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DIY Purifi Amp builds

TimoJ

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So what to do with anodized brushed aluminium? It's not easy to sand it down to flat surface. But I think anodization is a thermal conductivity barrier, so it should be removed.
 

maxxevv

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In PC modding, there was a time when people did "lapping" of the CPU and CPU cooler's contact faces.
Basically grinding/polishing the surfaces until they were as smooth and flat as possible. It does improved heat transfer efficiency. But that's a pretty extreme application compared to what you get with amp modules here. You are talking about maybe 20~100 times the heat transfer density in terms of Watts per given area.

I don't think its necessary in this amp module application.

But do clean the surfaces of any dirt thoroughly before mating the surfaces. Contact cleaner sprays and a simple air blower would probably be suffice for the preparation work.
 

mocenigo

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So what does a buffer board do exactly?

1. Works as a breakout board making the connections on the 36 pin board connector easily useable
2. It provide impedance adaptation, making it easier for sources to drive the Purifi 1ET400A module - you get more linear response, including better bass, for instance
3. It can be configured to provide additional gain- the Purifi module only has 12.8db of gain.
 

starfly

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1. Works as a breakout board making the connections on the 36 pin board connector easily useable
2. It provide impedance adaptation, making it easier for sources to drive the Purifi 1ET400A module - you get more linear response, including better bass, for instance
3. It can be configured to provide additional gain- the Purifi module only has 12.8db of gain.

Thanks for the explanation. So from my reading through this thread, if I were to get the Neurochrome buffer boards, I should then probably get two individual 1ET400A modules instead of the EVAL1 kit, right?

The EVAL1 kit has connectors for the power supply and also has XLR inputs and speaker terminals (I plan on adding my own terminals either way). Is it safe to assume the Neurochrome buffer board would have connections for XLR inputs (by soldering wires somewhere)? And would power go directly from the SMPS1200 to the two individual 1ET400A modules, vs the add-on board that comes with the EVAL1? And where would speaker terminals connect to?

I plan on studying the diagrams on the Purifi site more closely, but I'm currently on my phone which isn't an ideal medium for studying such things :)

Edit: I just saw on the Neurochrome site that the speaker outputs are on the buffer board, so that answers that question. And it also has a power supply connection. But since this would be using two separate modules + input buffers, requiring each to be powered individually, does the SMPS1200 have two power outputs, or would I need to use a splitter of some sort?
 
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mocenigo

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Thanks for the explanation. So from my reading through this thread, if I were to get the Neurochrome buffer boards, I should then probably get two individual 1ET400A modules instead of the EVAL1 kit, right?

Yes, you need two boards because the Neurochrome input boards are for mono constructions. Which is handy if you want the two channels physically separate, which in my opinion makes sense only if they are in different cases, or you want separate power supplies.
[...], does the SMPS1200 have two power outputs, or would I need to use a splitter of some sort?

No, the SMPS1200 has only one, but it is really trivial to make a "Y" cable, it is just a matter of splicing together two cables (I actually built mine).

Keep in mind that you have to provide regulators to bring the AUX to +-12V.

Also, you could use two SMPS600N400 supplies, I think. Note that the Gate Driver supply VDR there is 17.6 V, which is less than the 20V max but also more than the recommended 16V. I think this should not be a problem, but you can use a little buck converter (like the cheap ones that are used for arduino systems).
 
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No, the SMPS1200 has only one, but it is really trivial to make a "Y" cable, it is just a matter of splicing together two cables (I actually built mine).

Keep in mind that you have to provide regulators to bring the AUX to +-12V.

Also, you could use two SMPS600N400 supplies, I think. Note that the Gate Driver supply VDR there is 17.6 V, which is less than the 20V max but also more than the recommended 16V. I think this should not be a problem, but you can use a little buck converter (like the cheap ones that are used for arduino systems).

Still in planning phase, wont get the Hypex SMPS until sometime in June. Can’t I use Hypex also for the AUX?

From Purifi:
Use the AUX supply provided by the SMPS1200, or add your own regulator.
 

starfly

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No, the SMPS1200 has only one, but it is really trivial to make a "Y" cable, it is just a matter of splicing together two cables (I actually built mine).

Keep in mind that you have to provide regulators to bring the AUX to +-12V.

Also, you could use two SMPS600N400 supplies, I think. Note that the Gate Driver supply VDR there is 17.6 V, which is less than the 20V max but also more than the recommended 16V. I think this should not be a problem, but you can use a little buck converter (like the cheap ones that are used for arduino systems).

Thanks. I'm also debating building a 3ch amp for home theater duties in addition to stereo music listening. But that might add to the complexity.

I suppose a potential issue will be channel matching, right? Ensuring all channels have the exact same output level in a dual or triple mono setup.

I also wonder what the best setup would be for supplying power in a triple mono. I'm thinking a smps1200 + smps600, as I want the ability to completely disable the third channel with a switch as I won't be using it for the time being (it's with a future expansion of my system in mind). Would be a waste of energy for it to draw power all the time.
 

mocenigo

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Thanks. I'm also debating building a 3ch amp for home theater duties in addition to stereo music listening. But that might add to the complexity.

