I would hesitate to count on the heat getting to the side walls all the way from the back panel. Simple thermal calculation may illustrate this. Assume a heat source is placed in the middle of a 360mm x 70mm x 2mm plate, and actual heat sinking takes place on the end. This is equivalent to a 180mm x 70mm x 4mm plate with source on one end and sink on the other.
Thermal conductivity of aluminium is around 200W/mK.
200(W/mK)*0.07(m)*0.004(m)/0.18(m)=0.31W/K or 3.2K/W.
At idle, 5 UcD400's dissipate around 30W. Although the situation is a bit better for the modules placed more to the sides, you will recognise this is becoming a problem.
In short, try to find a way of mounting the modules on the side walls. That one side wall will sport 2 modules and the other 3 is an aesthetic issue you'll have to live with.
Thermal conductivity of aluminium is around 200W/mK.
200(W/mK)*0.07(m)*0.004(m)/0.18(m)=0.31W/K or 3.2K/W.
At idle, 5 UcD400's dissipate around 30W. Although the situation is a bit better for the modules placed more to the sides, you will recognise this is becoming a problem.
In short, try to find a way of mounting the modules on the side walls. That one side wall will sport 2 modules and the other 3 is an aesthetic issue you'll have to live with.
Not a big problem. Just buy one more module and there's three on each side. One can always use another channel...
Bruno,
Thanks.
But is it possible to put them above each other on the sidewalls, Will there be enough airflow for them being close together? Should I put them with the PCB toward each other, away from each other, or the PCB's facing the same way?
This should for example look like this
Frans
Thanks.
But is it possible to put them above each other on the sidewalls, Will there be enough airflow for them being close together? Should I put them with the PCB toward each other, away from each other, or the PCB's facing the same way?
This should for example look like this
Frans
Attachments
FransDHT said:
FransDHT, I think your pushing your luck in thinking you will get it all the gear into that enclosure. Either get a bigger one or two separate enclosures. You will find you may have to add something additional in the future and you wont have the room. I wouldn't put the modules one on top of the other as the bottom one may radiate extra heat to the top one.
and effective aircooling i think is needed for the output coil, which you are effectively taking out of a fresh-air-loop ... 
chrisb03 and matjans,
I know, I know, but the problem is that I like this enclosure. I don't want it higher (and there is no need for that). I would like it deeper, but I don't know where to get it.
I have seen enclosures at Conrad adn Monacor, but they are not aluminium (and have no cooling sides) and I read somewhere that that is needed.
This is maybe a way to keep the air flowing? Four to one side, one at the other:
Frans
I know, I know, but the problem is that I like this enclosure. I don't want it higher (and there is no need for that). I would like it deeper, but I don't know where to get it.
I have seen enclosures at Conrad adn Monacor, but they are not aluminium (and have no cooling sides) and I read somewhere that that is needed.
This is maybe a way to keep the air flowing? Four to one side, one at the other:
Frans
Attachments
Small suggestion;
Place all modules vertical instead of horizontal. The minimum height what you need is 76mm. Put the UcD400 in such a way that the coil is on top, because the coil is having the highest temperature.
Regards,
Jan-Peter
Place all modules vertical instead of horizontal. The minimum height what you need is 76mm. Put the UcD400 in such a way that the coil is on top, because the coil is having the highest temperature.
Regards,
Jan-Peter
Actually this last arrangement (diagonally) isn't that bad. Make sure you have ventilation holes in the bottom and the cover of the case, otherwise you still won't have any air flow.
Most of the heat comes off the T block, so these two measures should keep the modules happy.
Most of the heat comes off the T block, so these two measures should keep the modules happy.
Hi,
So I just might be able to keep my enclosure! Yes!
Another question: The guys at Hypex suggested I should have a soft start module, because otherwise my home electricity fuses would blow the moment I turned on the amp.
I guess I should put the line-fuse after this module? Or not?
Frans
So I just might be able to keep my enclosure! Yes!
