Can I also ask is the main ground of the circuit board isolated from the aluminium plate underneath?
Is the gound clean of noise? There reason I asked is because I planned to use the SMPS and linear transformer in the same case. The latter is for the opamp. I am just worried that the gound will be conteminated by the SMPS
Is the gound clean of noise? There reason I asked is because I planned to use the SMPS and linear transformer in the same case. The latter is for the opamp. I am just worried that the gound will be conteminated by the SMPS
ackcheng said:
The aluminum plate is connected to the GND of the mains (if you have that one connected as advised in the manual). It is not connected to the GND of the output voltage. So the mains GND and output GND are seperated. There is just a very small capacitor that connect between output GND and that aluminum plate.
As I do not have any mains GND available in my room. I have the mains GND not connected at the moment. I know this may not be safe so I plan to buy a balanced mains transformer cranking up my 100V (Japan) to balanced 220V with the center tap being used as mains GND. Then I plan to put a circuit in those 220V mains lines to detect if the current in both mains lines is the same, if not, there is a leak from one of the mains lines to the mains GND. Such a protection circuit is called an "aardlekschakelaar" in Dutch, I do not know the english name
This should make things very safe as the SMPS would now be floating (because of the transformer) and leakage to the mains GND would be detected as well. Best regards
Gertjan
As Gertjan points out, output GND is isolated from chassis and from input mains. The chassis is connected to mains EARTH, and for safety reasons it should be connected to the wall plug earth.
This allows separation of the amplifier GND (input, etc) from the chassis, allowing very quiet operation while keeping safety as the case is connected to mains earth.
The auxiliary output has floating GND as well, not connected to the +/-60V output GND. This allows flexibility as aux GND can be connected to output GND (for feeding a preamp, input stage of the amplifier, etc) or to -VSS, to feed the driver stage of our class-D modules (optional, only to decrease their idle power dissipation)
This allows separation of the amplifier GND (input, etc) from the chassis, allowing very quiet operation while keeping safety as the case is connected to mains earth.
The auxiliary output has floating GND as well, not connected to the +/-60V output GND. This allows flexibility as aux GND can be connected to output GND (for feeding a preamp, input stage of the amplifier, etc) or to -VSS, to feed the driver stage of our class-D modules (optional, only to decrease their idle power dissipation)
I did not know Japan had mains without earth in some places also? Here in the Netherlands most sitting rooms and bedrooms have no earth connection in the mains wall socket thats why we have the "aardlekschakelaar", earthleak protection switch which switches the mains off if you touch 1 of the mains wires. Very fast switching off and prevents you from"sticking"to the mains.ghemink said:
You sure know how painfull touching the mains,230V, can be
Bgt said:
I did not know Japan had mains without earth in some places also? Here in the Netherlands most sitting rooms and bedrooms have no earth connection in the mains wall socket thats why we have the "aardlekschakelaar", earthleak protection switch which switches the mains off if you touch 1 of the mains wires. Very fast switching off and prevents you from"sticking"to the mains.
You sure know how painfull touching the mains,230V, can be
Yes, overhere we have earth connection only in "wet places" like kitchens and sometimes for outlets that are made for airconditioners. However, in my current room, I have an airco, but no earth :-(
I know 230V does not feel funny, once back in the netherlands, I felt it, I was quite shocked. Therefore, In do not want to take any chances with safety and thus want to use a transformer. I also want to try balanced power.
Gertjan
The new version is available yet. (not too deep changes over the current one, just a thermal protection in case of failure to boot and I have a batch just over the desk ;-)
We can supply standard SPS80 with inmediate delivery from +/-40 to +/-60V (just specify at the time of ordering). If you require a higher output voltage that must be made on-demand, thus requiring a minimum order quantity (or a group order) as we must make custom wound transformers. Please contact us for details.
Best regards
We can supply standard SPS80 with inmediate delivery from +/-40 to +/-60V (just specify at the time of ordering). If you require a higher output voltage that must be made on-demand, thus requiring a minimum order quantity (or a group order) as we must make custom wound transformers. Please contact us for details.
Best regards
ackcheng said:
Yes, indeed, I was thinking of a 1000W balanced transformer, actually two for left and right seperate.
About the benefits of balanced power, there are many articles on the internet talking about the advantages of balanced power. I though to to give it a try myself as it allows me then to isolate the SMPS from the wall outlet (safety) and have balanced power at the same time. Can also then transform the 100V to 220V which maybe a bit nicer for the SMPS. At 100V operation, it uses a voltage doubler circuit, at 220V operation not. At 220V operation, the rectified high voltage should be nicely symmetrical and stable with respect to the center tapped GND level. So the rectified mains rails would be at about -150V and +150V more or less stable DC. With voltage doubling at lower voltage, the rectified mains rails are moving all over the place (if I`m correct) with a 50Hz or 100Hz frequency, just feels better to have them stable with respect to GND. I know in practice objectively it may not result in audible improved performance but as it subjectively "feels" better is is better
I usually try to back up my experiments with measurements as I`m an engineer, so once I have balanced transformers I will for sure do some measurements. Just wondering what kind of measurements would be best to check the benefits of balanced power. One of the benefits would be less radiation from the balanced power cables, so less chance of noise pickup by signal cables. To be honest, I don`t expect any significant improvement on the performance of the SMPS itself with balanced power as the output of the SMPS is already floating.
Best regards
Gertjan
Pierre said:
Hi Pierre,
At the moment I`m using it at 100V. Works fine. I have also used it with 220V using a transformer (but not isolated, meaning a single winding transformer as normally used for mains voltage conversion). I have no earth connection, I don`t like that so using it with an isolation transformer or even better with a center tapped balanced transformer would be the safest solution in that case.
Best regards
Gertjan
ghemink said:
Hello all,
I have just measured the UcD400 positive power rail on the scope (measured directly over the 470uF cap on the UcD PCB, so after the onboard inductors). With the UcD switched off, but SPS80 connected and powered on (so UcD in standby) the small amount of noise components that were on the SPS80 power rails are reduced more than 20-30dB on the UcD board. This means that remaining HF noise from the SPS80 is extremely small , in the order of a few mV peak-to-peak. Completely peanuts in comparison with what the UcD itself is generating at that point when you switch it on. So I'm very sure that any remaining noise from the SMPS does not harm the UcD as the power rails on the UcD board are very clean. The onboard UcD LC filtering works very well. When I switch on another UcD400 on the same powerlines, I can hardly see it in the noise level that reaches the 470uF cap on the other UcD board, less than 1mV or so peak-to-peak. So multiple UcDs on the same power lines do not "see" eachother. All these measurements were done without any signal supplied to the modules. However, now running some music on one module and the other in standby, hardly any change.
In other words, very happy with the SPS80 UcD combination.
Best regards
Gertjan
Ackcheng, thanks for the suggestion, we take note ;-)
Gertjan, we really thank you for taking the time to extensively test our SPS80 and demonstrate that it works perfect with UcD. Not that I want to insist, but they also work excellent with our BP4078 modules, of course
These modules are now nearly in the same power range as UcD700: They are >600W capable on 2 ohm, with two of them in bridge mode and a SPS80 you can drive a 4 ohm speaker to >1000W.
Impressive, believe me.
Gertjan, we really thank you for taking the time to extensively test our SPS80 and demonstrate that it works perfect with UcD. Not that I want to insist, but they also work excellent with our BP4078 modules, of course
These modules are now nearly in the same power range as UcD700: They are >600W capable on 2 ohm, with two of them in bridge mode and a SPS80 you can drive a 4 ohm speaker to >1000W.
Impressive, believe me.
ssanmor said:Ackcheng, thanks for the suggestion, we take note ;-)
Gertjan, we really thank you for taking the time to extensively test our SPS80 and demonstrate that it works perfect with UcD. Not that I want to insist, but they also work excellent with our BP4078 modules, of course
These modules are now nearly in the same power range as UcD700: They are >600W capable on 2 ohm, with two of them in bridge mode and a SPS80 you can drive a 4 ohm speaker to >1000W.
Impressive, believe me.
Hi Sergio,
I`m sure your BP4078 are worth a try as various people report good results. However, I have already 8 UcD400 modules and 4 UcD180 modules for my 2 active speakers, so no more needed for now. I also had ZAPpulse, but those gave me issues (reported elsewhere).
Anyway, your SPS80 works great, less issues (none so far) than with the KT6. Also the additional low voltage regulated supply maybe nice, have not tried that one. At least you went all the way to use Panasonic FC caps in that part of the supply (if I`m correct).
Is the SPS30 available already? Any 2nd version for the SPS30 planned? May get a few SPS30 supplies as well.
Next plan is to use the SPS80 with two UcD400s in bridged mode for woofer amps. The reason for bridging two UcD amps is to completely avoid power supply pumping.
Best regards
Gertjan
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