Building A Linear Power Supplies for HQPlayer Server

[elan120]

Disclaimer:  This power supply build is one of many different possibilities and options available that can fulfil the need for a high performance linear power supply.  Do search around to see what choice best fits your requirements and priorities before taking this route.  Same also applies to the build method and process as there are many different options available, where this build is based on either my current knowledge or tools available.  Everything you see in this thread is purchased at regular price as I am not sponsored or affiliated with any suppliers, where the intent is purely knowledge sharing, so hopefully you enjoy the read.

 

The journey for this build started last year as the new HQPlayer EC modulators took SQ of my system up a good margin, but since my server at the time can only push up to DSD128 with this new modulator, I started to plan for the current server where linear power supplies was in scope of this server build.  The challenge I soon faced was the higher power supply output current demand from the CPU, an i9-9900KS, which made the selection of capable power supplies on the market very limited.  I went ahead and completed the server build using a standard ATX power supply to get the server running while continuing looking for power supply solutions.

 

The first attempt to improve the power supply was trying Uptone JS-2 to power the CPU directly, unfortunately, it doesn’t have enough current output to satisfy the demand during bootup sequence.  Next option is using a HDPlex 400W AC-DC adapter with 19V output connected to a HDPlex 800W DC-ATX converter to supply power to the CPU while keeping the ATX power supply on ATX connection.  This combination worked and the SQ is noticeably better than the standard ATX power supply.  With this setup running, I was able to estimate the current requirement for this CPU, which prompt the succeeding step by replacing the HDPlex 400W AC-DC adapter with a Keces P8 running at 20V, again, only to power the CPU, and the SQ continue to trend up, so finally, I added another Keces P8 to HDPlex 800W DC-ATX converter to supply power to ATX connector, and again, moved the SQ up another notch.

 

After more time looking over limited options to power this server, I decided to source a few key components from Sean Jacobs (SJ going forward) with the plan for building two separate power supplies, hoping they will successfully provide quality power to this server.  This first build is the single rail higher current EPS power supply, once this is completed, I will move on to build the ATX power supply that will have 4 rails, 3 of the 4 rails will be used for ATX and the 4th rail with a 5V output is intended for the JCAT Net Card Femto.

 

In this EPS power supply build, due to the higher output current, there is going to be a high current path and a low current path, and point to point soldering will be used for the pre-filter section.  To begin the build, there is some basic metal work to get all the components fitted in various locations.

 

The first thing is getting the layout put together for all the key components and I used a basic CAD program to get the final layout decided before ordering the enclosure from Modushop.  The heaviest component is a 400VA transformer from Toroidy, with weight close to 9 pounds, it is essential to have the enclosure bottom cover reinforced.  In the pictures below, it shows a couple L-brackets were added to strengthen the bottom cover so it won’t bow when this transformer is installed.  In addition, instead of using only two self-tapping metal screws per side of the bottom cover, one additional screw is added in the center, and replaced the self-tapping metal screw by tapping all  screw holes to accept M4 button head screws and finished by using M4 nuts to help support the overall weight.
 

 

 

Key component layout:

 

Aluminum L-brackets added with standoffs to support transformer base plate:

 

The 4 phillips screws were later replaced with the same button head cap screws used for the brackets:

 

Test fit the transformer base plate:

 

 

Once the transformer support was done, 4 additional holes were drilled to mount the two Mundorf MLytic HC capacitors.

 

 

 

 

 

With the bottom cover reinforcement and pre-filter capacitor mounting done, time to get the back panel prepared for all the components.  There will be a total of 3 openings, one for the switch/fuse/IEC module, one for the DC output, and one for the output fuse holder.  In addition, two M3 screw holes were drilled and tapped to mount the switch module.

 

 

 

 

Next is having the two heat sinks on the side prepared.  The left heat sink panel has two M4 holes drilled and tapped to mount an IXYS VBE 55-06NO7 FRED bridge rectifier, two M3 holes to mount a SJ current booster.  The right heat sink panel has two M3 holes to mount SJ regulator module and two more M3 holes to mount the other SJ current booster.  In order to preserve the appearance of both heat sinks, these holes were drilled and tapped without protrude panels and simply using a heat shrink tubing helped to determine needed drill depth.

