DIY Purifi Amp builds

[zappa]

As for the case itself the Modu shup GX288 already solves the problem. But the great thing about Ghent is that they have the option to include all pre-assembled cable kits and connectors, so everything is really plug n' play. IMO this is a huge plus.

Hi,
Do you have more detailed information about the GX288 Box for EVAL1 (especially the pre-drilled back plate) ?
Thanks in advance

 

[Matias]

Hi,
Do you have more detailed information about the GX288 Box for EVAL1 (especially the pre-drilled back plate) ?
Thanks in advance

Nope, better to ask the manufacturer themselves, Modu shop.

 

[PNWer]

Update on Ghent case(s) for the EVAL1: They have had first articles for inspection - I've seen a photo with my parts inside! They are now waiting for rev 2 to address fine-tuning of dimensions and finish, etc.. So, we are getting closer... Maybe after so much time, no one cares but me?

Can you post the pictures of Ghent case ?
(Even better if you have Eval1 wiring layout photos)
How much will they be asking for it ?

 

[JimB]

Can you post the pictures of Ghent case ?
(Even better if you have Eval1 wiring layout photos)
How much will they be asking for it ?

TOO EARLY! They only had the first aluminum extrusion run for testing and back panel for parts integration fitting - no anodizing or silk screening. We'll have to wait a few more weeks for more. It will be very similar to what they offer for the Hypex NCore amps. A big factor in the timing is a decision to make a new case size - 250 mm wide for better power handling with 2 channels, but not as wide as their 300mm cases. I do expect them to offer wiring with their cases for DIY, since they have done that in the past.

 

[phoenixdogfan]

Having a small difficulty here. I finally got the back panel in, bolted everything together, connected the wiring harnesses, and connected the mains and the speakers. The back switch on the Ghent IEC socket illuminates, but not the front on/off indicator. When I power it on from the IEC I hear a small click which I have isolated as coming from the SMPS. Any ideas what this could be? i did remove the standby switch, my understanding is that just physically removing it was all I needed to do--nothing to wire under the chassis to bypass it in other words. So I don't think I had to do anything other than provide the nAMPON and the nFATAL wired connectection between the J4 on the Hypex and the J3 on the Purifi which I have done. I am questioning if the connections are good on the 3m connector, though they did pass continuity testing.

Since the fit is so tight between the Eval 1 and the back panel, I am also wondering if there could be some kind of short being introduced there, and how I would determine that.

Any troubleshooting ideas would be appreciated.

Also, since I have put line voltage through the unit (I've now disconnected it) how long before it's safe to do anything near the SMPS after all power has been disconnected? Some units, as understand it, retain current in their capacitors for a time, and I want to be completely safe in this regard.

 

[phoenixdogfan]

TOO EARLY! They only had the first aluminum extrusion run for testing and back panel for parts integration fitting - no anodizing or silk screening. We'll have to wait a few more weeks for more. It will be very similar to what they offer for the Hypex NCore amps. A big factor in the timing is a decision to make a new case size - 250 mm wide for better power handling with 2 channels, but not as wide as their 300mm cases. I do expect them to offer wiring with their cases for DIY, since they have done that in the past.

I presume the 250 mm wide case provides better cooling and therefore better power handling by forestalling thermal throttling.

 

[JimB]

Having a small difficulty here. I finally got the back panel in, bolted everything together, connected the wiring harnesses, and connected the mains and the speakers. The back switch on the Ghent IEC socket illuminates, but not the front on/off indicator. When I power it on from the IEC I hear a small click which I have isolated as coming from the SMPS. Any ideas what this could be? i did remove the standby switch, my understanding is that just physically removing it was all I needed to do--nothing to wire under the chassis to bypass it in other words. So I don't think I had to do anything other than provide the nAMPON and the nFATAL wired connectection between the J4 on the Hypex and the J3 on the Purifi which I have done. I am questioning if the connections are good on the 3m connector, though they did pass continuity testing.

Since the fit is so tight between the Eval 1 and the back panel, I am also wondering if there could be some kind of short being introduced there, and how I would determine that.
.

What have you done? I mean, what are the details? Pictures of your back panel (from the inside)? LEDs light on the EVAL1? I have not put anything in a case yet, but I have run all my sets, for operational testing, successfully, just as you see here. The standby switch was still on the system in this photo, but it made no difference when using a board with it already removed. My cable set includes the basic 5 wire interface from J4 to J3, which I have described at length earlier in this topic.

 

[JimB]

I presume the 250 mm wide case provides better cooling and therefore better power handling by forestalling thermal throttling.

The concern was with 200 mm wide cases. They had received guidance from others that this was thermally marginal for stereo systems. I think 200 mm is adequate for light to normal usage, but perhaps performance limiting or lifetime reducing, when used at highest powers. Hence the step up in width. I'm at least as concerned with case venting details as width, as I'll explain more in a future post. You should be in great shape with their 300 mm case. You retained the existing bottom venting, right? Just added holes for the EVAL1 set?

 

[phoenixdogfan]

The concern was with 200 mm wide cases. They had received guidance from others that this was thermally marginal for stereo systems. I think 200 mm is adequate for light to normal usage, but perhaps performance limiting or lifetime reducing, when used at highest powers. Hence the step up in width. I'm at least as concerned with case venting details as width, as I'll explain more in a future post. You should be in great shape with their 300 mm case. You retained the existing bottom venting, right? Just added holes for the EVAL1 set?

Yep. Just a new back end with holes for the Eval 1 inputs and outputs.

 

[phoenixdogfan]

What have you done? I mean, what are the details? Pictures of your back panel (from the inside)? LEDs light on the EVAL1? I have not put anything in a case yet, but I have run all my sets, for operational testing, successfully, just as you see here. The standby switch was still on the system in this photo, but it made no difference when using a board with it already removed. My cable set includes the basic 5 wire interface from J4 to J3, which I have described at length earlier in this topic.
View attachment 76228

Neither the LEDs on the Eval 1 board, not the LED for the front panel of the Ghent (which is connected to J5) are lighting up when the IEC is turned on. Will add pictures and go into more detail tomorrow. Again, what I hear is a mechanical click emanating from the SMPS which tells me the power is at least making it there. I'm wondering if that click isn't some kind of fault shut off mechanism. Does the SMPS normally have a click when it turns on? Not through the speakers, but from within the SMPS itself?

 

[TimoJ]

Does the SMPS normally have a click when it turns on? Not through the speakers, but from within the SMPS itself?

SMPS relay click is normal. Shortly after that click, Amp Enable turns on and the EVAL1 should operate. Are your Vaux voltage jumpers and connections set correctly?

 

[phoenixdogfan]

How about a DIY DAC/Streamer that supports Dirac? I'd buy that.

It's called the miniDSP SHD and has exis

SMPS relay click is normal. Shortly after that click, Amp Enable turns on and the EVAL1 should operate. Are your Vaux voltage jumpers and connections set correctly?

The jumpers are set to position 2-3. I will recheck the vaux connections which are on the six wire housing? Should not the led for the chassis which runs from J5 on the SMPS work even if the Vaux connections running to the purifi are not correct? In other words, I think whatever is wrong would need to be something that explains the failure of both the LEDS on the Purifi AND the ones running from J5 to the light on the chassis front.

 

[boXem]

It's called the miniDSP SHD and has exis

The jumpers are set to position 2-3. I will recheck the vaux connections which are on the six wire housing? Should not the led for the chassis which runs from J5 on the SMPS work even if the Vaux connections running to the purifi are not correct? In other words, I think whatever is wrong would need to be something that explains the failure of both the LEDS on the Purifi AND the ones running from J5 to the light on the chassis front.

Picture please

 

[JimB]

It's called the miniDSP SHD and has exis

The jumpers are set to position 2-3. I will recheck the vaux connections which are on the six wire housing? Should not the led for the chassis which runs from J5 on the SMPS work even if the Vaux connections running to the purifi are not correct? In other words, I think whatever is wrong would need to be something that explains the failure of both the LEDS on the Purifi AND the ones running from J5 to the light on the chassis front.

You are in the US, with 115VAC? If so, did you provide the mains voltage jumper on SMPS J3?

 

[phoenixdogfan]

You are in the US, with 115VAC? If so, did you provide the mains voltage jumper on SMPS J3?

Yes I am, and yes I did. I'm wondering if the SPMS could be bad. Any way you know to test for that. If I disconnected both wiring harnasses to the EVAL 1, would the SPMS still light up the Ghent LED powered out of J5? If I does not, does that indicate the SMPS is itself defective? And is it possible the SMPS has entered some kind of "standby mode" through some accident or improper setting from the factory? If so, is there a way to wake it up?

 

[starfly]

It's called the miniDSP SHD and has exis

The jumpers are set to position 2-3. I will recheck the vaux connections which are on the six wire housing? Should not the led for the chassis which runs from J5 on the SMPS work even if the Vaux connections running to the purifi are not correct? In other words, I think whatever is wrong would need to be something that explains the failure of both the LEDS on the Purifi AND the ones running from J5 to the light on the chassis front.

Vaux is not on the six wire housing (J1). It's either on the J4 10-pin connector (usually with a ribbon cable) or on the J5 7-pin connector.

J5 only outputs unregulated Vaux, and J4 can do both regulated or unregulated depending on how you configure J6&J7.

 

[phoenixdogfan]

Vaux is not on the six wire housing (J1). It's either on the J4 10-pin connector (usually with a ribbon cable) or on the J5 7-pin connector.

J5 only outputs unregulated Vaux, and J4 can do both regulated or unregulated depending on how you configure J6&J7.

So that the jumper would be on pins 2-3.

I am beginning to think the SMPS is a DOA. It neither light up the LED for the front faceplate from Ghent which I connected to J5 with the Ghent supplied connector, nor the leds on the Purifi. Would it fail to illuminate both sets of those LEDs even if I had misconnected the Vaux jumpers? Even when I entirely disconnect the Purifi harnasses, I get no power to the Ghent LED even though I can hear the SMPS clicking when I turn on the IEC power. Likewise, when I disconnect Ghent's harnass at J5, and leave the J4 and J1 harnesses connected to the Eval 1, the LEDs on the Purifi board do not light.

It seems to me the SMPS should be able to power up something if it was functional even if the jumpers were incorrectly set. And yes, I do have the power jumper to convert to US 115v in place.

I've also checked for continuity on the harnass to J1, and it's perfect. I've checked for continuity from the IEC plug and it's perfect for ground to the chassis screw, hot lead which is from the IEC plug prong to the red ternmination of the Ghent wiring harnass, likewise for neutral. And there is only one was to plug in the harnass, so I can't have neutral and hot reversed. Looking toward the front of the chassis (and toward the head shield) the hot lead is on the right side,and the neutral is on the left. And pins 2-3 on J6-J7 are the two leftmost pins.

 

[starfly]

My final build. Added guardian-86 speaker protection boards to this build from Neurochrome. Shouldn't really introduce much, if any, additional distortion based on the measurements done by Neurochrome @tomchr. I added these boards as I still heard pops on startup.

Otherwise this project was great fun, and I look forward to doing another project like this. Maybe a DAC or something.

 

[starfly]

So that the jumper would be on pins 2-3.

I am beginning to think the SMPS is a DOA. It neither light up the LED for the front faceplate from Ghent which I connected to J5 with the Ghent supplied connector, nor the leds on the Purifi. Would it fail to illuminate both sets of those LEDs even if I had misconnected the Vaux jumpers? Even when I entirely disconnect the Purifi harnasses, I get no power to the Ghent LED even though I can hear the SMPS clicking when I turn on the IEC power. Likewise, when I disconnect Ghent's harnass at J5, and leave the J4 and J1 harnesses connected to the Eval 1, the LEDs on the Purifi board do not light.

It seems to me the SMPS should be able to power up something if it was functional even if the jumpers were incorrectly set. And yes, I do have the power jumper to convert to US 115v in place.

I've also checked for continuity on the harnass to J1, and it's perfect. I've checked for continuity from the IEC plug and it's perfect for ground to the chassis screw, hot lead which is from the IEC plug prong to the red ternmination of the Ghent wiring harnass, likewise for neutral. And there is only one was to plug in the harnass, so I can't have neutral and hot reversed. Looking toward the front of the chassis (and toward the head shield) the hot lead is on the right side,and the neutral is on the left. And pins 2-3 on J6-J7 are the two leftmost pins.

Is the power supply outputting the right voltages from the various pins?

 

[boXem]

So that the jumper would be on pins 2-3.

I am beginning to think the SMPS is a DOA. It neither light up the LED for the front faceplate from Ghent which I connected to J5 with the Ghent supplied connector, nor the leds on the Purifi. Would it fail to illuminate both sets of those LEDs even if I had misconnected the Vaux jumpers? Even when I entirely disconnect the Purifi harnasses, I get no power to the Ghent LED even though I can hear the SMPS clicking when I turn on the IEC power. Likewise, when I disconnect Ghent's harnass at J5, and leave the J4 and J1 harnesses connected to the Eval 1, the LEDs on the Purifi board do not light.

It seems to me the SMPS should be able to power up something if it was functional even if the jumpers were incorrectly set. And yes, I do have the power jumper to convert to US 115v in place.

I've also checked for continuity on the harnass to J1, and it's perfect. I've checked for continuity from the IEC plug and it's perfect for ground to the chassis screw, hot lead which is from the IEC plug prong to the red ternmination of the Ghent wiring harnass, likewise for neutral. And there is only one was to plug in the harnass, so I can't have neutral and hot reversed. Looking toward the front of the chassis (and toward the head shield) the hot lead is on the right side,and the neutral is on the left. And pins 2-3 on J6-J7 are the two leftmost pins.

Is the ghent led switch at position 1 or 2?
Is eval1 enabled?
How are you bringing vaux to eval1?