Hi,
If they don't have a common ground I would not do it that way. Why not provide a common ground point, there should probably be one anyway.
Regards
If they don't have a common ground I would not do it that way. Why not provide a common ground point, there should probably be one anyway.
Regards
You can put all /ON lines in parallel by a SPST switch to GROUND. A seperate GROUND wire from the powersupply GROUND is advisable.
Succes!
Regards,
Jan-Peter
Thanks for the replies.
So, Jan-Peter,
Right now my modules and independent power supplies are all floating. Should I tie them all to a common chassis star ground? Or, can I keep them floating and use the 3rd pin off the A/C outlet as my chassis & /ON ground point?
Thank you,
mac.
Jan-Peter said:
So, Jan-Peter,
Right now my modules and independent power supplies are all floating. Should I tie them all to a common chassis star ground? Or, can I keep them floating and use the 3rd pin off the A/C outlet as my chassis & /ON ground point?
Thank you,
mac.
As you can see I'm running three independent power supplies. My concern lies in tying the center tap of the transformer secondaries together. The alternative as I see it is to use a 3-pole switch for three independent /ON lines. Recommendations appreciated.
Cheers,
mac.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Cheers,
mac.
mac said:
Hi Mac,
Go here:
http://www.printedelectronics.com/faqs/faqs_power.html
If using explorer hit control F, or if using another browser do whatever you need to do to bring up the text field search box, type in "star point" without the quotes, that should zip you right down to the section of interest.
Another search you might want to run aside from "star point", is google the terms "amplifier HQG High Quality Ground". A "HQG" simply means "star point", all your grounds run to a single spot in a star topology.
Really, you should start there and base your entire layout /wiring job around it, this should help ensure noise free operation, true with any amp I think.
You might consider some aluminum plates to help with cooling, and you might consider drilling some good vent holes in the bottom if you plan on closing that up, and more in the top, or on the sides towards the top, to help out with convection cooling, you don't want that sealed tight, of course if you do that, make sure you put some feet on it so the air can get under it .
You might also consider grounding the aluminum plate(s) (that you're going to bolt your T-Sinks to) to your HQG point as well, maybe one big strip of aluminum right across, can include all three modules, and your HQG point. One strip would just save you some wires, and likely provide even more cooling. It should be at least a few mm's thick, and don't view the plate itself as the "point" either.
Anyway, once you do that, you can use a SPST switch for all three modules without any problems, and that will go to your star point as well.
If I got any of that wrong I'm sure I'll be corrected, hope that helps ya.
Regards,
Chris
Hi Chris, The wood "chassis" you see in the photos is temporary until my custom fabricated aluminum ones are built. Thank you for the links. I'm still not sure that tying the center taps of the transformers to ground is the proper approach but I will read through your links. Thanks, mac.
+/- 50V - module getting very hot. Is this OK?
Gents,
I just completed the first of my powersupplies and the UCD180 modules I have connected to it get pretty hot even while being idle or at extremly low levels.
Is this normal?
I currently use no cooling whatosever (the modules are just flating around in their prototype case) and they get too hot to touch. As I currently use two modules on one PSU and both show the same behavior, I was wondering whether I am overshooting the voltage by 100%?
I use +/- 50V out of a 2x35V transformer
I measure -50v from "-" to GND and "+50V" from "+" to GND.
I plan to provide passive cooling for the modules once they are in their "final" case, but as they are said to be so "cool" 😉 I though I can give them a try without.
Please help I am a little concerned.
Gents,
I just completed the first of my powersupplies and the UCD180 modules I have connected to it get pretty hot even while being idle or at extremly low levels.
Is this normal?
I currently use no cooling whatosever (the modules are just flating around in their prototype case) and they get too hot to touch. As I currently use two modules on one PSU and both show the same behavior, I was wondering whether I am overshooting the voltage by 100%?
I use +/- 50V out of a 2x35V transformer
I measure -50v from "-" to GND and "+50V" from "+" to GND.
I plan to provide passive cooling for the modules once they are in their "final" case, but as they are said to be so "cool" 😉 I though I can give them a try without.
Please help I am a little concerned.
I measured ca. 70mA per rail. That becomes 3VA per rail (+/-46V), 6VA per channel. A part of that quiescent power is dissipated in the coil until smelling a bit electrical. Main part (I would guess >4VA) is dissipated in the ouput FETs. This will heat up the blue Al-heat conductor, because its thermal resistance may be to high, especially, if the is no free air flow. Jan-Peter already suggested to mount a small heatsink even at low ouput power. I mounted two channels on a 300mm x200mmx2mm Al groundplate, that seems to be enough (for low outputs at least).
Regards, Timo
Regards, Timo
Hi guys,
DOn't concern yourself with it warming up the way you're running it, just stop running it like that🙂
You have to imagine how hot a class A amp would get running it idle or at low input and no cooling, it wouldn't last 10 seconds.
You're being kind of hard on your module right now running it like that, at no input, or low level input, it is switching alot faster so you get alot more dissipation in the mosfets as it's switching between states. The mosfets are likely to run cooler if you cranked it up. But why take a chance, add your passive cooling to be on the safe side, then you can experiment with how hot it gets at idle/low level to a higher power output and not take a chance of it burning output devices.
Regards
DOn't concern yourself with it warming up the way you're running it, just stop running it like that🙂
You have to imagine how hot a class A amp would get running it idle or at low input and no cooling, it wouldn't last 10 seconds.
You're being kind of hard on your module right now running it like that, at no input, or low level input, it is switching alot faster so you get alot more dissipation in the mosfets as it's switching between states. The mosfets are likely to run cooler if you cranked it up. But why take a chance, add your passive cooling to be on the safe side, then you can experiment with how hot it gets at idle/low level to a higher power output and not take a chance of it burning output devices.
Regards
Finnished my last two UcD 180 yesterday...
These have BHC caps instead of the Rifa that I used in the first one... (still missing softstarts in the new ones...)
The BHC sounds much much better than the RIFA and I'm going to replace the RIFA's in this UcD180 an in my UcD400...
Testing UcD's 😀
Stefan
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
These have BHC caps instead of the Rifa that I used in the first one... (still missing softstarts in the new ones...)
An externally hosted image should be here but it was not working when we last tested it.
The BHC sounds much much better than the RIFA and I'm going to replace the RIFA's in this UcD180 an in my UcD400...
Testing UcD's 😀
An externally hosted image should be here but it was not working when we last tested it.
Stefan
Hi !
I've tested my 3 ucd modules this week, a great sound very detailed and good spacialisation of instruments, i've heard some ticks sometimes, but ucd are running in free air and it can come from there, or maybe coming from myaudigy2zs sound source. compared to a tripath evaluation board highs sound more detailed and mediums are not agressive.
I would like to replace the 5532 with a 8620, i've found R47 and R48 for a 100k replacement, but does someone could help me to locate the 12v zeners on the board ?
Thanks for your help
PA.
I've tested my 3 ucd modules this week, a great sound very detailed and good spacialisation of instruments, i've heard some ticks sometimes, but ucd are running in free air and it can come from there, or maybe coming from myaudigy2zs sound source. compared to a tripath evaluation board highs sound more detailed and mediums are not agressive.
I would like to replace the 5532 with a 8620, i've found R47 and R48 for a 100k replacement, but does someone could help me to locate the 12v zeners on the board ?
Thanks for your help
PA.
Hi pa
It is D1 and D2 . They are placed between the two SMD power transistors on the underside of the PCB...
Koldby
It is D1 and D2 . They are placed between the two SMD power transistors on the underside of the PCB...
Koldby
Hi, Thanks for the zener location info...
concerning ticks, it can be heard at any time, when nothing is playing, it is very short something like a sample point with no regular interval but maybe one for 5 minutes... i 'll make test with no source (signal to ground at the source extremity of a 10m balanced wire).
concerning ticks, it can be heard at any time, when nothing is playing, it is very short something like a sample point with no regular interval but maybe one for 5 minutes... i 'll make test with no source (signal to ground at the source extremity of a 10m balanced wire).
Hi Folks!
How to calculate resistor values for an U or H pad to connect an DEQ2496 (output 100 Ohms balanced) to an UcD180 module (input 10 KOhms balanced)? My target is -10dB attenuation.
I'm curently using the DEQ internal attenuator (software) to do this but I'd like to compare the sound using a pad.
How to calculate resistor values for an U or H pad to connect an DEQ2496 (output 100 Ohms balanced) to an UcD180 module (input 10 KOhms balanced)? My target is -10dB attenuation.
I'm curently using the DEQ internal attenuator (software) to do this but I'd like to compare the sound using a pad.
RMAA test of UcD180
For those, who are interested,
I played a bit with an external soundcard (Terratec Phase 24FW) and used it to perform a simple test with one channel of the UcD180 amp. Please don't ask for the conditions, the wiring was horrible, at least from the output of the amp. The input was connected via a balanced 6.3mm/XLR-adaptor and 5m XLR low noise cable.
Here are the RMAA results.
