I don't know how beneficial could be the upgrade of that capacitor. I haven't done that replacement yet.
From the picture which I see the first what I would advise you to do is to replace the filter capacitor if that is Wima MKS (polyester) type. You can replace it with two 0,33uF MKP2 (polypropylene) caps, one above and the other below the pcb at the same pins.
This is the single biggest improvement IMHO.
Than you can concentrate to Hypex decoupling capacitors as well as those 4 naked BC capacitors.
Do you ultimately need those two coupling caps at the left bottom?
These are not perfect for that tusk since they are polyester caps as well. You can replace them with some better ones but since they will be bigger you should find some other position for them.
From the picture which I see the first what I would advise you to do is to replace the filter capacitor if that is Wima MKS (polyester) type. You can replace it with two 0,33uF MKP2 (polypropylene) caps, one above and the other below the pcb at the same pins.
This is the single biggest improvement IMHO.
Than you can concentrate to Hypex decoupling capacitors as well as those 4 naked BC capacitors.
Do you ultimately need those two coupling caps at the left bottom?
These are not perfect for that tusk since they are polyester caps as well. You can replace them with some better ones but since they will be bigger you should find some other position for them.
Yep another question:
Hypex's SMPSs feature mains filter. Some pretend, out of the blue, that if your chassis has mains filter it can degrade the sound. My chassis does use a filtered socket, then some wird to the 2 SMPS. It sound terrific, but is this a problem in any way?
BTW, thread started in 2004, I'm a happy user of UCD400 here
Hope I'm not the last...
Hypex's SMPSs feature mains filter. Some pretend, out of the blue, that if your chassis has mains filter it can degrade the sound. My chassis does use a filtered socket, then some wird to the 2 SMPS. It sound terrific, but is this a problem in any way?
BTW, thread started in 2004, I'm a happy user of UCD400 here
Hope I'm not the last...Yep another question:
Hypex's SMPSs feature mains filter. Some pretend, out of the blue, that if your chassis has mains filter it can degrade the sound. My chassis does use a filtered socket, then some wird to the 2 SMPS. It sound terrific, but is this a problem in any way?
BTW, thread started in 2004, I'm a happy user of UCD400 here
Those filtered sockets usually use X and Y rated capacitors and some coils as well.
The coils are particulary problematic since they are put in series and can affect the performance of UCD modules.
Since Hypex SMPS is already filtered with AC rated capacitors I would try unfiltered IEC socket.
You should get the better result this way but YMMV.
I am also using unfiltered IEC socket for my SMPS and UCD modules.
I am looking for assistance on how to track down the buzz on the UCD400's/SMPS400 build in Ghent Cases.
I tested the monoblocks with another preamp and there they are working flawlessly.
The rest of the system consist of an Anthem MRX510 (2 prong plug, double isolated and these monoblock.
Nothing else connected to the Anthem, Nothing else plugged into the powerstrip.
When I plug in RCA-XLR cable there is a buzz. I tried various cable (DIY and bought) and it remains the same.
As soon as the amp is connect to the receiver it buzzes.
The RCA cables are as recommend by Hypex (pin1+3 to chassis on RCA, Pin 2 hot.)
I also tried with pin1 chassis and pin2 hot, floating shield on RCA, but that made the noise even louder.
I disconnected the shield on the UCD side, but that also had no effect.
I plug in a XLR terminated Cable it is there is no noise.
Connecting/disconnecting earth ground has not effect on the noise.
Any idea how I can get rid of this noise?
https://i.imgur.com/Nx1qjPY.jpg
I tested the monoblocks with another preamp and there they are working flawlessly.
The rest of the system consist of an Anthem MRX510 (2 prong plug, double isolated and these monoblock.
Nothing else connected to the Anthem, Nothing else plugged into the powerstrip.
When I plug in RCA-XLR cable there is a buzz. I tried various cable (DIY and bought) and it remains the same.
As soon as the amp is connect to the receiver it buzzes.
The RCA cables are as recommend by Hypex (pin1+3 to chassis on RCA, Pin 2 hot.)
I also tried with pin1 chassis and pin2 hot, floating shield on RCA, but that made the noise even louder.
I disconnected the shield on the UCD side, but that also had no effect.
I plug in a XLR terminated Cable it is there is no noise.
Connecting/disconnecting earth ground has not effect on the noise.
Any idea how I can get rid of this noise?
https://i.imgur.com/Nx1qjPY.jpg
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Hi,
Although the picture is quite big I can not see the connection from RCA neutral to the chasis.