 

Heat shrink tubing added to the drill bit:

 

 

Drilled hole with proper depth:

 

Test fit both bridge rectifier and SJ current booster module:

 

 

The front panel is the last panel that needs work, where two M3 holes were drilled and tapped to mount the 25W resistor that will be used in the pre-filter section.
 

 

 

 

 

 

 

All panels are done:

 

 

 

 

 

More to come...stay tuned...

 

 

[Exocer]

Very interested in the results and thanks for sharing!

[Gavin1977]

Following!  Very nice job and great tip to use supports for the toroidal.

 

I'm going to order the same toroidal for my SJ build, would you be able to supply dimentions for me including the baseplate?

 

For others following this thread...I just finished building an amplifier using the same Modushop chassis - you definately need a pillar drill/drill press for working with this as elan120 has used.  This other thing I noticed during my build is that the top and bottom panels are directional (Front/back) due to their drill hole spacing.  So if others are using this case just make sure you drill with the right orientation.  I wish Modushop would put basic stickers (front/back) or include some form of instructions with the panels.  If I was to do this project again then I'd definately invest in the inner baseplate - bottom of my amplifier looks like swiss cheese as I had to reposition everything (lesson learnt).

 

@elan120 I was wondering if feeding the JCAT card using bus-power, since this is from a SJ linear rail, will be pretty close to dedicated rail?  Did you ever recieve any feedback from SJ on this, or did you always intend to provide a dedicated rail.

 

Will be interested in you SQ comparisons of the SJ rail vs HDPlex.

[RickyV]

Very nice build with excellent components. Do you have a schematic drawing of the components layout? And what does the SJ current booster do?

 

This might be of interest too, https://evotronix.eu/main/

I bought 4 LC modules for the two nuc power supplies I am building.

[elan120]

11 hours ago, Gavin1977 said:

would you be able to supply dimentions for me including the baseplate

The transformer I use has the following dimension:

• Transformer diameter:  ~154mm
• Height~65mm + 25mm (side-wiring)

Base plate is 150mm x 150mm

 

 

 

11 hours ago, Gavin1977 said:

I was wondering if feeding the JCAT card using bus-power, since this is from a SJ linear rail, will be pretty close to dedicated rail?  Did you ever recieve any feedback from SJ on this, or did you always intend to provide a dedicated rail.

I have always had better result using a dedicated rail for all the devices and JCAT card is no different, this is the reason I plan to have a dedicated rail just for the JCAT card.  Building this separate rail will not add that much more work, once I am done with this build, I will post steps I take to build the next 4-rail supply, and you will see it is less involved than this build.

 

 

[elan120]

9 hours ago, RickyV said:

Do you have a schematic drawing of the components layout? And what does the SJ current booster do?

 

This might be of interest too, https://evotronix.eu/main/

I bought 4 LC modules for the two nuc power supplies I am building.

 

Thank you for the link.  Looks like they have good product offerings.

 

I did put together a schematic and ran simulations for the pre-filter section before deciding what I will incorporate in this build, but since it may or may not fit other supply requirements, I will think about whether to post it here later.

 

SJ current booster is a module Sean provide to help raise the output current from the base level at 1.5A to 5A.  This supply will have two, wired in parallel to raise the output current up to 10A.  The output Sean provide is quite conservative, actual maximum output can be higher, but other considerations will need to be planned more carefully, such as heat dissipation, transformer rating...etc.

 

 

[elan120]

With all the metal work completed and components mounted, time to wire everything together.  Due to the weight of the transformer, the transformer will be installed last and wiring will be done at the end.  To start, a 6 gauge copper wire was used to ensure there is enough cross section for the ground path between the two pre-filter capacitors negative terminators.

 

 

 

Next is to solder using Neotech 12 gauge solid core copper wire as high current wire from the bridge rectifier to the first pre-filter capacitor.  The same Neotech wire was also used to connect between the voltage inputs from both SJ current booster modules and the second pre-filter capacitor.

