Go Back   Home > Forums > Commercial Sector > Manufacturers > AKSA

AKSA Builders of market proven kits and modules at sound quality to rival the best in high end

Reply
 
Thread Tools Search this Thread
Old 7th October 2012, 11:41 PM   #1
diyAudio Member
 
supernet's Avatar
 
Join Date: Dec 2001
Location: Europe
Default Monoblock amplifiers - any significant (dis)advantages?

My amplifier (LF 100) need a decent case and while thinking about visual WAF friendly apperance, I have noticed that having two monoblock cases would make some asthetic and sonic benefits...better separation, placement amplifier close to speakers...but on the other hand, I am a bit worried about grounding issues. Each mono amp should have his own central grounding point, that means that both grounds meet together at extension main cord, compared to stereo amp where both channels meet each other at one central point with short (low impedance connection).

So...have anybody made practical test if monoblock amps are really better or this is just another audio myth?
  Reply With Quote
Old 8th October 2012, 01:26 AM   #2
andyr is offline andyr  Australia
diyAudio Member
 
Join Date: Nov 2003
Location: Melbourne (Oz, not Florida!)
Quote:
Originally Posted by supernet View Post
My amplifier (LF 100) need a decent case and while thinking about visual WAF friendly apperance, I have noticed that having two monoblock cases would make some asthetic and sonic benefits...better separation, placement amplifier close to speakers...but on the other hand, I am a bit worried about grounding issues. Each mono amp should have his own central grounding point, that means that both grounds meet together at extension main cord, compared to stereo amp where both channels meet each other at one central point with short (low impedance connection).

So...have anybody made practical test if monoblock amps are really better or this is just another audio myth?
I presume you have a "standard" LF100 ... which has 1 x PS PCB connected to 2 power transformers? So to move to monoblocs, you will have to cut that PS PCB in half.

I implemented my LF100/55/55s as monoblocks - so that's what I did (cut the 3 x PS PCBs in half). I can assure you there is no grounding issue when separating the 2 channels - as long as you drill a new hole in each half of the PS PCB, so you can implement a new "star ground" in each.

How do I know there is no "grounding issue" ... because my system is dead quiet - ie. no ground hum.

And the big advantage is that, as you noted, you can put the monobloc case right behind each speaker. (In my case, I have 3 amp modules, 1 active XO and 4 complete PSes in the one custom-designed case, sitting right behind each speaker. )

Go for it!

Regards,

Andy
  Reply With Quote
Old 8th October 2012, 05:30 PM   #3
diyAudio Member
 
supernet's Avatar
 
Join Date: Dec 2001
Location: Europe
Thx...Yes I have LF100, but with separate PSUs which were designed by myself. So no cutting here


Did you connect central ground point to mains earth(chassis) too? Probably you use insulated RCAs...
Attached Images
File Type: jpg PSU.JPG (178.0 KB, 366 views)

Last edited by supernet; 8th October 2012 at 05:41 PM.
  Reply With Quote
Old 8th October 2012, 09:29 PM   #4
andyr is offline andyr  Australia
diyAudio Member
 
Join Date: Nov 2003
Location: Melbourne (Oz, not Florida!)
Quote:
Originally Posted by supernet View Post
Thx...Yes I have LF100, but with separate PSUs which were designed by myself. So no cutting here

Did you connect central ground point to mains earth (chassis) too? Probably you use insulated RCAs...
OK, so one problem solved.

Yes, I use insulated RCAs - so mains earth never touches signal earth anywhere in my system. Mains earth is there solely to earth the chassis.

Regards,

Andy
  Reply With Quote
Old 8th October 2012, 10:50 PM   #5
diyAudio Member
 
supernet's Avatar
 
Join Date: Dec 2001
Location: Europe
Quote:
Originally Posted by andyr View Post
Yes, I use insulated RCAs - so mains earth never touches signal earth anywhere in my system. Mains earth is there solely to earth the chassis.

