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DIY Purifi Amp builds

Once again the SMPS is being returned repaired. The aux circuit was what needed repair. They said the 6 pole harness was good. They did not test the aux cable b/c they said it lacked crimps which it would b/c it was made with the 3m IDC cable. They did say it appeared to have been wired correctly. No matter. I will have the Ghent cable.

The Eval 1 arrived at Purifi yesterday. They will look at it beginning next week. Hopefully in two weeks I should have all the working components back in house and can start assembly anew.
 
Aardappel said:
Hi boXem, if you use the EVAL1 board but bypass the buffer (to reduce the gain), would the input signal still be EMI filtered or is that also bypassed?
Click to expand...
boXem | audio said:
Hi Aardappel, from EVAL1 documentation the filter seems to be bypassed.
Click to expand...

Hi,
Could it be a problem for a normal user (HiFi) ?
Or it's irrelevant because the signal we feed to the PURIFI modules is already "clean" (without any EMI or other hassles) ?
 
zappa said:
Hi,
Could it be a problem for a normal user (HiFi) ?
Or it's irrelevant because the signal we feed to the PURIFI modules is already "clean" (without any EMI or other hassles) ?
Click to expand...
Hi zappa,
There is a risk to have the noise disturbing the modulator behavior. DACs are not always clean. Our home environment is full of EM crap.
While I consider that products sold by professionals have to include these protections, I do not want to spread FUD, we are talking about DIY here, so I would say that if you don't hear any noise out of your speakers when no music is playing, this is a non issue.
 
Well Purifi looked at the Eval1 and Kim said it was in perfect working order. Also liked Ghent's wiring harnesses, so I guess I'll be using them. The repaired SMPS arrives at my door tomorrow. Still no idea why the aux section blew out twice. Hypex said my six pole harness was perfect, and they didn't check the five connection b/c it wasn't crimped (It wouln't have been given I was using the 3M IDC connector) but said it appeared to be wired correctly, so I have no idea what the root cause for these failures.

I will check out the SMPS by trying Ghent's LED first, then when the Purifi arrives I'll connect it with Ghent's harneses. If all the Leds light up, only then will I reinstall it in the case, first with the back off. If it works that way, I'll reistall the back and cross my fingers.

I put thermal paste under the base of the SMPS, could that possibly have caused any issues? Anyone know?
 
phoenixdogfan said:
I put thermal paste under the base of the SMPS, could that possibly have caused any issues? Anyone know?
Click to expand...
Nope. If you use too much, too thick, it could be worse than none - meaning, it would overheat at a lower power output than without the paste. But, applied properly, it improves thermal margin. It should have nothing to do with SMPS failures unless it was conductive and you got it where it shouldn't be.
 
phoenixdogfan said:
Well Purifi looked at the Eval1 and Kim said it was in perfect working order. Also liked Ghent's wiring harnesses, so I guess I'll be using them. The repaired SMPS arrives at my door tomorrow. Still no idea why the aux section blew out twice. Hypex said my six pole harness was perfect, and they didn't check the five connection b/c it wasn't crimped (It wouln't have been given I was using the 3M IDC connector) but said it appeared to be wired correctly, so I have no idea what the root cause for these failures.
Click to expand...
Before connecting the two cables to the EVAL1, power up the SMPS and DOUBLE CHECK the voltages on each pin at the EVAL1 ends. If all good, power down the SMPS for at least several minutes before connecting them to the EVAL1.
 
JimB said:
Before connecting the two cables to the EVAL1, power up the SMPS and DOUBLE CHECK the voltages on each pin at the EVAL1 ends. If all good, power down the SMPS for at least several minutes before connecting them to the EVAL1.
Click to expand...
To do that do I just put the hot lead on the pin and the neutral on the case. and record the voltage?
Do I find the correct voltages in the Hypex user guide?
 
JimB said:
Nope. If you use too much, too thick, it could be worse than none - meaning, it would overheat at a lower power output than without the paste. But, applied properly, it improves thermal margin. It should have nothing to do with SMPS failures unless it was conductive and you got it where it shouldn't be.
Click to expand...
It was a super thin coat and it was under the base plate of the SMPS and nowhere else, so I don't think it should have caused any problems. That leaves me with the back shorting things out or some short in the IDC connector. If it's the IDC connector, that irrelevant going forward b/c I'm using Ghent's wiring harness which is crimped, and looks to be a nice job. I will on second thought get the back "ventilated" b/c I just don't like the idea of the Eval 1 circuit board touching the metallic case back, especially if everything works without the case back.
 
phoenixdogfan said:
To do that do I just put the hot lead on the pin and the neutral on the case. and record the voltage?
Do I find the correct voltages in the Hypex user guide?
Click to expand...
Neutral lead on the ground pin(s) of each cable. Voltages per the Hypex datasheet (allowing for your mains AC voltage).
 
zappa said:
Hi,
Could it be a problem for a normal user (HiFi) ?
Or it's irrelevant because the signal we feed to the PURIFI modules is already "clean" (without any EMI or other hassles) ?
Click to expand...
As @boXem | audio says if you hear no odd noises then its not a problem. Its just something that commercial products should take care of as a precaution.
 
Hogh said:
Been waiting for this but now Eval2 is online
Click to expand...

I have been so lucky to actually use these for some weeks now.

Easy to implement, I think, and the sound combined with 1ET400's, is absolutely fantastic, in my setup.

The package I received contained everything I needed to hook them up to Hypex SMPS 1200A400's.

I can recommend them, no problem.
 
Last edited:
KarVi71 said:
I have been so lucky to actually use these for some weeks now.

Easy to implement, I think, and the sound combined with 1ET400's, is absolutely fantastic, in my setup.

The package I received contained everything I needed to hook them up to Hypex SMPS 1200A400's.

I can recommend them, no problem.
Click to expand...
Very nice! Are you driving it with the XLR output of the NAD C658 to the EVAL2/1ET400 combination with the buffer bypassed or not bypassed?
 
This thread along with the review on the site inspired me to purchase the Eval1 kit.

I've got a bunch of vintage gear including tubes. I wanted to see if something more "accurate" would improve my listening enjoyment.

So, I've got a dac (RME ADI-2 DAC FS v2).

I will admit to being gain and db challenged. My question is on the Gain/bypass jumpers. Any opinions on whether or not to utilize the 14db of pre-gain?

I'm starting to build the Eval1. Everything is in the Ghent case with the exception of the power supply. USPS seems to be having the normal holiday slow down.

A second question is on the Speakon connectors. How do those get wired up if I'd like to use them? The banana plugs work for now, but since they are there.

TIA!
 
Last edited:
drfous said:
This thread along with the review on the site inspired me to purchase the Eval1 kit.

I've got a bunch of vintage gear including tubes. I wanted to see if something more "accurate" would improve my listening enjoyment.

So, I've got a dac (RME ADI-2 DAC FS v2).

I will admit to being gain and db challenged. My question is on the Gain/bypass jumpers. Any opinions on whether or not to utilize the 14db of pre-gain?

I'm starting to build the Eval1. Everything is in the Ghent case with the exception of the power supply. USPS seems to be having the normal holiday slow down.

A second question is on the Speakon connectors. How do those get wired up if I'd like to use them? The banana plugs work for now, but since they are there.

TIA!
Click to expand...
What is the maximum output voltage of your preamp? 2V or less? Use the EVAL1 gain. 4V or higher? Maybe bypass the extra gain.

As for speakONs, that has been addressed in some slightly earlier posts. Try reading starting from page 85. Here is one in the pages that follow:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-87#post-564666
 
JimB said:
What is the maximum output voltage of your preamp? 2V or less? Use the EVAL1 gain. 4V or higher? Maybe bypass the extra gain.

As for speakONs, that has been addressed in some slightly earlier posts. Try reading starting from page 85. Here is one in the pages that follow:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-87#post-564666
Click to expand...

Thanks for pointing me to the wiring!

I'm most likely to use my Schiit Freya for preamp. It has 3 modes: passive, JFET buffer and Tube Gain (14db). Since this little experiment is about keeping it clean, I'm thinking I will most likely use the passive mode.

Thanks again!
 
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