 

 

Solder wire between bridge rectifier negative output and first pre-filter negative terminal:

 

 

 

Solder wire between bridge rectifier positive output and first pre-filter positive terminal:

 

 

 

Solder wire between second pre-filter positive terminal and both SJ current booster voltage inputs:

 

 

 

 

 

 

Next up is the wirings between SJ Voltage Regulator and SJ Current Boosters.

 

 

 

 

 

[Dev]

great thread Elan. eagerly following the build.

[Exocer]

3 hours ago, elan120 said:

I have always had better result using a dedicated rail for all the devices and JCAT card is no different, this is the reason I plan to have a dedicated rail just for the JCAT card.  Building this separate rail will not add that much more work, once I am done with this build, I will post steps I take to build the next 4-rail supply, and you will see it is less involved than this build.

 

Probably a silly question to respond with but what about a dedicated 19v rail into something like an HDPLEX 400W/800W DC-ATX converter directly to an expansion card? I would think even this would fare better than bus power and would sit somewhere between bus power and a dedicated LPSU direct to the card... 

 

Something like this:

 

PaulHynes SR-7T > HDPlex DC-ATX Convert > Direct to card

[Nenon]

Nice job @elan120. Can't wait for your reaction when you plug it in to your computer :). 

Don't forget the isolation pads on the regulators. 

[elan120]

36 minutes ago, Exocer said:

what about a dedicated 19v rail into something like an HDPLEX 400W/800W DC-ATX converter directly to an expansion card?

Based on my experience thus far, having dedicated rail work better, and this is the key reason why for this and next power supply build, so I can remove the two LPS's feeding the HDPlex 800W DC-ATX converter.

[elan120]

21 minutes ago, Nenon said:

Don't forget the isolation pads on the regulators. 

Very good eyes Nenon and thanks for the reminder.  I only put them on the heat sink to see how they fit and plan for the wiring so didn't bother with the mica pads, but when I am ready to wire them, they will for sure have the mica pads added.

[RickyV]

9 hours ago, elan120 said:

 

Thank you for the link.  Looks like they have good product offerings.

 

I did put together a schematic and ran simulations for the pre-filter section before deciding what I will incorporate in this build, but since it may or may not fit other supply requirements, I will think about whether to post it here later.

 

SJ current booster is a module Sean provide to help raise the output current from the base level at 1.5A to 5A.  This supply will have two, wired in parallel to raise the output current up to 10A.  The output Sean provide is quite conservative, actual maximum output can be higher, but other considerations will need to be planned more carefully, such as heat dissipation, transformer rating...etc.

 

 

 

Ah you have the SJ regulators too, that why I was confused about the booster modul.

Does SJ sell the regulators now to anyone? And may I ask what they cost?

[wittao]

Congrats Elan, very nice job and idea!

Viktor

[basillus]

Elan Exciting... What is the reason that you use an 80v electrolyte that fills a lot, instead of, for example, 2x 2 mlytic 22000uf / 25v which fills less and isn’t two 22000uf electrolytes in parallel better than 1?

[elan120]

6 hours ago, RickyV said:

 

Ah you have the SJ regulators too, that why I was confused about the booster modul.

Does SJ sell the regulators now to anyone? And may I ask what they cost?

Yes, these are the key components I sourced from Sean, but the cost question is best answered by Sean.  He has different options available for these modules, and I was quoted with a package total of 5 rails with specific options, so I really don't know what the individual price was.

[elan120]

46 minutes ago, basillus said:

What is the reason that you use an 80v electrolyte that fills a lot

They are indeed bulky, but they were designed specifically for high current application that fits this power supply requirement well.  In addition, they have very low ESR rating which is also another important criteria I was looking for.  Finally, as a side benefit, it comes with chassis mount configuration, which is easier to have them installed and wired.  The need for an 80V rating is based on the power supply design topology where the transformer secondary output is rated at 18VAC, this output will rectify to about 25.5VDC, with +/- 5% of local power fluctuation, it could go as high as 26.7VDC, so higher voltage rating on these capacitors is essential for this power supply.

