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DIY Purifi Amp builds

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JimB

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Thread Starter #2,041
Is 'Delron' just a typo that's stuck? Deltron is a reasonably well known manufacturer of similar terminals:
https://www.dem-uk.com/deltron-comp...ctors/4mm_90deg_pcb_mounted_insulated_socket/
YES! It (DELTRON) was molded in the tops of early sockets we saw pictured, but not once they went into production (none of my 16 sockets are marked at all). I suspect they are not the brand used anymore. My references should be "DELTRON-style". I'll fix some of those as I see them...
 
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Measuring thermal paste improvement requires two, precisely comparable builds, assemble the two different ways. I'll likely do a simple temp check with a low test load at some time...
My unit is pretty much identical to yours, just without paste or additional heat sinks. If you describe your test method (including probe locations) I can try to do the same and measure. There will still be a lot of variables (different test equipment, different ambient temp, etc), but I'm happy to give it a try.
 
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JimB

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Thread Starter #2,043
My unit is pretty much identical to yours, just without paste or additional heat sinks. If you describe your test method (including probe locations) I can try to do the same and measure. There will still be a lot of variables (different test equipment, different ambient temp, etc), but I'm happy to give it a try.
I'll keep that in mind. The most useful tests will be with top cover in place.
 

phoenixdogfan

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AMPEN doesn't look right. It looks like the PS is going into standby mode. Need you to measure all these relative to GND and report back :

SMPS Stand-by
Amp Standby
DC-Error
Amp Enable

See page 7 of the Hypex PS datasheet for signal details.

https://www.audiosciencereview.com/forum/index.php?attachments/smps1200axx0_09xx-pdf.49157/
Ok. I've looked at this and retested a couple of ten times.

What I am finding to make a long story short is I'm getting 60vDC off the high voltage pins and 12vDC off the VDR connections. Both of those seem within the correct range based off the Hypex PS datasheet p7. But they immediately fall off until reaching 0 Vdc.

The Vaux pins of both J4 and J5 are consistently measuring at 14v Dc, which does not seem correct b/c the data sheet indicates they should be 22v DC. Again the exact same issue: They exhibit this voltage for a split second when the amp is turned on and then fall rapidly to 0v DC.

Amp Standby on J5 shows 0v DC from the moment power turns on
SMPS Standby on J5also show 0v DC.

Amp enable on J4 also shows zero.

Finally, and this is the joker in the deck, DC Error on J4 flashes 14v DC when switched on before dropping to zero.

Based on the Hypex Data sheet I would not expect to read any voltage from Amp Standby, or Smps Standby because those are both input pins, so that seems normal.

However, Amp enable is an output pin and it appears to be outputting zero voltage when it should be outputting a 50v.

Finally, the DC error pin is an input pin. I am clueless why it outputs a 14v DC surge when the amp is powered up.

It does appear the behavior is consistent with the SMPS going into standby even though it isn't connected to anything. I'm inclined to pitch the thing into file 13 and order a new one.

Anyone have any ideas?
 
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JimB

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Ok. I've looked at this and retested a couple of ten times.

What I am finding to make a long story short is I'm getting 60vDC off the high voltage pins and 12vDC off the VDR connections. Both of those seem within the correct range based off the Hypex PS datasheet p7. But they immediately fall off until reaching 0 Vdc.

The Vaux pins of both J4 and J5 are consistently measuring at 14v Dc, which does not seem correct b/c the data sheet indicates they should be 22v DC. Again the exact same issue: They exhibit this voltage for a split second when the amp is turned on and then fall rapidly to 0v DC.

Amp Standby on J5 shows 0v DC from the moment power turns on
SMPS Standby on J5also show 0v DC.

Amp enable on J4 also shows zero.

Finally, and this is the joker in the deck, DC Error on J4 flashes 14v DC when switched on before dropping to zero.

Based on the Hypex Data sheet I would not expect to read any voltage from Amp Standby, or Smps Standby because those are both input pins, so that seems normal.

However, Amp enable is an output pin and it appears to be outputting zero voltage when it should be outputting a 50v.

Finally, the DC error pin is an input pin. I am clueless why it outputs a 14v DC surge when the amp is powered up.

It does appear the behavior is consistent with the SMPS going into standby even though it isn't connected to anything. I'm inclined to pitch the thing into file 13 and order a new one.

Anyone have any ideas?
Sure. If you connect nothing, set the three jumpers as required (120VAC and UNregulated Vaux), apply power and cannot get the expects VOLTS out, and have it stay ON (with no load), then Hypex needs to say how they tested it, different from you, and determine that it was fine. For instance, did they use 220VAC? If they have no explanation, and it works fine for them, but clearly not for you, they should replace it.
 
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Sure. If you connect nothing, set the three jumpers as required (120VAC and UNregulated Vaux), apply power and cannot get the expects VOLTS out, and have it stay ON (with no load), then Hypex needs to say how they tested it, different from you, and determine that it was fine. For instance, did they use 220VAC? If they have no explanation, and it works fine for them, but clearly not for you, they should replace it.
Good point. They probably didn't test it at 120VAC. I agree Hypex should replace it.
 

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I still suspect if the 110V/240V has anything to do with the main problem.

It looks like the SMPS is shutting down for some other reason.

Remove the 110V link power it up and see if the SMPS will start or not.

Wait 15 seconds, then measure if you get any voltage at the output
 
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JimB

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I rigged a temperature test of my "vane" build today, with both channels outputting 98W into 8 ohm resistors for 90 minutes (~50% maximum - MUCH more than can be used for ANY unclipped music). The temperature rises over ambient were ~:
SMPS, 14.7C
Amp, 13.6C
Case, 10.7C
The dissipation here corresponds to about 25% of maximum power into 4 ohms (about the limit for almost any music, unclipped), and about 12% of maximum power into 2 ohms (1/8th - about the limit for 'normal' music, unclipped - the level Purifi references).

I am PLENTY happy with these figures! I'll have NO thermal concerns for these amps under any conditions I can run. The case is doing it's job, WELL! :cool:

Over to you, @beren777 to compare the same parts, but without my added pin-heatsinks (fiddly, not recommended for most people) and without my thermal compound (easy!).

Some details. The amp was placed on a hard surface with unobstructed air space all around. The test signal was 100Hz sine wave. The temperatures were taken with small thermocouples with thermal compound to enhance contact. The SMPS point was taped to the top of its heatsink. The Amp point was pressed against the top of its heatsink plate at a point near one of the output transistors (under the 'blob'). The Case point was on top of the case, in the center. The case was closed the entire time.
The amp: https://www.audiosciencereview.com/...-purifi-amp-builds.10478/page-102#post-643138

The measured points, and overall set-up:
IMG_6687 crop 10p.jpg
IMG_6675 crop 20p.jpg
IMG_6676 crop 10p.jpg
 
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Doodski

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The test signal was 100Hz sine wave.
Nice test for thermals.
2 things that are usually done while testing this way is to monitor the total current draw with a multimeter and look for the current draw increasing as the output remains at the same level and as the amp heats up. The current draw should go up a little, then settle and stay the same and if it starts increasing rapidly then there is a thermal runaway situation and you will know to shut the test down before the amp lets loose some smoke. Why did you use 100 Hz? Usually 1kHz is used. :D
 
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JimB

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Nice test for thermals.
2 things that are usually done while testing this way is to monitor the total current draw with a multimeter and look for the current draw increasing as the output remains at the same level and as the amp heats up. The current draw should go up a little, then settle and stay the same and if it starts increasing rapidly then there is a thermal runaway situation and you will know to shut the test down before the amp lets loose some smoke. Why did you use 100 Hz? Usually 1kHz is used. :D
Hi. Thanks for the comments. I really wasn't worried about thermal run-away. I would have even run at 100% if my load resistors could take it.

Why 100 Hz? I thought Amir had issues with high power at lower frequencies, and I think the power supply is a bit more challenged there. The two choices I had handy were 40 and 100 Hz. I compromised. Anyway, I just wanted to conclude something quantitative about the thermal performance of the case, which I expected to be 'plenty good'.
 

Doodski

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Hi. Thanks for the comments. I really wasn't worried about thermal run-away. I would have even run at 100% if my load resistors could have take it. Why 100 Hz? I thought Amir had issues with higher powers at lower frequencies, and I think the power supply is a bit more challenged there. The two choices I had handy were 40 and 100. I compromised. Anyway, I just wanted to conclude something quantitative about the thermal performance of the case, which I expected to be 'plenty good'.
It definitely tested well for thermal performance. :D
 
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JimB

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Thread Starter #2,055
Previous measurements done here by @elberoth , seems as the hottest parts on the Purifi amp are the vertical PCB and the chip next to it.
https://www.audiosciencereview.com/...-of-purifi-1et400a-amplifier.7984/post-237859

PS This measurement guided me on where to install the heatpipes in my build
Right! Though the hottest parts are not the most heat sensitive (transformers). Others (the vertical PCB) are likely not output power dependent. In any case, since those parts are not heatsinked, we want good, cool air flow for them. You'll see that the Ghent case has bottom slots immediately adjacent to those areas, and under the input board (which has regulators on it).
1611514327166.png
1611515019007.png

It also has good venting top and bottom. These are good practices for this type of build.
1611514830997.png


There have been a variety of other 'cooling' approaches shown in this topic over the past year, some more aggressive, and some less.
 
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somebodyelse

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It also has good venting top and bottom. These are good practices for this type of build.
The middle set of slots to either side of the amp modules would have been better turned through 90 degrees so they'd be acting like heatsink fins rather than a heat flow barrier.
 
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JimB

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The middle set of slots to either side of the amp modules would have been better turned through 90 degrees so they'd be acting like heatsink fins rather than a heat flow barrier.
Yes, I like your thinking! That could have been very slightly better for heat transfer from the case bottom to air at that location, but air flow to the parts above was the primary goal right there. I doubt I would find more than a degree difference in case temp on the 'isolated' rib in the middle. The output transistors are beyond those slots and the primary path for heat from the output transistors through the case is already much better than through the heat-spreader. Bottom line, no significant loss of ability to transfer heat away from the output transistors, but better air flow at the desired point. Personally, I would not change them.
 
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@JimB What fused inlet filters did you use tor your builds please, and was it a simple task to remove the two unneeded caps within the filter? Thanks.
Hi, @JohnM-73. I didn't choose them. They were provided, unexpectedly, as an upgrade bonus on my special cases from Ghent. They proved to be both good and bad as a substitution of a plain input switch. I addressed it here:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-98#post-617372

Exactly what to do to disconnect the internal caps grounding in a specific device can vary. While I did it for the ones I was given, I won't detail this because I don't really want to encourage it.
 

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Apologies if this has been asked but there are 103 pages ;

Im interested in setting one of these stereo amps up - is there a running gear list (BOM) you guys have figured out of everything required to get a stereo amp up and running?
 
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