DIY Purifi Amp builds

[JimB]

I think they'd have to make a case that requires the builder to remove the banana jacks from the PCB?

Not necessarily. We'll have to wait and see what they can offer. I have made a few suggestions and requests and pointed them to this topic on ASR. Remember that you can keep the on-board sockets WITHOUT having them protrude through a back panel, as described starting from here:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-25#post-344882
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-25#post-344897

 

[Labjr]

Not necessarily. We'll have to wait and see what they can offer. I have made a few suggestions and requests and pointed them to this topic on ASR.

Perhaps I should have said the simplest solution. Otherwise would involve adding extensions to jacks and plugs, which is what I'd prefer. I think PCB mounted jacks cause problems.

 

[TimoJ]

Nice! How did you do your wiring from the EVAL1 J3 to J4 of the SMPS?

EVAL1 side is the stock connector, all 5 wires came with the board. SMPS side red connector is from an old PC motherboard firewire bracket cable (also USB bracket connectors have similar but without the position key). I cut the original black wire connectors from that side and crimped new ones. Luckily the needed connectors were identical to RC servo wire connectors and I happened have those and suitable pliers.

 

[mocenigo]

The more I read the less confident I am to build this.
I thought it would be as easy as assembling a PC. It is not.

Especially when I want to build mine using two Neurochrome buffer boards and 1 SMPS1200A400, the default cable kit doesn't do that.

It is not that difficult, I can guarantee you. Mine was my first full amp build. And it is significantly more complex than the one you are envisioning.

 

[phoenixdogfan]

Your local workshops are ripping you off big time for both things.

I would suggest you do a search online (wherever you may be located) for similar services. If you can create the required CAD files for the laser cutting, I'm very sure you can get it done for both process at about 1/5 to 1/4 of what you were quoted above.

The shop will be creating the CAD files from the Drawing in section 6.1 of the Purifi Eval 1 document, and my case and Eval 1 unit. It's the engineering time to create the CAD file that I will be primarily paying for. If anyone has a CAD file for this, I could obviously save quite a few coins if you'd be willing to share. If anyone can, my thanks in advance.

 

[phoenixdogfan]

EVAL1 side is the stock connector, all 5 wires came with the board. SMPS side red connector is from an old PC motherboard firewire bracket cable (also USB bracket connectors have similar but without the position key). I cut the original black wire connectors from that side and crimped new ones. Luckily the needed connectors were identical to RC servo wire connectors and I happened have those and suitable pliers.

I plan to order a connector from 3M for this. Only thing I am the tiniest bit cloudy on is how to fit the wires to the connector(s). Is it bare wires? Crimped wires? I think this is the final thing I have to get straight to be completely good to go. Just need to know exactly (expain it like I'm 5yrs old), pls.

 

[JimB]

I plan to order a connector from 3M for this. Only thing I am the tiniest bit cloudy on is how to fit the wires to the connector(s). Is it bare wires? Crimped wires? I think this is the final thing I have to get straight to be completely good to go. Just need to know exactly (expain it like I'm 5yrs old), pls.

Example:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-24#post-329791

 

[phoenixdogfan]

Example:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-24#post-329791

So, as I understand this, you cut off the crimps at the Hypex end, strip off a small ammt of bare wire and use the blade end of a jeweler's screwdriver to drive the wire into the appropriate connector which has something to hold the bare wire in and extablish a good connection? Sound about right? No crimps or soldering needed?

 

[somebodyelse]

So, as I understand this, you cut off the crimps at the Hypex end, strip off a small ammt of bare wire and use the blade end of a jeweler's screwdriver to drive the wire into the appropriate connector which has something to hold the bare wire in and extablish a good connection? Sound about right? No crimps or soldering needed?

The style of connector in that link is known as an insulation displacement connector (IDC) so there's no need to strip the wire. As you drive the wire into place the contact cuts through the insulation and grips the wire underneath. No crimps or soldering needed.

 

[JimB]

So, as I understand this, you cut off the crimps at the Hypex end, strip off a small ammt of bare wire and use the blade end of a jeweler's screwdriver to drive the wire into the appropriate connector which has something to hold the bare wire in and extablish a good connection? Sound about right? No crimps or soldering needed?

As @somebodyelse said (got to love that user name in this reference!), this is an IDC connector, and you force the wire down into a contact slot by pressing down on the wire on both sides of the slot, not into the slot itself - don't push any tool into those slots. It's not too difficult, but it must be done right. Maybe read up on it before doing it. Here I indicate the 'contact slots' (red circles), tabs to fold down to retain the wires (green boxes), and where to press down on the wire to force the wire into the slots (blue squares).

 

[phoenixdogfan]

As @somebodyelse said (got to love that user name in this reference!), this is an IDC connector, and you force the wire down into a contact slot by pressing down on the wire on both sides of the slot, not into the slot itself - don't push any tool into those slots. It's not too difficult, but it must be done right. Maybe read up on it before doing it. Here I indicate the 'contact slots' (red circles), tabs to fold down to retain the wires (green boxes), and where to press down on the wire to force the wire into the slots (blue squares).
View attachment 61061

That silver thing in the second and fourth slots from the top are crimps and need to be removed from the slots where the wires will be inserted, correct? And the three black things occupying slots one, three, and five are the connector wires, and they do not need to be stripped b/c the "contact slots" penetrate the insulation and establish the connections, correct? So I just need to remove the crimps from the slots I'm using, use the jeweler's screwdriver to create space for the wires (after cutting off their crimps and leaving their insulation intact) and push the wires into the slots I'm holding open with my screwdriver?