[elan120]

All wires used in the SJ voltage regulator module are low current path, and Mundorf 18 AWG solid core silver are being used here.  To connect between SJ voltage regulator and SJ current booster is very straightforward, as all the ports are clearly labeled to help make sure where the wires should be soldered.  The ground wire from SJ voltage regulator is routed to the 6 AWG ground bus between the two Mundorf pre-filter capacitors.
 

 

 

 

 

 

 

 

A KEMET 0.1uF C0G (NP0) ceramic capacitor was added right after the bridge rectifier to help suppress high frequency noise.

 

 

 

 

At this point, all the front section wiring is getting close to be done.  Time to move on to the back panel area.  To start, the output fuse holder and output connector, a GX16-4 connector, is installed and Neotech 16 AWG solid silver wires are soldered between them.

 

 

 

 

Once the back panel is bolted to the enclosure, output wiring from both SJ current booster is soldered to the fuse holder soldering pad located at the bottom of the fuse holder.  Once the back panel is bolted to the enclosure, output wiring from both SJ current booster is soldered to the fuse holder soldering pad located at the bottom of the fuse holder.  In addition, a Mundorf Metalized Oil-Impregnated Polypropylene bypass capacitor is also added to the output connector.

 

 

 

 

 

As a safety precaution, when building a power supply, it is very critical to have the earth pin from the IEC connector connected to the power supply chassis.  The picture below show the ring connector used with 18 AWG GREEN/YELLOW pigtail bolted to the chassis, and later it will be soldered to the earth pin of the IEC connector.
 

 

 

 

 

 

 

More wiring work will come soon...

 

 

 

 

 

[Dev]

Looks beautiful. Thanks for sharing. I bet it would sound awesome when its done 👍

[elan120]

On 5/25/2020 at 5:48 PM, Dev said:

Looks beautiful. Thanks for sharing. I bet it would sound awesome when its done 👍

Thank you, Dev, for the kind word.

[elan120]

Once the back panel output section wiring is done, it's time to move to the front panel.  The only component on the front panel is the 25W power resistor between the two pre-filter capacitors.  It will also have the high current Neotech 12 AWG solid core copper wire soldered to both terminals.

 

 

 

 

 

Two bypass capacitors were also added to the second pre-filter capacitor, a 4.7uF Mundorf Aluminum Oil Series Metalized Oil-Impregnated Polypropylene film capacitor and a KEMET 0.1uF C0G (NP0) ceramic capacitor to help blocking the high frequency noise.

 

 

 

 

 

Here is an overview of the progress thus far:

 

 

Next up is the transformer installation...heavy stuff!

 

 

 

 

 

 

 

[RickyV]

1 hour ago, elan120 said:

Once the back panel output section wiring is done, it's time to move to the front panel.  The only component on the front panel is the 25W power resistor between the two pre-filter capacitors.  It will also have the high current Neotech 12 AWG solid core copper wire soldered to both terminals.

 

 

 

 

 

Two bypass capacitors were also added to the second pre-filter capacitor, a 4.7uF Mundorf Aluminum Oil Series Metalized Oil-Impregnated Polypropylene film capacitor and a KEMET 0.1uF C0G (NP0) ceramic capacitor to help blocking the high frequency noise.

 

 

 

 

 

Here is an overview of the progress thus far:

 

 

Next up is the transformer installation...heavy stuff!

 

 

 

 

 

 

 

 

Wow cool Elan really nice clean build. Also thanks for sharing the bypass capacitor values. 

What I couldn't see clearly was if you use one or two output connectors, looks like one 4 pole.

[RickyV]

3 hours ago, elan120 said:

Once the back panel output section wiring is done, it's time to move to the front panel.  The only component on the front panel is the 25W power resistor between the two pre-filter capacitors.  It will also have the high current Neotech 12 AWG solid core copper wire soldered to both terminals.

 

 

 

 

 

Two bypass capacitors were also added to the second pre-filter capacitor, a 4.7uF Mundorf Aluminum Oil Series Metalized Oil-Impregnated Polypropylene film capacitor and a KEMET 0.1uF C0G (NP0) ceramic capacitor to help blocking the high frequency noise.

