How to drive 8 pairs of MJL21193/94? - Page 5 - 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 11th May 2009, 03:39 PM   #41
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
Quote:
Originally posted by nigelwright7557
I now use +/-60V and that seems to be a lot better.
Sadly the price of electrolytics rockets above 63V.
Amplifier power rockets above 63V, too. And amp rails are never as stiff as you expect them to be based on trafo regulation specs.
  Reply With Quote
Old 11th May 2009, 04:35 PM   #42
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
 
Join Date: Nov 2005
LarsClausen(LCAudio) once showed how to use seperate standard +/- supply fore each half of the balanced/bridged amp, using smaller voltage caps
But ending with a single higher voltage cap across + to -
Ground would be sort of floating
__________________
sometimes we know very little, and sometimes we know too much
  Reply With Quote
Old 11th May 2009, 04:57 PM   #43
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Quote:
Originally posted by wg_ski


Amplifier power rockets above 63V, too. And amp rails are never as stiff as you expect them to be based on trafo regulation specs.

Thats becasue the output power is V squared/ speaker impedance.
  Reply With Quote
Old 11th May 2009, 05:40 PM   #44
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default Why are you needing all that power Satji?


Do you have speaker enougth to all that power?

Will be some special application, alike football field or enormous open air alive performance or something in a such direction?

Man!.... this heatsink cannot hold all that power.

I feel curious....just that.... i have some speaker here, used into automobile, so bad they are(low efficiency) that needs 400 watts RMS to move..is this your case?

Carlos
Attached Images
File Type: jpg mtx - jack hammer.jpg (87.6 KB, 365 views)
__________________
Convertion of 8 speaker output wire into standard 2 wires; https://www.youtube.com/watch?v=toZjKw3uUMo; Unbeatable!; https://www.youtube.com/watch?v=u4tGBiqMnzQ
  Reply With Quote
Old 11th May 2009, 06:05 PM   #45
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default I understand that some applications needs power.


I am very curious about yours....please, let me know.

regards,

Carlos

http://www.youtube.com/watch?v=2SBEJffbwHk
__________________
Convertion of 8 speaker output wire into standard 2 wires; https://www.youtube.com/watch?v=toZjKw3uUMo; Unbeatable!; https://www.youtube.com/watch?v=u4tGBiqMnzQ
  Reply With Quote
Old 11th May 2009, 08:30 PM   #46
sajti is offline sajti  Hungary
diyAudio Member
 
Join Date: Apr 2003
Location: Vác, Hungary
I want to use it for 2 different application:

- home system to drive my 8ohms Focal loudspeaker, mainly in class A, up to 100W.

- to drive the front, and subwoofer in a party (my subwoofer contains 2x18" Beyma loudspeakers, and can handle 1800W rms)

I know that this heatsink is not enough. This is for test only. I'm not sure the final solution. I have two possibilities:

1, 40cm long heatsink for each module
2, keep this heatsink, and use forced cooling with variable speed fan

Sajti
  Reply With Quote
Old 26th August 2009, 09:01 AM   #47
sajti is offline sajti  Hungary
diyAudio Member
 
Join Date: Apr 2003
Location: Vác, Hungary
I had no time in the last few weeks, but now I start to do some measurements, and try some other solution.

So, the prototype contains now: 4pairs of MJL21193/94, and NJW0281/0302 as drivers and no predriver. I measured the input impedance, which is 12kohms, with 2ohm load (it means 4ohm nominal load for the bridged amplifier). It's not so hard load, and I can drive it with White follower using ECC99 (150V/18mA anode current). I still working to put it together...

Sajti
  Reply With Quote
Old 26th August 2009, 09:33 AM   #48
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Zin=12k with 2r0 load.
Zin>4k with 2ohm reactive load?
What about Zin dips when abuse occurs?
__________________
regards Andrew T.
  Reply With Quote
Old 26th August 2009, 09:38 AM   #49
sajti is offline sajti  Hungary
diyAudio Member
 
Join Date: Apr 2003
Location: Vác, Hungary
The driver tube can drives 1kohm load with full output swing (60Vpp), so some impedance drop can not be problem. If I use all the output devices (8pairs), there will be no B drop even with 2ohm balanced load.

Sajti
  Reply With Quote
Old 26th August 2009, 09:55 AM   #50
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
tell me if this is balderdash.

Maximum output 30Vpk.
Maximum current into 2r0 15Apk.
Maximum current into 2ohm ~45Apk.
Maximum current through each output device ~5.6Apk (during normal use - no abuse).
typical gain @ 5.6Apk ~ 45 to 60.
typical maximum base current ~45Apk/45 ~1Apk.
typical NJW gain @ 0.1Apk to 5Apk, ~constant @ 100.
typical driver base current ~10mA+driver bias ~?mA. Try 20mA
typical impedance 30V/0.02A ~1k5 for normal drive conditions.
__________________
regards Andrew T.
  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
mjl21193/94 indestructable?? mikefromaus Solid State 2 16th January 2008 03:34 PM
FS: MJL21193 and MJL21194 - new zener_diode Swap Meet 9 27th December 2007 04:36 AM
MJL21193/21194s N-Channel Swap Meet 1 18th September 2005 04:04 AM
MJL21193 and MJL21194 HuntTheShunt Parts 1 5th December 2004 01:11 PM


New To Site? Need Help?

All times are GMT. The time now is 09:05 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