The amount of stored energy is a certain factor T times the amount of power (=energy per second) the amp is supposed to put out.ewildgoose said:
If the caps are recharged 100 times per second, and we want to lose (and recharge) no more than 10% of total stored energy every mains cycle (translates to 5% voltage droop), the rule of thumb becomes to store T=0.1 joules per watt (=seconds!) of rated power.
This figure in seconds also works out to be the product of load impedance and storage capacitance.
T=C*R
or
C=T/R
This is for a single rail. For dual rail systems like UcD you get two caps of half that value.
Example: For T=0.1s (rather conservative in CE terms), a half-bridge class D amplifier designed to operate into a 4ohm load requires two capacitors of
C=0.5*T/R=0.5*0.1/4=12500uF
If the fact that output power factors out is counterintuitive, consider the fact that an amp of 4 times the power will have twice the supply voltage so the same capacitance will hold 4 times the energy. Naturally, at twice the rated voltage the caps will be a bit bigger too.
Do not forget to multiply the capacitance by the number of channels connected to the power supply...
Another part of your question concerned the use of transformers.
Normally you will use one transformer per power supply. If one 2x50V supply is used to power two amps, there is only one transformer. If you have two transformers you should have two independent power supplies too (dual mono).
The only exception would be if you were to attempt making a "super-screened pair" where two transformers are stacked on top of eachother into a single steel pot and placed in parallel (but with the magnetic fields going opposite ways) with the aim of getting super-low stray field. Such an excercise is most probably overkill, given the already low stray field of good toroids.
Hope this sheds light on your question.
While the crossover unit's pin 1 is not DC connected to the chassis, it is DC connected to the signal ground of the electronics (ie the electronics are floating).ghemink said:
Since it's differential throughout, the UcD module is not very sensitive to "pin 1 problems" so whatever you do you're unlikely to run into trouble. The recommended way would be to connect the power supply ground to the UcD ground and from there straight to chassis (such that no power supply return current flows through the chassis). XLR pin 1 is tied to the chassis as well.
Again, should you omit the connection between pin 1 and chassis, the UcD modules are most unlikely to complain, because of their internal construction.
Actually it isn't necessary to use 3-wire mains cords. They only make sense if you have a mains filter with Y cap, and I have already advised firmly against those.
Cheers,
Bruno
Hi Bruno,
Its a highly thorough answer to my question, thanks!
I guess I was asking a more basic question than you anticipated! My impression is that these modules have much lower PSU requirements than a similar Class a/b amp? As such, whilst a decent Class A/B amp will have perhaps a dual mono p/s and fairly exotic components, what would you consider as being a baseline for a decent UCD powersupply?
I would assume dual rectification, and a beefy torroid would be standard. However, would you still use a dual mono supply for a "decent", but not highly exotic UCD amp? Also, the LCAudio power supply seems like a nice starting point for a quick build (it has dual rectifiers, and two 10,000 caps), but it doesn't include any smaller bypass caps for the big capacitors - is this an issue for an amp like the UCD which has decent PSRR?
Sorry, much more basic questions, but I have very little experience, and as a beginner once you start reading about all the options available it all starts getting even more complicated...!
If we were to get specific, I'm curious about trying a dual channel UCD 400 (when they are out) which would make the full 400W into 4 ohm for use with a dual sub woofer setup.
Thanks
Its a highly thorough answer to my question, thanks!
I guess I was asking a more basic question than you anticipated! My impression is that these modules have much lower PSU requirements than a similar Class a/b amp? As such, whilst a decent Class A/B amp will have perhaps a dual mono p/s and fairly exotic components, what would you consider as being a baseline for a decent UCD powersupply?
I would assume dual rectification, and a beefy torroid would be standard. However, would you still use a dual mono supply for a "decent", but not highly exotic UCD amp? Also, the LCAudio power supply seems like a nice starting point for a quick build (it has dual rectifiers, and two 10,000 caps), but it doesn't include any smaller bypass caps for the big capacitors - is this an issue for an amp like the UCD which has decent PSRR?
Sorry, much more basic questions, but I have very little experience, and as a beginner once you start reading about all the options available it all starts getting even more complicated...!
If we were to get specific, I'm curious about trying a dual channel UCD 400 (when they are out) which would make the full 400W into 4 ohm for use with a dual sub woofer setup.
Thanks
The PSU requirements are a bit lower than with linear amplifiers only in terms of transformer size (power that you don't need to dissipate doesn't need to be delivered to begin with). The cap size is not significantly smaller because in clip, peak current demand will be identical to that of a linear amp.ewildgoose said:
UcD doesn't need any bypass caps on the main caps, simply because all bypassing has been taken care of on the module. No HF currents leave the module, so HF impedance of the power supply is inconsequential.
The UcD modules are not much more insensitive to the "sound" of the power supply caps though. If you try different varieties of similarly spec'ed caps you will hear the same kind of sonic differences as you would expect with linear amps.
It is hugely frustrating but even a circuit with 120+dB of PSRR across the audio band will still sound appreciably different when different power supply caps are used. The influence reduces with better PSRR, but not very quickly.
