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New Leco Amp modules 650W/8R-1200W/4R
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Marko View Drop Down
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Joined: 28 January 2009
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Points: 271 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Marko Quote  Post ReplyReply Direct Link To This Post Posted: 02 January 2014 at 6:17pm
Originally posted by DjLeco DjLeco wrote:

All discussions are friendly, no problem gentlemans!
 
In the new year we must be more good, more understanding, more maleable.
 
Output devices are MJW21195+MJW21196, very robust if not exceeding SOA curve.
 
Modules are just for selling, not exchanges. Smile
 
Someone on other forum tryed to throw dirty on my work, saying the amp will not survive playing sinewave in shorted output, at variable signal level, because sensing transistors of protection, cannot act so fast...
 
I laught and I offered him his video, to chill itself...
 
Also shared to all of you:
 
 
Comments are welcomed!

Great video, especially the crazy part at 05:00 min...
I would also like to know the price, please PM
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Young Croc
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Points: 820 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 02 January 2014 at 6:57pm
Price will ve 150 euros without heatsink, just 4 pieces are with heatsink, wich are reserved deja by one customer.
 
MJW21195,MJW21196, have same SOA as MJL21193,MJL211194 just package is a little smaller for MJW (TO247 vs TO264), that's why I have used MJW, because smaller package same SOA, also I cannot fit 12xTO264 on that heatsink+2x TO3P prefinals, not enough space to fit'em..


Edited by DjLeco - 02 January 2014 at 6:59pm
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Points: 988 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 03 January 2014 at 4:11am
Originally posted by DjLeco DjLeco wrote:

 
MJW21195,MJW21196, have same SOA as MJL21193,MJL211194 just package is a little smaller for MJW (TO247 vs TO264), that's why I have used MJW, because smaller package same SOA, also I cannot fit 12xTO264 on that heatsink+2x TO3P prefinals, not enough space to fit'em..
oh misunderstanding, I was talking about NJW21193G + NJW21194G, which are TO-3P, slightly smaller than MJL TO-247 (by a very small margin, in real life it doesn't make any difference on pcb/heatsink size). But SOA on NJW21193G is a bit better than the MJL you use. At 100V it takes 4A for 100msec vs 3.5A on MJL. 
In fact, NJW21193+21994 has the highest SOA of ON Semi bipolar range and it's the pair of choice of Lab.Gruppen class TD amps Thumbs Up




Edited by ArthurG - 03 January 2014 at 8:45am
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Points: 1209 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SMP Quote  Post ReplyReply Direct Link To This Post Posted: 03 January 2014 at 7:13am
please explain why you wish to change class with temp? surely class AB is fine and no real need to change bias coz of heat? I have never found any need to change biasing due to a temp change. incidentally I use 4281/4302 for a class AB I develop here
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Points: 820 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 03 January 2014 at 9:17am

I bought some time ago 125 pairs of MJW21195+21196, and I must to use it.

 
Also I have couple tens of pairs of NJW21193-21194, as I will use it.
 
When heatsink is cold, on AB class will pass just bias curent in idle mode, with classical superdiode.
 
During high curent passing on output devices the heatsing temperature will grow, superdiode trying to compensate (decrease bias) until official value, but the bipolar transistor have negative coeficient temperature, and will have tendancy to increase current colector same time with temperature, because slow compensation of superdiode circuit, when teatsink is hot (70 degrees above), the bias will be higher in idle mode, and dissipate more heat, existing risk to thermal avalanche, if bias are a little higher than one predefined value.
 
Thats's why , On Semi, developed THERMAL TRACK trannies, with indide bias diode (5 pins).
 
Also, I used smaller heatsink for mine application, and B class amplifiers have bigger randament than AB class amplifiers.
 
So why is that I prefear to slow bias untill B class, when heatsink temperature increases, I raise up a litlle randament, also higher compensation of negative coeficient temperature of bipolar transistors.
 
Also, LabGruppen, uses B class amplifiers on their design, eben in TD class amplifiers, bipolar part of it is B class, that's why also they uses small heatsinks


Edited by DjLeco - 04 January 2014 at 12:28am
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Points: 1209 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SMP Quote  Post ReplyReply Direct Link To This Post Posted: 03 January 2014 at 10:34am
I see you are using "Amplified Diode" to generate bias..I do not use such an arrangement as temperature co-efficiency is an issue. "differential PD" does not give such issues slightly less stable but is only small not so significant and bias can remain class AB always.

Yes TD is a class B Topology aids in efficiency but does little to sonic ability always an issue were differential driver circuits are used also in class B. I use pure class A drive run hot but sonics much better than Cascoded drive which require higher component count as they need more CCS's to operate effectively and have too many PN Junctions in  signal path which can cause non-linearity at high signal swings and inferior transfer function.

But each to their own I guess and we each do our own thing
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Points: 255 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Tan-2 Quote  Post ReplyReply Direct Link To This Post Posted: 03 January 2014 at 6:37pm
We sure do... But it's also interesting to see different designs..
Logic will get you from A to B. Imagination will take you everywhere.
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Leco,

your dummy load is dying! If the dummy load had ability to speak it would say... please, hook me off cuz I can't stand this torture anymore! LOL
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Points: 820 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2014 at 12:36am
Originally posted by M4trix M4trix wrote:

Leco,

your dummy load is dying! If the dummy load had ability to speak it would say... please, hook me off cuz I can't stand this torture anymore! LOL
Yes I know that.
 
I will use it until it will be "open circuit".
 
I don't have place to put mine 1 ohm/1000Watts resistors(4 pieces/channel)...
 
 


Edited by DjLeco - 04 January 2014 at 12:36am
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Young Croc
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Points: 820 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2014 at 9:06am
SMP, no more technical discussion.
 
I said what I have to say, I showed what I have to show.
 
I don't want to be like other project(first one), where one "colleague" of mine, buyed prototype on test PCB, watched all discussion, tryed then to clone it, and het his self BIG, look mates, there's mine amplifier , and so on...
 
That colleague nickname is "Black", and he officially STOLE mine schematic and make another type of PCB, saying is HIS project...
 
 
Post 44 above
 
 
Here's that PCB that he buyed, stole the schematic and so on:
 
 
Sorry for puttin' links to other forum, but there was that discussion.
 
 


Edited by DjLeco - 04 January 2014 at 9:09am
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Points: 1209 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SMP Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2014 at 9:15am
no offence intended I merely ask out of interest. I have no wish or need to "clone" or copy your design I have one or two of my own Class AB both BJT & MOSFET. you clearly believe your design is of commercial value. at present I have no desire to manufacture amplifiers. but when I do I will use my own designs. i merely wondered why there was a need to alter so drastically. as in normal use a class AB will migrate to single phasic conduction as the output voltage swings high. so I could not see any benefit to it. forgive me but I thought this is a forum where ideas and knowledge are freely exchanged guess it is not a forum at all. I could not understand your commentary as not English so I gained no useful exchange from it
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Points: 1209 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SMP Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2014 at 9:24am
I am also a DIY member as well "blueroom" 
http://www.diyaudio.com/forums/solid-state/172617-class-ab-amp-made-me-5.html

as the guy said without any topology your test video or results do not mean a great deal it is as you know customary on both DIy & Blueroom to show topology or it becomes pointless a little like showing photos of speakers or the items in physical sense with no sound pointless means nothing as it proves nothing and again circuit is no "Secret" a very simple topology class B is class B it has been done so often
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