| destroyer X |
We have been talking for long time, and i asked him to let me post some schematics.
Those circuits i did not assemble, so, i cannot evaluate, as not hearing i have not this condition.
As Bora is experienced, i suppose he had constructed some prototypes.
Now, presenting Bora to forum friends.
regards,
Carlos |
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| destroyer X |
The adress are there if you want to visit.
regards,
Carlos |
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| destroyer X |
One is bridged, very good to use as subwoofer, as can produce a big voltage swing.
I will post in PDF because of quality.
regards,
Carlos |
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| destroyer X |
You can see that is dated of September.
regards,
Carlos |
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| destroyer X |
Because there are many that loves simetrical amplifiers, in special this one that have simetrical input.
Bora will be tracking, to answer the questions that may appear.
regards,
Carlos |
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| mwmkravchenko |
Thank you Carlos and Bora.
MArk |
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| destroyer X |
That we really apreciate....you Kravitchenko.
This thread started with luck!
regards,
Carlos |
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| jaycee |
The Delta is rather... interesting!!
The catch is the BF469/470 is obsolete now. What would you suggest in replacement ? I've only ever found Japanese devices (notably by Toshiba and Sanyo) as close to these. |
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| destroyer X |
confused to find a good replacement, because the samples i have in my home, measured 150 of gain, showing me that it is a very low gain unit.... as this small value of gain may had be used to calculate the entire amplifier gain, a good replacement will need reduced gain too....well, Bora may have solution.
Bora place is advanced related New York time line.... around 4 hours i imagine, soon he will be here to suggest some replacement.
The first package of amplifiers Bora sent me, have 25 units....i believe that may have one or two more amplifiers that will interest you.
Amplifiers will be posted in groups of 3 units, a very good idea from Bora, this way, all comments will be around the last post 3 units.... a very few comments and questions will appear related older posted units.
Having curiosity Jaycee, try to visit his home page, where you will have more options.
regards,
Carlos |
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| pinco |
Hi,
I made his Studio amplifier and Omni protection board, Studio is excellent amplifier, very nice sound and superb stability, it is my first diy amplifier, and I am very pleased, Thanks Bora!!!,
Vinko |
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| pinco |
| Omni protects the power transistors in case of overload, the speakers in case of power amp malfunction, protects amplifier in case of short circuit in loudspeaker or speaker cable or too low impedance of connected speakers, and also performs a muting function when the power supply is turned ON or OFF. |
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| Ultima Thule |
Thanks Carlos for your presentation of Bora and his amplifiers! :)
I would like to ask Bora what is the purpose of Q3 and Q4 in the Delta design?
Does that connection have a name(after perhaps from some inventor), I have a weak memory I have seen it somewhere.
Cheers Michael |
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| destroyer X |
I cannot wait the day to have another dinner with you, the virtual one we have, in front of the swiming pool.
hehe...was great!...unforgeatable!
Well, Bora may be very happy...when a single forum guy accepted some amplifier, the work done is already paid!
Bora is a little bit busy, as he have two main professions...and some others secondaries responsabilities too.
regards,
Carlos |
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| pinco |
This is Studio and Omni, sorry for little mess on the desk, it is testing phase.......
Vinko |
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| darkfenriz |
| quote: | Originally posted by jaycee
The Delta is rather... interesting!!
|
Could you explain how it works?
I'm completely puzzled.
Looks like a positive feedback Schmidt trigger to me.
Or maybe I just drunk too little coffee today?
regards |
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| ilimzn |
| It's a Vbe compensation technique... not sure who the author was originally but it appears in Hawksford's papers. |
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| boraomega |
Hello everybody!
I can't believe there are already 16 posts. I've got very busy day and it was impossible for me to join earlier. First of all I have to thank Carlos for his good will and all efforts. He posses GREAT and, in today's world, pretty rare personality with amazing positive attitude! Hopefully, no one took seriously his grossly exaggerated joke-remarks about me in some previous posts! Carlos... Carlos... :smash:
I also have to stress that some of the simulation results (mainly THD) should be taken "with a good pinch of salt" for, practical results were in some cases more than 10 times worst.
ILIMZN - thanks for answering to "Ultima Thule" for me. As I expected, you gave correct answer with maybe little addition that it is actually linearising technique that I have learned from big master Hawksford. I hope, no one think even for a second that it is my invention! It is generally known as "linearised cross-quad". Anyone interested for more details should search for Hawksford's articles on the WEB.