 

 

 

 

 

Here is an overview of the progress thus far:

 

 

Next up is the transformer installation...heavy stuff!

 

 

 

 

 

 

 

 

Never mind the question about the output connector, confused again.

[HeeBroG]

Totally awesome attention to detail and master level workmanship. Simply the neatest job I have seen. Great work!👍

[elan120]

Installing the transformer is fairly straightforward, other than being heavy, it basically drops in the space reserved nicely.  Once the transformer is bolted down with nylon insert lock nuts, it is time to solder the primary wires to the IEC power entry module, and the reserved safety pigtail is soldered to the earth(ground) pin of the IEC together with the ground wire from the transformer primary wirings.  After all the primary wires are soldered, I left the secondary wires unsoldered and did a quick functional test by plug in the power core and turn on the power switch to measure the voltage on the transformer secondary output.  This transformer was ordered with 0-18VAC spec., and it was measuring about 19.1AC, which is about right without load.
 

 

 

 

 

 

Once the transformer functional test is successful, secondary wires were cut to proper length, the final soldering work is to solder them to the bridge rectifier.  With the final soldering done, the entire circuitry is now complete and the next functional test is to see how this power supply performs.  To do this, I normally will start with conservative approach by using undersized fuses to make sure that no load voltage reading at different locations is as expected.  For this power supply, there are four voltage readings I am interested in:

1. Voltage at the positive terminal of the second capacitor.  This will indicate the voltage after the rectifier.  For this power supply, with no load, 18VAC secondary output should rectify to about 26+ VDC.
2. Voltage at the input of the voltage regulator.  This should be the same as the voltage reading above.
3. Voltage at the output of the voltage regulator.  This should read slightly above 12VDC as an indicator that the voltage regulator is working properly.
4. Voltage at the DC output connector.  This will likely be reading a bit lower than the voltage reading at the output of the voltage regulator due to some line loss.
    

 

 

 

 

To do the initial voltage measurements with a new device, my preferred method, once again, the conservative approach, is using a variac to slowly increase the input power to the transformer primary and see how the first voltage reading listed above responds, and carefully observe the other three voltage readings once this voltage reading starting to go above 14~15VDC until the input power is at the line level.  This approach is a safer way to do the initial power on test, anytime reading isn’t correct, simply shut down the variac to find out the root cause.  If a variac isn’t available, the only way to test would be to take a deep breath, turn on the power, and hope nothing bad happened.
 

 

 

 

When all four voltages measured are as expected, a light amount of output load can be added, and gradually increasing the load together with a proper size fuse to see how the power supply is performing with the same four voltage readings.  The load I use is the low cost method, a resistive load, using different value power resistors to check what voltage readings I get as resistor value decreases.  Another handy tool I use is an in-line watt meter, again, low cost, albeit not extremely accurate, but very effective to see how current and wattage respond to different loads.
 

 

 

 

Final test is to increase the load all the way to the power supply maximum rating at 12A by using an 1R/200W power resistor.  The test went well, and at this time, it is time to adjust voltage regulator output.  To do this, voltage readings from (3) and (4) will be taken while adjusting the blue color potentiometer on the voltage regulator module.  Voltage reading at (3) is the regulator output, which was pre-adjusted at the factory, but this is not going to be the voltage reading at the destination due to line loss.  Once the power supply is connected to the load, adjust voltage output while monitoring voltage reading at (4) to be slightly above 12V.  In my case, it turned out to be 12.02V.  Once this is established, go back and check voltage reading at (3), it should not be higher than 12.4V, and if it is also satisfactory, the voltage output adjustment is done.
 

 

 

 

 

 

With the final voltage output adjustment done, this project is now officially completed.  Time for some pictures and install the power supply to the server.  I will post more listening impressions once it has some burn-in time, but the first impression is very positive.

 

 

 

 

 

 

 

This was a fun and rewarding project, and I hope you enjoy reading this build process along the way, once I have all the parts received for the ATX power supply, I will post the build process here as well.