HOLO Audio MAY DAC

[lpost]

Well, it's a bunch of resistors...the power supply barely gets warm though. It doesn't need much space at all, if that helps.

 

Enjoy it!

[Extreme_Boky]

The May enclosure seems to be completely sealed (air-tight even). That will probably place the oscillators (and maybe resistors' arrays) in the sweet spot; however, the heat dissipation is just a touch too much. Have been working with electronics a long time, used and built class A amps as well. The electrolytes inside that enclosure will not like that heat, especially if they are 85deg C types.

[lpost]

I would hope they are 105C but still, 85C should last a good many years as it's only 38C on the outer surface and I would expect exactly the same inside. After an hour or so of being powered on the temp doesn't change.

 

 

This pic shows 105C.

 

[Quadman]

22 minutes ago, dkdali said:

And good to know it’s normal though quite surprising for a dac!

Per stereophile:

 The May uses an op-amp input stage and a discrete, class-A transistor output stage.  The converter chassis runs class-A warm-to-the-touch.

 

So do not stack components on top of the dac chassis.  Mine runs about 98 degree Fahrenheit.

 

Although I didn't look at every cap the ones I spotted easily are 105 C

[Quadman]

Here's your heat source.  4 Transistors biased into class A.  Facing down near back of dac, but heat rises.

[Extreme_Boky]

Great photo. Thank you!

 

 

[Hiker]

I had a dac that ran hot , over 110 degrees if I remember , I purchased a tiny whisper fan to put behind  it . Worked great brought the temperature way down . The specs on the fan for self noise were vanishing low and it gave me piece of mind .

[barrows]

13 hours ago, Quadman said:

Here's your heat source.  4 Transistors biased into class A.  Facing down near back of dac, but heat rises.

If the DAC chassis gets too hot to keep ones' hand on, that is a bit disturbing.  I am a little disappointed that if those transistors are the cause, that they are not attached to better heat sinking.  Usually too hot to keep ones' hand on is the point where things internally are hot enough to compromise long term durability.  I would encourage May owners to pay attention to keeping the DAC as cool as possible, starting with not stacking it directly with the power supply, and putting it on some footers which allow for more airflow around all sides of the chassis. 

[sledwards]

14 hours ago, Quadman said:

Here's your heat source.  4 Transistors biased into class A.  Facing down near back of dac, but heat rises.

Quadman. Any chance that the bottom cover has some sort of thermal interface material located over the top of those 4 transistors, with the intent being to have a thermal conduction path to the bottom cover?

[dkdali]

Moving the Zenith below the May has helped and it is at least 5 degrees cooler then with the Zenith on top.

Another factor with the previous setup was that it was on top of my Powerplant which also has some heat radiation which was going up into the May. The Zenith is cooler so that is probably part of the improvement.

I will be looking in to getting a rack as my 5 stack + amp on the side (and etherregen on the back) is getting a bit silly...

20210422_155401225_iOS.heic

[Quadman]

1 hour ago, sledwards said:

Any chance that the bottom cover has some sort of thermal interface material located over the top of those 4 transistors, with the intent being to have a thermal conduction path to the bottom cover?

I didn't see any thermal interface on the bottom plate.  My dac, not PSU, sits on my now unused phono stage, with nothing on top of it but 3 brass weights with felt base for extra damping of top plate.  It runs just warm to the touch and my IR thermometer show 98 degrees F.  That is not hot.  We'll have to see after @dkdali removes the Innuos from the top of his dac if it still runs hot.  If it has good open air around it it should just be warm, if not then something is wrong inside the dac, and I would unplug and notify Tim

[Quadman]

2 minutes ago, dkdali said:

I will be looking in to getting a rack as my 5 stack + amp

You still have a lot of stuff on the dac.  Is it just warm to the touch now so you can leave your hand there?

[dkdali]

1 minute ago, Quadman said:

You still have a lot of stuff on the dac.  Is it just warm to the touch now so you can leave your hand there?

I can. Now it feels like a power amp - hot but not burning (if that makes sense)

But as I wrote then I will be looking in to getting a rack - potentially I could have the power supply and dac on separate shelves. That´s 6 shelves + 1 for when I get my dream Blue Hawaii SE amp for the STAX with separate power supply -> 7 shelves.....