Another question: The guys at Hypex suggested I should have a soft start module, because otherwise my home electricity fuses would blow the moment I turned on the amp.
I guess I should put the line-fuse after this module? Or not?
Frans
UCD400 PSU design
About the power supply for Ucd400, other than large vol caps, should one consider adding a choke as well to reduce the ripples further?
About the power supply for Ucd400, other than large vol caps, should one consider adding a choke as well to reduce the ripples further?
Jan-Peter, Bruno, the UcD400 has been out for some time now (also most likely review units), have got any response you want to share with us?
mounting direction of UcDs
Hi Frans,
if you mount the modules nearly diagonal, I would put them upside down in a manner, that the output choke is passed by the "vertical" air flow nearly first. That would guarantee always fresh/cool air for the chokes. It's not as good for the rest of the parts, but they generate far less heat. And don't forget to let enough spacing between modules to enable the "Kamineffekt" (don't know the English description).
BTW, a very nice idea, to stratify the modules inclined.
Good luck,
Timo
Hi Frans,
if you mount the modules nearly diagonal, I would put them upside down in a manner, that the output choke is passed by the "vertical" air flow nearly first. That would guarantee always fresh/cool air for the chokes. It's not as good for the rest of the parts, but they generate far less heat. And don't forget to let enough spacing between modules to enable the "Kamineffekt" (don't know the English description).
BTW, a very nice idea, to stratify the modules inclined.
Good luck,
Timo
Bruno Putzeys said:
Separate supplies improves imaging? I understand the UcDs have decent PSRR, so how does this happen?
Francois.
Hi Frans,
Thank you for posting the link of your case supplier. That's about the kind of rack-mount chassis I had in mind to look for while I'm considering to build a 2 channel UCD amp myself. I think I won't have to proceed my search.
Last week I visited the new Hypex facility where I met Jan-Peter who was kind enough explain some more details on the minor differences between the 180 and 400 version.
I think I'll start off with the UCD180's to get a feel with the technology.
As I also live in Groningen, it would be nice to team up and learn from eachothers experiences. I hereby offer you my help, if needed with your construction. For example, don't forget the space needed for wiring and in-/output terminals.
In case (😉 you won't be able to fit all required parts for your 5 channel amp into your 2HE chassis, I'd be glad to buy it form you.
Gerald
Hi Gerald,
Nice to know there is someone nearby with the same interest, and speaks dutch!
As soon as the enclosure arrives I will let you know if I can use it!
I had thougt of the space for wiring, in- and output terminals and the soft start module. I do not know the size of this module however, so that could become a problem (but I don't think so).
Frans
Nice to know there is someone nearby with the same interest, and speaks dutch!
As soon as the enclosure arrives I will let you know if I can use it!
I had thougt of the space for wiring, in- and output terminals and the soft start module. I do not know the size of this module however, so that could become a problem (but I don't think so).
Frans
Security regulations require that the line fuse be the first thing after the plug.FransDHT said:
Re: UCD400 PSU design
Pi-filters (CLC) are possible from the first point of view, but the second issue still needs to be taken into account, requiring all sorts of damping circuits.
Chokes can be used to good effect to smooth the ripple current going into the mains, but vacuum-tube-amp style choke input circuits are not a good idea, since they need a minimum load to operate correctly (loaded, the supply produces a dc voltage equal the average rectified voltage. unloaded, it produces the peak voltage). Apart from that, they are undamped rc circuits that will respond very strongly to load variations.ackcheng said:
Pi-filters (CLC) are possible from the first point of view, but the second issue still needs to be taken into account, requiring all sorts of damping circuits.
65dB is certainly decent, and it will insure a channel separation of better than 100dB over most of the audio range. 100dB is not infinity though, so there is a small difference. Any difference, however small, is worth an investment from an audiophile's point of view.DSP_Geek said:
That said, a pair of UcD's sharing one supply still have better stereo imaging than most linear amps, including mono blocks.