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DIY Purifi Amp builds

kukocz

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@MicroAudio that make sense. Thank you for explanation.

@phoenixdogfan at the end - for sure it is not something to worry about. I performed small investigation if this is something unusual and if it can be mitigated.

I faced another problem with READY signal. I planned to use it to feed burton’s LED when amp is fully operating.
It should be high when amp is ready (two red leds on Eval1 board are on). Unfortunately my multimeter shows strange thing but usually voltage close to 0.
Based on documentation R6_A1/A2 resistors should not be present for HW mode.
A02C4B11-BBF3-4100-AA77-88FD32C551F4.jpeg

My board looks like follows.
0009B893-7680-4DC0-9237-9E937A95AC95.png
There is a smd element without description but with white line.
My board seems to be somehow 50/50 in HW/SW mode :)
Do you have similar smd in place of R6_A1/A2?
 

TimoJ

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Just how loud is the click? Loud enough to damage your speakers? To startle? To my mind a soft click does not harm at all. I am still awaiting my final drilled case to assemble my Eval1, but I'm not losing any sleep whatsoever over a minor click upon turn on. If it's more than minor I'd of course like to know, but otherwise...well, I guess I'm just not as perfectionisic as others on this thread.
Quiet click that you just notice, it won't startle. But I don't like how it sounds, you get very similar (but louder) sound if you connect 1.5V battery directly to tweeter and I always seem to think that, when I hear the click... Of course DC to tweeter isn't possible since there's crossover with filter cap.
 

TimoJ

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What is interesting, when you touch with your fingers the “amp enable” wire, clicks and crack noises are audible from the speakers. Maybe S1 has the advantage over the long wire because the path is short B and not exposed to external interference... Maybe this is why S1 is quieter...?
So maybe some resistor and/or capacitor from he ampon line to ground would make the click quieter? We should check with an oscilloscope how the line behaves during the switch on/off time.
 

Luc

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Delaying won't change anything. I was surprised that S1 would not cause a click, indeed it does.

i hope it does and i'll check it out when wired.

I just turned on my system to re-check if there is or not a "click".

1. i turn on the smps (the amp stays off, S1 down)
2. i turn on the source (pc) and plug it to the dac
3. i turn on the dac, volume to zero
4. i turn on the purifi : S1 to up position
Absolutely NO CLICK at all for me. Total silence with my ears at 10cm from the medium and the highs drivers.
 

TimoJ

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i hope it does and i'll check it out when wired.

I just turned on my system to re-check if there is or not a "click".

1. i turn on the smps (the amp stays off, S1 down)
2. i turn on the source (pc) and plug it to the dac
3. i turn on the dac, volume to zero
4. i turn on the purifi : S1 to up position
Absolutely NO CLICK at all for me. Total silence with my ears at 10cm from the medium and the highs drivers.
Do you have pre-gain stage enabled or disabled? Maybe it effects this also.
 

kukocz

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Thanks!
Are you able to check if there is any voltage on J3.2 when amp is fully operating (Onboard LEDs are on)?
It’s weird... I also noticed that all holes on my PCB are filled with tin. Manufacturing procedure changed? My eval1 kit was used before? I ordered it directly from purifi...
 

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maty

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The delay output is something different and does not exist in HYPEX SMPS, HYPEX has AMP-ENABLE, I have AMP-ENABLE & Delay-Out (SMPS1K_PFC). also, hypex doesn't have a power factor corrector.

Delay output is an output that will be activated AFTER full stabilize of the power supply rails, and will immediately trip once disconnecting the SMPS or putting it into stand by...

Part 1 - Power Factor Correction Introduction
https://sound-au.com/lamps/pfc.html


pfc0-f2.gif

Figure 2 - Block Diagram Of Switchmode Power Supply
 
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Luc

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Thanks!
Are you able to check if there is any voltage on J3.2 when amp is fully operating (Onboard LEDs are on)?
It’s weird... I also noticed that all holes on my PCB are filled with tin. Manufacturing procedure changed? My eval1 kit was used before? I ordered it directly from purifi...

Just to make sure as i'm no electrician...
Voltage between pin 2 of J3 connector and what other point?
Currently i'm not using that pin J3.2
 

kukocz

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Just to make sure as i'm no electrician...
Voltage between pin 2 of J3 connector and what other point?
Currently i'm not using that pin J3.2
And ground GND (could it be also gold plated area around mounting holes on EVAL1 PCB which is also grounded).
Thanks in advance!
 

Luc

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And ground GND (could it be also gold plated area around mounting holes on EVAL1 PCB which is also grounded).
Thanks in advance!

Hummm... the measurement is not very precise. My dmm's probably a bit cheap.
Unstable measure, but anyway less than 100mV
 

kukocz

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Hummm... the measurement is not very precise. My dmm's probably a bit cheap.
Unstable measure, but anyway less than 100mV
So similar case to mine.
I’ve asked directly purify what’s going on...
 

MicroAudio

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Could you please share some specs on that SMPS, and the advantages compared to an hypex one?
What about the efficiency curve at low levels? What is the idle power consumption?

SMPS in STANDBY mode power consumption is 1.9W

SMPS in RUN mode power consumption is 10.7W Amplifier not connected

Hope that answers your question.

Thanks
 

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grobalt

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Thinking about some purifi diy amps, are the eval kit buffer sufficient ? I dont care about 1% neurochrome improvement for 120Dollar as an example
Chain ist Trinnov Altitude 16 to auverdion DSP with +6db Output to purifi
 
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Luc

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i find the purifi buffer board sufficient.
i hesitated taking the nord buffers, but pricey... the nice thing is to put the opamps of your choice ;-)
for me the neurochrome buffer is of little to no interest
 

Luc

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the nord buffers - or equivalent - would be my big improvement to the purifi kit
 

grobalt

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the nord buffers - or equivalent - would be my big improvement to the purifi kit
But the Nord is more than 350 Euro per Channel, thus isnt cheap as well, right ? This ist the Same price than the amp channel
 
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J

JimB

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Based on documentation R6_A1/A2 resistors should not be present for HW mode.
View attachment 72905

My board looks like follows.
View attachment 72907
There is a smd element without description but with white line.
My board seems to be somehow 50/50 in HW/SW mode :)
Do you have similar smd in place of R6_A1/A2?
I have four boards - none are populated there.
 
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