They said: "Get a headphone setup - you wont need as many boxes".... ;-)

[barrows]

A good rack is certainly a good idea, with enough shelf spacing to allow for airflow around each component.  Additionally, a good rack which addresses vibrations can improve performance.  Stacking components atop each other is about the worst way to go, as they can also share noise from the power supplies in some cases: the magnetic field from transformers is often strong enough to couple into another chassis.  John Atkinson noted this happening in his testing (measurements) of the MSB Analog DAC and power supply when stacked. 

[Hiker]

I built this for my headphone system , castors on the rear legs and felt pads under the front to easily move it beside my lazy Boy recliner.

The top shelf is waiting for the arrival of the KTE May dac ,.The wrack is maple stained with black cherry and finished in a clear coat .

[GoldenOne]

So my may when standalone typically measures 38-39C, sometimes a degree or so higher/lower if room temp is hot or cold.

I got the serene recently and tried various combinations of having the may with it's PSU sandwiched between it and serene, may ontop of serene etc etc, but in all cases it was getting up to about 45C. 
Not really "concerning" or anything. But for peace of mind I've moved it and am keeping may standalone again. I think the answer here is:

- Don't put stuff ontop of may
- Don't put may ontop of hot stuff

Unfortunately May does just need a little breathing room, but hey, when we're this deep into audio with a 20kg slab of DAC, making a little space for it is hardly a huge ask.

[lpost]

Since my gear is away in an open closet, I can't hear any fans. Though this one is super slow and quiet. Just moving a touch of air makes a significant difference in case temps.

 

 

[Hiker]

31 minutes ago, lpost said:

Since my gear is away in an open closet, I can't hear any fans. Though this one is super slow and quiet. Just moving a touch of air makes a significant difference in case temps.

 

 

Ha ,  right on 

[Hiker]

3 hours ago, GoldenOne said:

So my may when standalone typically measures 38-39C, sometimes a degree or so higher/lower if room temp is hot or cold.

I got the serene recently and tried various combinations of having the may with it's PSU sandwiched between it and serene, may ontop of serene etc etc, but in all cases it was getting up to about 45C. 
Not really "concerning" or anything. But for peace of mind I've moved it and am keeping may standalone again. I think the answer here is:

- Don't put stuff ontop of may
- Don't put may ontop of hot stuff

Unfortunately May does just need a little breathing room, but hey, when we're this deep into audio with a 20kg slab of DAC, making a little space for it is hardly a huge ask.

That stack looks great ! ,..When things get warm here , I just have to open a window ,,..photo taken this morning,..

[Extreme_Boky]

22 hours ago, Quadman said:

Here's your heat source.  4 Transistors biased into class A.  Facing down near back of dac, but heat rises.

 

 

I had a closer look.....sharpened-up your photo a bit... what the heck are those cut-outs in the PCB?? 

[sledwards]

I hope that’s an illusion and I am looking at a clear conformal coating. Those can’t be cut-outs.

[Extreme_Boky]

I think I know what they are....

 

It is a shiny solder-residue, as a side product of final, manual soldering done. Combined with just the right amount of reflections => PCB cut-outs.

[Miska]

Looks like left-over solder flux to me... (not washed)

[Extreme_Boky]

Initially I thought that was an attempt to fine-tune the ground currents distribution along the ground-fill, but they (the cut-outs ) appeared to  be way too deep for a multi-layer PCB design... 

[Quadman]

59 minutes ago, Extreme_Boky said:

 what the heck are those cut-outs in the PCB?? 

 

They sure do look odd in the photo and I don't remember them looking that odd in person.  Below picture shows what I think are the items that you point out with your arrows.

 

Using your arrows as guides the right arrow has to be this omron 2 pole relay switch.  The middle arrow is probably that bank of 4 small caps and the Left arrow is that tiny device under the USB board, I can't read it to make out what it is.  Kitsune site has some decent shots of it.  So this is flux residue combined with solder and shadow reflections making it look very odd.