Mine Leco V3 Power Amplifier

[DjLeco]

I worked alot to build this one (just 10 modules made), is all in one amplifier ClassAB+B, (initially it was one ClassH prototype but I quit on that and keep AB+B class).
Each module contains balanced to unbalanced stage, IOC limiter (input output comparator limiter), thermal protection, overload and shorted output protection, auto fan based on heatsink temperature DC out protection (triac crowbarr), missing supply rail protection.
This amp is stable 2 ohms, and output current capability is around 50Amps RMS, limited by overload at 39Amps RMS.

Is based on Leco SMPS, custom version for 5,5Kwatts.

I have measured on dummy load as seen in videos (all are in Romanian language but is easy to see and understand what I have done there).



Bottom side

http://s13.postimg.org/6sjsj7qbb/Leco_V3_Bottom.jpg



Top side

http://s13.postimg.org/5g23hbsvr/Leco_V3_Top.jpg



Output stage

View image: Output stage



Some components mounted

View image: DSCN2157

View image: DSCN2158

View image: DSCN2159



On all following tests, the cooling was very poor, one small fan just move the air!



Output current capability on 1 ohm dummy load:



https://www.youtube.com/watch?v=7N9bGpcKHrs



Thermal limiting and main supply current draw from soket wall at 1 ohm load:



https://www.youtube.com/watch?v=vXiCzzpsfnk



Output current capability on 2 ohms and thermal limiting:



https://www.youtube.com/watch?v=7CGDSu9w_IE



Some scope captures:


Sinusoidal 10kHz:
View image: 1 10k Hz Sin


Triangular 10kHz:
View image: 2 10k Hz Tri


Rise-Fall Times on 8 ohms dummy:
View image: 3 10k Hz Rise Fall Times Dupa Bobina


8 ohms+1uF capacitive load on 10kHz squarewave:
View image: 5 10k Hz 1u F Capacitiv

8 ohms+1uF capacitive load on 10kHz squarewave detail:
View image: 6 10k Hz 1u F Capacitiv Detaliu


Maximum out voltage before clipping 8 Ohm on 10kHz sinusoidal:
View image: 7 10k Hz Vrms Max 8 Ohm


Maximum out voltage before clipping 8 Ohm on 10kHz squarewave:
View image: 8 10k Hz Out Max Drept Cu 8 Ohm Load


Max level then shorted output:
View image: 9 Limitare La Scurt Pe Iesire


And now movies of above scope captures:


Leco V3 rise and fall times +capacitive load:

https://www.youtube.com/watch?v=b3aRnI0nfO4&feature=youtu.be


Leco V3 maximum output on sinusiodal and squarewave signal:

https://www.youtube.com/watch?v=BWNUFg5dgnQ&feature=youtu.be


Leco V3 reactive load 1000Hz 8 Ohm+143uH:

https://www.youtube.com/watch?v=Y4xE_w7JCWE&feature=youtu.be


Leco V3 shorted output and overload: (nice movie!!!)

https://www.youtube.com/watch?v=LH6TSYm7QTI&feature=youtu.be


During tests it was one scope probe uncalibrated, so now is OK


1000Hz probes compensation:
View image: Sonde compensate la 1k Hz

10000Hz probes compensation:
View image: Sonde compensate 10khz


212Vpp between 10% and 90% in squarewave at 10kHz on 8 ohm load, 3,6uSec rise time:
View image: 10 90% 212 Vpp


Max out in squarewave at 10kHz capacitive load 1uF on output:
View image: 10khz Max out cu 1u F la iesire


Clean output at 100Hz on 8 ohm dummy load on output, almost 860 watts (yeloow is output signal, blue is input signal):
View image: Vmax out la 100 Hz 8 Ohm


Clean output at 100Hz on 2 ohm dummy load on output, almost 2300 watts (yeloow is output signal, blue is input signal):
View image: Vmax out la 100hz 2 Ohm


And movies of above scope captures:



1000 and 10000Hz probes compensation:

https://www.youtube.com/watch?v=45bljGxShas&feature=youtu.be


Leco V3 Amplifier Slew Rate Test+1uF Capacitor:

https://www.youtube.com/watch?v=_XRtqYWGOuI&feature=youtu.be



Leco V3 At Output 83-84Vrms/8Ohm Load:

https://www.youtube.com/watch?v=sRbl-yiexkY&feature=youtu.be


Leco V3 At Output 77-78Vrms/4Ohm Load:

https://www.youtube.com/watch?v=vOWOysoFKD0&feature=youtu.be


Leco V3 At Output 67-68Vrms/2 Ohm @ 224Vac

https://www.youtube.com/watch?v=I_Q4Lr38iXk&feature=youtu.be



Leco V3 Damping Factor At 8 Ohm 100Hz (it falls around 2-3mV when load connected, DF more than 6000)

https://www.youtube.com/watch?v=PLVYt5XFL_c&feature=youtu.be



Input Output Comparator limiter in action on 8/4/2 ohms loading:

https://www.youtube.com/watch?v=_f-4JvsPS6o



Linearity in Hi Freq 1000 to 60000Hz at 450W rms until above 0,05% THD or more appears (red led is flashing):

https://www.youtube.com/watch?v=Ot1jPkRdnQ0


Linearity from 5Hz to 200000Hz at 150 and 100watts/8 ohms:

https://www.youtube.com/watch?v=lSMabN6qM5o&feature=youtu.be



Some pictures during final assembly:

http://postimg.org/image/h4hsy8q9x/

http://postimg.org/image/cnpfzkc1x/

http://postimg.org/image/q9q5s3tol/

http://postimg.org/image/tum1bby85/

http://postimg.org/image/5up33al8l/

http://postimg.org/image/objhu416t/

http://postimg.org/image/dm5t1updx


Testing at home on mine top speakers:
https://www.youtube.com/watch?v=qKv0pJ1Er44&feature=youtu.be


His first event, played flawless and very clean audio:

https://www.youtube.com/watch?v=DNovsvt_N-k&feature=youtu.be

 

[andrewlebon]

Hello DjLeco
greetings pictures to small to see
warm regards
Andrew

 

[DjLeco]

This forum uses older version of interface, and displays small thumbs of pics instead all size pic.

I have edited to direct links, I hope now is OK!

Regards from me too!

 

[andrewlebon]

IOC LIMITER

Hello DjLeco
greetings input output comparator could you explain its working
is it from crown amps
warm regards
Andrew

 

[DjLeco]

The working principle is to take signal from input final stage and from output final stage too (divided corectly too), and when mismatching, it acts, on balanced input stage to cut the input signal.

Crown uses error amplifier stage for IOC
That's not the schematic that I use, the schematic above is a joke, longtime ago.

 

[bimo]

The working principle is to take signal from input final stage and from output final stage too (divided corectly too), and when mismatching, it acts, on balanced input stage to cut the input signal.

Crown uses error amplifier stage for IOC
That's not the schematic that I use, the schematic above is a joke, longtime ago.

http://www.diyaudio.com/forums/solid-state/221737-ultimate-amp-protection-circuit.html?highlight=ultimate

 

[DjLeco]

No, I use trannies for that circuit and LDR light dependant resistor.

 

[sajti]

Excellent work! Especially the smd parts! What kind of heatsinks are You using?

Sajti

 

[DjLeco]

Hi Sajti, Aavid thermalloy, made in Italy.

 

[sajti]

Your pcb gives me a new idea to plan new version of my pcb...
You can see the picture of the old version

Sajti

 

[DjLeco]

Nice, looks like mine!

Cood luck and present us your project too!

 

[andrewlebon]

Hello DjLeco
greetings can you share good short circuit protection
warm regards
Andrew

 

[DjLeco]

Sorry for that but it was made exclusive for this project, I cannot share.
Generally short protection, limits output current at maximum value limited, as you see, at mine amplifier, it cuts from 30-40A rms on output to 1,8Arms, wich minimise dissipation, also limiter cuts off signal toi minimum, if error persists.

Is a multislope protection.

 

[andrewlebon]

short circuit protection

Hello DjLeco
greetings its ok i understand i made the PL380 QSC overcurrent work
here pl380 overcurrent protection with qsc LM13700 limiter
warm regards
Andrew

 

[DjLeco]

Nice work, but I prefear to use LDR instead LM13700, I cut signal when limiting, directly in balanced to unbalanced stage, in this way, not even input stage cannot be overloaded, if too big signat at amplifier input, presumming volume knob is not at maximum (as must be).

 

[sajti]

presumming volume knob is not at maximum (as must be).

I hate the volume knobs, so I not use them in my amplifiers, only if specially requested.

Sajti

 

[kevinkr]

This appears to be commercially oriented since schematics and other details have not been shared and there is a statement to the effect that they cannot be shared. Posting commercial projects to the general forums is only OK if all details required to construct a working copy are also shared with the membership.

This thread will be moved to the vendors forum.