DIY Ucd180HG vol pot value question
Sorry for postin into wrong thread!
The following question is now posted in "Ucd180 questions" thread
Hi,
I recently rebuild my Hypex Ucd180HG amplifier and added a input selector switch and also a vol pot. Previously it was being used as power amp.
After my modifications some problems occurred (all inputs, same problem);
1. Signal can be heard even when the pot is turned down
2. Volume gets too loud very quickly
3. Pretty much no bass.
Wiring should be all fine and correct. Vol pot is Alps Blue 10K.
I tried with an attenuator plug/interconnect cable and this seemed to give me more adjusting room bit the pot and treble/bass were much better in balance. Though the max vol pot position is not even too loud. (The latter is probably caused by my attenuator being maybe tad too much. I have to check the resistor values I used on it.)
Problems were not present when amplifier was used as power amp.
Nice, if someone has some hint for troubleshooting the problem.
Best,
M
Sorry for postin into wrong thread!
The following question is now posted in "Ucd180 questions" thread
Hi,
I recently rebuild my Hypex Ucd180HG amplifier and added a input selector switch and also a vol pot. Previously it was being used as power amp.
After my modifications some problems occurred (all inputs, same problem);
1. Signal can be heard even when the pot is turned down
2. Volume gets too loud very quickly
3. Pretty much no bass.
Wiring should be all fine and correct. Vol pot is Alps Blue 10K.
I tried with an attenuator plug/interconnect cable and this seemed to give me more adjusting room bit the pot and treble/bass were much better in balance. Though the max vol pot position is not even too loud. (The latter is probably caused by my attenuator being maybe tad too much. I have to check the resistor values I used on it.)
Problems were not present when amplifier was used as power amp.
Nice, if someone has some hint for troubleshooting the problem.
Best,
M
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Let me ask general question :
UCD (phase shift feedback loop that contains output filter inside loop, I am considering single R//RC feedback, basic Bruno Putzey's design) vs IRS2092 (phase shift self oscillating without output filter in feedback loop)
Subjective sound quality ?
THD?
etc ..
UCD (phase shift feedback loop that contains output filter inside loop, I am considering single R//RC feedback, basic Bruno Putzey's design) vs IRS2092 (phase shift self oscillating without output filter in feedback loop)
Subjective sound quality ?
THD?
etc ..
Hello All,
I just tried to upgrade my 400AD modules by removing the BDX33/34 transistors and connecting the 12V supply to my HG power supply. I measured the power supplies and checked all connections. I see that the amodules are not starting up anymore and see that the amplifer enable connection is put on both modules towards 11 Volts.
I am not aware of a schematic where I can check much deeper, but what can have gone wrong?
Kind regards,
Harrie Munnik
I just tried to upgrade my 400AD modules by removing the BDX33/34 transistors and connecting the 12V supply to my HG power supply. I measured the power supplies and checked all connections. I see that the amodules are not starting up anymore and see that the amplifer enable connection is put on both modules towards 11 Volts.
I am not aware of a schematic where I can check much deeper, but what can have gone wrong?
Kind regards,
Harrie Munnik
Hello All,
I just tried to upgrade my 400AD modules by removing the BDX33/34 transistors and connecting the 12V supply to my HG power supply.
Have you measured the output voltage of the BDX33/34 before the mod?
In HxR version the output should be around 15V.
Try to raise the voltage to 15V.
The input opamps are working at +-12V.
Have you measured the output voltage of the BDX33/34 before the mod?
In HxR version the output should be around 15V.
Try to raise the voltage to 15V.
The input opamps are working at +-12V.
No, I did not measure the voltage. The voltage now comes from the HG power supply. There are no HxR regulators on this older version of the UcD400AD. I cut away the transistors just like it is on the instruction that came with the powersupply. It is not easy to raise the voltage. I would need to build another power supply with additional regulators.
I am now thinking of putting the transistors back and see if the modules still work. I hope they are not

The strange thing is that the amplifier enable goes toward 11 V when powering up. I read somewhere on this thread that it should go towards 0V? Or did I misinterpret that?
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No, I did not measure the voltage. The voltage now comes from the HG power supply. There are no HxR regulators on this older version of the UcD400AD. I cut away the transistors just like it is on the instruction that came with the powersupply. It is not easy to raise the voltage. I would need to build another power supply with additional regulators.
I am now thinking of putting the transistors back and see if the modules still work. I hope they are not
The strange thing is that the amplifier enable goes toward 11 V when powering up. I read somewhere on this thread that it should go towards 0V? Or did I misinterpret that?
I just figured out that with the new supply for the opamps the amplaifier enanble switch dows not work anymore. Connecting this to the powerground solved the issue.
UcD 400 HG with HxR regulators opamp voltage
I have the UcD 400 HG with HxR regulators. Is the input opamp fed with +/- 12V?
I'm looking to change it for AD8620 which only takes in maximum 24v supply.
I have the UcD 400 HG with HxR regulators. Is the input opamp fed with +/- 12V?
I'm looking to change it for AD8620 which only takes in maximum 24v supply.
