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

Chip Amps Amplifiers based on integrated circuits

Modulus-86  build thread
Modulus-86  build thread
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 3rd March 2015, 07:54 AM   #241
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
yes. you are measuring with reference to output level.
The feedback is tapped into the output level.
__________________
regards Andrew T.
  Reply With Quote
Old 3rd March 2015, 08:37 PM   #242
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Quote:
Originally Posted by soongsc View Post
For the same output level? Even if you reduce the input to get the same test output?
An increase in closed loop gain of 6 dB will reduce the loop gain by 6 dB, hence, the amplifier 'sees' 6 dB less error correction. This means any error signals, including distortion, will experience 6 dB less suppression, hence, be 6 dB higher. That's fundamental control systems theory right there...

Franco and Sedra/Smith cover this in detail. I suspect Jung does as well. For the full reference, see the Reference Texts section on my website.

National Semiconductor/TI's "Op-Amps for Everyone" is a handy reference as well. See Equation (5-7) in Chapter 5: http://www.ti.com/lit/ml/sloa077/sloa077.pdf

~Tom
__________________
Modulus-86, 186, 286, 286 Kit, & 686: 40-240W (8Ω) at <-120dB THD. HP-1: 3W/20Ω, -130dB THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right

Last edited by tomchr; 3rd March 2015 at 09:00 PM.
  Reply With Quote
Old 5th March 2015, 08:29 PM   #243
cogitech is offline cogitech  Canada
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
Really nice to watch as people build these and listen. I've put my plan on the back-burner for now and opted for a much cheaper "summer amp". I suspect I will eventually build a Modulus-86, but my current budget simply cannot make it float. Keep up the great work everyone. I continue to watch in envy.
  Reply With Quote
Old 7th March 2015, 08:44 AM   #244
Domi_78 is offline Domi_78  France
diyAudio Member
 
Join Date: Jul 2008
Location: Conflans-Sainte-Honorine
Hello,
The progress of my project in pictures:

The HIFI2000 case comes from another abandoned project.
The list of components ordered from Mouser USA was delivered in 48 hours in France.
The toroidal transformer (2x20V, 160VA) and some miscellaneous ordered from Audiophonics were delivered within 48 hours.
I am still waiting circuit boards ordered from Tom. They are shipped, but in transit through the US for more than a week ... So, no yet in France
I expect from China delivery of a protection module based on the chip upc1237.
I take this waiting to prepare the cabinet, already well advanced. Note the introduction of a double bottom that will help conceal part of the wiring.

To be continued ...
__________________
Friendly, Dominique. RIAA Pacific LDA, SqueezeBox Touch + WD 1To USB, Tuner Aston Wamba, DAC AD1865 SRPP (Siemens E188CC), MODULUS-86 Rev. 2.0, Passive 6 dB Xo, Altec 515-8G/VOTT, TAD TD4001/TH4001, Subwoofer : JBL 2241H/4641 + Xilica XP-4080 + Proline 3000.
  Reply With Quote
Old 7th March 2015, 11:25 AM   #245
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
Quote:
Originally Posted by tomchr View Post
An increase in closed loop gain of 6 dB will reduce the loop gain by 6 dB, hence, the amplifier 'sees' 6 dB less error correction. This means any error signals, including distortion, will experience 6 dB less suppression, hence, be 6 dB higher. That's fundamental control systems theory right there...

Franco and Sedra/Smith cover this in detail. I suspect Jung does as well. For the full reference, see the Reference Texts section on my website.

National Semiconductor/TI's "Op-Amps for Everyone" is a handy reference as well. See Equation (5-7) in Chapter 5: http://www.ti.com/lit/ml/sloa077/sloa077.pdf

~Tom
I think you are mixing the units. Distortion is measured in terms of the output signal. Not all distortion are respond linearly to outer loop gain. Anyway, I just wanted to know the reason you came up with those numbers. Not that it really matters to me.
__________________
Hear the real thing!

