Hi Johan,
So, the use of a non-hysteresis self-oscillating feedback before the filter actually puts your circuit in the IcePower league. If your experiment was really long ago you might knock out their patent😀.
The switching frequency on your design is determined by the secondary pole(s) formed by the op-amp's secondary pole and the delay of the switching chain. Taking control over the switching frequency simply requires the addition of an RC filter between the op amp and the comparator.
Cheers,
Bruno
So, the use of a non-hysteresis self-oscillating feedback before the filter actually puts your circuit in the IcePower league. If your experiment was really long ago you might knock out their patent😀.
The switching frequency on your design is determined by the secondary pole(s) formed by the op-amp's secondary pole and the delay of the switching chain. Taking control over the switching frequency simply requires the addition of an RC filter between the op amp and the comparator.
Cheers,
Bruno
Someone asked earlier about a "reference DIY class D design". (don't remember if it was in this thread or another) And I believe someone answered that "there isn't any yet"...
Anyone have any suggestions about what basic type of circuit to base such a design on? UCD in some form? Something else?
In a collaborative DIY effort, we don't have to worry about patents 🙂.
Anyone have any suggestions about what basic type of circuit to base such a design on? UCD in some form? Something else?
In a collaborative DIY effort, we don't have to worry about patents 🙂.
johanps said:
Hi Johanps,
I've followed your site now for a long time. I think the best depends on the audience. The best DIY reference design for who? The goal should be a robust circuit with simplicity and low part count.
I think the UCD circuit best meets these expectations, and apperently it can sound excellent. The dual N channel drive is another nice aspect of it, keeping the output symetrical, and part count low, important features that elude most DIY's.
The input comparator can be replaced by an integrated comparator making it even simpler to wire up a test circuit.
Possibly one comparator, integrated H bridge with UCD feedback/control loop would be the most straight forward reference design of all.
Chris
Chris,
You're right, there isn't anything like a one-fits-all-solution. I was thinking in terms of a simple, yet effective, good sounding and robust circuit that could be the "gainclone" starting point for people getting interested in class D. And that could be made to deliver close to "high-end" sound with proper attention to detail.
I forgot to ask if there is any such effort ongoing in some other thread here? (I have seen/followed some other threads mostly based on fixed-frequency triangle wave PWM...) Otherwise, time to start a new thread for that purpose?
You're right, there isn't anything like a one-fits-all-solution. I was thinking in terms of a simple, yet effective, good sounding and robust circuit that could be the "gainclone" starting point for people getting interested in class D. And that could be made to deliver close to "high-end" sound with proper attention to detail.
I forgot to ask if there is any such effort ongoing in some other thread here? (I have seen/followed some other threads mostly based on fixed-frequency triangle wave PWM...) Otherwise, time to start a new thread for that purpose?
Hi,
Not to my knowledge. It's not a bad idea, however we need clarity on one issue from the very start, that which is of course, our end goal. So for now I'm assuming it's understood this should be a reference "start here" base design, with the objectives of being robust, simple in theory and in practice, and as a bonus, the potential to sound very good. This later part is the usual complication..
To avoid such complication we should forget about the overall sound as being one of the goals, for it could have far too great an influence over other critical design decisions and parameters.
If the end circuit should have anything more than respectable sound it will be a true testament to the circuits robustness.
Please have the honor of starting the thread as it's your idea, I'll keep an eye out for it.
Chris
EDIT:
There's talk of a reference design here but no work on a plan yet it seems.
http://www.diyaudio.com/forums/showthread.php?threadid=36528
Not to my knowledge. It's not a bad idea, however we need clarity on one issue from the very start, that which is of course, our end goal. So for now I'm assuming it's understood this should be a reference "start here" base design, with the objectives of being robust, simple in theory and in practice, and as a bonus, the potential to sound very good. This later part is the usual complication..
To avoid such complication we should forget about the overall sound as being one of the goals, for it could have far too great an influence over other critical design decisions and parameters.
If the end circuit should have anything more than respectable sound it will be a true testament to the circuits robustness.
Please have the honor of starting the thread as it's your idea, I'll keep an eye out for it.
Chris
EDIT:
There's talk of a reference design here but no work on a plan yet it seems.
http://www.diyaudio.com/forums/showthread.php?threadid=36528
There was also some discussion about establishing a forum category for class D under "Amplifiers". Any news about that?
Sorry for my limited searching ability (not fun when sitting at home using a modem).
Anyway, I saw that the Class-D-forum feature request seems to have stalled (voting system still non-operational), so I went ahead and created that new thread under solid-state amps: http://www.diyaudio.com/forums/showthread.php?s=&threadid=36852. Please join there and comment on the setup...
Anyway, I saw that the Class-D-forum feature request seems to have stalled (voting system still non-operational), so I went ahead and created that new thread under solid-state amps: http://www.diyaudio.com/forums/showthread.php?s=&threadid=36852. Please join there and comment on the setup...
update
Hi Guys,
Duty called and i have been away in Korea and the Benelux for a while, so I apologise for the lack of update.
Anyway, I have got the UcD up and running and have compared in to the ICEpower modules.
Suffice to say that the sound quality from the UcD 400 module as implemented by Jan Peter is first rate.
The amp was knocked up using a conventional linear PSU (1500VA transformer, with 20000uF per rail of C, and pretty conentional front end stage.)
Compared with with an ICEpower 500A amplifier of sililar spec.
Result: The UCD gives a warmer more spacious sound, which gives you the listen all day feeling - drop your shoulders and forget about the hardware kind.....
Bass performance is good, midrange excellant, with no fatigue in the HF.
The two units were measured after this. We performed FFT of THD, linearity, THD&N vs freq etc
The UcD outperformed the ICEpower by a significant margin in all of the above tests - what was even more amazing was that the UcD amp had not been played with at all - just plug and play!.
Good job!
Best Regards
Sheriff
Hi Guys,
Duty called and i have been away in Korea and the Benelux for a while, so I apologise for the lack of update.
Anyway, I have got the UcD up and running and have compared in to the ICEpower modules.
Suffice to say that the sound quality from the UcD 400 module as implemented by Jan Peter is first rate.
The amp was knocked up using a conventional linear PSU (1500VA transformer, with 20000uF per rail of C, and pretty conentional front end stage.)
Compared with with an ICEpower 500A amplifier of sililar spec.
Result: The UCD gives a warmer more spacious sound, which gives you the listen all day feeling - drop your shoulders and forget about the hardware kind.....
Bass performance is good, midrange excellant, with no fatigue in the HF.
The two units were measured after this. We performed FFT of THD, linearity, THD&N vs freq etc
The UcD outperformed the ICEpower by a significant margin in all of the above tests - what was even more amazing was that the UcD amp had not been played with at all - just plug and play!.
Good job!
Best Regards
Sheriff
Poetic
Hi Bruno,
Class D and Poetry... How do you have time for it all...
I was in Belgium last night and i spent about 2 hrs trying to get on the right road out of antwerp - most of the motorway exits were closed.....perhaps you should get involved with your countries road maintanance program too....
🙂
Cheers
sheriff
Hi Bruno,
Class D and Poetry... How do you have time for it all...
I was in Belgium last night and i spent about 2 hrs trying to get on the right road out of antwerp - most of the motorway exits were closed.....perhaps you should get involved with your countries road maintanance program too....
🙂
Cheers
sheriff
OT: Antwerp / poetry
I'm afraid my poetic side has gotten a tad on the background recently.
But well, they have all traffic information on the Web: www.werkeninantwerpen.be . Just to make sure you're informed of what's coming at you if you need to be there 🙂
Have a look at www.grimmaudio.com too.Sheriff said:
I'm afraid my poetic side has gotten a tad on the background recently.
Yes... stay away from Antwerp if you can afford to. They planned to do all those maintenance works on the ringroad. By the time they got started it turned out that at the very same time the town had begun redoing its central streets as well. No communication.Sheriff said:
But well, they have all traffic information on the Web: www.werkeninantwerpen.be . Just to make sure you're informed of what's coming at you if you need to be there 🙂
Sheriff,
Thanks or your nice comment.......
It is nice to hear that an amp what has good measurement specs do also have good sound tests
Regards,
Jan-Peter
www.hypex.nl
Thanks or your nice comment.......
It is nice to hear that an amp what has good measurement specs do also have good sound tests
Regards,
Jan-Peter
www.hypex.nl
Grimm
Hi Bruno,
Yes you have been busy...
I have emailed Grimm audio a couple of questions and will await their reply.
I have got a few good links with some higher end studios here in the UK - could prove interesting...
Cheers
Sheriff
Hi Bruno,
Yes you have been busy...
I have emailed Grimm audio a couple of questions and will await their reply.
I have got a few good links with some higher end studios here in the UK - could prove interesting...
Cheers
Sheriff
UCD question for Bruno
Hi Bruno
I intend to use three UCD 180 modules for an active two-way system.
The woofer will be driven by two of them in bridge mode. A single one will be used for mid-high.
Shall I synchronise the two bridged modules ? And if so, how ? Or shall I simply not bother at all ?
Regards
Charles
Hi Bruno
I intend to use three UCD 180 modules for an active two-way system.
The woofer will be driven by two of them in bridge mode. A single one will be used for mid-high.
Shall I synchronise the two bridged modules ? And if so, how ? Or shall I simply not bother at all ?
Regards
Charles
Hi
I read about that as well, but maybe Bruno has some tried-out values for guidance. And maybe it is not necessary at all.
Regards
Charles
I read about that as well, but maybe Bruno has some tried-out values for guidance. And maybe it is not necessary at all.
Regards
Charles