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DIY Purifi Amp builds

Hogh

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When the amplifier is idling, the SMPS is consuming about 10W, the amplifiers about 1.5W each. 10/13 = 77% (ok, 90% was excessive).

I dont have equipment to measure power consumption but i just tried measuring the SMPS1200a400 supply current in idle (nothing connected) and standby. The RMS current measured with a fluke 177 drops from ~95 mA to ~62 mA. Im on 230 VAC so the power factor must be quite bad at low power to meet the 9 W from the datasheet. Anyway if the power factor remains similar then the power is only dropped by 62/95 going into standby. Not as much as I expected. This may explain why early datasheets had standby power as "TBD" and completely dropped it in the later versions ;)
 

tomchr

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I see you also used the Neurochrome Input boards. How did you tried to make the i2c connection? I can't find datasheet for those boards, to see the pinout.
The Neurochrome Purifi/Hypex Buffer operates the amp module in hardware mode. No I2C is needed. If you want to use software mode, you can hack it by connecting 31 of the 36-pin connector to ground using the appropriate 1% resistor (see Table 8 of the Purifi 1ET400A data sheet). The SDA and SCL are brought out on the 10-pin connector for the power supply.

I did consider adding a footprint for that resistor on the board, but I figured few would use it.

Tom
 

tomchr

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When the amplifier is idling, the SMPS is consuming about 10W, the amplifiers about 1.5W each. 10/13 = 77% (ok, 90% was excessive).
No issue with the external relay cutting everything.
That's the approach I take. I have a soft start circuit that controls the power to the SMPS. The soft start consumes ~10 mW when off.

Tom
 

lealoureiro

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The Neurochrome Purifi/Hypex Buffer operates the amp module in hardware mode. No I2C is needed. If you want to use software mode, you can hack it by connecting 31 of the 36-pin connector to ground using the appropriate 1% resistor (see Table 8 of the Purifi 1ET400A data sheet). The SDA and SCL are brought out on the 10-pin connector for the power supply.

I did consider adding a footprint for that resistor on the board, but I figured few would use it.

Tom

Thanks for your answer!

I understand, not ideal but still feasible I believe. When using those 2 boards separately which of them has the 10 pin connector, but SMPS1200 only has 1 output. I saw some people using a ribbon cable with 2 output connectors (one in the middle of cable), the are of two boards are connected in parallel?

Regarding the Neurochrome and FE02 input buffer, is there any difference how they handle the input voltage of the balanced input or that mostly has to do with gain level selected?
 

tomchr

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I'm not familiar with the FE02. The Neurochrome buffer has a differential output. The output remains differential even if a single-ended source is used. As far as I know the Neurochrome buffer is the only one that maintains a differential output with a single-ended source. Having a differential output allows the Purifi amp to be driven to clipping. Some also claim it sounds better.

You're correct. The modules are daisy-chained on the 10-pin ribbon cable. For a stereo amp, just make a cable with three connectors (one for the SMPS and one for each amp).

You need to split the power supply as well. I make the SMPS Splitter for that exact purpose.

Tom
 

boXem

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So, I suppose, there is no issue with unplug and plug the mains cable ? (it will be healthy for the PS and Amp module to do that all the time) ?
I personally got my back blocked for 2 weeks while unplugging mains cable from the wall. So not so healthy :D
 

lealoureiro

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Thank you for the info tomchr and boXem | audio :)

Another think a get confused regarding the purpose of the the J4 and J5 connectors in SMSP1200, i see some builds here that were using one or the order, and some builds a combination of both... J4 is mainly to give power to Input Buffer boards and J5 to power auxiliary like LEDs and Switches ?
 
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JimB

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For the vacuum cleaner?!? :oops:
Well, if that's what you need. Top alternatives include: leave it plugged in for future use, in that location (let me know what brand you buy so I can get stock in that company before you buy one for every room in your house!), OR, don't vacuum, OR let "the Boss" do it (if you have one of those in your home). :p
 
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JimB

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Thank you for the info tomchr and boXem | audio :)

Another think a get confused regarding the purpose of the the J4 and J5 connectors in SMSP1200, i see some builds here that were using one or the order, and some builds a combination of both... J4 is mainly to give power to Input Buffer boards and J5 to power auxiliary like LEDs and Switches ?
Both J4 and J5 have Vaux available. J4 has additional amp interface functions, while J5 has additional SMPS functions. Please refer to the Hypex datasheet. In the Ghent case, with their optional cable set, J4 is used to give a five wire interface with the Purifi input board, and use the J5 for their front panel LED.
 

tomchr

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Another think a get confused regarding the purpose of the the J4 and J5 connectors in SMSP1200, i see some builds here that were using one or the order, and some builds a combination of both... J4 is mainly to give power to Input Buffer boards and J5 to power auxiliary like LEDs and Switches ?
Have you read the Hypex SMPS1200 data sheet? I've attached the relevant connector pinouts here (from page 10 of the data sheet).

Personally I prefer to use J4 for the connections to the Buffer. Why run many cables when you can run one?

Tom
 

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Naturlig

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Thank you for the info tomchr and boXem | audio :)

Another think a get confused regarding the purpose of the the J4 and J5 connectors in SMSP1200, i see some builds here that were using one or the order, and some builds a combination of both... J4 is mainly to give power to Input Buffer boards and J5 to power auxiliary like LEDs and Switches ?

Here is an example of my test build with the Modushop GX288 cabinet. The cabling is my first try and NOT yet finished, I could not wait to hear the sound of the Neurochrome buffer together with the 1ET400A amp module. And the sound from this build is indeed excellent. TomC knows how to it!
The next will be to insert the splitter card from Neurochrome and redo the cabling.
20210411_104704.jpg
 

boXem

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Here is an example of my test build with the Modushop GX288 cabinet. The cabling is my first try and NOT yet finished, I could not wait to hear the sound of the Neurochrome buffer together with the 1ET400A amp module. And the sound from this build is indeed excellent. TomC knows how to it!
The next will be to insert the splitter card from Neurochrome and redo the cabling.
View attachment 123341
If you cannot respect 3 mm of minimal distance between the SMPS and the chassis, you should insert an insulation sheet.
 

Naturlig

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If you cannot respect 3 mm of minimal distance between the SMPS and the chassis, you should insert an insulation sheet.

I see, ok, thank you much for the comment.
I measured the distanse to be 3mm, however I will be on the safe side to insert insulation here. May be that the perspective in the picture is not perfect.
 

boXem

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I see, ok, thank you much for the comment.
I measured the distanse to be 3mm, however I will be on the safe side to insert insulation here. May be that the perspective in the picture is not perfect.
I guess it was an optical effect, I had even the feeling that the grounding wire was pinched :D.
3 mm should also be the minimum distance to the Purifi boards BTW.
 

TimoJ

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Here is an example of my test build with the Modushop GX288 cabinet. The cabling is my first try and NOT yet finished, I could not wait to hear the sound of the Neurochrome buffer together with the 1ET400A amp module. And the sound from this build is indeed excellent. TomC knows how to it!
The next will be to insert the splitter card from Neurochrome and redo the cabling.
View attachment 123341
Your AC connection/ground wiring looks weird. Is that top connector IEC middle pin i.e. ground tap? Looks like it goes to PSU.
 
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