Last edited by soongsc; 7th March 2015 at 11:37 AM.
  Reply With Quote
Old 7th March 2015, 11:30 AM   #246
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
My V1 boards seemed to have vanished into thin air. I had to request registered delivery for the V2 which Tom was kind enough to upgrade to Express delivery which took only about 3 days.
__________________
Hear the real thing!
  Reply With Quote
Old 7th March 2015, 11:37 AM   #247
Domi_78 is offline Domi_78  France
diyAudio Member
 
Join Date: Jul 2008
Location: Conflans-Sainte-Honorine
Quote:
Originally Posted by soongsc View Post
My V1 boards seemed to have vanished into thin air. I had to request registered delivery for the V2 which Tom was kind enough to upgrade to Express delivery which took only about 3 days.
- For mine, no comment ...
Attached Images
File Type: jpg Capture d'écran PC-Dom le 2015.03.07 à 10.59.41.JPG (111.3 KB, 639 views)
__________________
Friendly, Dominique. RIAA Pacific LDA, SqueezeBox Touch + WD 1To USB, Tuner Aston Wamba, DAC AD1865 SRPP (Siemens E188CC), MODULUS-86 Rev. 2.0, Passive 6 dB Xo, Altec 515-8G/VOTT, TAD TD4001/TH4001, Subwoofer : JBL 2241H/4641 + Xilica XP-4080 + Proline 3000.

Last edited by Domi_78; 7th March 2015 at 11:42 AM.
  Reply With Quote
Old 7th March 2015, 11:47 AM   #248
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
I have lately been reading these news about mail being dumped. In Taiwan, one mailman was caught dumping mail into the sea. Another news was probably somewhere in the US some 13000 mail was trashed.
__________________
Hear the real thing!

Last edited by soongsc; 7th March 2015 at 11:56 AM.
  Reply With Quote
Old 7th March 2015, 11:00 PM   #249
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Over the past 3-4 years, I've shipped about 300 orders to various destination, both international and domestic. The only board shipment I've ever seen disappear in the mail was the one to soongsc. It shipped January 6th, 2015 and hasn't been seen since...

Shipping to Western Europe generally takes 2-3 weeks. Shipping to Canada takes about a week or week-and-a-half, and shipping within the the US takes 3-7 days.

I will be more than happy to ship via Express Mail, but most customers balk at the $45 shipping cost. Express Mail arrives in a few days and is fully trackable. If you want even faster delivery, I'll be happy to ship via FedEx or UPS. The shipping fee will be over $100 for international destinations, but you'll have the boards tomorrow...

~Tom
__________________
Modulus-86, 186, 286, 286 Kit, & 686: 40-240W (8Ω) at <-120dB THD. HP-1: 3W/20Ω, -130dB THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right

Last edited by tomchr; 7th March 2015 at 11:05 PM.
  Reply With Quote
Old 7th March 2015, 11:17 PM   #250
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Quote:
Originally Posted by soongsc View Post
I think you are mixing the units. Distortion is measured in terms of the output signal. Not all distortion are respond linearly to outer loop gain. Anyway, I just wanted to know the reason you came up with those numbers. Not that it really matters to me.
Definition: Total harmonic distortion (THD) is ratio of the sum of the powers of the harmonics to the power of the fundamental.

As long as we are talking distortion caused by non-linearities within the amp and the amp is operated closed loop and without clipping, the harmonic distortion components show up as an error signal within the loop and is attenuated by the loop gain.

There are distortion mechanisms where this does not apply. THD, however, is not one of them. The various transient-related distortions (SID, TIM for example) would be examples. However, in case of a well-designed amp, such as the Modulus-86, there is no appreciable transient-related distortion when used as an audio amplifier. The Modulus-86 can slew from rail-to-rail even with a single-sample rail-to-rail step at 192 kHz sampling rate (assuming any audio circuit was able to generate this).

~Tom
__________________
Modulus-86, 186, 286, 286 Kit, & 686: 40-240W (8Ω) at <-120dB THD. HP-1: 3W/20Ω, -130dB THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right

Last edited by tomchr; 7th March 2015 at 11:21 PM.
  Reply With Quote

Reply


Modulus-86  build threadHide 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
Modulus-86: Composite amplifier achieving <0.0004 % THD+N. tomchr Vendor's Bazaar 2421 17th May 2019 12:10 AM
Build Thread: OBEOS Tytte71 Multi-Way 15 1st October 2011 06:02 PM
Dome's Build Thread. joe58 Full Range 12 1st September 2010 04:05 PM
SE - Build Thread soundengine355 Solid State 6 27th June 2009 12:19 AM
New Project Build Thread ryoung Multi-Way 5 19th April 2008 01:15 AM


New To Site? Need Help?

All times are GMT. The time now is 03:00 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki