Dx Troyan, a 650 watts channel amplifier.
Made for my Greek friends..... dear Sakis and dear Fótios..... also to powerholic friends from our forum.
Was not assembled and tested....but, as supply voltage is the one i am using in the Fokker, also the circuit (exception is the V/I limiters)...and Fokker is playing here, at my home, all day long...i do not imagine a problem this one can produce....Fokker is dead stable at my home.
This VAS circuit gonna be tested with 100 volts soon...this is the circuit we have to be very carefull.
Supply power needed will be twice the output power..do not forget fuses in series with the output line..to speaker protection...also a protector will be a good idea to be used.
Output transistors..use the more modern ones....MJL21193 and others
Minimum of 6 pairs when using 8 ohms...better to use 10 pairs
Minimum of 8 pairs when using 4 ohms...better to use 12 pairs
Minimum of 10 pairs when using 4 ohms and entering distortion, 12 pairs
Minimum of 12 pairs when using 2 ohms and entering distortion, 14 pairs
Supply condensers..to 8 and 4 ohms, use 40 thousand plus 40 thousand microfarads.
I suggest you to use rail fuses..half the value used in the output line.
Use short cables, and thick cables from supply to the amplifier..if longer than 40 centimeters, then install, at least, 470uf each rail, near the power transistors colectors.
Heatsink, minimum size is 24 by 30 centimeters...having 24 fins, each one of them measuring 30 by 10 centimeters (high)... use fan blower to help to cool the monster down.
Picture shows Fokker amplifier... the technics is only a case to power supply..the heatsink is good for continuous full power over 8 ohms..not good for continuous in 4 ohms (but can hold music, can hold average power)...very small for 2 ohms operation.
Fokker is the same amplifier without the V/I limiter...and using 90 volts instead of 100 volts... Fokker sound is very good..the second best sound i have...first is the Dx Blame ST....this one was not assembled..but as Fokker is the same...we can understand that this one was assembled too.
Schematic is showing only two output pairs, to show you
that each emitter resistance must have 220 ohms to the V/I limiter transistor base.
This V/I limiter is simple..you can make it better if you want...it is up to you.
I do not like, and i do not use..but there are controversies, so..here you have one using V/I limiter..be happy!
The real quantity of output pairs will depend you supply under load..your heatsink size, your impedance and the way you gonna use the amplifier..if to parties..full distortion..them we have to think about with some care.
Last post..you can see output transistor suggested quantities.
THIS AMPLIFIER IS NOT TO BE USED WITH 2 OUTPUT PAIRS.
You can try better limiters...here you have one a little bit better
But there are others that interacts the positive with the negative... even better...this one will be tried in one of my amplifiers...just to check how better it is.
The values you see are not to Troyan.... this one is for 8 ohms, to a 70 volts supply amplifier, and the threshold when the limiter starts to work (sadly) is when the amplifier is having more than 42 volts rms over the speaker....in other works....more than 220 watts.
Then we can reduce the number of output transistors..as power will be limited..
Man!... you can used it...enjoy..... i will never use the stuff in my home amplifiers.... good to save money, to reduce power output, to reduce costs..and to reduce audio quality too.
My comments without any attack:
1., Would you explain me how does the output protection works, and why it is better or more effective than a conventional circuit? What is the purpouse of the diodes there, and of the 220r resistors in the transistor's collectors?
2., Why are CCS-transistors's reference transistors are medium power MJE devices?
3., Why are the CCS-transistors of the drivers are power output devices?
4., What is the benefit of using 100n capacitors instead of ~100uF as filters in the CCS's reference circuit? 100nF does nothing with PSRR in these subcircuits.
5., What about the phenomenon called beta drop? Is a simple EF OP stage enough here?
6., Are you sure MJE15033/34 is an optimal driver pair here, to drive up to 12 pairs of OP devices?
7., Is really 15...18mA current needed for the CCS's references (2×5,6k, 2×6.8k)?
8., 750Wrms on a 4r speaker load produces 30A peaks. Think about it.
Anyway it looks OK, and should work, but probably it will sound muddy when pushed hard - if it not blowed yet.
I would never build it without modifications.
Don't forget, designing a such high power rated amplifier requires different type of knowledge and experiences then designing a small or medium audiophile amplifier.
If you don't like my comment, feel free to add me to your ignore list!
I am trying the V/I limiter from Rodd Elliot
Aldotin...will answer you latter...visits arriving my home.
Ladies have not arrived yet.
A fast reading, seems to me you ask theories...i know nothing about that..and when i know i do not answer, or i use to say i do not know..because i do not like, and do not want to atract people that loves theories to transform the thread in a box ring.
I see you are new..registration from 2008 or 2009...do not know me..i am a long time here..have learned something..from here..also about people behavior too.
I have build some amplifiers..i am 59 years old..have studied something about electronics..but i am addicted to practice, to build and to listen...theories sometimes helps.... i use my skills, basic things learned..the amplifier is playing here with 90 volts..without E/I limiter...so..it works..this interests me more..the rest.
I do not know.
Carlos ! ............. Lower :hypno2: what about using 70V supply ? Is this PA amp or hi-fi amp ?
Reasons why i have made this amplifier
Aims to publish this amp.
Meet my friend Sakis desires, to verify the benefits of V/I limiter versus some losses of sonic quality... ... to produce a power amplifier for powerholics, fanatics by power .... show to a few rare and arrogant engineers, that anyone, armed with a calculator and basic knowledge of electronics can design amplifiers so dense and crowdy as they produce to show themselves off, ... and that these amplifiers almost always does not offer much advantage in the same ratio the multitude of sub circuits can induce us to think..
Tp demonstrate and prove that complexity and
multiplicity of circuits does not bring to you,
necessarily, superior sound quality .. demystify
and demystify (mystification and myth) that CCS
current mirror, sink current and voltage regulators
Alert, underline and highlight, for starters, that
what provides energy to a power amplifier is the power supply, and from the power supply you will produce your output power, and the ratio of audio power produces and heat generated is dependend from the amplifier class only... the complexity and multiplicity of circuits does not generate more power, as audio power is a direct consequence of your power supply energy.
to be continued......
Why i have made these amplifier, Fokker and Troyan..almost the same, small variations
....... To show that a bad designer, beginner or inexperienced, always tend to refine the draft.. dense and crowdy circuits are signs or lack of
competence... as this increases production costs . having benefits that are
uncertainty, feeling unsafe, and having the desire to show to their communitty they know a lot, then some of them will create nainly visual complexity and multiplicity of circuits, there will be using all sorts of existing sub circuit, CCS, voltage regulator, current
sink, current mirror, V / I limiter ... and this ends up being one type of fee that is paid for the vanity of the designer and by their need to self promote, appear to be known to be famous... some of them, deepply unshamed, use tenths of resistances in parallel that can be substituted by few ones as a power transistor emitter resistances..just to increase the complexity to the fast eye inspection.
This amplifier, not only the Fokker, but also the Troyan, offers mainly power, and because it’s
supply voltage, not because of crowdy circuitry as you may know, the sound quality is very good, as any amplifier where the signal levels and polarization of the transistors is correct, or at least, not much wrong, but nothing extraordinary ... not nearly offers the sound of Dx Blame ST,
Prove that most people do not read the whole thread, which only make speed reading, a kind of dinamic reading was famous during the sixties, and will soon give their opinion, a criticism often moved by intimate, internal own needs, ironic post questions, use of sarcasm and doubts about the designer technical decisions token the same way they doubt about themselves, they post a reflection of their disturbed souls.. .. opine that the amplifier will not work when it is already working and playing good music... that opine that will burn, or explode, ... as they are burning inside because of envy, and exploding of angry because they could not do the same... when the amplifiert was tested full power and proved stable .... show that we have 220 thousand noble companions and some human waste too... thanks God, a minority... some poor souls lost in this world, by and accident of our destiny, landed in our wonderful forum bringing negativity and the worst human defects... third-class people, in what concerns the human qualities.... my amplifier is an alert..they will, probably, with enormous chances, produce an amplifier alike these crowdy ones i am showing you.
Schematic does not show you the correct quantity or output pairs
Each case may need your own study about how many pairs you gonna use..this depends your power supply performance (to me measured real life)...your heatsink used, the type of use you gonna give to it.
I can help if you need, to choice the number or output pairs.... the schematic diagram was simplified, showing few pairs only...more pairs will be needed.
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