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

Ncore design refinement
Ncore design refinement
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 22nd June 2019, 07:49 PM   #51
Antoinel is offline Antoinel  United States
diyAudio Member
 
Join Date: Jan 2012
Location: Pennsylvania
Ncore design refinement
Can UcD180LP be coerced to subjectively sound like another amp; say a BJT-based Class AB ? The attached schematic is for a prototype "compound" power amp which attempts to tackle this hypothesis.

This amp operates trouble free [no externally induced oscillation] because of the following two properties which are inherent in it:

1. The voltage gain of UcD is 13.1 dB or Vout = 4.52 times its Vin.
2. The chosen toroid transformer has a voltage step-down ratio of [115/24]=4.79

The operational trick is this ratio of 4.52 to 4.79 = 0.94.

The resultant stepped-down voltage output of UcD will always be 0.94 the output voltage of BTL. BTL is 94% voltage-shadowed [boot-strapped] by UcD. Thus BTL does little [6%] work versus UcD which does it all; up to the specified 180W/4 Ohm.

BTL is low-power and maybe Class A. Its differential power outputs drive UcD directly as required without the use of OpAmps as I showed in my previous posts.

This prototype is amenable to an A/B subjective comparison. The schematic is [say] for setup A. Setup B [not shown and suggested] requires a mechanical relay to simultaneously disconnect the primary and secondary windings of the transformer. Setup B enables BTL to drive the inputs of UcD which solely drives the loudspeaker without interference [for better or worse] from BTL in setup A.

The case of a Class T BTL instead of a BJT BTL in the compound power amp will follow in a next post.
Attached Images
File Type: jpg BTLUcD.jpg (566.7 KB, 263 views)
  Reply With Quote
Old 23rd June 2019, 03:43 PM   #52
Antoinel is offline Antoinel  United States
diyAudio Member
 
Join Date: Jan 2012
Location: Pennsylvania
Ncore design refinement
The application note for UcD180LP by Hypex Electronics specifies 180 W into a 4 Ohm load with an attendant 1% THD. This level of distortion is expected to be lower in the prototype compound amp; described as follows:

1. Distortion is an electrical signal which is stepped-down from the power output of UcD to the power outputs of BTL.

2. BTL recognizes this distortion [it sez not mine!] and/but still corrects it anyway and instantly via its negative feedback loops.

3. The resultant cleansed signals at the outputs of BTL are forwarded to the inputs of UcD so as to continually effect a lowered THD content in the region of its maximum power output.

3a. The absence of distortion signals in the 24 Vac winding driven by BTL says it will also be simultaneously absent in the 115 Vac winding driven by UcD. Transformer action in action!.

The first Typical Performance Graph [7.1] in the Application Note is entitled THD vs. Power (1 kHz, 4 Ohm). The above 3 points suggest:

1. The shape and/or flatness of the graph is expected to be different; for better or worse; especially vis a vis the parent absolute THD which is superb.

2. The line in the graph at ~150 W rises sharply to indicate the onset of increased levels of THD. The slope of this line in [7.1] is expected to be diminished in the compound amp. Thus, the resultant graph/line continues with a gentle ascent.

Best
Anton
  Reply With Quote
Old 23rd June 2019, 03:47 PM   #53
Reactance is offline Reactance  South Africa
diyAudio Member
 
Reactance's Avatar
 
Join Date: Jun 2005
Location: Cape Town
I don't get the value of this thread it feels like a monologue for class-d sound + philosophy mixed with audiophile nonsense. sorry.
__________________
There’s nothing worse than the smell of burned output transistors!!
  Reply With Quote
Old 23rd June 2019, 04:00 PM   #54
ds23man is offline ds23man  Netherlands
diyAudio Member
 
ds23man's Avatar
 
Join Date: Oct 2006
Location: Hypex's doorstep
+1
  Reply With Quote
Old 23rd June 2019, 07:14 PM   #55
Antoinel is offline Antoinel  United States
diyAudio Member
 
Join Date: Jan 2012
Location: Pennsylvania
Ncore design refinement
Hello Reactance and ds23man,

Thanks for your honesty. Healthy skepticism on your part is +1.

I hope that you consider experimenting with this compound prototype. Its assembly is easy and highly detailed. How will anybody learn its "truth"; if any?

Quite perceptive of you Reactance. I have a Philosophy Doctorate; but in Inorganic Chemistry. It spilled over.

Frankly, my DIY objective is to understand the value to performance for this suggested compound prototype; by posting or writing it out loudly... It'll help me unravel its audiophile sense or nonsense.

Best
Anton
  Reply With Quote
Old 24th June 2019, 05:07 AM   #56
ds23man is offline ds23man  Netherlands
diyAudio Member
 
ds23man's Avatar
 
Join Date: Oct 2006
Location: Hypex's doorstep
Better to move this to a new topic.
  Reply With Quote
Old 24th June 2019, 09:17 AM   #57
kartino is offline kartino  Indonesia
diyAudio Member
 
kartino's Avatar
 
Join Date: Feb 2005
Location: Gunungkidul Indonesia
I am a Bruno's fans since 2005.

Salute to you. Here is my DIY Amplifier, UcD fullbridge, which tested on live music, to drive 2 x 18" speaker with no problem.
If you know him, then you know that his is consistent to design class D amplifier as self oscillation post filter feedback.
Even very poor design and poor material like myself as above still amazing result I can get. Many thanks to Bruno
Attached Images
File Type: jpg UcD Fullbridge.jpg (186.5 KB, 163 views)

Last edited by kartino; 24th June 2019 at 09:20 AM.
  Reply With Quote
Old 24th June 2019, 09:57 AM   #58
hidjedewitje is offline hidjedewitje  Netherlands
diyAudio Member
 
Join Date: Jan 2016
Location: The Netherlands
Quote:
Originally Posted by jgazal View Post
Is this new refinement going to be available in diy kits?
I asked Lars at the AES presentation about the driver and amplifier. He said both the driver and amplifier will become available for DIY market eventually.

The goal for the amplifier was by the end of summer and for the driver it is the end of the year.

Personally I would expect some delays though personally due to their significant performance improvement. I am more curious about the price range for the drivers.
  Reply With Quote
Old 24th June 2019, 04:37 PM   #59
Antoinel is offline Antoinel  United States
diyAudio Member
 
Join Date: Jan 2012
Location: Pennsylvania
Ncore design refinement
Quote:
Originally Posted by ds23man View Post
Better to move this to a new topic.
In closing, the compound prototype under study has roots from the patent: US 4,107,619. It is entitled Constant Voltage-Constant Current High Fidelity Amplifier. It was granted in 1978 to Threshold Corporation; Nelson S. Pass inventor.

Best wishes
Anton
  Reply With Quote

Reply


Ncore design refinementHide 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
FS. Audio Refinement Complete CD Player bigaudioscotto Swap Meet 3 29th June 2015 11:29 AM
What Amp did you replace with NCore NC400 or What Replaced Your NCore? Jmdesignz2 Class D 4 8th December 2014 12:24 PM
WTB: Audio Refinement Multi 3 in silver trusound Swap Meet 0 2nd October 2009 08:33 PM
6C33C SE Amp - Ideas on refinement? GlidingDutchman Tubes / Valves 44 12th May 2009 10:39 AM
Audio Refinement CD Complete john65b Swap Meet 1 4th April 2008 04:07 AM


New To Site? Need Help?

All times are GMT. The time now is 01:09 PM.


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