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 December 2001, 08:43 AM   #1
diyAudio Member
 
Join Date: Dec 2001
Location: Howick South Africa
Has anyone built the 350 Watt Mosfet amp as shown in Andrea's Home Page? It,s in Italian (a copy from an electronics mag) but seems to be detailed enough to build without translation. I like the look of it, and it give a good enough to use PCB layout etc.
I would appreciate any comments, ideas etc as I have made the board and will start building as soon as funds permit.
His web page is http://www.geocities.com/researchtriangle/8231
  Reply With Quote
Old 11th December 2001, 11:14 AM   #2
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Iīve had a look at Andreas homepage but couldnīt find a 350W amp. Could you be a bit more precise?

william
  Reply With Quote
Old 11th December 2001, 11:42 AM   #3
diyAudio Member
 
Join Date: Dec 2001
Location: Howick South Africa
Try http://www.geocities.com/researchtri....html#DOC_AMPL

It,s in a section right at the bottom of his page under "documentation: amplifiers". Just scroll down and you will see the heading plus pages to download. His page contains a lot of advertising and it all needs to open before you get to the real meat of his page.
I found some of the scanned article pages did not download properly, and got him to mail them to me. If you want copies I can mail them to you.

DieterD
  Reply With Quote
Old 11th December 2001, 04:12 PM   #4
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Hello DieterD,

this amp looks like one I build many times with good results. Itīs just like the old crescendo from elektor slightly modified (the original used 2 + 2 2sj50/2sk135)
I would suggest some minor changes:

swap the bf drivers for BD139/140 or better MJE340/350. This makes a big improvement in speed/attack, clarity and bass performance.

donīt use a capacitor in the feedback loop. A simple servo with an OP77 will do a lot for bass performance.

separate the power supply for the driver and output section. You can use a pair of LT317/337 set at about 3-4 volts above the output section voltage.

I īdonīt know how the mosfets used here sound but you can still buy some 2sk135/2sj50 (although named differently nowadays).

Are you sure you need all the power? With a 40-50 Volt supply you could go for a higher bias (200-250mA per fet) and BC550/560 in the differential stage wich would also improve the sound. You just have to change a few resistors to get the thing running again.

regards,

william

  Reply With Quote
Old 12th December 2001, 06:15 AM   #5
diyAudio Member
 
Join Date: Dec 2001
Location: Howick South Africa
Hi William,
Thanks for the info, I see from your reply that you have a lot more knowledge about amps etc than I have, and if I get stuck I will mail you direct (if you dont mind)
I need the power as my son plays in a band and wants to use his equipment to do live performances in halls etc. Unfortunately we dont have the money to buy factory made amps, eg Peavey or Crown, as the exchange rate here in South Africa makes importing goods very expensive, so I want to try & build a few "biggish" amps and use those. I have built a few ESP amps, bridged them and now want to try my hand at something bigger, and this one seems to be the logical next step. I assume one could bridge two of these and get a fair amount of power out of it?

Thanks again,
"sprechen sie Deutch?"
  Reply With Quote
Old 12th December 2001, 09:47 AM   #6
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
http://meltingpot.fortunecity.com/br...plifier_p6.jpg Same amp as here http://users.swing.be/edwinpaij/ampli_mosfet.htm
  Reply With Quote
Old 12th December 2001, 01:13 PM   #7
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Hello DieterD,

if you want to bridge then have a look at an old elektor project called the "kilowatter". Itīs almost the same design with 2 x 4 mosfets bridged. I think this would be what you need including ventilator cooling. Iīve got the original article and I believe theyīve brought out a cd with all the articles and layouts.

regards,

william
  Reply With Quote
Old 12th December 2001, 01:54 PM   #8
Dirk is offline Dirk  Belgium
diyAudio Member
 
Join Date: Oct 2001
Location: Gent, Belgium
For what it's worth, I heard from a designer from Elektor that they don't consider the "kilowatter" as a very good amplifier. More recently, they published the "Titan" amp which they find very good (and which is quite complicated).

Regards,

Dirk
  Reply With Quote
Old 12th December 2001, 03:56 PM   #9
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Hello Dirk,

I think youīre right concerning the audiophile qualities if you want to go for the very best(all those zener diodes canīt be good) but for a PA system this wouldnīt hurt.

Elektor (elektuur) designers often talk about good and bad in terms of measured performance. A few years ago they (one) told me the kilowatter was a lot better than the crescendo.....
I havenīt ever heard the kilowatter but looking at the circuit topologie it canīt sound that bad. I suggested DieterD had a look at the article cause there are a lot of nice and usefull features (balanced in/ bridging mode / fans / layout) he can also use for the 350 watter mentioned above.

william
  Reply With Quote
Old 14th December 2001, 07:42 AM   #10
diyAudio Member
 
Join Date: Dec 2001
Location: Howick South Africa
Hi William,

Is there an Elector home page where these articles are available?

DieterD
  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
Andrea Ciuffoli's power follower SteveG Solid State 11 3rd February 2014 02:53 PM
Andrea Bocelli - L'Abitudine (feat. Helena) Jean Music 13 2nd January 2010 08:57 AM
BiCMOS Bipolar+MOSFET better than MOSFET lineup Solid State 5 8th December 2009 11:46 AM
Custom designed transformer for Andrea Ciuffoli 6c33c OTL AMP.... zxcxz Tubes / Valves 2 10th July 2009 04:14 PM
Andrea Ciuffoli's KT88 PP blacklight Tubes / Valves 21 29th April 2008 10:35 AM


New To Site? Need Help?

All times are GMT. The time now is 05:08 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2