DIY Purifi Amp builds

[phoenixdogfan]

Not really. Their is no need for that adapter/splitter board with the Purifi EVAL1, and a couple of those cables are specifically for the Hypex NC400 amp module.

I know you would not use the board, but the cable with the molex connectors at each end looks like it could plug directly into the Eval 1. And yes I know you'd be paying for some stuff that had no use except for NC400s (specifically the cables that go from the board to the NC400s), but the other cables would they work, after all, the board is taking the unitary output of the SMPS and splitting it to the NC400s? I am thinking that the cables that go from the SMPS to the board could just as easily go from the SMPS to the Eval 1, amirite?

 

[phoenixdogfan]

No. The Purifi evaluation kit does not include a power supply or case.

But you really don't need a buffer board, right. It can be use with the buffer it has engaged, or not?

 

[phoenixdogfan]

Good start. I do know that the Purifi cable set includes the housings for the SMPS1200A400 ends of the cables - you just have to insert the free, crimped ends into the proper holes. They do NOT include two free wires for the (highly recommended!) nampON and nFATAL connections described by Dudi:
https://www.audiosciencereview.com/...iy-purifi-amp-builds.10478/page-7#post-293025

That Ghent case (which I have) does support the SMPS1200 and will get switched power to it, but it does not accommodate this build, directly. Are you prepared to do your own mounting holes, and cabling to the back panel connectors? And have the front panel say ncore? I do believe Ghent will offer at least one good case option for us (hopefully, at least two), but I have not seen anything specific from them yet. Does anyone else have newer information on this?

I already own that case, is it possible for him to just make a new back panel to accommodate the Purifi with its proper cut outs. The mounting holes for the boards should be a trivial problem.

 

[mocenigo]

But you really don't need a buffer board, right. It can be use with the buffer it has engaged, or not?

indeed it does not need a replacement buffer. My use of the Neurochrome Universal Buffer is a personal, optional, decision. Subjectively, I think it is even cleaner and has better dynamics and control with it. Whatever that means, of course.

 

[Dimitri]

All this building talk is making me hungry

 

[mocenigo]

I know you would not use the board, but the cable with the molex connectors at each end looks like it could plug directly into the Eval 1. And yes I know you'd be paying for some stuff that had no use except for NC400s (specifically the cables that go from the board to the NC400s), but the other cables would they work, after all, the board is taking the unitary output of the SMPS and splitting it to the NC400s? I am thinking that the cables that go from the SMPS to the board could just as easily go from the SMPS to the Eval 1, amirite?

yes but such a cable is already provided with the kit. One side is terminated with crimped sleeve terminals which you can cut away to use a different PSU, or just insert into a provided JST case to then plug the latter in the SMPS1200A400

 

[JimB]

yes but such a cable is already provided with the kit. One side is terminated with crimped sleeve terminals which you can cut away to use a different PSU, or just insert into a provided JST case to then plug the latter in the SMPS1200A400

I think the cables you are describing are only supplied by Purifi as an extra order item, now, AND they no longer include the housings for the power supply end (changed since we bought our first EVAL1 kits).
https://purifi-audio.com/vare/cable-kit/
The required housings, and a way to get them, have been described earlier in this topic.

 

[JimB]

I already own that case, is it possible for him to just make a new back panel to accommodate the Purifi with its proper cut outs. The mounting holes for the boards should be a trivial problem.

You can send him a dimensioned drawing and ask for a quote.

 

[JimB]

I know you would not use the board, but the cable with the molex connectors at each end looks like it could plug directly into the Eval 1. And yes I know you'd be paying for some stuff that had no use except for NC400s (specifically the cables that go from the board to the NC400s), but the other cables would they work, after all, the board is taking the unitary output of the SMPS and splitting it to the NC400s? I am thinking that the cables that go from the SMPS to the board could just as easily go from the SMPS to the Eval 1, amirite?

The only cable that you could use in that set is the 6-conductor power supply cable. Better to get the Purifi cable set and add the (two) missing connector housings. How to do that has been addressed in earlier posts in this topic.

I am hoping Ghent will offer the two essential cables set in a future case kit. If so, perhaps he can offer them, separately. This is purely speculation on my part.

 

[mocenigo]

I think the cables you are describing are only supplied by Purifi as an extra order item, now, AND they no longer include the housings for the power supply end (changed since we bought our first EVAL1 kits).
https://purifi-audio.com/vare/cable-kit/
The required housings, and a way to get them, have been described earlier in this topic.

my mistake: I had ordered TWO cable harnesses with my Purifi order because I knew I could do some mistake. A cable kit then is not included. However I got the extra housings.

 

[phoenixdogfan]

Yes, UNLESS, they can use the same volume setting (precisely, such as digitally stepped) for each track. This depends on what volume controls @JimM has, but I don't think this is reasonably achievable with his gear (I also have some of those items). I'll suggest finding a volume setting that will work for the entire session (the range of selections). Then measure the test tone level, at the speaker terminals. This is what will be used, there after to setup a session. Once a session starts, no changing the volume. Right?

And it must be matched to withing .1db, something which I know I don;t know how to do.

 

[JimB]

And it must be matched to withing .1db, something which I know I don;t know how to do.

Voltage matched to within about 1%.

 

[phoenixdogfan]

Is there a step by step posting on how to assemble a no frills (no 12 v trigger, On/off switch, variable gain stage, 3rd party bufffer or Op amp) version using the Eval 1 Kit, a Hypex SMPS 1200A400, to create an amp which replicates the one Amir tested. Something with a parts list, vendor sourcing for anythin not from Hyprx or Purifi, illustrated detailed instructions on how to wire the plug housing, and pictures on where to insert those plugs?

Something like that would be extremely helpful for those of us who have little electronics background and who just want to bolt, solder, and snap one of these together.

 

[phoenixdogfan]

So, I finally got around to making a decision/commitment, ordering parts, and trying one out. Here, I insert two of the previously mentioned jumpers into the Purifi J3 plug at slots p1 and p3. I wound the original three 'power' jumpers together, then wound the two added 'signal' wires together. This was for 'neatness' and facilitating identifying wires at the other end. Finally, those two were loosely wound together just to be 'tidy'.
View attachment 51175

Here is the overall cable, with the previously mentioned 3M plug for connecting to J4 of the Hypex SMPS1200A400.
View attachment 51176

As described before, overall connections are:
View attachment 50622

I used my ohmmeter to find the ends of the one wire I wanted to do at a time, and then cut off the free end connector of just that one wire. This helped avoid a wiring error. Of course, you could also label all wires. I used the full length of the jumper wires, cutting off just the crimp at the SMPS end, then pressed the end of the wire into its slot of the IDC plug. Here is a close up of the "back side" of the IDC plug, showing positions 2, 6 and 10 used:
View attachment 50493

And here is the "front side", showing positions 1 and 3 used:
View attachment 51177

It was a bit more 'fiddly' than I'd like to get the wires punched down, carefully, so as to ensure good contact and not damage the wire slots of the contacts. Of what I had, my best 'tool' was a jewelers screw driver set. The back end of the bits was about perfect to fit in the 'gate' of the connector and press the wire into it, cleanly. The blade of the properly sized bit was used to ensure the wire to the left and right sides of the center gate were pressed down completely, as well. I was also able to get the little tabs of the wire insulation holders folded down with the screwdriver blade (seen best on middle position, #6, above, which you can expand for more detail).
View attachment 51178

All connections ohmmed out "0.0", end to end, so hopefully it will be trouble free for the life of the amp. Later, I'll likely add a bit of heatshrink over just the area of the IDC crimp connections (not down where the plug engages the SMPS socket). As I have a total of three to do, I might also try doing one of these by stripping and soldering the ends - just have to take care not to let flux or solder get to the contact area. Clamping the connector with the contact area up, and the wires down, while soldering, helps.

EDIT
Now installed, with a zip-tie and heat-shrink sleeve:
View attachment 51179

That is absolutely perfect. I now believe I know how to connect the Eval 1 to the SMPS. It all lays out now. Thank you.

 

[phoenixdogfan]

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

Pretty much how I envision mine looking, but I'll use my Ghent Case with a remade backing with new cut outs to accommodate the EVAL 1 just as it is.

I will only be connecting the six wire J1 on the Eval 1 to its J1 counterpart on the SMPS, then I will connect J3 on the Eval 1 to the J4 on the SMPS but with the original 3 wires and two additional wires for nAMPON and nFATAL. Then its a matter of setting the jumpers for 115v on J3 of the SMPS, and the jumpers for unregulated voltage on J6 and J7, connecting the IEC on J2, and we're off to the races.

Now if Ghent will only sell me a new back plate for the Eval 1.

 

[Count Arthur]

Now if Ghent will only sell me a new back plate for the Eval 1.

Do you have any tools? Many of these cases are made from aluminium panels which are very easy to cut and drill.

 

[phoenixdogfan]

Do you have any tools? Many of these cases are made from aluminium panels which are very easy to cut and drill.

That's a little beyond my pay grade, and I have no tools. I live in Nashville, and if worse come to worse I have identified a shop who does custome laser cut metalwork. I'm sure I could enlist their help if and when the plague tide rolls back out.But obviously Ghent, who specializes in this very thing is plan A.

 

[JimB]

That's a little beyond my pay grade, and I have no tools. I live in Nashville, and if worse come to worse I have identified a shop who does custome laser cut metalwork. I'm sure I could enlist their help if and when the plague tide rolls back out.But obviously Ghent, who specializes in this very thing is plan A.

Remember, you can just install the EVAL1 board set back from the back panel a fraction of an inch, and wire up to the back panel and connectors you have.

 

[Labjr]

Remember, you can just install the EVAL1 board set back from the back panel a fraction of an inch, and wire up to the back panel and connectors you have.

I'd probably set it back far enough to plug in some XLR plugs with wires to solder to panel mount XLR jacks.

 

[JimB]

I'd probably set it back far enough to plug in some XLR plugs with wires to solder to panel mount XLR jacks.

Using just the pins, not the whole body or back shell, yes. This has been addressed a couple times, before. See the example from @mocenigo, IMG-0501, where he did this to connect to an intermediate buffer board. You can do the same, direct to the back panel connectors.
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-43#post-371141

You might make these using a good, short, male-to-male mic cable, cutting it in half, and disassembling the ends to yield two such harnesses.