by UcD180's/400's (if the voltage on the rails is right) you would get:
A) Better sound due to class D design at low power.
B) higher continuous power rating, because class D is more efficient and is less of a burden on the small transformer - net result is like you would replace the transformer with a larger one when remaining in class AB.
C) A nice cool receiver with oversized heatsinks for the UcD's where the output stages don't slowly kill the rest of the circuitry with high temperatures.
Is this a correct assumption, or would the 30-50% improvement in efficiency go unnoticed? I think even worst case, you'd gain a few (2 or 3) db's vs the AB amps before clipping, that is a world of difference for an amp?
Caps shouldn't be a large problem. For example, my old (and ready to be replaced) Yamaha receiver is "5*120W" (right...) and has 22.000uf caps. 6250 should do for 1 channel fully driven at 8 ohms, so as a result in worst case you have 2/3 of what they really need. I think this is already much better than how the japanese engineers calculate their requirements...
Too bad it's so hard to find the VA specs of receivers. Can this be easily derived from the claimed power consumption on the back of the receiver?
Sorry, but your assumption is not quite right. At full power, it will make no difference to audio power output whether the amp inside is class-d or class-ab. Class-d will only provide more efficiency in terms of heat.
richie00boy said:
I think even at full power, class D would consumes less since only at the maximum output voltage, power consumption likely is the same or similar as Class AB has little voltage drop there over the output transistors. However, when you go further down the sine-wave, class D will consume less then Class AB, so even at full power, classD will burn less power, would have to do calculations to get an exact number.
Best regards
gertjan
The way that class-d works is to draw the max current with every pulse, but the duration is such that it averages out to be the same average current that a class-b amp would draw. Class-d amps are more efficient in heat terms not electrical power drawn from the supply. Therefore the transformer for a class-d amp cannot be any smaller than that for a class-b amp.
Using your example, going down the sinewave say to halfway, the class-b amp will be drawing half the max current, but the class-d amp will draw the max current but only for half the time. Thus as far as the load upon the supply they are both the same. The fact that the class-b transistors will also have half the supply voltage across them means that they will get hot, whereas the class-d amp will have very little voltage across them, so it runs cool.
Using your example, going down the sinewave say to halfway, the class-b amp will be drawing half the max current, but the class-d amp will draw the max current but only for half the time. Thus as far as the load upon the supply they are both the same. The fact that the class-b transistors will also have half the supply voltage across them means that they will get hot, whereas the class-d amp will have very little voltage across them, so it runs cool.
Hi richie00boy,
before you post some more nonsense, you might do yourself a favour and redefine for yourself the following terms:
-efficiency
-power dissipated in the load
-power dissipated in the amplifier
-total power drawn from the power supply
-waveform of current drawn by the switching stage from the reservoir capacitors
-waveform of current drawn from the mains transformer into the reservoir capacitors
-average value of current waveform
-true RMS value of current waveform
Best regards,
Jaka Racman
before you post some more nonsense, you might do yourself a favour and redefine for yourself the following terms:
-efficiency
-power dissipated in the load
-power dissipated in the amplifier
-total power drawn from the power supply
-waveform of current drawn by the switching stage from the reservoir capacitors
-waveform of current drawn from the mains transformer into the reservoir capacitors
-average value of current waveform
-true RMS value of current waveform
Best regards,
Jaka Racman
Instead of ******* at someone, why don't you do us a favor and explain the issue so that we may all learn.
Hi,
I will try to use simple analogies so you IT guys might understand. Esentially difference between class AB and class D amplifier is like between linear and switching power supply. While the first is esentially a variable resistor, the second is esentially a variable transformer or variac.
Now imagine a 230V AC power source and light bulb whose brightness you want to adjust. You might connect a variable resistor in series with the lightbulb or you might connect light bulb to the variac connected to the 230V power supply. In first case power drawn from the power supply is equal to the sum of power dissipated in the light bulb and the resistor, in second case only to the power dissipated in the lightbulb plus 1% to 2% of losses in the variac.
Best regards,
Jaka Racman
I will try to use simple analogies so you IT guys might understand. Esentially difference between class AB and class D amplifier is like between linear and switching power supply. While the first is esentially a variable resistor, the second is esentially a variable transformer or variac.
Now imagine a 230V AC power source and light bulb whose brightness you want to adjust. You might connect a variable resistor in series with the lightbulb or you might connect light bulb to the variac connected to the 230V power supply. In first case power drawn from the power supply is equal to the sum of power dissipated in the light bulb and the resistor, in second case only to the power dissipated in the lightbulb plus 1% to 2% of losses in the variac.
Best regards,
Jaka Racman