By the way ILIMZN, I am following most of your posts for quite some time, and all I can say is... congratulations!!!... you posses remarkable knowledge as well as fine sense for details and even more for essence of designs. I am glad to say I know you!
Damn... "darkfenriz"! I was hoping that no one would recognize it! Yes, it was started as an audio amp. idea, but ended as High-End Schmidt trigger... of course, high power one. |
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| Dragance007 |
| i have listened to amplifier called "Sigma" once...i sounded really nice...but i didn't know that the designer is from my country...funny :) |
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| choky |
| quote: | Originally posted by Dragance007
i have listened to amplifier called "Sigma" once...i sounded really nice...but i didn't know that the designer is from my country...funny :) |
"speak Serbian........"
(".....and entire world will understand ya!")
:clown: |
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| destroyer X |
Projacala...you see!...this is amplifier....hehe
The thread main responsable, Baraomega arrived...good to see you Bora.
regards,
Carlos |
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| viktor1986 |
| My picture of Studio amplifier.Soon more...... |
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| choky |
| quote: | Originally posted by destroyer X
Projacala...you see!...this is amplifier....hehe
The thread main responsable, Baraomega arrived...good to see you Bora.
regards,
Carlos |
hehe-almost.......
pojacala-amplifiers
pojacalo-amplifier
pretpojacalo-preamplifier
;) |
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| boraomega |
It seems, I overlooked jaycee's question. Sorry!
One will find BF470/469 frequently in my designs and there are few (for me) good reasons for that: at one moment I've managed to obtain cheaply a significant quantity of them, I have BF470/469 simulation model in my SPICE program, they appear to exhibit more linear transfer characteristic than majority of similar units on the "current fashion" list,
and their internal capacitance's are significantly lower allowing less
problems and faster amps. Praxis proved me right for now. They use to be readily
available anywhere ( for previously mentioned reason I am not aware that they are discontinued?!), they are in a handy package-case and with very usable Uce and
dissipation.
Even thou I didn't test them as replacements, I strongly believe that something like MJE340/350 or newer version like BF869/870 (I think they are in different package?) should be adequate. Certainly, there must be at least a dozen of Japanese complementary pairs to fulfill requirements. Maybe Sanyo's 2SC3116/2SA1248 or alike...
Pozdrav od sveg srca za sve moje "zemljake", a ja bez razlike pod time podrazumevam sve one koji razumeju ove reci! |
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| chicco_36 |
Karlos, you must learn serbian or even better macedonian! :D
Here on south of Europe we have some miracles in electronics too!
I'm glad for my neighbours from north, same for us macedonians!
Bora, radujem se sto tvoje znaje i iskustvo nalazi pravo priznanje, a diyAudio sajt je pravo mesto za svakog audio fanatika.
Najsrdacniji pozdrav! = (best regards) |
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| destroyer X |
I told you...i will learn Macedonian too.
regards,
Carlos |
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| destroyer X |
Serbia is the correct name....i wrote Servia and this is wrong.
I am afraid that Servia can be something very bad.
Alike your wife's mother moving into your home!.... oh!...pain!!!.... oh!...do you like your mother in law?
hehe..i can send mine to you!...if you promiss not return.
regards,
Carlos |
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| r!sc! |
Hi there! Whoo, so much people from the Serv(b)ia :D
Bora is a great guy. Everytime when we ( young audio enthusiast :) ) have some problems in our audio works, Bora is there to help and advice us. Thanks Bora!
Ziveli ljudi! = Cheers people!
Boban |
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| destroyer X |
Cheers,
Carlos |
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| pinco |
| quote: | Originally posted by destroyer X
Cheers,
Carlos |
If you say " Zivjeli ljudi" you can even spook Croatian....
Pozdrav svima, poseban pozdrav Bobanu i Bori, !!!! |
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| Samuel Jayaraj |
Bora, your Goliath amplifier is a straight adaptation of Elektor's Crescendo amplifier. I wonder how it works at all, since you have used vertical mosfets and there is no Vgs, or Vbe multiplier or any other temperature sensing mechanism at work. If anyone has every tried this amp practically, thermal runaway should have occured some time or the other. Any explanations?
The other designs look great. Perhaps I'll try them out after I have finished with the GEM (testing prototype in two hours time!!) |
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| wintermute |
I believe WES in Sydney still have BF469 and BF472 (higher voltage but otherwise same as BF470) I bought 30 BF469's a while back. http://www.wagner.net.au/
futurlec also has BF469's but they don't have bf470's or bf472's
Tony. |
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| zeonrider |
Ma dobar je Bora , samo kad je dobre volje i kad ima neke koristi od toga. Seti se Boro seme PHASE LINEAR koju si mi poslao. Ja sam mislio da si ti neki naucnik u pogledu audio elekrtonike, a ti si obican skljupac sema i dobar AMATER.
POZDRAV SVIMA |
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| boraomega |
| quote: | Originally posted by Samuel Jayaraj
Bora, your Goliath amplifier is a straight adaptation of Elektor's Crescendo amplifier. I wonder how it works at all, since you have used vertical mosfets and there is no Vgs, or Vbe multiplier or any other temperature sensing mechanism at work. If anyone has every tried this amp practically, thermal runaway should have occured some time or the other. Any explanations?
The other designs look great. Perhaps I'll try them out after I have finished with the GEM (testing prototype in two hours time!!) |
Thank you Samuel for noticing that mistake, and I apologize to all others too. Frankly, I never noticed that I typed IRFP models instead of 2SK1056/2SJ162 and that schematic (with a mistake) has been on my site for last few years. Disaster! Without Vbe multiplier, IRFP's would certainly have a sad destiny! Hopefully, anyone with experience will probably immediately notice another clue: bias trimmer is only 250 ohms and knowing the threshold voltages for opening IRFP's, will realize that current through drivers would have to be almost 300mA to produce necessary voltage drop for both sides.
The schematic is very similar to Crescendo (as well as at least a few dozen others one could find all over the WEB) which is one of more or less generic topologies well known and widely used. |
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| boraomega |
| quote: | Originally posted by zeonrider
Ma dobar je Bora , samo kad je dobre volje i kad ima neke koristi od toga. Seti se Boro seme PHASE LINEAR koju si mi poslao. Ja sam mislio da si ti neki naucnik u pogledu audio elekrtonike, a ti si obican skljupac sema i dobar AMATER.
POZDRAV SVIMA |
Ruzno... bezobrazno... i nicim zasluzeno!
Bilo bi posteno da se jave svi oni sa kojima sam do sada kontaktirao samo iz ciste koristi... |
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| viktor1986 |
JA NE DOZVOLJAVAM DA SE BILO KO NA TAKAV NACIN OBRACA BORI.BORA MI JE MNOGO POMOGAO U "SAZREVANJU" U OVOJ OBLASTI I MNOGO MU SE ZAHVALJUJEM JER SAM DOSTA NAUCIO OD NJEGA A ZELIM DA SE TAKO I NASTAVI.JA SAM DO SADA URADIO BORINO POJACALO STUDIO I UNIVERSAL I OBA SU PRORADILA.STUDIO JE PRORADIO IZ PRVE I BEZ GRESKE JE SVIRAO I DAVAO LEP ZVUK.KAZEM LEP JER NEMAM KVALITETNE ZVUCNE KUTIJE KAKO BI UTISAK BIO UPECATLJIV.
Sve u svemu,svako ko napravi neko Borino pojacalo se nece pokajati. |
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| planet10 |
| quote: | Originally posted by destroyer X
I am afraid that Servia can be something very bad.
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Or something very good... an excellent race car driver...
dave |
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| sardonx |
I was going to say something about the "Servia" thing.. but then i thought hey maybe that's how they say it in Brazil.
Also... there is no accent on the 'a'. We're not French ;) |
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| viktor1986 |
I made boraomega Studio amplifier and I am very pleased with sound. I strongly recommend you too built this HI-END amplifier. My friend has also built Studio amplifier. Soon he will post those pictures’s here. I made also Universal amplifier but with IRFP240 and IRFP9240 instead 2SK1058 and 2SJ162.You can found something more if you click here http://www.hifi.co.yu/forum/viewtopic.php?t=551
I am currently working on Legend amplifier but with 8 IRFP250.
POZDRAV SVIMA. |
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| jacco vermeulen |
| quote: | Originally posted by sardonx
I was going to say something about the "Servia" thing.. but then i thought hey maybe that's how they say it in Brazil. |
You mean Brasil.
Don't make fun of Carloz. |
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| boraomega |
| Here you go Carlos... Do you see what those youngsters are prepaired for... and with older members... |
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| choky |
| quote: | Originally posted by jacco vermeulen
You mean Brasil.
