Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 16th October 2011, 08:46 AM   #11
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Drums get that hard sound when clipped (or even with a fast attack limiter), and some DC is introduced in the process... No DC servo?
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 16th October 2011, 02:49 PM   #12
AP2 is offline AP2  Italy
diyAudio Member
 
Join Date: Dec 2009
Location: Italy
Quote:
Originally Posted by Eva View Post
Drums get that hard sound when clipped (or even with a fast attack limiter), and some DC is introduced in the process... No DC servo?
---
Amp has a fast limiter (developed in DC) but not a single pulse of drum snaps, if the first impulse is not clipped (natural, for a time). this is my special alc present on all amps. but in this case, modulated bursts about 90%. (then not square)
DC servo, yes, the modulator has a loop through part of the NFB (filtered by a sub-rc). (I used two NFB) in the series Amp. DPA-400/600. the latter is widely used for bass guitar with enthusiasm .. (Attack, high harmonics of the string, etc. ..), I mean, amplifier product without problems in two years.
Pending the measures, I think that the psu to the DPA-400 has been pushed to get a good realism of percussion, so it seems the easiest answer. or the "R" for factors that do not know, decrease during acceleration.
few more days and I'll know.


Regards
  Reply With Quote
Old 17th September 2012, 09:09 PM   #13
AP2 is offline AP2  Italy
diyAudio Member
 
Join Date: Dec 2009
Location: Italy
Hi,
The tests have focused on psu (for heating of the coil of the woofer), this measure of piece of music has been performed by changing the type of power supply, on the same amp.
The graphics show a segment of the same captured file.
the probe was added to the amplifier output (resistive 8R).
The acquisition started with the trig. the start of the song, repeated by changing the power supply.
Internal: power supply of the A-400 integrated amplifier.
external: 600VA toroidal high flux, with 2x68000uF +4 x470uF and BYW29-200 fast diode (8x).
-----------------------------------
Only one comment:
During the sound, as opposed to as many people think, the difference increases in relation to the presence of the transient. (the faster the modulation of the current, the greater the drop in voltage). this means that the bulk capacitor on the power supply unregulated, does not do the work that we believe. completely changing the angle of the peaks, as you see also, regardless of whether the power is high, or in the range of 50w peak
Regards
Attached Images
File Type: png A-400-Power Integration.png (138.6 KB, 373 views)

Last edited by AP2; 17th September 2012 at 09:20 PM.
  Reply With Quote
Old 17th September 2012, 10:18 PM   #14
diyAudio Member
 
Join Date: Apr 2010
I don't get the point AP2 is up to. Can anybody please translate his experiments, experiences and theories into proper english or german or do some summary?
  Reply With Quote
Old 18th September 2012, 11:01 AM   #15
AP2 is offline AP2  Italy
diyAudio Member
 
Join Date: Dec 2009
Location: Italy
I apologize for my English, I am sure that in the short AudioPower shows this new amp (also for diy version), showing this new research directly on the site, complete with all the measurements.

in summary, we show that the drop voltage(on psu) does not have a relationship only with the loss of power.
the envelope is changed right where expresses the character of the musical instrument.
In fact, if we reproduce a sound very close to the geometric characteristics of the original envelope, we get an spl closer to the original instrument (with less power required), and obvius, in fidelity as the dynamics of musical instrument.
----------------------------
"Closer" mean that is not possible reproduces same spl of musical instrument's.(in relation to the same energy imprinted).
the first reason is phase of emission of the pressure/depression, plus inefficient transducer that is the loudspeaker.
  Reply With Quote
Old 21st September 2012, 05:27 PM   #16
AP2 is offline AP2  Italy
diyAudio Member
 
Join Date: Dec 2009
Location: Italy
Hi, The DPA-400-F1 diy version.
Simple... ready and complete to drive a nice pair of full range speakers as Magneplanar or B & W or other models with reactive load between 2R to 2.7R without perceptible distortion or fatigue in the range of 200 to 730W output.

not only a transient, may exceed 730W with the APC system, this amplifier corrects in real time the power, even if the load at that instant is 1R, the output power remains 730W without additional thd. (this system is activated below 2R) This lets you hear is full and clean orchestral envelope.
(some musical instruments in the presence of crossover in the speaker, generate extra absorption, creating audible thd.
we usually we lower the volume in this case).
at end...this amplifier (after one year of testing) is also indestructible

P.S. this in photo is one for my lab, so not have label on alluminum frame.

Regards
Attached Images
File Type: jpg DPA-400-F2.jpg (43.5 KB, 297 views)
File Type: jpg DPA-400-F3.jpg (18.4 KB, 283 views)
File Type: jpg DPA-400-F.jpg (63.8 KB, 228 views)

Last edited by AP2; 21st September 2012 at 05:34 PM.
  Reply With Quote
Old 24th September 2012, 10:12 PM   #17
AP2 is offline AP2  Italy
diyAudio Member
 
Join Date: Dec 2009
Location: Italy
Hi,
some additional info.
There are 3 versions with different setups (F1-F2-F3) with different prices.
This idea allows, according to use, better performance.
the smallest power is the DPA-400/F3.
F1-F3 are for audiophile use.
F2 is for guitar bass, sub, musical instruments with power output 600w(4R) . All model not need fan.
------------------------
I'm sure I can say that in this moment, the DPA-400 is the only amp that can offer a dynamic uncompressed (or not adds compression to the input signal)
the acoustic power will seem like double (if the speaker holds up well) hehe!

Regards
Attached Images
File Type: png Diagr-DPA-400-Fx.png (34.1 KB, 220 views)
File Type: jpg DPA-400-F.jpg (60.6 KB, 102 views)

Last edited by AP2; 24th September 2012 at 10:23 PM.
  Reply With Quote
Old 25th September 2012, 12:24 PM   #18
diyAudio Member
 
Join Date: Sep 2005
Location: Tuscany, Italy
Very interesting the F2 version (I'm a bassist).
But what is then the difference between the DPA-600 (already present at AudioPower) and this (new) DPA-400 if the F2 version is 600 Watt @ 4 ohm?

Regards,

Roberto
  Reply With Quote
Old 25th September 2012, 03:43 PM   #19
AP2 is offline AP2  Italy
diyAudio Member
 
Join Date: Dec 2009
Location: Italy
Quote:
Originally Posted by washburn_it View Post
Very interesting the F2 version (I'm a bassist).
But what is then the difference between the DPA-600 (already present at AudioPower) and this (new) DPA-400 if the F2 version is 600 Watt @ 4 ohm?

Regards,

Roberto
Good question (already received from others via email).
The DPA-600, already offers new performances just used for bass guitar, as well as a high-definition (feels the touch of strings) just before the "big hit", which is very popular with bass players (in this amplifier is repeatable to each shot), this has been well studied and is a big difference compared to competitors. but .. Power Unit of DPA-600 requires a fan (although its speed rotation is controlled by the temp.), but for a few millimeters, does not allow the mounting 1U case.
second reason, the F2 has 30mm high, then it can be revolutionary (even with extension up to 750w) if mounted in a case very close to the size of the module.
AP perhaps have one project in mind at short.
--------------------------------
Also, this new versions have some special components oversized,so the price is also higher than the DPA-600.
  Reply With Quote
Old 25th September 2012, 03:51 PM   #20
diyAudio Member
 
Join Date: Sep 2005
Location: Tuscany, Italy
Thanks for the reply.
When is the "launch" of the DPA-400 planned?
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone one tried AudioPower.it yet? fb Class D 15 5th February 2012 04:14 PM
Which design to have in-a-car-like sound pressure? Doug Kim Multi-Way 39 29th July 2008 11:49 AM
Sound pressure in time domain jamikl Full Range 6 26th March 2006 02:11 AM
Sound pressure, is that the same? destroyer X Solid State 17 9th May 2004 11:51 PM


New To Site? Need Help?

All times are GMT. The time now is 07:38 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2