Cheers,
Bruno
Dear Jan Peter
I was hoping we could all help each other to keep this forum free of advertising. I know everybody has their small projects, they make hint about how good it is, what progress there is, how it works etc.
But don't you think your above post is a little over the limit of reasonably close to direct advertisement?
Cheers
Lars
I was hoping we could all help each other to keep this forum free of advertising. I know everybody has their small projects, they make hint about how good it is, what progress there is, how it works etc.
But don't you think your above post is a little over the limit of reasonably close to direct advertisement?
Cheers
Lars
....hm, I don't see the problem.
The whole thread is about the UcD180...........
Should I answer all questions anonymous? In a way is every answer from myself a form of an advertisement.
Regards,
Jan-Peter
www.hypex.nl
The whole thread is about the UcD180...........
Should I answer all questions anonymous? In a way is every answer from myself a form of an advertisement.
Regards,
Jan-Peter
www.hypex.nl
Lars,
Coming from this is a surprise...... .
Jan-Peter probably should have posted the link on the vendors bazaar but I don't think he is outwardly trying to advertise or is this a case of professional jealousy.
Jan-Peter seems to have a good product and I for one want to know about it and he along with Bruno have been very forthcoming with help and implementation ideas.
They have not been trolling for ideas to steal rather the opposite, besides this is by far the best thread going at the moment.
Regards,
Jam
Coming from this is a surprise......
. Jan-Peter probably should have posted the link on the vendors bazaar but I don't think he is outwardly trying to advertise or is this a case of professional jealousy.
Jan-Peter seems to have a good product and I for one want to know about it and he along with Bruno have been very forthcoming with help and implementation ideas.
They have not been trolling for ideas to steal rather the opposite, besides this is by far the best thread going at the moment.
Regards,
Jam
Well, Lars..................
Since the thread is about his product............and he didn't start it........... I don't see a problem.
Sounds rather funny coming from you in the first place. Sure that there isn't some jealousy buried in your response???????? Starting threads about one's own product is more in line with your actions.
Jocko
Since the thread is about his product............and he didn't start it........... I don't see a problem.
Sounds rather funny coming from you in the first place. Sure that there isn't some jealousy buried in your response???????? Starting threads about one's own product is more in line with your actions.
Jocko
Dear Jan-Peter
I hope again you don't misunderstand my point. I think also you are very helpful to answer all kinds of questions in here, and i appreciate you are being honest about your place in the audio industry. (As should everyone).
What i mean there is a difference between answering questions, discussing ideas and so on, or saying:
"Now our order system is ready to take your order." Click here!
I don't know where the line is, and i don't want to be the judge of where it should be. But i would rather not like a forum where all kinds of companies post purely commercial statements (such as the one above) But then that's just my opinion.
All the best from
Lars
I hope again you don't misunderstand my point. I think also you are very helpful to answer all kinds of questions in here, and i appreciate you are being honest about your place in the audio industry. (As should everyone).
What i mean there is a difference between answering questions, discussing ideas and so on, or saying:
"Now our order system is ready to take your order." Click here!
I don't know where the line is, and i don't want to be the judge of where it should be. But i would rather not like a forum where all kinds of companies post purely commercial statements (such as the one above) But then that's just my opinion.
All the best from
Lars
Lars,
Indeed I agree with you it's difficult to know where the line is....
But this topics goes only about the UcD180. I have got a lot of emails the last weeks about;
Where can I order this?
How is the sound comparing with.........?
Hereby the answer where it can be orderd, and about the other question I don't give direct comments (better or worse) about other products also not by private email.......
Regards,
Jan-Peter
www.hypex.nl
Indeed I agree with you it's difficult to know where the line is....
But this topics goes only about the UcD180. I have got a lot of emails the last weeks about;
Where can I order this?
How is the sound comparing with.........?
Hereby the answer where it can be orderd, and about the other question I don't give direct comments (better or worse) about other products also not by private email.......
Regards,
Jan-Peter
www.hypex.nl
I pulled the link to the order forms- that was probably too close to advertising in the non-commercial areas. Anyone who wants this stuff can certainly find it and anyone interested can certainly email Jan-Peter.I can understand why the link to the order form has been removed, but I dont think it matters anyway, Jan-Peter is frequently here and his signature helpfully points to a web site where I am sure you anyone can find the order link if they need it
I will probably be using it as soon as the UCD400 modules are available.
Now back to planning my UCD180 amp.....
PS Jan-Peter, please keep watching listening and posting here, its much appreciated.
I will probably be using it as soon as the UCD400 modules are available.
Now back to planning my UCD180 amp.....
PS Jan-Peter, please keep watching listening and posting here, its much appreciated.
I would like to jump to the support of Jan Peters (as others have), I’ve been following this thread and others relating to UCD – JP has offered much support to customers / users on these threads – and I don’t feel his posting was in anyway meant to gain free advertising – and even if it where, many users requested links for more information!
Jan Peters,
Where did you source the PCB Spade connecters you use for Power & Speaker connections on your UCD boards– I tried Farnell online – but trying to find anything without the catalogue is a complete waste of time.
John
Jan Peters,
Where did you source the PCB Spade connecters you use for Power & Speaker connections on your UCD boards– I tried Farnell online – but trying to find anything without the catalogue is a complete waste of time.
John
