Bora is a nice guy from Serbia - Yugoslávia

[viktor1986]

Hello everybody!
I am writing this to contribute and inform DIY community about another
design by Dr. Bora Jagodic. I found that thread on the best Croatian
Audiofil.net DIY forum two days ago, and I thought it is worth sharing it
with wider audio community. It is about his power amplifier design named
"Techno" that has been built and tested by well known and respectable
Croatian audiophile and DIY enthusiast "Dioklecijan" that he published on
Croatian Audiofil.net forum. My old friend from school, which speak English
better than me, helped me to make this translation of his posts:

"This days I've finished amplifier Techno with output stage done according
to schematics from Borivoje Jagodic. You can find that schematic on his
site: http://bas.elitesecurity.org/mojiprojekti1.html . Preamplifier stage
is my own idea with SMD OPAMP-s TLE2071.

Here are some photographs of progress of that project:
http://img.photobucket.com/albums/v...an/IMG_0878.jpg
http://img.photobucket.com/albums/v.../IMG_0877_1.jpg
http://img.photobucket.com/albums/v...ecijan/amp1.jpg

Here is how it looks today:
http://img.photobucket.com/albums/v.../IMG_1080_1.jpg
and here is how it will look when I finally close the case-enclosure:
http://img.photobucket.com/albums/v.../IMG_1077_1.jpg

Some technical aspects:
Output transistors are ONSEMI 2SA1302/2SC3281 (thanks to "Pinco"), and the
rest is all according to schematic. Because those transistors have high GBW
it is necessary to put capacitor of between 150-330pF in parallel to
existing 10k resistor at the input of amp. Otherwise it might oscillate!
Everything else should be done by schematic.
Mains transformers were 29V/200VA per channel + separate transformer for
preamp.

Amplifier posses power in abundance. Control is immaculate, and in my tests
it was working with Focal Electra 1028, and with Electra 905, Diapason
Micra and JBL CM42. Amp is biased at 90mA and if anyone is going to build it
I suggest bigger heatsinks than mine.

Sound of this amplifier is very pleasant for listening, with extraordinary
dynamic and excellent detaileness. As audiophiles would say "it sound
musically". Under 10.000 kuna (Croatian national currency, about
??kuna=1Euro) in the shop you won't find better amp. This is valid if amp is
done properly and with high quality components!"

Second post:
" http://img.photobucket.com/albums/v.../IMG_1082_1.jpg
http://img.photobucket.com/albums/v...an/IMG_1081.jpg

Here is the preamplifier. It consist of input buffer and second stage with
6dB gain, which is very low but amp itself has high gain so together it is
enough. I also predict a variable output for connection of subwoofer or
alike and that stage has slightly higher gain of around 9dB. Supply is
standard with LM317/337 but maybe one day it will be replaced with some
superregulator version.

Answer to Boban's question:
With regards to a character of the sound, I will put Techno somewhere
between Audio Analogue Puccini SE and Rotel 1070, and I'll say it took
musicality from Puccini and detailness from Rotel, but overall impression is
that it is better than both those amplifiers!
Of course, it slightly lacks that specific transparency that PassAleph5
posses (but anyway that is a specific virtue of Pass masterpieces).
For real assessment, I believe, it will take more than this 10 days that I
spent with sound of Techno amplifier."

Dioklecijan's setup: Marantz CD14, Nottingham Analogue Spacedeck-Benz Micro
ACE, Denon DVD3910, Sansui TU-X1, DIY; Phono Preamp, Pass Labs BLS, Pass
Labs Aleph 5; Focal Electra 1027BE, VDH 102MKIII, Cable Talk ConcertAnswer to Boban's question: With regards to a character of the sound, I will put Techno somewhere between Audio Analogue Puccini SE and Rotel 1070, and I'll say it took musicality from Puccini and detailness from Rotel, but overall impression is that it is better than both those amplifiers! Of course, it slightly lacks that specific transparency that PassAleph5 posses (but anyway that is a specific virtue of Pass masterpieces). For real assessment, I believe, it will take more than this 10 days that I spent with sound of Techno amplifier."

[sith]

Under 10.000 kuna (Croatian national currency, about ??kuna=1Euro)

1€ = 7,2 kunas

[destroyer X]

He send me his last schematics, all them made before his entrance in the Hospital... and his disease needs some care.

The first thing he need to avoid are problems.

This way, i think he will not track the thread, and also will not be able to answer all the mails he use to receive...and they use to be more than 60 mails a day.

Many of those mails are people constructing and needing instructions...he used to help them...but some of them made criticisms on him.... a tragedy when we face not gratefull folks...you help them and a knife come into your heart....well..this is life...and people thinks different.... this is also very interesting..as we can select people to be near us...the good ones, the ones match our own needs.

Some of those designs were constructed...i have asked Bora informations about the ones constructed...and also those guy's mails, as they can be a support for constructors.....for sure Bora will have to ask folks, in advance, if they want their adress published and if they want to give that support to some beginners that may ask that...this wast a lot of time and sometimes generate unfair results.

Well...as i think he is a very good, a respectable designer, that made many good amplifiers that some friends mine have constructed.. i am happy to show his new designs.

Bora is a Doctor...he is not someone that hold the computer and started to tell stories...his has Post Graduation folks...he is a teacher in University, a respectable guy.....but this is very bad as he has not time to follow the thread with the constance we may need...also he has not time to be over people's shoulder when constructing...also he is not a magic to discover, in advance, all the foolishes people can make with his amplifiers.

For sure, Bora's amplifier will not work under watter, nor with excesses of voltage in the rails, or excesses of voltage in the input or reactive loads...will not work after beeing smashed by a truck or something alike...there are limits of reliability that depends on the constructor competence.

I will publish his designs and schematics in sequence...i have not assembled his designs, as i do not have FETs easy in my place..they are rare and expensive here.

I cannot tell about sonics as i never have listened to them...i suppose they are very good, as circuit solutions are very modern.

This one is called 3FET line BV

regards,

Carlos

[destroyer X]

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[destroyer X]

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