Sorry to be so obtuse, but I'm a complete neophyte at this, and I need to get it right in my head before I can assemble correctly.

 

[JimB]

That silver thing in the second and fourth slots from the top are crimps and need to be removed from the slots where the wires will be inserted, correct?

No. Those are the metal contacts in positions that are unused for the cable. None of the preinstalled contacts are ever removed.

And the three black things occupying slots one, three, and five are the connector wires, and they do not need to be stripped b/c the "contact slots" penetrate the insulation and establish the connections, correct?

Correct. Those positions have the required wires pressed in place.

So I just need to remove the crimps from the slots I'm using, use the jeweler's screwdriver to create space for the wires (after cutting off their crimps and leaving their insulation intact) and push the wires into the slots I'm holding open with my screwdriver?

No. You press the wires into place in the body, as-is. The body supports the metal contacts, always. You do not try to open anything or you will not get a good contact. The edges of the slots I circled in red a like opposing knives that cut through the wire insulation and bite into the metal conductor in the wire when it is pressed down into the narrow space. That is how the electrical contact is made. In this device, there are two places for such contact (most multiconductor IDCs have only one such contact slot). Regarding use of a punch-down tool, I made due with my jewelers screw driver bit, using the back end of it to just fit in the center opening. You must force the wire down into the slots, fully, without touching the metal contacts. The exception is that you should fold down the little tabs in the green boxes (two pairs) to hold the wire from being pulled away, later.

Maybe learn more about the principle of these?
https://en.wikipedia.org/wiki/Insulation-displacement_connector

 

[boXem]

A small teaser for those who think that existing solutions are a bit complicated to integrate (chassis and wiring) and/or would like a mono solution.
More info later.

 

[JimM]

Phoenixdogfan you can also buy a SYSLY IDC 10 2x5 pins male header breakout board terminal block connector for $13.99 at Amazon to make connections from the IDC connector.
JimM

 

[phoenixdogfan]

No. Those are the metal contacts in positions that are unused for the cable. None of the preinstalled contacts are ever removed.


Correct. Those positions have the required wires pressed in place.


No. You press the wires into place in the body, as-is. The body supports the metal contacts, always. You do not try to open anything or you will not get a good contact. The edges of the slots I circled in red a like opposing knives that cut through the wire insulation and bite into the metal conductor in the wire when it is pressed down into the narrow space. That is how the electrical contact is made. In this device, there are two places for such contact (most multiconductor IDCs have only one such contact slot). Regarding use of a punch-down tool, I made due with my jewelers screw driver bit, using the back end of it to just fit in the center opening. You must force the wire down into the slots, fully, without touching the metal contacts. The exception is that you should fold down the little tabs in the green boxes (two pairs) to hold the wire from being pulled away, later.

Maybe learn more about the principle of these?
https://en.wikipedia.org/wiki/Insulation-displacement_connector

Ok I think I see four little tabs in each green box. I fold those tabs outward using the screwdriver or just fold them inward so the wire rests on top of them? And all I'll really be doing is cutting of the crimps Purifi has on the wires in its kit and inserting the unstripped wires into the appropriate slot using the flat end of the jeweler's screwdriver blade to nudge them into the slot while not touching the contact points circled in red so as to not damage them? And the silver colored metal bits in the slots unused in yoour photo and which run the length of each slot are not removed b/c the wires rest on top of them when pressed into the slot? So they are underneath the wires in slots 2, 6,, and 10 in the photo?

 

[ironhorse128]

Finally got the speaker connectors from China (they are actually really good quality, full metal). Removed the original banana terminals and the switch from the PCB. I also wired sense wires from the PCB to the speaker terminals.
Still waiting for power switch, not sure how to do all that. I maybe just switch AmpOn signal with the switch since I use an external relaybox to switch the main power.

Here are few pics of my amp's current status. (speaker terminal soldering joints are fully flowed with lots of solder and heat. For some reason picture reflections makes them look bad)

View attachment 60943View attachment 60944

@TimoJ : Very cool build. I have a beginners question though. Why did not go thou the hassle of connecting these speaker binding posts? Why did't you use the existing banana plugs of the eval1? It is because you are not using banana plugs or is the another reason? I am considering a eval1 based build myself and want to understand the pros and cons.

 

[TimoJ]

@TimoJ : Very cool build. I have a beginners question though. Why did not go thou the hassle of connecting these speaker binding posts? Why did't you use the existing banana plugs of the eval1? It is because you are not using banana plugs or is the another reason? I am considering a eval1 based build myself and want to understand the pros and cons.

I use quite heavy bi-wired speaker cables (with locked banana connectors) and those PCB mounted connectors didn't feel stable enough. Maybe if you could somehow add an extra support for them, but in stock form they are supported with just two solder joints.

 

[Billy Budapest]

Can't wait for Ghent to release his Purifi EVAL case, then it should be trivial.

When is this coming?

 

[kn0ppers]

A small teaser for those who think that existing solutions are a bit complicated to integrate (chassis and wiring) and/or would like a mono solution.
More info later.

Looks like LT3042 and LT3093 LDOs to form a low-noise bipolar PSU and some SOIC-8 OpAmp, might be LM4562, OPA1612, LME49724 or OPA1632?

 

[Dimitri]

I thought it would be as easy as assembling a PC. It is not.

There are people that have a hard time assembling a PC. But is no different than trying to use one PC power supply into another where you have to add a couple of connectors.
I might have to put one together just to see what all those gianormous issues are.