Input opamp is fed with +-12V but it wouldn't hurt to confirm this with measurement as well.I have the UcD 400 HG with HxR regulators. Is the input opamp fed with +/- 12V?
I'm looking to change it for AD8620 which only takes in maximum 24v supply.
Do search this forum related to AD8620.
I have read somewhere that it heats considerably even at +-12V.
AD823
Hmm... another chip I like is AD823.
Will use that, as it sounds musical and somehow forgiving on lesser recordings and very good at micro-details.
Will let you guys know how the UcD 400 HG/HxR sounds on my Wharfedale Opus 2-2 speakers vs the LM4562. Source is a Benchmark DAC2 (all original LM49860 inside) and right now sound is a bit too neutral for my taste.
Hmm... another chip I like is AD823.
Will use that, as it sounds musical and somehow forgiving on lesser recordings and very good at micro-details.
Will let you guys know how the UcD 400 HG/HxR sounds on my Wharfedale Opus 2-2 speakers vs the LM4562. Source is a Benchmark DAC2 (all original LM49860 inside) and right now sound is a bit too neutral for my taste.
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AD823
I swapped the opamps for AD823 and it sounds better.
Also changed the small supply capacitors for UKA1H101MPD 100uf/50v at the primary regulators and UKA1C221MED 220uf/16v at the opamp supply after the HXR regulators.
Changed the output filter capacitors for 2 x WIMA 0.33uf/250v MKP (farnell part 1890269).
Also, the input capacitors are now WIMA MKS2-2.2U/50 instead of the 680nf originals.
All parts
Should've done the mods in steps to evaluate the quality of sound but all in all sounds more clear now.
I swapped the opamps for AD823 and it sounds better.
Also changed the small supply capacitors for UKA1H101MPD 100uf/50v at the primary regulators and UKA1C221MED 220uf/16v at the opamp supply after the HXR regulators.
Changed the output filter capacitors for 2 x WIMA 0.33uf/250v MKP (farnell part 1890269).
Also, the input capacitors are now WIMA MKS2-2.2U/50 instead of the 680nf originals.
All parts
Should've done the mods in steps to evaluate the quality of sound but all in all sounds more clear now.
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As Hypex does not answer message anymore in their " contact " form on their website, I ask in case someone knows:
- what it the threshold for DC protection to kick in with their SMPS and UcD ?
- some modules are quite old now, is there knows parts failure like caps overheated?
- what it the threshold for DC protection to kick in with their SMPS and UcD ?
- some modules are quite old now, is there knows parts failure like caps overheated?
There should be no cap overheating in a good ventilated enclosure.- some modules are quite old now, is there knows parts failure like caps overheated?
If you are making a caps replacement each one has to be 105C rated.
MKP capacitors are much better for coupling than MKS ones.Also, the input capacitors are now WIMA MKS2-2.2U/50 instead of the 680nf originals.
Also you don't need to put the cap at the original position because MKP caps are considerally bigger but it is a worth an effort.
There should be no cap overheating in a good ventilated enclosure.
If you are making a caps replacement each one has to be 105C rated.
OK let me reformulate my question, as electrolytic caps have life expectancy of thousands of hours, as that life expectancy decreases with heat, what can be an expected recap schedule for these modules?
Maybe 30 years, don't know but I'm concerned about a slowly fading SQ as caps degrades. Maybe 10 years (soon!), maybe I should take my medication... 😉
Look at the datasheets.
Caps which are declared at 105C very often have a specification of life expectancy at 85C.
Then try to assume what would be the temperature inside the enclosure.
After that ask yourself how often do you listen to the music and how long are your sessions.
Most likely you should be fine with much more than 10 years.
Besides that recaping can be beneficial for UcD modules.
I recommend Panasonic FC.
Caps which are declared at 105C very often have a specification of life expectancy at 85C.
Then try to assume what would be the temperature inside the enclosure.
After that ask yourself how often do you listen to the music and how long are your sessions.
Most likely you should be fine with much more than 10 years.
Besides that recaping can be beneficial for UcD modules.
I recommend Panasonic FC.
OK I keep that in mind for when I change it as the big caps are Hypex branded. Tiny ones are branded but the gray cans.
I have already changed all caps (Hypex branded included) for Panasonic FC.OK I keep that in mind for when I change it as the big caps are Hypex branded. Tiny ones are branded but the gray cans.
I have already changed all caps (Hypex branded included) for Panasonic FC.
What voltage for the bootstrap capacitor... it's 8mm in dia and original value is 220uf/35v. Can I go with 470/16V in there?
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Where is that capacitor?What voltage for the bootstrap capacitor... it's 8mm in dia and original value is 220uf/35v. Can I go with 470/16V in there?
Anyway, you should stick to original specs (voltage, capacitance, temperature).
Bootstrap cap
Near the vertical board, closest to the two pots.
Where is that capacitor?
Anyway, you should stick to original specs (voltage, capacitance, temperature).
Near the vertical board, closest to the two pots.
An externally hosted image should be here but it was not working when we last tested it.
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