Elektor's "Ulti Amp" - Page 3 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Elektor

Elektor News and offers from Elektor Magazine

Reply
 
Thread Tools Search this Thread
Old 9th April 2010, 11:15 AM   #21
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Additional low power supply

The required additional low power supply for the main board.
Attached Images
File Type: jpg UA_power_supply.jpg (186.6 KB, 1067 views)
File Type: jpg UA_add_pw_supply.jpg (331.4 KB, 1044 views)
  Reply With Quote
Old 18th April 2010, 10:26 AM   #22
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Ulti Amp upgrade

Replacing the VAS transistors MJE15031 (T12) and MJE15030 (T13) with transistors 2SA1209 and 2SC2911.

To remain stability with Sanyo 2SA/SC transistors place a 47pF styroflex cap from base to collector for both semiconductors and replace the feedback 220pF cap Cfb for a 100pF styroflex or silvered mica cap.

Lower the idling VAS current to 12mA, by replacing the emitters resistors (R31…) . New resistor value 33 Ohms.

Lower the idling current in the second differential stage to 10mA, this comes down to 5mA per transistor leg.

Replace R51, 100E resistor by a 10E resistor and remove the short to power-ground.
  Reply With Quote
Old 18th April 2010, 10:33 AM   #23
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Datasheet 2SA/SC

for your information the 2SA1209/2SC2922 datasheet.
Attached Files
File Type: pdf 2SA1209.pdf (48.3 KB, 138 views)
  Reply With Quote
Old 26th October 2010, 01:58 PM   #24
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Original matched dual transistors in this Elektor can be obtained (online) in Germany. Supplier is DSI who still offering the BFX36 and 2N914.

GES GmbH - www.Electronicpool.de - abgekündigte und schwer beschaffbare elektronische Bauteile

regards,
Piersma
  Reply With Quote
Old 12th February 2013, 12:52 PM   #25
diyAudio Member
 
Join Date: Feb 2013
Hello "Piersma"
You seems to be the ULTI- specialist! Especially when I see how long you ingaged in this topic. I plan to start with this project in autumn this year. Before starting I would like to have solved all changes and improvements in the circuit and the bom.
At the moment I am just preparing a real pre-amp ( no caps in the signal line) with
proven design. If you are interested I would like to send you a pdf.-file for information. The only problem is, the paper`s language is german. I would be very pleased, if I could get any informations about your ULTI build phase. arothfr
  Reply With Quote
Old 12th February 2013, 06:35 PM   #26
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default More info

Arothfr, please sent a private message for more information.
  Reply With Quote
Old 13th February 2013, 12:05 PM   #27
diyAudio Member
 
Join Date: Feb 2013
Hi Piersma,
thank you very much for your quick reaction. Yes, I plan to build the ULTI-Amp!
When I read the ELECTOR pages, I decided for many years, this should be the right one. For the professional out looking, it shouuld fit into a YAMAHA- case of the M50 amp. My first steps will be to check are all part I need available, next must be what kind of issues are known. Here I would like to contact you; what experience did you
make, What are your next projects ? Regards : arothfr
  Reply With Quote
Old 13th February 2013, 03:31 PM   #28
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Ulti Amp

Till this current day i still use the Ulti Amp as one of my preferred audio amplifiers. Ten years ago I a got a lot of emails from German builders who ran into trouble with this Elektor Amplifier, due to issues not mentioned (experienced) by Elektor. You should read this threat very carefully if you plan to build this "beast". You probably will run into problems sourcing the original parts by Elektor. Cross reference parts are still available.

Latest amplifier builds were Elvee's Circlophone and Roender's RFC-100.
  Reply With Quote
Old 13th February 2013, 04:00 PM   #29
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Duals

For your information.
Attached Files
File Type: pdf duals.pdf (53.9 KB, 172 views)
  Reply With Quote
Old 19th February 2013, 12:05 PM   #30
diyAudio Member
 
Join Date: Feb 2013
Hello Piersma,

here some interesting information for your next project " the ULTI pre-amp".
Name and quality of sound fits together; this one is real professional!
Have a look at the circuit ( Done with LT1028AP, OPA 637BP,OPA 627BP ), open this link............, Regards arothfrhttp://www.huennebeck-online.de/dy/pre-1/pre-1.pdf
  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
I need comments about "100W power amp. elektor april 1982" jinkuchi Elektor 78 22nd February 2011 05:15 PM
What makes an amplifier "bright", "warm", or "neutral"? JohnS Solid State 51 13th December 2009 07:42 PM
Pls comment on "Compact audio amplifier" from Elektor goldyrathore Solid State 11 3rd March 2003 09:20 AM
Anyone used Scan-Speak's "Flow Resistors" or "Aperiodic Vents"? Ignite Multi-Way 3 18th November 2001 09:42 AM


New To Site? Need Help?

All times are GMT. The time now is 12:22 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