The DIY'rs Cookbook | Page 69 | Headphone Reviews and Discussion - Head-Fi.org

mourip · Apr 6, 2017 at 8:22 AM

I am really happy with replacing the SMPS with an LPS for my D16 and am now looking at my Mutec USB to do the same.

Having opened it up previously and read posts here and elsewhere I can see that it will not be as easy a task, especially if I want the mod to be reversible/transparent. It looks as if many have opted to leave the SMPS in place and to solder the LPS leads to the existing +/- connections that come from the SMPS board as seen here.

While this is reported to work it seems to me that one is leaving the existing SMPS circuitry in parallel with the LPS. I would think that this might have unintended consequences and might not have all of the benefits of using the LPS straight into the main board. I do understand the desire to preserve the warranty however I wonder if someone with more theoretical understanding of electronics than I have could weigh in on this thought.

Much appreciated,

Paul

johnjen · Apr 7, 2017 at 2:13 AM

I did yank out the SMPS from my 3+, but it wasn't 'easy'.

As for the consequences of leaving it in, it probably won't make any real difference at least in an audible sense.
Perhaps it will pull a small amount of current, until the output filter caps 'fill up', but that would be about it as far as I can see.

JJ

Superdad · Apr 7, 2017 at 10:55 AM

johnjen said:
I did yank out the SMPS from my 3+, but it wasn't 'easy'.

As for the consequences of leaving it in, it probably won't make any real difference at least in an audible sense.
Perhaps it will pull a small amount of current, until the output filter caps 'fill up', but that would be about it as far as I can see.

JJ

Another client of ours contacted Mutec about using an UltraCap LPS-1 in place of their internal SMPS. Here is what they wrote back:

"Yes, the MC-3+USB does not need 1.2A, so from that all good. But using a linear power supply you must remove the internal power supply of the MC-3+USB. That means you must remove the whole PCB out of the case and de-solder the power supply from that. Dont simply connect the two cables of the linear power supply to the pins of the MC-3+USBs SPS. That would let the secondary stage of the SPS run as well! Please also consider that when doing this modification, you are losing the warranty claim.

I have attached a PDF showing the PCB print of the mainboard. The two DC outputs of the internal SPS are marked with + and -. At these points you must connect the cable of your linear power supply.

Please report how your MC-3+USB performs after the modification has been carried out.

Good luck!

Regards, Chris.
Dipl.-Ing. Christian Peters

Geschäftsführer / CEO

MUTEC Gesellschaft für Systementwicklung
und Komponentenvertrieb mbH
Siekeweg 6/8
12309 Berlin, Germany

-----------

Refreshing to see such an open-minded response--and from the CEO no less. But you can see he cautions against just tacking in an external supply without removing/disconnecting their stock one.

mourip · Apr 7, 2017 at 2:43 PM

Refreshing to see such an open-minded response--and from the CEO no less. But you can see he cautions against just tacking in an external supply without removing/disconnecting their stock one.

Thanks. That was about what I thought. Much appreciated.

I agree that for a manufacturer he is being very open. Julian who often posts for Mutec on CA is also very helpful

...as are you!

Best,

Paul

johnjen · Apr 8, 2017 at 3:53 AM

superdad said:
snip

"Yes, the MC-3+USB does not need 1.2A, so from that all good. But using a linear power supply you must remove the internal power supply of the MC-3+USB. That means you must remove the whole PCB out of the case and de-solder the power supply from that. Dont simply connect the two cables of the linear power supply to the pins of the MC-3+USBs SPS. That would let the secondary stage of the SPS run as well! Please also consider that when doing this modification, you are losing the warranty claim.
snip

Click to expand...

Thanks for that clarification.
And its good to know that simply supplying the output voltage to the secondary, that it will 'activate' that portion of the circuit, which in turn means it probably will generate some noise.

That kinda makes me glad I yanked mine out now.

JJ

Golfnutz · Apr 8, 2017 at 7:25 AM

mourip said:
I am really happy with replacing the SMPS with an LPS for my D16 and am now looking at my Mutec USB to do the same.

Having opened it up previously and read posts here and elsewhere I can see that it will not be as easy a task, especially if I want the mod to be reversible/transparent. It looks as if many have opted to leave the SMPS in place and to solder the LPS leads to the existing +/- connections that come from the SMPS board as seen here.

While this is reported to work it seems to me that one is leaving the existing SMPS circuitry in parallel with the LPS. I would think that this might have unintended consequences and might not have all of the benefits of using the LPS straight into the main board. I do understand the desire to preserve the warranty however I wonder if someone with more theoretical understanding of electronics than I have could weigh in on this thought.

Much appreciated,

Paul

Define pins. Are they the wires Mourip posted in the picture above, or did he mean these pins?

mourip · Apr 8, 2017 at 8:19 AM

golfnutz said:
Define pins. Are they the wires Mourip posted in the picture above, or did he mean these pins?

Those are the wires that supply AC to the SMPS from the IEC inlet. You would not want to connect DC to them under any circumstances. The pins I posted are the +5v/0v DC output of the SMPS and the DC power input to the main board. These are the best points to connect the LPS to the main board however just not with the SMPS still in place

Connecting an LPS to these pins with the SMPS still in place will allow the Mutec to run but as Superdad explained will still energize part of the SMPS which continues to be part of the circuit. It could sound slightly better but could also have unintended consequences, most likely introducing some of the very noise that you are trying to remove.

Better seen here...

Golfnutz · Apr 8, 2017 at 9:04 AM

mourip said:
Those are the wires that supply AC to the SMPS from the IEC inlet. You would not want to connect DC to them under any circumstances. The pins I posted are the +5v/0v DC output of the SMPS and the DC power input to the main board. These are the best points to connect the LPS to the main board however just not with the SMPS still in place

Connecting an LPS to these pins with the SMPS still in place will allow the Mutec to run but as Superdad explained will still energize part of the SMPS which continues to be part of the circuit. It could sound slightly better but could also have unintended consequences, most likely introducing some of the very noise that you are trying to remove.

Better seen here...

I get all that (your photo and mine are coming from the same place). Just curious what he meant by 'pins'. As you can see in the photo I posted, those wires are connected to pins. Was just asking for clarification (didn't want to assume anything).
I think the only way to be certain about any of this would be to take measurements before removing SMPS, with LPS connected to the 2 contact points (your photo), and after SMPS is removed, with LPS connected to same 2 contact points.

mourip · Apr 8, 2017 at 9:29 AM

golfnutz said:
I get all that (your photo and mine are coming from the same place). Just curious what he meant by 'pins'. As you can see in the photo I posted, those wires are connected to pins. Was just asking for clarification (didn't want to assume anything).
I think the only way to be certain about any of this would be to take measurements before removing SMPS, with LPS connected to the 2 contact points (your photo), and after SMPS is removed, with LPS connected to same 2 contact points.

Thanks for the reply.

Personally, by pins I guess that I assumed he meant the two long pins that protrude from the underside of the SMPS board to the top of the main board beneath and can be shown in the photo as having the new LPS leads soldered to them with the SMPS left in place. AFAIK they are the only source of DC for the board. Perhaps Superdad will check back in soon.

Based upon Superdad's post, the quote from Mutec, and my own understanding I plan to remove the SMPS. I figure removing it cannot sound worse, only potentially better. I can easily understand anyone's hesitancy regarding losing the warranty and that it is a much more involved job.

Have you already done the mod? If not, if you have the tools to take those noise measurements before and after that would be instructive for us. I do not own an oscilloscope but usually can tell lowered noise by more detail and a blacker background. Always worth it! It sure helped with my D16 and Antelope LiveClock.

Golfnutz · Apr 8, 2017 at 3:47 PM

mourip said:
Thanks for the reply.

Personally, by pins I guess that I assumed he meant the two long pins that protrude from the underside of the SMPS board to the top of the main board beneath and can be shown in the photo as having the new LPS leads soldered to them with the SMPS left in place. AFAIK they are the only source of DC for the board. Perhaps Superdad will check back in soon.

Based upon Superdad's post, the quote from Mutec, and my own understanding I plan to remove the SMPS. I figure removing it cannot sound worse, only potentially better. I can easily understand anyone's hesitancy regarding losing the warranty and that it is a much more involved job.

Have you already done the mod? If not, if you have the tools to take those noise measurements before and after that would be instructive for us. I do not own an oscilloscope but usually can tell lowered noise by more detail and a blacker background. Always worth it! It sure helped with my D16 and Antelope LiveClock.

Sorry no Mutec yet, thinking about it.

Muziqboy · Apr 8, 2017 at 5:00 PM

New additions on top of the LPS mods that I recently did are a couple of TOPAZ line noise suppressing Ultra-Isolators.
I'm powering up the NUC and the monitor with a 500va that has a .001pF capacitance rating and a 1kva also with a .001pF powering up the rest of the gear.

I was researching into this about a year ago and should have gotten it then as the prices on these things are going up now since these are no longer made and a little hard to find in good condition.
Got lucky and found a brand new 500va and a used 1kva that looks almost new.

IMO another step in the right direction as far as SQ improvement

Here's a good thread on CA about the benefits of using these.
https://www.computeraudiophile.com/forums/topic/29662-discussion-of-ac-mains-isolation-transformers-started-wposts-moved-from-quotlps-1-troubleshootingquot-thread/?do=findComment&comment=589394

Middy · Apr 8, 2017 at 5:36 PM

I tried the Airlink balanced isolation transformer. Very nice boost but not the value of the Topaz Americans can pick up cheap. The Crux of the Topaz being is very low winding Capacitance.
As John S explains. I though my airlink gave me 10% -15% but it's with my UK Home electrics so this varies with your local noise. Plug and play for me..
:blush:

.
Musiqboy have a look at DC offset filters. Mine was an investment incase I got noise off the Transformer. Humming buzzing ECT. It added too the SQ the one I got.
Cheap and rock solid.
Good luck
Dave
http://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/

Muziqboy · Apr 8, 2017 at 6:11 PM

Thanks for that link Dave, will look into that. Both the TOPAZ I have here is silent. I can only hear a very slight humming/buzzing when I put my ear up to it, otherwise it is dead silent from my listening position. As for the added boost in SQ, another veil removed with the music coming at you with immense clarity.

Glad I pulled the trigger on these. For me, a very worthy addition to the system.

johnjen · Apr 8, 2017 at 7:37 PM

mourip said:
Thanks for the reply.

Personally, by pins I guess that I assumed he meant the two long pins that protrude from the underside of the SMPS board to the top of the main board beneath and can be shown in the photo as having the new LPS leads soldered to them with the SMPS left in place. AFAIK they are the only source of DC for the board. Perhaps Superdad will check back in soon.

Based upon Superdad's post, the quote from Mutec, and my own understanding I plan to remove the SMPS. I figure removing it cannot sound worse, only potentially better. I can easily understand anyone's hesitancy regarding losing the warranty and that it is a much more involved job.

Have you already done the mod? If not, if you have the tools to take those noise measurements before and after that would be instructive for us. I do not own an oscilloscope but usually can tell lowered noise by more detail and a blacker background. Always worth it! It sure helped with my D16 and Antelope LiveClock.

Yes those are the pins.
They run from the SMPS board to the mainboard and are a bit of a bugger to remove, so be careful.
And be aware that there are 4 pins, 2) 120Vac input and 2) 5Vdc output.
These pins also serve to hold the SMPS board in place, so they are somewhat 'robust', which adds to the difficulty in their removal.

As a reference I did take some noise measurements and posted them earlier in this thread.

JJ

Middy · Apr 9, 2017 at 6:17 PM

Just the link for the Topaz details from John S.
Balanced Isolation. Sine wave regeneration and DC blocking. In that order the biggest boosts to fidelity with better power.
I sold my OPPO HA1 for cents.. £300 but that going to the Lps1 fund now i changed the wifes mind for my old gear.
Now we have baby coming..god help us.. :blush:

Ill try the ISO regen...Then baby things until 2043.
https://www.computeraudiophile.com/forums/topic/29662-discussion-of-ac-mains-isolation-transformers-started-wposts-moved-from-quotlps-1-troubleshootingquot-thread/
Hope the link helps :blush:

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