Don't make fun of Carloz. |
CarloZ ?!
hehe, Brazil is not even typo;
Brasil is Brazil in Serbian.
btw- to my felow Serbians (and other speakin' same language,no matter how its called) -please save fights for personal mails.....
like Grunf sez - "tko leti vrijedi , tko ne leti ne vrijedi" ;
Alan Ford comics.....for other innocent members of this forum....... |
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| darkfenriz |
| quote: | Originally posted by boraomega
Damn... "darkfenriz"! I was hoping that no one would recognize it! Yes, it was started as an audio amp. idea, but ended as High-End Schmidt trigger... of course, high power one. |
Are you being sarcastic here?
Or joking? Laughing at me or what?
Or you don't mind wrong circuits signed with your name?
Please answer clearly that either I am wrong (and why?) or "delta" is wrong and nobody should even try to build it the way it is drawn on attached schematic.
And if I am wrong, forgive me picking on.
Sorry for this, but my English isn't that sophisticated and it is not alway clear to me wheater someone is joking or not.
regards |
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| boraomega |
| I am neither selling nor buying anything. I am here to enjoy and relax following my life-motto: "Live your life as an exclamation... not as an explanation" |
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| Ultima Thule |
| quote: | Originally posted by destroyer X
I cannot wait the day to have another dinner with you, the virtual one we have, in front of the swiming pool.
hehe...was great!...unforgeatable!
Well, Bora may be very happy...when a single forum guy accepted some amplifier, the work done is already paid!
Bora is a little bit busy, as he have two main professions...and some others secondaries responsabilities too.
regards,
Carlos |
Thank You very much Carlos, I enjoy the virtual dinner with you, very nice und unforgetable, I can imaging sitting in front of the pool with Brazilian music and dancing chicas in the light of fire and red sunset light! :flame:
Thank you also Bora and Ilimzn for pointing into the Hawksford direction.
In one of the Hawksford papers I see on p.509 pic.15 that he uses two CCS instead of one as in the Delta design, Bora have you seen any Hawksford paper with the crossconnected transistors using only one CCS or is this your own idea?
I don't have much paper from Hawksford so maybe somewhere else it's maybe explained?
Darkfenriz,
I don't see any "Looks like a positive feedback Schmidt trigger", BTW, who is joking here, have another cup of Brazilian coffee, Carlos is our bartender tonight! ;)
Cheers Michael :) |
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| destroyer X |
everything they want without bother me, because i am sure they are good guys and always very educated with me.
Jacco Vermeullen have enormous sense of humor... and his automobile antena use to shake a lot...i do not know what kind of movement he does inside his car...hehe.
All those guys here are nice and close friend...Greg is other good friend.
I do not mind.... the oposite, i love when people make jokes with me.... as in my culture, the first thing that happens when we love someone...turning good friends, is to be more intimate, talking more deep and emotional subjects, we use to hug our friends, and we can tell everything to them...including tell critics, we can critisize too!...all those are signs off friendship between us...respect is for Bosses and to strange people.... distant relatioship is to bad guys, that we use to ignore.
My idea is...talk good things or even bad things...but talk about me, that will prove that i have some interesting existence...that people can accept me.
I conclude that, referenced in my culture uses, because the ones i do not accept, i do not talk with them....it is clear the difference when someone is not educated, when have bad intentions, and very different from those guys that use to make jokes with me...i like that...some social life, not only transistors.
Ultima Thule, this guy is very king...we have old relatioship, beeing gentle one each other...he can advance to intimate conversations without any possibility to be misunderstood by me.... and many others too.
All those, my ELEKRTONIKE friends
Hey guys!, just to remember, forum is in English, because International acepted language.... please, i am just trying to help me and help you all....always post in English first, and them repeat in your own language...giving conditions to all guys understand what you are talking about...to have all guys really partipating.
This way...i will have also, the chance to learn some words...checking the English text to make convertions...but please, do not do...ahahahaha, as some bad brasilians do with some visitors.
The visitor, the tourist ask:
- How can i say "do you have cold beer?"
And some bad brazilian guys teach them:
- "Você tem cara de bunda"...this is the way to ask for a beer!
And the meaning is that the guy have a very strange face...ehehe (SY..do not translate...not offensive..just funny the word...gluteus).
