Building a Monster... Class A - 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 27th January 2009, 03:37 PM   #1
diyAudio Member
 
Join Date: Jan 2009
Send a message via MSN to Adrculda Send a message via Yahoo to Adrculda
Red face Building a Monster... Class A

Hi everyone...
well after pokin around the net and lurkin around here, i came to the conclusion that i have to do something with my spare time and what better to do and try and fry myself trying to build a monster LOL

i came across the Elliott Sound Products website and a certain Project 117 caught my eye...

After reading the page several times over came to the demented idea.. I Have To Build one, but not that one must beef it UP!!!
so after a couple of hours on the computer i slowly reviewed and "improved" a couple of items:

- Power Supply
DOUBLED the caps from 8 to 16 10,000uf caps
TRIPLED the Transformer from a 2KVA to a 6KVA unit ( in case i want to add a second channel )
RECTIFIERS went from 2 x 35A units to 3 x 50A units
Also Bumped the voltage from 135V to 142V (i believe will be 140V) by using a 12v transformer instead of the 6V as well as using 5A rectifiers instead of the 1A ones shown

-Amplifier section
As of right now...
board was a 1 piece deal, but i moved the drivers onto a separate board to fit a larger heat sink and forced cooling along with slots cut into the board for breathing room for the resistors. Also number of drivers was increased from 18 to 40 !! ( see diagrams )

I WILL do other changes on th course of the build, but that's it for now...

AS OF TODAY...
dropped off the pre-driver section to have a few board made up.
the guy was amazed at first and was wondering if i was building a welder of some sort
When i told him what i was working on he gave me the look and with a tiny voice he asked if he heard right...
At this point I couldn't resist the temptation, but had to trow in that i left the flux capacitor out of the diagram since that's the top secret part of it

long story short...
$50 for 4 boards and got him to order me 2 forced cooling heat sinks, really nice ones at that!!
Its pretty much a square aluminum tube with copper honeycomb design inside and a wall thickness about 3/16 on the mounting side.
dimensions are as follows 120mm x 120mm x 400mm long, and though it was a steal for $70 each. He uses them to keep triacs cool dissapating over 3500W into the tunnel and keeping it at only 22C.

As far as the transformer goes...
The closest i found so far was a monster 8KVA toroid with 2oo/440V primaries and Tripple tapped secondaries at 25, 60, 120V on each secondary... $500 ( I think its a bit too big.. i mean i don't want to "brown out" the whole neighbour hood when i turn my amp on or i'm listening to music )

STILL TO GO:
Need to find BOM so i can start ordering some parts cuz the ones that were on the schematic are there but its incomplete information.
If anyone has any info on this would be appreciated.

Thanks
Adrian C.
  Reply With Quote
Old 27th January 2009, 04:05 PM   #2
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
Quote:
Insanity Can Be Yours :-)
1,500W / 4 Ohms Power Amplifier
Rod Elliott (ESP)
Introduction

This project is mainly in answer to those for whom no amount of power is enough.
Yes, it is like plain insanity to me, too.

Nevertheless, it is a challenge to try to see how many watts can be mastered by an audio amplifier.
Even good old Nelson Pass has made some really insane amplfiers
when it comes to power and current output to speakers.

Here is the basic schematic from Rod Elliott Project 117.
Uses many MJL21193/94 or MJ15024/25 TO-3 metal can transistors.

Click the image to open in full size.
Figure 1 - 1.5kW Power Amplifier
__________________
lineup
  Reply With Quote
Old 27th January 2009, 04:49 PM   #3
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
why?

there are a number of really good class A designs on this forum, in the Pass section, and elsewhere online...

for that matter, the Krell copiers all have schematics here and they use copious numbers of output devices...

Guess I am saying that if ur going through the expense of heatsinking that much which = $$, you might as well build an amp that happens to be a good circuit to start with??

_-_-bear

PS. do you really want to hear the sound of a fan cranking when you run the amp??
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 27th January 2009, 04:56 PM   #4
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
Not to rain on anybody's parade, but this post screams of "newbie". An appropriately experienced builder would know that the auxiliary supplies don't need 5A rectifiers for example. And would already have acquired the necessary toroid(s) before proceeding. And that P117 isn't and can't be made to work class A. It would be insanity for a newbie to attempt this.

