jam said:Gertjan,
Very neat layout. I plan to build mine in an acrylic/aluminum case.
Regards,
Jam
Still waiting for the UCD700.............
Hi Jam,
It would look even cooler if I had used a thick copper plate to mount the modules on. In fact, the same DIY shop also had copper plates, of course a bit more expensive. Maybe an idea for the next version. The acrylic is of course a bit sensitive to scratches so I don`t know how long it stays nice to look at.
Regards
Gertjan
Acryl UcD case
Gertjan,
That looks great! Would you be able to provide a circuit or description of what you used (sizes etc)? I want to see what my options are before I take the leap. I was thinking maybe a dual mono setup. This way I can oversize the transformer in the view to upgrade to the UcD400 in the future.
Chris
Gertjan,
That looks great! Would you be able to provide a circuit or description of what you used (sizes etc)? I want to see what my options are before I take the leap. I was thinking maybe a dual mono setup. This way I can oversize the transformer in the view to upgrade to the UcD400 in the future.
Chris
Sorry to intrude off topic.
Due to cost contrains I ended with 2 * 10000uF as PS caps, NON-audiophile type. I plan to buy Elna Cerafine in near future.
Has anyone tried to combine plain vanilla caps with HiEnd caps to increase power supply capacitance? Is it nonsense?
In case it works, where do I put the Elna? Right after the rectifiers or as last caps?
I once read that it's better to mix cap values; 2*4700 + 2*10000 uF, for example. This should avoid some "resonances".
Any comments?
I will try a 4 channel amp
Thanks to the wise that shall help us, humble beginners!
Mauricio
Due to cost contrains I ended with 2 * 10000uF as PS caps, NON-audiophile type. I plan to buy Elna Cerafine in near future.
Has anyone tried to combine plain vanilla caps with HiEnd caps to increase power supply capacitance? Is it nonsense?
In case it works, where do I put the Elna? Right after the rectifiers or as last caps?
I once read that it's better to mix cap values; 2*4700 + 2*10000 uF, for example. This should avoid some "resonances".
Any comments?
I will try a 4 channel amp
Thanks to the wise that shall help us, humble beginners!
Mauricio
Re: Acryl UcD case
Hi Chris,
Everything is the same as I reported somewhere earlier in this thread.
I use a 250W transformer from partsexpress, I used a softstart circuit from LCaudio and a predator power supply from LCaudio. Then I added those 4 10000uF ELNA Cerafina caps as additional power supply filtering/buffering. These caps are big as you can see. Oh yes, I also added a fuse of 4 amp (I live in a 100V country) in the primary circuit. No other protection is added. I
I did not oversize the transformer because this stereo amp is going to be used to drive a tweeter and two midranges in an active system so I think that 250W transformer is more than enough.
By the way, as I mentioned, this is still meant as a temporary solution. For longer term use, it maybe beneficial to drill some holes in the case to get a bit of airflow to cool the output choke etc.
I like the idea of Jam of using frostic acrylic, that must look really great. However, I just found these acrylic boxes by accident, they did not have frosted acrylic boxes. Building the boxes yourself with frostic acrylic mybe not that easy, glueing them together etc.
Best regards
Gertjan
chrisb03 said:
Hi Chris,
Everything is the same as I reported somewhere earlier in this thread.
I use a 250W transformer from partsexpress, I used a softstart circuit from LCaudio and a predator power supply from LCaudio. Then I added those 4 10000uF ELNA Cerafina caps as additional power supply filtering/buffering. These caps are big as you can see. Oh yes, I also added a fuse of 4 amp (I live in a 100V country) in the primary circuit. No other protection is added. I
I did not oversize the transformer because this stereo amp is going to be used to drive a tweeter and two midranges in an active system so I think that 250W transformer is more than enough.
By the way, as I mentioned, this is still meant as a temporary solution. For longer term use, it maybe beneficial to drill some holes in the case to get a bit of airflow to cool the output choke etc.
I like the idea of Jam of using frostic acrylic, that must look really great. However, I just found these acrylic boxes by accident, they did not have frosted acrylic boxes. Building the boxes yourself with frostic acrylic mybe not that easy, glueing them together etc.
Best regards
Gertjan
Re: Re: Re: Acryl UcD case
Yes, just in parallel to do LCaudio caps. I modified the power resistor in the softstart circuit since Japan is a 100V country, the original resistor value was too high (330 Ohm) to charge up the power supply caps in time, I now use 120 Ohm.
The gain is 26dB, so a factor 20. So with 1.5V or so input voltage you are blasting full power.
Best regards
Gertjan
chrisb03 said:
Yes, just in parallel to do LCaudio caps. I modified the power resistor in the softstart circuit since Japan is a 100V country, the original resistor value was too high (330 Ohm) to charge up the power supply caps in time, I now use 120 Ohm.
The gain is 26dB, so a factor 20. So with 1.5V or so input voltage you are blasting full power.
Best regards
Gertjan
rha61 said:
Hello Alain,
I suppose that you had to cut the existing power supply leads on the printed circuit to be able to use an external power supply for the AD826?
I noticed the AD826 has a very high bias current of 3µA. What input resistance are you using, 10k or 100k? 100k results in 300mV offset voltage! Can this cause problems (operating point, etc...), or am I wrong? The coupling caps are mandatory, then.
Yves
AD826
Hi Alain,
Thanks for the report. Unfortunately, my soldering skills and my knowledge of electronics are such that I would trust myself installing an external PSU for the AD8620, or swapping opamps myself. That's why I was interested in your comments about differences among opamps when using the onboard supply.
If you do not mind another question, do you think it would be worthwhile using the AD286 instead of the NE5532 with the onboard supply?
Ciao,
Goliardo
Hi Alain,
Thanks for the report. Unfortunately, my soldering skills and my knowledge of electronics are such that I would trust myself installing an external PSU for the AD8620, or swapping opamps myself. That's why I was interested in your comments about differences among opamps when using the onboard supply.
If you do not mind another question, do you think it would be worthwhile using the AD286 instead of the NE5532 with the onboard supply?
Ciao,
Goliardo
Which powersupply
Hi all,
I've also been captivated by the magic of the UCD modules and I am planning to use these to power a pair of DIY monitors with an efficiency of about 91,5dB's for 2,83V/m and a smooth impedance of 5 ohms. For those interested, the speakers are the Proteus designed by Tony Gee, see: http://home.hetnet.nl/~geenius/Proteus.html
The plan is to get the following items:
1) LC Audio softstart circuit
see: http://www.schuro.de/preisl-softstart.htm
2) Encapsulated torroid transformer
see: http://www.schuro.de/preisl-trafos.htm
3) Power supply board with 2x 10.000 uF Slit Foils
see: http://www.schuro.de/preisl-ntke10-63sf.htm
4) single UCD180 module
My question is twofold, the PS board can handle 2x35 volts maximum > what transformer rating do I need to get? 160VA 35V?
Secondly, would it be advisable to get a DC filter as well?
I'll mount the electronics on a custom alumium panel which mounts in a sealed part of the speaker enclosure.
Do you reckon it's worth upgrading the UCD module with an AD8620 opamp?
Is the mix of components I've chosen a solid one?
Best regards,
Richard
Hi all,
I've also been captivated by the magic of the UCD modules and I am planning to use these to power a pair of DIY monitors with an efficiency of about 91,5dB's for 2,83V/m and a smooth impedance of 5 ohms. For those interested, the speakers are the Proteus designed by Tony Gee, see: http://home.hetnet.nl/~geenius/Proteus.html
The plan is to get the following items:
1) LC Audio softstart circuit
see: http://www.schuro.de/preisl-softstart.htm
2) Encapsulated torroid transformer
see: http://www.schuro.de/preisl-trafos.htm
3) Power supply board with 2x 10.000 uF Slit Foils
see: http://www.schuro.de/preisl-ntke10-63sf.htm
4) single UCD180 module
My question is twofold, the PS board can handle 2x35 volts maximum > what transformer rating do I need to get? 160VA 35V?
Secondly, would it be advisable to get a DC filter as well?
I'll mount the electronics on a custom alumium panel which mounts in a sealed part of the speaker enclosure.
Do you reckon it's worth upgrading the UCD module with an AD8620 opamp?
Is the mix of components I've chosen a solid one?
Best regards,
Richard
Attachments
I find that paralleling caps of different qualities to get a mix of the qualities of both rarely works. In all cases I've tried, I've always gotten the worst of both types combined (except in small-signal supplies where you can make rcrc input filters - in such constructions using different c's can compound to a better result).maxlorenz said:Sorry to intrude off topic.
Due to cost contrains I ended with 2 * 10000uF as PS caps, NON-audiophile type. I plan to buy Elna Cerafine in near future.
Has anyone tried to combine plain vanilla caps with HiEnd caps to increase power supply capacitance? Is it nonsense?
In case it works, where do I put the Elna? Right after the rectifiers or as last caps?
I once read that it's better to mix cap values; 2*4700 + 2*10000 uF, for example. This should avoid some "resonances".
Any comments?
I will try a 4 channel amp
Thanks to the wise that shall help us, humble beginners!
Mauricio
There is no hard and fast rule how to combine caps for damping of resonances. It all comes down to analysing (or testing) the network in case. The ratios tend to end up on the order of 10:1 to 100:1.
Another silly question. Here's a link to the circuit for the lcaudio power supply. It has to brifge rectifiers. Is this ok as the ground is a little different compare to the usual circuit. I'm going to use one power supply for each ucd (mono blocks).
http://www.lcaudio.dk/com/predpsu.gif
http://www.lcaudio.dk/com/predpsu.gif
Output Inductor
Hi Bruno and Jan Peter,
Just a quick question regarding the output inductor choice. Why did you go for the ferrite type I can see on the pictures and not a toroidal core like some other Class-d manufacturers seem to be opting for? Is it because of power loss issues or linearity? Also do I assume that the output current limit imposed on the UcD180 is set by output inductor saturation rather than mosfet or other limits. My only concern is that although the output current rating is fine for a steady impedance load, there is not much headroom for low impedance dips in a loudspeakers impedance characteristic.
Regards
Robin
Hi Bruno and Jan Peter,
Just a quick question regarding the output inductor choice. Why did you go for the ferrite type I can see on the pictures and not a toroidal core like some other Class-d manufacturers seem to be opting for? Is it because of power loss issues or linearity? Also do I assume that the output current limit imposed on the UcD180 is set by output inductor saturation rather than mosfet or other limits. My only concern is that although the output current rating is fine for a steady impedance load, there is not much headroom for low impedance dips in a loudspeakers impedance characteristic.
Regards
Robin