Well.... brasilians are a very happy and free people.... our problem..freedon is too much, even to make mistakes, i was already advised by moderators that i cannot write in my language, to avoid messages that others cannot understand be every forum guy, and this allow that some words can have the meaning hidden...ehehehhehe.... and this happens, as only your language partners can understand....sometimes they can be a little bit excessive.
To avoid that Forum Management enter to ask to write in English, and this is always a shame for us, i am, in advance, telling you all, that this will happen soon, if we do not change our way of write.
First in English...or my "Englander".... and second your language...and i am afraid that the forum management do not feel happy with other languages here...because International... even followed or preceded by English.
In my mind, was prefered that you can express with audio messages, with video messages and even with music too...all those human expression forms.....but this is my way of life....not forum capacities and regulations.
SY, one fair moderator...as he normally do not fail in judgements, and when fail, he is enougth man to reverse his actions....because of this i respect him very much....he is a real man!...he have Brazilian friends and he can understand some words...so he is observing my excesses... and he punished me a couple of times and i do not change myapreciation related him...fair...he is fair!
Wonderfull mood has David Slugos, the Planet 10.... he has fat electrons that move shaking...ahahahha!
Be happy guys...life is short....it is full of problems....disease, wars and terrible mankind strikes...let's be happy.
Najsrdacniji posdrav....best regards,
Carlos |
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| darkfenriz |
Dear dr. Jagodic
You are most welcome to live your life as You wish.
So am I.
Human rights themselves.
Maybe I am a bit idealistic or romantic, but I don't want anybody to be led astray.
So I think, that these differential and voltage amplification stages of "delta" ... |
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| darkfenriz |
| ...work in an inverting mode, so together with differencial stage they produce a positive feedback. |
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| darkfenriz |
| However it could be easily fixed to make an amp work properly... |
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| darkfenriz |
this should have been clear to prevent anyone from making a mistake.
In my ill romantic mind at least.
regards |
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| Steven |
| quote: | Originally posted by Ultima Thule
Thank you also Bora and Ilimzn for pointing into the Hawksford direction.
In one of the Hawksford papers I see on p.509 pic.15 that he uses two CCS instead of one as in the Delta design, Bora have you seen any Hawksford paper with the crossconnected transistors using only one CCS or is this your own idea?
I don't have much paper from Hawksford so maybe somewhere else it's maybe explained?
|
Ultima Thule is pointing at: J4 DISTORTION CORRECTION CIRCUITS FOR AUDIO AMPLIFIERS, M.O.J. Hawksford, JAES, vol.29, no.7.
You can find it here: http://www.essex.ac.uk/ese/research...blications.html
Except for common mode range and noise there is hardly any difference between using two current sources I and one resistor R, or one current source 2I and two resistors, each 0.5R.
Steven |
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| Ultima Thule |
Yes Steven, that's the paper, thanks for clearing this out!
Bora,
have you tested in your Delta design with and without how the Hawksford distorstion correction circuit makes any difference, any listening experiences and/or measured?
BTW, those distortion and BW figures in your schematics, are those measured or from simulations?
Cheers Michael |
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| ChocoHolic |
Hi Darkfenriz,
I think you are right.
Also to my understanding this Hawksford error canceling diff amp turns signal polarity to the opposite of a normal diff amp.
...see figure 15 in Hawksford papers Chapter "5 Indirect Distorsion Cancellation Topologies"....
Let's go stage by stage:
When the input signal moves upwards:
==> Ic of Q1 increases, due to error cancelling diff arrangement.
==> Ube of Q11 increases.
==> Ic of Q11 increases.
==> Ic of Q12 increases.
==> Output moves downwards.
Input at Q1 is inverting.
Base of Q2 is noninverting input and getting the feedback signal.
...urghs... !!
Great that you noticed this point ! |
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| ChocoHolic |
| quote: | Originally posted by darkfenriz
However it could be easily fixed to make an amp work properly... |
???
Are you sure?
I would expect that your proposal does not change the polarity, but
just resulting in less gain... |
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| darkfenriz |
Thank you ChocoHolic, my great tutor.
Yes, what I've drawn also isn't free from drawing mistake.
It should look like this: (attachment)
Good example of error correction amongst us. |
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| ChocoHolic |
| quote: | Originally posted by darkfenriz
Thank you ChocoHolic, my great tutor.
|
:Ohno:
...hope you are joking, we have better guys (and ladies !!!) here...
| quote: | Originally posted by darkfenriz
Yes, what I've drawn also isn't free from drawing mistake.
It should look like this: (attachment)
Good example of error correction amongst us. |
Yes this circuit would match to my understanding. |
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| lumanauw |
Hi, Steven,
What exactly this Delta (Hawksford) configuration do? I mean compared to standard 3 stages (+VBE multiplier biasing scheme)? |
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| Steven |
Hi Lumanauw,
Nothing special. The Delta is also a three stage amp, with differential input stage, VAS stage and output buffer stage.
The special thing is the use of a differential cross quad circuit as input amplifier. Vbe cancelling is used to decrease the distortion of the input differential amplifier. This works for relatively small differential input signals only, so do not use this for amplifiers without feedback to the input stage, or add the Vk voltage sources as described by Hawksford in his paper.
BTW This cross quad arangement is not invented by Hawksford, but exists already for decades, so better not call it a Hawksford configuration. Who knows who invented it?
Steven |
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| Ultima Thule |
Steven,
thanks for your input!
I just got curious to this circuit, would like to know if there's other people who have used it and what's their experiences with it.
As you mentioned Steven the Vk voltage can be "omitted" and the Base can be connected directly to the opposit transistors Collector if, as stated in the Hawksford paper, the signal is small, else there should be a Vk not equal to the Collector potential added if the input signal is larger.
I have to read the paper more carefully sometime to get into the subject.
But is the cross quad arrangement patented, does anybody know?
Well, next week I will get my "new" soundcard so hopefully I can start to make some real measurements. :)
Cheers Michael |
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| destroyer X |
But i change my mind.
You have so deep knowledge, that almost every amplifier is already known by you..... so.... the fun related discover things may had finish in your live...hummmm...
I will continue to be the way i am...as every new amplifier...new posted, seems a new world to me.
Now i will think to reach you related the respect the community have to you...but will not want anymore to have so deep knowledge...as things turns common.... loose taste this way.
No, there are not double ideas hidden in my text...the words have the correct meaning...really, you were someone to reach related know how, and this was perceived when i entered the forum. and i told you...in a post...and i was not kidding..this happened a year and half ago....you continue to be an explendid EE...but i think i will try to reach your respectability ...the knowledge i do not want anymore...better to have fun learning slowly.
I understand those things because i had passion to travel using Jet Planes.... and i entered a Japanese Company, i had to travell 15 days of each month.... all the pleasure finished, i had already travelled to every brazilian town.... i could identify and remenber the Pilots name...all thing turns very boering to me, I expect, and really wish that you continue to feel good constructing things, because your level is to design, and be distant from production... the pleasure to hold the soldering iron and sometimes to burn some finger..hehe.
regards,
Carlos |
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| Tom2 |
| quote: | Steven said,
BTW This cross quad arangement is not invented by Hawksford, but exists already for decades, so better not call it a Hawksford configuration. Who knows who invented it? |
The earlist reference I have is:
Raimondo Caprio, "Precision Differential Voltage-Current Converter",
Electronics Letters, Vol.9 No.6, 22nd March 1973.
Papers with S. Pookaiyaudom as one of the authors that were published
in the later part of the 70's uses the topology.
I think Brett Wilson referred to the cross topology as the Pookaiyaudom
quad (or something like that) in the early 80's in one of his papers???
Tom |
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| lumanauw |
Hi, Carlos,
I think someone like Steven still enjoys analog cct :D Read his footage of "Dodo's faith....." |
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| destroyer X |
this is good, despite of enormous know how, did not loose passion for those things.
You know, when things turns obligation, normally our interest reduce.
Working with audio...well....may be a little boering.
Beeing a hobby is very nice...but transistors all day may be terrible.
Thanks Lumanauw
regards,
Carlos |
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| viktor1986 |
Studio amplifier.
DRPONJA built this. |
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| Ultima Thule |
| quote: | Originally posted by Tom2
The earlist reference I have is:
Raimondo Caprio, "Precision Differential Voltage-Current Converter",
Electronics Letters, Vol.9 No.6, 22nd March 1973.
Papers with S. Pookaiyaudom as one of the authors that were published
in the later part of the 70's uses the topology.
I think Brett Wilson referred to the cross topology as the Pookaiyaudom
quad (or something like that) in the early 80's in one of his papers???
Tom |
Hi Tom,
Thanks for your info!
Do you have any paper in electronic format like pdf or so in the subject you could e-mail me?
Carlos,
I agree with you, sometimes it's better to not know too much, it's much more fun then! :)
Cheers Michael |
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| destroyer X |
Better to have pleasure with music...when we worry too much...half the pleasure gone.
regards,
Carlos |
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| destroyer X |
I already sent him all the positive energies i could....and will keeping thinking on him along this day.
Bora, alike all of us, loves his father, and living a bad moment, reason why he is not here with us.
regards,
Carlos |
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| Tom2 |
| quote: | Ultima Thule said,
Do you have any paper in electronic format like pdf or so in the subject you could e-mail me? |
The papers I have are xerox copies from journals I copied back in
1990. I have about five references. The copies are in good shape. The papers are short. If you want I can scan them and e-mail them to you.
I'll have to experiment what format works best ( jpg, pdf or tiff??).
I can give you the references if you have access to a university library also.
Tom |
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| Ultima Thule |
Carlos,
thank you for telling us about Bora, I started to wonder where our friend was. Our thoughts is with him!
Tom,
if it's not too much job scanning those pages, please do so, I guess pdf is the favourable choice.
Unfortunately I don't have any close access to university library, but please give the refferences.
Many thanks in advance Tom,
Michael |
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| Tom2 |
Ultima Thule,
No problem, I will scan and convert them in the next few days.
I've been wasting to much time playing Doom anyway. :hot:
Tom |
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| Steven |
I just returned from a course I attended for a week, a follow up course on Marketing. I enjoyed it a lot. It's not about electronics, nor about audio, but still I liked it.
Carlos, don't be afraid, I still have an affection for analog electronics. Although I hardly do anything with it professionally, it continues to be a hobby of mine, and I enjoy to find simple ways to realize a certain function.
Anyway, it was never my intention to belittle Bora's Delta amplifier, calling it nothing special. I just meant that the design was straightforward. It looks like a lot of attention to detail went into this amplifier.
Regards,
Steven
BTW Tom, could you send me a copy of your scans too? |
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| Tom2 |
Steven,
Yes, will do.
Tom |
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| DR_PONJA |
Hello members of DIY-Audio Forum! I’m from Serbia, like Dr. Bora, Viktor, Boban and others. I wish to say hello and to our neighbors, The Croats, The Bosnians, The Slovenians, The Macedonians and The Montenegrins. Simply, The Yugoslavs.
I was really happy when I read all posts in this thread, especially the Subject: "Bora is a nice guy from Serbia - Yugoslavia".
Bora is really nice guy from Serbia! He gave me some his projects and, I can say, 24 hour building support ;-) I made his project called Studio, but with two modules, so I got then stereo Hi-Fi amplifier. It has 2 x 85 W at 8 ohms, Slew Rate 50 V/us, THD 0.003% in frequency band between 20 Hz and 16 kHz etc. You can see details about this project on, now very famous, Boras WEB presentation: www.bas.abshost.net.
Studio is working excellent! I tested it on my Starlet speakers with Visaton drivers (I made them, too)… and overall impression was - "Lets rock 'n' roll!!!". Later, I tested it with some softer music, like Pink Floyd, Simon & Garfunkel, Muddy Waters, some Dixieland music groups… My impressions where then on higher level… I can not use any English word for this… I hope that my Serbs will understand me ;-)
Back to the "Studio"… I added him device for the remote volume control, and 100% my addin for remote on/off…
All in all, I wish to test Studio on better speakers. I think Studio can snow better sound on better speakers than I own.
I have plans to build Boras Legend with The Tube Limiter and The Lead Pro for my guitar. I think that will be good combination for rockin' and blues/jazzin' ;-)
PS: Excuse me for my bad English, but I'm learning… ;-)
Ponjavić Dušan |
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| destroyer X |
texts posted.....always you conduct your opinnions and evaluations in a kind way and beeing always fair.
Also you have the use to talk clear what you feel without the intention to hurt people...i could see that.
I could see that you had not bad intentions related your opinnion...and i could see that people that have too much experience, do not turn excited easily, when observe some sligtly different amplifiers, as already watched thousands.
But it is good to see that you have this love inside your heart, related those things, our circuits, amplifiers and simple ideas too.
I feel good with that, this means that my future will be better than i suppose....i was thinking that we had the chance to loose some interest when advancing in knowledge....you saying the opposite, is very good to listen.
regards,
Carlos |
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| destroyer X |
This way, i think that his problem related his father health is still beeing hard to him.
All of us, soon or latter, we will have to face those life things...the fact that we can be sick, and that the life is not ethernal for no one of us.
I already lost all my more important parents...father and mother already gone... also Grandmother and Grandfather..... i go missing them hardly, with daily rememberings, but feeling happy, as they had good lives, and that i am lucky, as i never lost any of my sons.
My best wishes for Bora.
regards,
Carlos |
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| DR_PONJA |
I didn't knew for that Boras tragedy. I'm really sorry for that. I can almost feel that pain because I've lost my mother five weeks ago. I'm sad because I can not materialize my feelings, maybe that will bi too much to try.
Bora, life goes on, you must keep walking through it, with had up to sky. |
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| DR_PONJA |
| Here is a pic of Studio. |
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| destroyer X |
It is so pretty, that i think you could spend some time more to make it completelly perfect.
The output cables can go together inside gray plastic tube, that will confuse it's color with the bottom panel.
Also the wire you have at your rigth can follow the same idea...inside tube, all them together, and panel cables (the ligth red ones... the pretty ones, can be hidden soldered under the board.
This way...you can choice some ligth color....iluminate corners and put some glass or acrilic top....to watch this pretty machine daily.
It will be something to show!...really!
I save the image, it is pretty to see.
You may think..."what a boering guy!, searching for defects in my construction!".... not exactly this way.... i could not silent about that, because your construction is so near the perfection...so close!...why not to turn it perfect?...my intention is positive.
By the way, Doctor Ponja, world languages are very interesting, and there are names that have strange meanings in other languages.... for example, i have the use to smile when i read your nick name (Ponja, do not know if family name).... this remenber in my language, esponja... sponge may be in english... some material that absorbs watter...alike a plastic foam that absorbs watter...and we use here, to call our friends that drink too much...we call them esponja...because they absorb alcoholl alike some sponge can do....the name sounds good to me...if i laugh someday about that.... i was laughing with you, together you...not laughing of you!...completely different.
regards,
Carlos |
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| RSK |
Hello to all members. I have completed and tested the Studio Amp by our Dr.Bora
Construction,
Input stage matched by hfe DMM.
Output stage using MJ15003/15004.
DC offset around 5mV.
I listened to all type of music with this amp and all I can say is,
What a marvelous piece of electronics.
This amp is fantastic. Soundstage is wide, bass deep and powerfull and the highs are clear and not sharpe.
BTW, my speakers are JMLab.
The preamp used is also Bora's contribution. A headphone amp, full discrete (which I built earlier). Bora recommended it as preamp as well.
To have a second opinion, I took the stereo set to my friends house to compare with his amp (a commercial unit costing over 1,000.00 USD). But I have big problem now!!
I find difficulty to take it back
My heartfull thanks to Bora for all his assistance during constructing the headphone amp and Studio amp.
Sorry I have to borrow a digital camera for the image.
I will do it later once I have completed the full casing.
Cheers. |
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| viktor1986 |
| MJ15003&MJ15004 for output?2SC5200&2SA1943 is better. |
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| jmateus |
Hi all
I had a chance to build the Studio amplifier by Dr.Jadovic some
time ago and recently I exchange some e/mails with him who
asked me my impressions about this amplifier.Of course I couldn't more positive about its quality, it is in fact a marvellous amplifier
and I do not understand why people didn't post more opinions
about it. Probably because not too many people built it...or too
busy commenting about other devices.....
Anyway, Dr. Jadovic gives on his schematic several alternatives
about the output transistors including the MJ15003/15004. But
he leaves to the consructor the option to use any of the 5
different BJT outputs that are included in his schematic.
One thing is for sure, the 15003/4 are not a good choice, they
are the 2N3055/2955 in a beefy version but still outdated
transistors that do not render justice to this excellent design.
I used the On semis MJ21193/21194 with great improvement
over the 15003/4 (wich I tried also) but I also tryied the MJ802/
MJ 4502 and these are not bad even though the voltage ratings
are quite low if you want a good margin of safety.
All in all the 2SA1943 and 2SC5200 are the best outputs you
can use on this amplifier...and on all the amplifiers that take
BJT's. |
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| 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." |
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| sith |
| quote: | | Under 10.000 kuna (Croatian national currency, about ??kuna=1Euro) |
1€ = 7,2 kunas :D |
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| 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 |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Well...names are hard...very complicated...but i am copying the way i have received.
Those names will never be accepted by a Marketing Deppartment.
regards,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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| destroyer X |
Attached,
Carlos |
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