I suppose a potential issue will be channel matching, right? Ensuring all channels have the exact same output level in a dual or triple mono setup.

I also wonder what the best setup would be for supplying power in a triple mono. I'm thinking a smps1200 + smps600, as I want the ability to completely disable the third channel with a switch as I won't be using it for the time being (it's with a future expansion of my system in mind). Would be a waste of energy for it to draw power all the time.

Hypex has also more powerful power supplies, just check their catalogue. If the AUX or the Gate drive are too high just bring them down with little buck converters followed by a little cap, or regulators.
 
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JimB

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So what to do with anodized brushed aluminium? It's not easy to sand it down to flat surface. But I think anodization is a thermal conductivity barrier, so it should be removed.
It should be no problem. It's aluminum oxide and has good thermal conductivity, and is quite thin. It just shouldn't be too rough. I would not try to remove it. If it is very rough (heavy grained - unlikely inside a case), then you could use a bit of 'fine' wet-dry paper (maybe 600 grit) to polish it out just a little. Use it wet, with water.
 

3ll3d00d

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Hypex has also more powerful power supplies, just check their catalogue. If the AUX or the Gate drive are too high just bring them down with little buck converters followed by a little cap, or regulators.
worth noting that the smps3k needs you to wire half the connected modules out of phase (for signal input and loudspeaker output) if using below 100Hz, I guess this will be a problem if supplying an odd number of channels.
 

mocenigo

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worth noting that the smps3k needs you to wire half the connected modules out of phase (for signal input and loudspeaker output) if using below 100Hz, I guess this will be a problem if supplying an odd number of channels.

Oh, because of supply pumping? So they are using power diodes and not mosfets there as rectifiers. Did not know that, I assumed that all Hypex SMPSs had mosfets...
 

iBaloo42

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Given that the EVAL1 board has superbly high performance and that the VTV site is mostly dedicated to selling snake oil, I'm not seeing any reason to not use the former or to even consider the latter.
@SIY I'm considering to buy a VTV Purifi unit. Why are you qualifying VTV as a snake oil salesman? It seems to be very harsh... Are there any bad stories or other reasons that you can share, please?
 
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SIY

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@SIY I'm considering to buy a VTV Purifi unit. Why are you qualifying VTV as a snake oil salesman? It seems to be very harsh... Are there any bad stories or other reasons that you can share, please?

They're not at the level of someone like Ted Denney, but nonetheless, their site makes a lot of questionable sonic claims. This, for example. At least the pricing isn't stupidly high. But it's "solving" a "problem" which doesn't seem to exist.
 

phoenixdogfan

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This forum helped me out with doing my 1ET400A / SMPS1200A400 build so I thought I would share it. I really wanted to keep it as simple as possible to start with to get it up and running and I am really happy with the results. It was very easy for a first build. I used a 12v IEC trigger from Audiophonics for switching it on/off and it works flawlessly. I am really enjoying the sound detail and clarity this produces and the extra power is exactly what my Theophany M5 speakers needed. Super happy.
https://www.audiophonics.fr/en/power-supply-kits/audiophonics-trigger-12v-230v-slave-power-supply-device-p-10661.html?search_query=12v trigger&fast_search=fs
View attachment 50626View attachment 50627
Your build is exactly what I want to do except I want Nampon and Nfail wired up from J3 on the Eval 1 to J4 on the SMPS. When done that way it really becomes a simple, no frills job. I'll control off and on with a smart plug connected to my home wifi network and I'll get a preamp/dac which will output 10-12 v rms (Octo Research Pro 8), and call it a day.
 

starfly

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For this build I'll probably get one of those Hifi2000 cases, so that I can get the rear and front plates custom machined with cutouts. How are you guys mounting these modules to the base plate? Do you get a base plate custom machined with M3 screw holes in it?
 

TimoJ

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For this build I'll probably get one of those Hifi2000 cases, so that I can get the rear and front plates custom machined with cutouts. How are you guys mounting these modules to the base plate? Do you get a base plate custom machined with M3 screw holes in it?
I used their Galaxy Maggiorato GX288 case. Drilled 3.5mm holes to the bottom plate, used Purifi's drawings as a template and checked print scaling with the EVAL1. Same for the PSU. Also drilled backpanel and front panel holes, drill press with a step drill.

I posted pics here, I have added front panel switch after that: https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/post-385389
 

starfly

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I used their Galaxy Maggiorato GX288 case. Drilled 3.5mm holes to the bottom plate, used Purifi's drawings as a template and checked print scaling with the EVAL1. Same for the PSU. Also drilled backpanel and front panel holes, drill press with a step drill.

I posted pics here, I have added front panel switch after that: https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/post-385389

Right, I don't have such fancy tools, just a regular hand-held drill which will not be as precise. But those holes you drilled, were you using a type of drill bit that inserts a tread so you can just screw it in? Or do you have to use a nut that goes to the outside of the case?
 
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