Elektor's "Ulti Amp"

[freddyjazz]

From Elektuur 1994 the amp multi-amp, I have a for 90% ready PCB's and missing parts to make two ampfliers.
All the papers with descriptions are with it and also the trafo's. Hr. Piersma do know somebody who want to buy this and make the two end ampfliers?
Because my age it is for me impossible to make it further.
greetings Freddyjazz

 

[Wuschel0815]

Hi Piersma,
theLink to the Elektor document in english ist broken.
If you want, i can send you the original article. But it is in German language.....

 

[Wuschel0815]

Has annyone a Softstart-PCB for the Ulti-Amp for me ?
drilled or undrilled..

 

[Piersma]

The Dutch Ulti-Amp version is in my possession !

 

[Tailgunner]

SSM types

Hi Rudy,

I did not use SSM matched pairs in this amplifier.
I used the 2N2918 and BFX36 matched pairs for the gain stages, according to the original schematic.
If you modify the schematic it is possible to use SSM or MAT types, last mentioned pairs will make the sound better !
Just lower the railvoltage or use some zenerdiodes in the collectors.

best regards
Piersma

Do those zenerdiodes effect the performance (soundquality) of the amplifier? Are red leds also an option?

 

[Piersma]

The dynamic zener resistance is very low, not impacting the overall gain of the first amplifier stage.

 

[tiefbassuebertr]

If I recall right, there was an elektor version from Ulti-Amp with low power voltage but very high output current for driving low impedance loudspeakers, e. g. ribbon speakers. The topology looks like those from Ulti-Preamp in the attached file, but instead the small signal transistors in the output buffer there was in use power BjT devices from Sanken or Toshiba.
Maybe it was this elektor power amp project:
https://www.elektormagazine.com/magazine/elektor-199211/32717
https://www.elektormagazine.com/magazine/elektor-199212/32782
Maybe one of the member can upload the schematic - thank you very much.

P.S.: The threads under
https://www.diyaudio.com/community/threads/direct-drive-ribbon-amp.46986/
https://www.diyaudio.com/community/threads/direct-drive-ribbon-amp-power-requirement.318915/
https://www.diyaudio.com/community/threads/are-very-low-impedances-really-that-hard-to-drive.400790/
https://www.diyaudio.com/community/threads/driving-low-impedance-loads.56875/
https://www.diyaudio.com/community/...-25w-class-a-into-1-ohm-resistive-load.31616/
https://www.diyaudio.com/community/threads/amp-that-can-drive-low-impedance-ribbon.65759/
don't provide the wanted information.