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 15th September 2018, 07:22 PM   #4341
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Quote:
Originally Posted by BYRTT View Post
Tried google abbreviation and if it means self-resonant frequency i have to read up on that subject to have any serious meaning or thoght about it : ) then again is it stupid think some reason can be we do parelell capacitors to up its value but inductors need coupled in series to up value.
SRF = self-resonant frequency indeed.

The equivalent circuit for a capacitor is an inductor (ESL) in series with a resistor (ESR) in series with a capacitor (C). You'd expect a resonant frequency of SRF = 1/(2pi*sqrt(LC)). sqrt() = square root. Thus, if C increases, you would expect the SRF to decrease, thus, the lowest point in the curve (where you read the ESR) to shift down in frequency as C is increased.
In your measurement the resonant frequencies of the 1C -> 8C capacitors are smack on top of each other (approx. 1 kHz). That strikes me as odd. Does L decrease by N as you start adding more caps in parallel. In theory it does, but you're adding a lot of lead inductance with the clip leads, so the SRF should move. Your measurement doesn't show this movement, which makes me wonder why.

I don't think it's a limit of the test equipment. Rather, I think it's a limit of the test setup. I'd debug that and retake the data.

Quote:
Originally Posted by BYRTT View Post
Test can be seen below with usual impedance curves plus advanced data for capacitor dialog, even shorted wire was tested as a capasitor and also tried inductance menu but it told component probably not was a inductor or vaule is below unit specs 0,05-100mH.
A piece of wire is an inductor. Figure roughly 1 nH/mm.

Neat instrument, though. It looks to be very useful for the hobbyist. For capacitor/inductor measurements you'll want the ability to calibrate out the lead inductance of the instrument itself. Does the software offer this option?

Tom
__________________
Modulus-86, 186, 286, & 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; 15th September 2018 at 07:24 PM.
  Reply With Quote
Old 16th September 2018, 12:03 AM   #4342
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Modulus-86  build thread
Hi BYRTT,
Your sampling frequency might be 44.1 KHz, but that means your bandwidth is going to be 1/2 of that. There has to be an anti-aliasing filter in there to prevent frequencies higher than 22.05 KHz from appearing as a false image, and since filters are no "brick wall" responses, you will lose some bandwidth to that. Notice how early CD players responded to information up to about 20 KHz? Same reason.

I'm not using an RTX6001 which samples at 192 KHz, and that allows me close to 96 KHz bandwidth at 24 bits or better. I'd have to look that figure up.

Beware of using too high a supply capacitance. Your conduction angle on the rectifier diodes becomes very small, which forces the peak currents to be much higher than they should be. This excited HF ringing, and you've read about that. Let's just say that it is easier to block a 120 Hz ripple than it is higher frequencies. So very high levels of capacitance actually harms you more than helps you.

Best, Chris
__________________
"Just because you can, doesn't mean you should" © my Wife
  Reply With Quote
Old 16th September 2018, 03:29 AM   #4343
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Quote:
Originally Posted by anatech View Post
So very high levels of capacitance actually harms you more than helps you.
Very true. Too low ESR can be harmful as well. If the resonant Q of the decoupling and supply capacitance gets too high, you'll start having ringing on the power supply. That's not good either.
Some use snubbers to tame the Q. A well-placed electrolytic can will do the same thing.

Tom
__________________
Modulus-86, 186, 286, & 686: 40-240W (8Ω) at <-120dB THD. HP-1: 3W/20Ω, -130dB THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
  Reply With Quote
Old 16th September 2018, 04:19 AM   #4344
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Modulus-86  build thread
Yup.
__________________
"Just because you can, doesn't mean you should" © my Wife
  Reply With Quote
Old 23rd September 2018, 07:34 AM   #4345
meszarosa is offline meszarosa
diyAudio Member
 
Join Date: Feb 2017
Modulus-86  build thread
Smile Succesful build of an AMP

Hello Tom,
I just wanted to send you a picture about a succesful build of a stereo Modulus-86 based amplifier. Thanks for the support during the build! Sounds absolutely good, I'm very satisfied with sound quality!


I reused my old AMP's case and Heatsink for the build. Loudness was also tested (turned up the volume to approx same level, where my old AMP was), although the SMPS-86 turned to be just a little weak, when listening to "tchaikovsky 1812 overture"... When the cannons kicked in, the SMPS-86 went into overcurrent limit hickup mode, and restarted the amplifier
photo_2018-09-23_08-11-07.jpg
  Reply With Quote
Old 23rd September 2018, 08:01 AM   #4346
TioFrancotirador is offline TioFrancotirador  Poland
diyAudio Member
 
Join Date: May 2014
Location: Poland
Quote:
Originally Posted by meszarosa View Post
Hello Tom,
I just wanted to send you a picture about a succesful build of a stereo Modulus-86 based amplifier. Thanks for the support during the build! Sounds absolutely good, I'm very satisfied with sound quality!


I reused my old AMP's case and Heatsink for the build. Loudness was also tested (turned up the volume to approx same level, where my old AMP was), although the SMPS-86 turned to be just a little weak, when listening to "tchaikovsky 1812 overture"... When the cannons kicked in, the SMPS-86 went into overcurrent limit hickup mode, and restarted the amplifier
Attachment 705178
Nice! What is the stepped attenuator that you have in your build?
  Reply With Quote
Old 23rd September 2018, 11:17 AM   #4347
meszarosa is offline meszarosa
diyAudio Member
 
Join Date: Feb 2017
Modulus-86  build thread
Quote:
Originally Posted by TioFrancotirador View Post
Nice! What is the stepped attenuator that you have in your build?
It's not a stepped attenuator, but a fully balanced preamp, based on Bruno Putzleys published preamp design, with alps potmeter, extended with an input selector(4 channels) , and implemented fully SMD, in order to be small enough to fit into the limited space I had. Psu is integrated LDO with 7A4700 and 7A3301, primarily running from the same +/- 24V, as the Modulus86.
  Reply With Quote
Old 24th September 2018, 03:59 AM   #4348
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Quote:
Originally Posted by meszarosa View Post
Hello Tom,
I just wanted to send you a picture about a succesful build of a stereo Modulus-86 based amplifier. Thanks for the support during the build! Sounds absolutely good, I'm very satisfied with sound quality!
Excellent. That's good to hear. It looks like a very nice build. I'd probably add some ventilation holes in the top and bottom above/below the heat sinks to allow them to breathe a bit better. That aside, it looks very nice.

I'm curious to see the front of the amp too. Show off that wood! Cherry?

Quote:
Originally Posted by meszarosa View Post
SMPS-86 turned to be just a little weak, when listening to "tchaikovsky 1812 overture"... When the cannons kicked in, the SMPS-86 went into overcurrent limit hickup mode, and restarted the amplifier
Yeah. The 2.5 A output current of the SMPS-86 is not quite enough for a stereo amp - especially with 4 Ω load. That's why I generally recommend going for a dual-mono build if you're the type who likes to crank the music loud.
That said, as you also pointed out, exceeding the current limit is rather undramatic. Just annoying.

The SMPS-86 is great for a small desktop amp, though. For the money, and in terms of ease of use and compactness, it's hard to beat. Those wanting more power can ponder over the Mean Well RPS-200-27-C. A pair of those would drive the MOD86 to clipping with a 4 Ω load without much fuss.

Tom
__________________
Modulus-86, 186, 286, & 686: 40-240W (8Ω) at <-120dB THD. HP-1: 3W/20Ω, -130dB THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
  Reply With Quote
Old 24th September 2018, 05:12 AM   #4349
chrisb is offline chrisb
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
meszarosa - for those of us who might be interested in implementing an "integrated" amp with any of Tom's Modulus amps, could you share a URL for what appears to be a quite nicely implemented kit version of the Putzley design.
__________________
you know I canít quit you, baby
  Reply With Quote
Old 24th September 2018, 07:48 AM   #4350
meszarosa is offline meszarosa
diyAudio Member
 
Join Date: Feb 2017
Modulus-86  build thread
Quote:
Originally Posted by tomchr View Post
Excellent. That's good to hear. It looks like a very nice build. I'd probably add some ventilation holes in the top and bottom above/below the heat sinks to allow them to breathe a bit better. That aside, it looks very nice.

I'm curious to see the front of the amp too. Show off that wood! Cherry?

Tom

The ventilation holes exists, just it was not visible on my previous picture.
I've got no pictures on my phone on the full-assembly, but it looks like an original amplifier. See the following link: Google Image Result for https://www.illel.fr/temp/an_photos/29438.jpg


The front view of the Amplifier (including the MOD86):
(have to say: the woodwork is original from my old Amplifier, not my own work)

amp_front.jpg
  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 2407 12th September 2018 05:27 AM
Build Thread: OBEOS Tytte71 Multi-Way 15 1st October 2011 07:02 PM
Dome's Build Thread. joe58 Full Range 12 1st September 2010 05:05 PM
SE - Build Thread soundengine355 Solid State 6 27th June 2009 01:19 AM
New Project Build Thread ryoung Multi-Way 5 19th April 2008 02:15 AM


New To Site? Need Help?

All times are GMT. The time now is 09:48 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki