DIY Purifi Amp builds

[JimB]

Are they any bandwidth implications if the gain of the input buffer is changed as described above?

I have no time to pursue it now, but it might reduce stability in the buffer stage, if the gain is "too" low (though I suspect not in this case). Others might be able to advise...

 

[mocenigo]

Is that a problem?

According to the spec sheet, the centers of the two connectors are 23 mm apart. So you have a whole mm in the middle. If this is done properly, the two holes won't touch.

 

[tmortimer]

Hello
below the photos of my Purifi amp, it is cheaper than the Audiophonics and does not require a lot of work ... In an aluminium case with a fully vented cover
And at least I have the buffer and its discreet supply made by PurifiView attachment 54879View attachment 54881View attachment 54882View attachment 54883

That looks great. Nice and clean. What is that you've used to handle the standby/power switch etc?

 

[Matias]

@Dbfr what is this nice case? Motu? Did you custom ordered it or do they already have it Purifi EVAL ready?

 

[mocenigo]

@Dbfr what is this nice case? Motu? Did you custom ordered it or do they already have it Purifi EVAL ready?

Looks like a modu/hifi2000 galaxy case to me, with the "screwless front panel" option

 

[somebodyelse]

That looks great. Nice and clean. What is that you've used to handle the standby/power switch etc?

It's a relay with a mains voltage coil. The front panel switch supplies the coil, so it doesn't need to be rated for the full supply current. The PSU supply is switched by the relay contacts.

what is this nice case?

Looks like one of the Hifi2000 cases available from modushop.biz (manufacturer), audiophonics or diyaudiostore.com
I think they'll all do custom machining if it's not something you want to do yourself.

 

[mocenigo]

It's a relay with a mains voltage coil. The front panel switch supplies the coil, so it doesn't need to be rated for the full supply current. The PSU supply is switched by the relay contacts.

Do you have a reference/part number for that? Looks cool

Seems to be this part https://www.conrad.de/de/p/schneide...ais-230-v-ac-8-a-2-wechsler-1-st-1667395.html

 

[somebodyelse]

Do you have a reference/part number for that? Looks cool

I read it from the full resolution photo - Schneider RSB2A080P7. Farnell have them, and the socket mount with the screw terminals. That style of relay is widely used industrially, so you'll be able to find a load of alternative suppliers and manufacturers, relays with a higher current rating, or for different mains voltages.

 

[wineds]

Do you have a reference/part number for that? Looks cool

Seems to be this part https://www.conrad.de/de/p/schneide...ais-230-v-ac-8-a-2-wechsler-1-st-1667395.html

Another option might be a SS relay. I have had issues with some equipment with contact based relays and SMPS high inrush current at switch on which can cause arcing and subsequently contact damage.

https://au.element14.com/multicomp/...32vdc/dp/2841458?MER=AT-MER-ALL-BT-HIST-ALL-0

 

[mocenigo]

Another option might be a SS relay. I have had issues with some equipment with contact based relays and SMPS high inrush current at switch on which can cause arcing and subsequently contact damage.

https://au.element14.com/multicomp/...32vdc/dp/2841458?MER=AT-MER-ALL-BT-HIST-ALL-0

Well, @tomchr uses mosfets in his speaker protection circuit, to create de facto SS relays. Makes sense

 

[ikir]

I’ve been looking for information about Purify diy projects, curious if someone can point to a good build guide. I am noob in this and honestly a bit lost, but I would like to build amp based on Purify modules.

thank you.

 

[JimB]

Hello below the photos of my Purifi amp...

And at least I have the buffer and its discreet supply made by PurifiView attachment 54879

Looks like you spliced two cable sets together, right? Pin-outs are the same on both ends for 6-wire power cable with the Hypex power supply, but not for the 3-wire interface. How did you do yours?

 

[JimB]

I’ve been looking for information about Purify diy projects, curious if someone can point to a good build guide. I am noob in this and honestly a bit lost, but I would like to build amp based on Purify modules.

thank you.

There is a lot of information in this forum topic if you read it through. Maybe make some summary notes of useful points as you go. There should be some good “kit” options available in the next few months.

 

[mocenigo]

Hello
All that is written above is correct
The case is a modushop, I provided them with a plan so that they drilled my rear panel (saving time)
A 230V industrial type relay directly cuts the SMPS, it is against my principles to leave a power supply on.
I used the unregulated output from the J4 connector to supply the button's LED with a resistor.
I used two identical HYPEX harness wired pin to pin for the main supply, and the small HYPEX harness from J5 connector for the auxiliary supply
I don't wire the AMP ON input of the EVAL1, after discussion with them, their controller manages the start / stop market plop.
However, I wired the ERROR output of EVAL1 to the DC ERROR input

What do you mean by "start / stop market plop" ? (sorry if it something obvious, but I did not wake up well this morning, my brain is not functioning)

 

[ChrisPa]

What do you mean by "start / stop market plop" ? (sorry if it something obvious, but I did not wake up well this morning, my brain is not functioning)

Power up noises
- delayed power up/stable supplies is handled by the hypex smps

 

[jsy]

https://neurochrome.com/collections...ducts/purifi-1et400a-hypex-nc500-input-buffer

 

[jsy]

I had seen it, it seems to be a good product, but the price ....
better take the eval1!

Seems like it costs ~$50 more than the eval1, doesn't ship from Denmark, doesn't clear customs, and actually buffers for a power amp use case (unlike the eval1). Pretty reasonable

 

[TimoJ]

Seems like it costs ~$50 more than the eval1, doesn't ship from Denmark, doesn't clear customs, and actually buffers for a power amp use case (unlike the eval1). Pretty reasonable

EVAL1 is about 125$, this is 2x149$. And it ships from Canada and doesn't clear customs i.e. +24% VAT in my case. Pretty expensive.
What does that "actually buffers for a power amp use case" mean?

 

[barrows]

I doubt (but am ready to be proved wrong when it gets measured) that the Neurochrome input boards are going to outperform the Purifi eval module. Take a look at the datasheets for the OPA 1612 vs the OPA LM4562 used on the Neurochrome buffer for starters, and the discrete regulators on the eval board might be an advantage as well (of course one could use to choose Hypex regs for the Neurochrome).
What the Neurochrome offers is more flexibility in layout/design, the ability to make a dual mono amp, or mono blocks. Additionally, I believe the Neurochrom boards are made in Canada, likely to a bit higher standard of quality than the Asian made eval board. Making boards in NA is quite a bit more expensive than making them in Asia, so one has to expect to pay for that difference.
Neurochrome's work is usually really nice, so I do suspect these boards will be worth the asking price.

 

[mocenigo]

I doubt (but am ready to be proved wrong when it gets measured) that the Neurochrome input boards are going to outperform the Purifi eval module. Take a look at the datasheets for the OPA 1612 vs the OPA LM4562 used on the Neurochrome buffer for starters, and the discrete regulators on the eval board might be an advantage as well (of course one could use to choose Hypex regs for the Neurochrome).
What the Neurochrome offers is more flexibility in layout/design, the ability to make a dual mono amp, or mono blocks. Additionally, I believe the Neurochrom boards are made in Canada, likely to a bit higher standard of quality than the Asian made eval board. Making boards in NA is quite a bit more expensive than making them in Asia, so one has to expect to pay for that difference.
Neurochrome's work is usually really nice, so I do suspect these boards will be worth the asking price.

They are meant for people doing monoblocks or "pure dual mono" amps, and DIY audience willing to use their features and the corresponding flexibility. Because of the "monoblock" and "DIY" audiences they are not pure breakout boards, i.e. they have a simple buffer on board that can be bypassed. Handling two different SKUs is very expensive for a small business. I think Tom's product will be useful, and of course it does not cater to those that want a simple stereo setup with no tweaking.