I would not rely on the results, but for a first impression it should be okay.
Regards, Timo
For those, who are interested,
I played a bit with an external soundcard (Terratec Phase 24FW) and used it to perform a simple test with one channel of the UcD180 amp. Please don't ask for the conditions, the wiring was horrible, at least from the output of the amp. The input was connected via a balanced 6.3mm/XLR-adaptor and 5m XLR low noise cable.
Here are the RMAA results.
I would not rely on the results, but for a first impression it should be okay.
Regards, Timo
Attachments
Nice results, tiki!
I assume you used at least a resistive voltage divider just at the amplifier load in order to get the right voltage amplitude for the soundcard's input. But did you use a low pass filter? If so, could you detail it?
Thanks!
I assume you used at least a resistive voltage divider just at the amplifier load in order to get the right voltage amplitude for the soundcard's input. But did you use a low pass filter? If so, could you detail it?
Thanks!
Bonjour Pierre,
no, I don't speak french, unfortunately.
Thanks for your comments. The load was a simple power "potentiometer", 9.2Ohms, Kantal wire wound on a ceramic toroid. I placed the wiper to get an appropriate input voltage level for the soundcard. This was not symmetrical, of course. It was difficult to find the correct wiper position, next time I would use an additional external resistor divider to get a symmetrical signal too.
I did not use any extra lowpass, the wiring out of the amp were ca. 2m 2.5sqmm measurement cables. Together with the unknown impedance behaviour of the pot there might be some influence on the frequency range.
The pot is a very old one, maybe over 30 years. The contacts are corroded a bit therefore, so please don't beat me, if the pictures show results, not as good as expected.
Ther was an effect too, which I could not separate late in the night. The input connections of the soundcard are balanced 6.3mm sockets. I used XLR-adaptors plus simple patch wires with alligator crimps to connect these to the pot. Maybe I did something wrong with the +/-/GND-lines. At least whilst the 1W-test my LCD-monitor(!) flickered a bit, a sign for ground loop currents? Also the much worse results at the 1W-test can be based on that.
When I get the new soundcard (ESI quatafire) and the appropriate cabling, I will repeat this test with a better setup sometimes.
Regards, Timo
no, I don't speak french, unfortunately.
Thanks for your comments. The load was a simple power "potentiometer", 9.2Ohms, Kantal wire wound on a ceramic toroid. I placed the wiper to get an appropriate input voltage level for the soundcard. This was not symmetrical, of course. It was difficult to find the correct wiper position, next time I would use an additional external resistor divider to get a symmetrical signal too.
I did not use any extra lowpass, the wiring out of the amp were ca. 2m 2.5sqmm measurement cables. Together with the unknown impedance behaviour of the pot there might be some influence on the frequency range.
The pot is a very old one, maybe over 30 years. The contacts are corroded a bit therefore, so please don't beat me, if the pictures show results, not as good as expected.
Ther was an effect too, which I could not separate late in the night. The input connections of the soundcard are balanced 6.3mm sockets. I used XLR-adaptors plus simple patch wires with alligator crimps to connect these to the pot. Maybe I did something wrong with the +/-/GND-lines. At least whilst the 1W-test my LCD-monitor(!) flickered a bit, a sign for ground loop currents? Also the much worse results at the 1W-test can be based on that.
When I get the new soundcard (ESI quatafire) and the appropriate cabling, I will repeat this test with a better setup sometimes.
Regards, Timo
Thanks, Tiki.
I have played a little bit with RMAA thinking on using it for testing amplifiers. It is quite nice for that! Although my soundcard is more limited and has no balanced i/o.
Of course results should be better using an alluminium power resistor and then a couple of small resistors or a good potentiometer as the voltage divider. This way you can test it to higher powers as well.
The "good" way to do tests is using a quite complex lowpass filter to avoid getting hf transients into the soundcard input, that could deteriorate results.
Please read AudioPrecision's app.note on how to do these measurements. However, I think that you can get quite approx. results without that filter, as you did.
Best regards,
Pierre
I have played a little bit with RMAA thinking on using it for testing amplifiers. It is quite nice for that! Although my soundcard is more limited and has no balanced i/o.
Of course results should be better using an alluminium power resistor and then a couple of small resistors or a good potentiometer as the voltage divider. This way you can test it to higher powers as well.
The "good" way to do tests is using a quite complex lowpass filter to avoid getting hf transients into the soundcard input, that could deteriorate results.
Please read AudioPrecision's app.note on how to do these measurements. However, I think that you can get quite approx. results without that filter, as you did.
Best regards,
Pierre