Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

dual nc400 + SMPS1200
dual nc400 + SMPS1200
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th August 2019, 03:22 PM   #21
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
Power draw without the external vref is 28W, with it: 24.4W

Output of the regulator I compared and the nc400 does appear to detect this rail's voltage before deciding to use it or not. There isn't any difference in idle draw with the Vdr supply higher than 16.5VDC. The voltage after the rectifier is 28VDC so am in the process of acquiring a smaller 15VAC transformer to replace the 18VAC 15VA one I'm currently using to reduce the regulator losses. Hypex states a simple unregulated supply should be okay also so I will test and compare with that next.
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote
Old 12th August 2019, 03:51 PM   #22
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
Supplying the Vdr with +16V via the bench supply: 19.8W idle. Linear regular currently adding about 5W to the 24.4W total. Total current draw @ 16V is 110mA.
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote
Old 12th August 2019, 09:07 PM   #23
DDF is offline DDF  Canada
diyAudio Member
 
DDF's Avatar
 
Join Date: Sep 2004
Location: Ottawa
Quote:
Originally Posted by spikestabber View Post
They redesigned the entire softstart circuitry on the new SMPS1200 runs, the SMD side has significant redesign over the "V7" I previously had, they removed the V marker denoting what it is on the silkscreen on the new one.
Thanks for sharing your investigations.

Have you looked into whether component substitutions on the SMPS1200 can provide the needed Vdr?
  Reply With Quote
Old 13th August 2019, 06:13 AM   #24
pos is offline pos  Europe
diyAudio Member
 
pos's Avatar
 
Join Date: Feb 2008
Location: Paris
Very interesting, thank you!
Would it not be possible to rise the Vdr output of the SMPS1200 with a simple DC-DC converter?
__________________
2019-01-16: rePhase 1.4.3
  Reply With Quote
Old 13th August 2019, 12:51 PM   #25
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
Quote:
Originally Posted by DDF View Post
Thanks for sharing your investigations.

Have you looked into whether component substitutions on the SMPS1200 can provide the needed Vdr?
This was something I was looking at, now that I have a dead SMPS1200 to dissect I was more curious how the Vdr was derived. Vdr appears to be derived from the to220 bdx34 darlington at the far right of the board on the heatsink side, opposite of the bridge rectifier side. There are some SMD components underneath this. The voltage is derived from its own unregulated winding which is rectified straight after the SMPS transformer and snakes around the board to the Vdr regular mentioned previously. It looks like some kind of shunt or zener referenced thing. I have powered up this piece on the bench supply, and 15.95V comes off the Vdr supply after the regulator. Did Hypex actually state why the original Vdr supply didn't work?

It's almost like this supply must exist before the actual HV comes up for the nc400 to use it, maybe there is more to this? I have no issues having the nc400 accept the same voltages offboard as long as the supply exists before HV....

Anyone with an SMPS600 able to confirm if the Vdr on theirs comes up before the main HV?
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote
Old 13th August 2019, 01:53 PM   #26
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
I don't plan on touching my new one simply because I want to be able to complain to hypex the moment it has issues after just a few years. However here is the top left of the old vdr circuit. 2 bog standard diodes with a series resistor looks to be the reference. Bottom left of picture isolated vdr supply to regulator visible.
Attached Images
File Type: jpg 20190813_083930.jpg (1,003.2 KB, 62 views)
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote
Old 13th August 2019, 02:06 PM   #27
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
r42 in that picture, changing its value changes the output voltage, increasing the resistor value raises. Default resistor is 470ohm, all black, probably 1% or better tolerance.
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote
Old 13th August 2019, 02:10 PM   #28
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
Anyone else wanting to experiment, you can safely inject power at points L10 & L12 to power the Vdr circuit, just be sure to verify the polarity of the capacitor connected to that point to ensure its correct.
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote
Old 13th August 2019, 06:35 PM   #29
DDF is offline DDF  Canada
diyAudio Member
 
DDF's Avatar
 
Join Date: Sep 2004
Location: Ottawa
I wrote Hypex, and they recommend not overdriving Vdr, as it will quickly reduce NC400 lifetime.

They were also unable to recommend an SMPS1200 component swap to bring Vdr to target for the amp modules.
  Reply With Quote
Old 13th August 2019, 09:45 PM   #30
spikestabber is offline spikestabber  Canada
diyAudio Member
 
Join Date: Feb 2015
Quote:
Originally Posted by DDF View Post
I wrote Hypex, and they recommend not overdriving Vdr, as it will quickly reduce NC400 lifetime.

They were also unable to recommend an SMPS1200 component swap to bring Vdr to target for the amp modules.
Thanks, I have kept Vdr at exactly 16V, with the offboard PSU I was able to get things down to 22-23W idle which amounts to a noticeably cooler case, if that increases the SMPS1200 lifetime significantly then fine by me. Down by about 7 watts.
__________________
Soekris dam1021-12v2 dual-mono balanced: https://imgur.com/gallery/RVBQozq
nc400: https://imgur.com/iORCyna | TT2USB: https://imgur.com/a/p6OiS | HD800 | KEF R300
  Reply With Quote

Reply


dual nc400 + SMPS1200Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hypex NC400 Dual Monoblock Build, questions... jayzon87 Class D 2 27th March 2018 01:19 PM
Hypex SMPS1200 Power Supply dtaylo3 Class D 8 23rd September 2016 11:34 PM
FS: Hypex NC400 Dual mono (assembled) $1,400 OBO Lvtouch Swap Meet 0 25th July 2015 06:01 PM
FS: Hypex NCore NC400/SMPS600 Dual Mono Power Amp wafflee Swap Meet 2 10th August 2013 02:50 AM
Hypex SMPS1200 A700 hanswolek Class D 17 16th September 2010 02:19 PM


New To Site? Need Help?

All times are GMT. The time now is 02:53 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki