Hiraga "le monstre" - Page 86 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 25th September 2012, 06:26 AM   #851
neazoi is offline neazoi  Greece
diyAudio Member
 
Join Date: Aug 2007
I am not sure if it is the 20W version but I am sure that is has some kind of dc-dc converter so that it feeds the amplifier with a dual rail supply out of a single 12v one.
__________________
Great DIY site: http://www.neazoi.com
  Reply With Quote
Old 25th September 2012, 06:56 AM   #852
jeepy is offline jeepy  Switzerland
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by neazoi View Post
I am not sure if it is the 20W version but I am sure that is has some kind of dc-dc converter so that it feeds the amplifier with a dual rail supply out of a single 12v one.
Probably based on Le Monstre topology and could be good enough in a car. Interesting input stage with TO220 drivers! The overheat protection makes sense. Also it may be workking in class for the first watts only. splitted PSU is very bad in audio. Good enough for a car maybe.
  Reply With Quote
Old 25th September 2012, 06:57 AM   #853
neazoi is offline neazoi  Greece
diyAudio Member
 
Join Date: Aug 2007
Also nothing special in components, I can see some 5% carbon resistors and some inductive power bricks.
__________________
Great DIY site: http://www.neazoi.com
  Reply With Quote
Old 25th September 2012, 01:22 PM   #854
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Quote:
Originally Posted by permaneder View Post
I'm in doubt that your amp really runs class A up to 20W.

At an idle current of 1A and +- 21V supply rails the amp would draw more than 40W per channel (= total 84W). That would be too much power dissipation for the unsufficiant heat sinking capabilities of your amp's casing (I can't see any fans in your pictures).

So I believe it has a class AB setting to lower the power dissipation of the output transistors of the amp and the pulsed supply.
Hi, i imagine so the heatsinks do seem rather small, unless of corse the amp is biased low maybee ? there are no fans indeed. so you mean it would be "class a" for low power levels then when its cranked up it would go into B ?
one thing ive always wanted to know how would one test if an amp like this is in b or a ?

Im pretty sure it has "dc-dc converter" too.
"splitted PSU is very bad in audio. Good enough for a car maybe. " yeah id rather have 2 x 12v batterys. but i can see there is no point remaking the PSU for this thing as it would be a shame to take apart something that works.

well ill have a listen and see how it is and if i don't want it i might upgrade some of those components and/or sell it on. it cost me 80 with post and packaging, not bad realy.
Cheers

Last edited by Rixsta; 25th September 2012 at 01:25 PM.
  Reply With Quote
Old 25th September 2012, 01:30 PM   #855
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
ahh another question, what kind of lead acid battery would you use with this ? u think i can get away with less than 40ah. can always try i guess. and does anyone know a good charger circuit or kit to charge 12v battery.
  Reply With Quote
Old 25th September 2012, 01:45 PM   #856
jeepy is offline jeepy  Switzerland
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by Rixsta View Post
ahh another question, what kind of lead acid battery would you use with this ? u think i can get away with less than 40ah. can always try i guess. and does anyone know a good charger circuit or kit to charge 12v battery.
The 2 x 45Ah used on Le Monstre last less than 3 hours. You can use the battery of you car to make a try 30 minutes. A 4Ah charger costs less than 50 euros (maybe 30 in DIY. Many schematics on the net.)
  Reply With Quote
Old 25th September 2012, 01:49 PM   #857
neazoi is offline neazoi  Greece
diyAudio Member
 
Join Date: Aug 2007
Quote:
Originally Posted by jeepy View Post
The 2 x 45Ah used on Le Monstre last less than 3 hours. You can use the battery of you car to make a try 30 minutes. A 4Ah charger costs less than 50 euros (maybe 30 in DIY. Many schematics on the net.)
You can't use the car battery for that long if the engine is not switched on. You must use deep cycle SLA batteries or switch the engine on, or else the car battery will be damaged.
__________________
Great DIY site: http://www.neazoi.com
  Reply With Quote
Old 25th September 2012, 04:53 PM   #858
diyAudio Member
 
Join Date: May 2009
Location: The Fool on the Hill
Quote:
Originally Posted by Rixsta View Post
Hi, i imagine so the heatsinks do seem rather small, unless of corse the amp is biased low maybee ? there are no fans indeed. so you mean it would be "class a" for low power levels then when its cranked up it would go into B ?
one thing ive always wanted to know how would one test if an amp like this is in b or a ?

Im pretty sure it has "dc-dc converter" too.
"splitted PSU is very bad in audio. Good enough for a car maybe. " yeah id rather have 2 x 12v batterys. but i can see there is no point remaking the PSU for this thing as it would be a shame to take apart something that works.

well ill have a listen and see how it is and if i don't want it i might upgrade some of those components and/or sell it on. it cost me 80 with post and packaging, not bad realy.
Cheers
Measure the voltage drop across the .47Ohm resistors. Ohm's law: R=U/I; I= U/R; Iidle=Udrop voltage/.47. The amp is working class A up to 20W if idled by approx. 1A. The lower the current, the earlier the amp slips to class B.

The power supply is a pulsed two-rail type. Correctly dimensioned, it should measure at least +-20V. It converts the 12V battery voltage to 2 x 21V.

The topology of the 20W Hiraga is not at all identical to Le Monstre.

80 GBP is a very reasonable price though...
  Reply With Quote
Old 25th September 2012, 11:07 PM   #859
diyAudio Member
 
Join Date: Jun 2012
I built the 20W version a few years back. I remember liking its midrange very much. Bass-wise it was not the best match for my ATCs. Not sure if its a good fit for a car amp.
  Reply With Quote
Old 26th September 2012, 12:23 AM   #860
diyAudio Member
 
Join Date: Feb 2009
this amp has a DC-DC converter. that is for sure. wich also need much of the heatsinks. i guess it is low bias. and 2x20W calss A/B. and maybe 2x2.5W classA.
20W class A at 4 ohm. will demand over 3A bias. and at +/-21V that is above 126W dissipation pr ch pluss all that the DC-DC supply dissepates.
so a total of around 300W not very likely

BTW: it is a cheap amp that is scraped, and used the chassis and the DC-DC supply from that amp.
but it looks good however. there is not mutch classA power in this.

Last edited by AudioSan; 26th September 2012 at 12:33 AM.
  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
Conversion of Hiraga's "Le Monstre" to a Circlotron tiefbassuebertr Solid State 12 1st May 2011 07:26 AM
Hiraga Monstre with SMPS? weissi Solid State 2 25th July 2008 09:44 PM
Hiraga 30W vs. Le Monstre JohanH Solid State 103 14th April 2008 10:27 PM
HIRAGA Monstre amplifier modules a333bt Swap Meet 5 14th October 2007 03:11 PM


New To Site? Need Help?

All times are GMT. The time now is 09:07 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