Physical construction of a project like this is 99.999% of the work. The circuit itself is nothing. The majority of the "bill of materials" is wiring harnessses, custom machined parts, heavy iron and hardware - not transistors, resistors,and capacitors. And you won't really know what you need until you seriously sit down and start mocking it up. That process may take weeks or months depending on your shop capabilities and how frustrated you get along the way. It may take several iterations and false starts before everything starts falling into place.

I'm about 2 months into the actaul build of four 2kW/channel PA amps. The design process took about 2 years from concept to a prototype board working on a test bench. Then the fun really began. The final chassis design and layout started in March and finally came together back in October. There were a lot of problems with fit and finish to figure out, and without a real machine shop it's a CHORE. I've just now got the power supplies and supervisor boards built, tested, and running. The front end and temp sensor circuits are under construction now. The power amp boards will be done LAST, because it is a known working amp design, just scaled up a bit from the prototype. It's an old class B design that I've used since 1990 at voltages up to +/-127V and adapted to class H by adding the QSC-style rail switches. The modules have already been mocked up and tested for proper fit and airflow. The project 117 writeup has no real mention of what's required to get a big amp like this working, fit into a chassis and reliable, but the basic steps are pretty much the same regardless of design and always different in the details. It is assumed that the builder can do all of this without any hand-holding. If you can't, the project is too big for you. If you've got access to a complete machine shop and manufacturing facilities - great - it will make life a lot eaier than it has been for me.
  Reply With Quote
Old 27th January 2009, 05:31 PM   #5
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Oh, in that case, you guys think it's the same idiot who keeps coming back every moon cycle ?
__________________
2015 : World Cup Cat Hacky Sack
  Reply With Quote
Old 27th January 2009, 06:36 PM   #6
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
wow, it took till post 4 to finally point out that there is no class
A..

For that much power 7 pairs of mosfets tacked on to the
blameless would be as far as I would go.(class AB/B)
BJT,s just don't seem to have the SOAR to be economical
at insane levels
For Insane power class d is the only way to go.
I just saw the 24 1KW power amps at the eagle's concert
(lucky me , sitting right next to them)
all class D/ no heatsinks in back (24 X QSC 1KW).
OS
  Reply With Quote
Old 27th January 2009, 07:06 PM   #7
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
But class D is even less newbie-friendly at this power level. That requires a working knowledge of high frequency magnetics and more specialized test equipment. You can overbuild a class B amp (relatively) easily. Switching circuits are a lot harder to overbuild and still get nanosecond rise times and low overshoots.
  Reply With Quote
Old 27th January 2009, 07:35 PM   #8
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
That is why I mentioned the 7 pair of Vertical mosfets,
as I have not yet advanced enough to try a D.

Rod , in the article mentioned that he never built the project
and that IF someone did they better have the big cash and
know what they were doing..

A pair of Hypex UCD 700's are what I meant, not building from
scratch. A project using them is still 800-1K$
OS
  Reply With Quote
Old 27th January 2009, 07:47 PM   #9
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Quote:
Originally posted by ostripper
That is why I mentioned the 7 pair of Vertical mosfets,
as I have not yet advanced enough to try a D.

Rod , in the article mentioned that he never built the project
and that IF someone did they better have the big cash and
know what they were doing..

A pair of Hypex UCD 700's are what I meant, not building from
scratch. A project using them is still 800-1K$
OS

Think $ 800 - 1K is bad, go look here....

http://www.higherfi.com/amplist/amplist.htm
__________________
Kindest regards
Nico
  Reply With Quote
Old 27th January 2009, 08:03 PM   #10
diyAudio Member
 
d to the g's Avatar
 
Join Date: Aug 2006
Location: minimalopolis
Quote:
Originally posted by Nico Ras



Think $ 800 - 1K is bad, go look here....

http://www.higherfi.com/amplist/amplist.htm
I live about 20 minutes from here, and they had advertised for a tech position. When I answered the ad and enquired into the compensation, the gentlemen was incredibly rude. He told me that just being able to touch this equipment would be it's own compensation.
  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
MHz Class-D MCD-255 building question gogowatch Class D 60 30th March 2008 04:11 AM
class T for building waveguides twenty Class D 11 5th September 2006 05:12 AM


New To Site? Need Help?

All times are GMT. The time now is 12:25 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