If RCA is isolated from the chasis with plastic washers then you should provide a connection from RCA neutral to the chasis.
I am using these modules for years now and have never used J6 for DC Error and also never used J5 Pin1 for the SMPS standby. You could try to disconnect them as well.
I am using a simple standard connection described in SMPS400 manual at page 1 from the very beginning and without any operational issues so far.
With this approach my setup is dead quiet with the ear almost touching the tweeter.
Although the picture is quite big I can not see the connection from RCA neutral to the chasis.
If RCA is isolated from the chasis with plastic washers then you should provide a connection from RCA neutral to the chasis.
I am using these modules for years now and have never used J6 for DC Error and also never used J5 Pin1 for the SMPS standby. You could try to disconnect them as well.
I am using a simple standard connection described in SMPS400 manual at page 1 from the very beginning and without any operational issues so far.
With this approach my setup is dead quiet with the ear almost touching the tweeter.
Hi Baka.
I did connect the Pin1 on the XLR directly to chasis ground. That did not have any affect, the slight noise remains. I have now tried it with 3 others different pre-amps, and there the UCD's are totally quiet. I think the problem is not with the amps, but more with the connection between my receiver and the Hypex.
I have to build one more and will leave the J5 and J6 disconnected to to see if that has any effect.
I did connect the Pin1 on the XLR directly to chasis ground. That did not have any affect, the slight noise remains. I have now tried it with 3 others different pre-amps, and there the UCD's are totally quiet. I think the problem is not with the amps, but more with the connection between my receiver and the Hypex.
I have to build one more and will leave the J5 and J6 disconnected to to see if that has any effect.
I have just noticed the slightly upgraded document: https://www.diyclassd.com/documenten/download/944
It is stated that "J5 is not needed in this application".
OK old thread for these amps started in 2004...
They're still for sale in 2019 but are people still buying them?
Anyway, as I may or may not add a buffer in my amp case I'll need space. (a simple 10K pot prior the the UcDs buffered input). Now in dual mono I wonder if only a single SMPS400A400 for my pair of UcD400HG HxR is a real step down or will have technically no impact (mind that there is a drawback going dual mono, maybe it can't be heard but the fact is that there is a slight output voltage difference between the two SMPS400!).
A dual mono vs single supply feedback please =)
Thanks!
They're still for sale in 2019 but are people still buying them?
Anyway, as I may or may not add a buffer in my amp case I'll need space. (a simple 10K pot prior the the UcDs buffered input). Now in dual mono I wonder if only a single SMPS400A400 for my pair of UcD400HG HxR is a real step down or will have technically no impact (mind that there is a drawback going dual mono, maybe it can't be heard but the fact is that there is a slight output voltage difference between the two SMPS400!).
A dual mono vs single supply feedback please =)
Thanks!
I have started first with one SMPS400A400 feeding two UcD400HGs.
Later on, after a year or so, I have added the second SMPS400A400.
The difference is not night and day but I could notice a bit of better focus, soundstage and overall tighter presentation than before.
For me it was worth an upgrade.
I do not notice the channel disbalance so I think it should not be an issue with you as well.
But, of course, YMMV.
Strictly apply the documents related to ground wiring.
I am using them for almost 5 years without any issue.
Just provide an adequate heatsinks.
With only one SMPS used to power two modules, be it SMPS400A400 or SMPS1200 you are loosing some benefits I have mentioned before.
Hello everyone,
Not sure this is the right post to ask this.
I have a pair of UcD400-HG and a pair of UcD2k. The small modules are feed with Hypex linear PS, the big ones with the SMPS3KA700. Can anyone confirm if these modules/PS combos have DC/offset speaker protection in the outputs ??
Thanks in advance.
C.A.
Not sure this is the right post to ask this.
I have a pair of UcD400-HG and a pair of UcD2k. The small modules are feed with Hypex linear PS, the big ones with the SMPS3KA700. Can anyone confirm if these modules/PS combos have DC/offset speaker protection in the outputs ??
Thanks in advance.
C.A.
I am using UcD400 modules. My modules are adjusted to have around 10mV DC on the output itself being disconnected from the source component.
I think they do not have a circuit which automatically null any DC on the output.
If so, any DC on the input of these modules would be amplified.
You can measure their outputs with your source component connected.
Outputs of the modules must not be connected to the speakers in the time of measurement.
Thank you for taking the time to answer me. I guess they do have speaker DC protection, as indicated in the TDS of the linear PS. The SMPS have similar feature. I got confirmation from another source after post. I would have rather preferred a relay on the outputs too, but this is already something.
Regards,
C.A.
Regards,
C.A.