That`s a point that bothers me Wouldn`t be better if each mono amp central ground would also be connected with mains earth and insulated RCAs?
  Reply With Quote
Old 8th October 2012, 11:17 PM   #6
andyr is offline andyr  Australia
diyAudio Member
 
Join Date: Nov 2003
Location: Melbourne (Oz, not Florida!)
Quote:
Originally Posted by supernet View Post
That`s a point that bothers me Wouldn`t be better if each mono amp central ground would also be connected with mains earth and insulated RCAs?
Not IMO.

Mains earth is dirty - it should never touch signal earth. So I use insulated RCAs to keep signal earth separate from the chassis (which is connected to mains earth).


Regards,

Andy
  Reply With Quote
Old 9th October 2012, 02:48 AM   #7
diyAudio Member
 
Join Date: Jul 2003
Location: wyoming
Quote:
Originally Posted by supernet View Post
That`s a point that bothers me Wouldn`t be better if each mono amp central ground would also be connected with mains earth and insulated RCAs?
For safety's safe it is best to connect mains earth to the psu star earth.
On the LF board the signal ground is connected to power ground with 2 diodes and a 10R resistor, so signal ground is not directly connected to power ground, which is directly connected to star earth on the psu.

Not connecting the mains earth to psu earth is fine as long as nothing catastrophic ever happens.
  Reply With Quote
Old 9th October 2012, 04:43 AM   #8
diyAudio Member
 
Join Date: Jul 2003
Location: wyoming
Quote:
Originally Posted by supernet View Post
So...have anybody made practical test if monoblock amps are really better or this is just another audio myth?
I meant to include this in my earlier post, so I'll just add it here. I used to have a pair of Aksa 55's each in their own case near the speaker so as to run short speaker cables, as Andy does. The drawback to this is you need an extra power cable.
Given that Aksa's and LF's are designed to be dual mono, with each channel with a separate board, power supply and transformer, it makes little difference if they are in one case or two.
As to the audio myth of monobloc configuration automatically being better, well, the new Naksa 70's are not dual mono and sound great, a step up from the LF series for sure.
  Reply With Quote
Old 9th October 2012, 04:44 AM   #9
jcx is online now jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
safety rated "double/reinforced" insulation for xmfr, proper internal construction allows for floating electrical equipment: "Class II" - the 3 A mini 2 pin plug may be OK for a 100 W monblock amplifier
  Reply With Quote
Old 9th October 2012, 04:59 AM   #10
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Quote:
Originally Posted by supernet View Post
That`s a point that bothers me Wouldn`t be better if each mono amp central ground would also be connected with mains earth and insulated RCAs?
You're asking - no, begging - for a nasty ground loop. Why would you want monoblocks and then connect the output grounds together via the power ground? The signal grounds should come back together via the RCA cables at the preamp. Any slight ground variances due to signal currents won't make an iota of difference as the output ground is 'floating'.

Please remember that any voltage drops in a cable happens in both conductors. 'Ground' (earth if you will) is not the same at the load as it is at the source. You MUST obey Ohm's law. You can try to force your way with ground straps or larger gauge wires but there is always resistance whatever you do. Don't fight it, work within the limits.

G
  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
Consonance Billie 300b Monoblock Amplifiers $750 TV Man Swap Meet 0 21st December 2011 12:33 AM
Carver Silver - 9t Monoblock Amplifiers the apostate Solid State 2 16th July 2009 04:44 AM
Velleman K8010 monoblock tube amplifiers bonnel Tubes / Valves 2 12th April 2008 10:07 PM
Mosfet monoblock amplifiers DocLorren Swap Meet 2 10th September 2007 03:53 PM
what are the advantages and dis adv of IMP cone subwoofers? diysmartdeep21 Subwoofers 3 15th February 2005 02:01 PM


New To Site? Need Help?

All times are GMT. The time now is 02:50 PM.


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