It might be the way I am reading your english, but this seems to be back to front.
BJTs which do suffer from secondary breakdown at high voltage gain the most from a stepped supply drive. The high voltage is only applied when a HV transient is applied. Keeps the devices cooler and uses the higher short term SOAR effectively.
Yes thats true, but have seen a lot of commercial class AB amplifiers with secondary breakdown problems too....
Im working as sales Manager for PA Audio since 4 years, about 30 % Amplifiers Class AB and H failure against secondary breakdown from different brands (but only 3-5 % defective SMPS) in warranty time.
between expensive Big Brands and No Name amps was no different in reliable
from sold Class D amplifiers failure about only 5 %
and some handcrafted NMOS working since 2 years without failure too
again,....BJTs in high power output stage No thanks
I hate aftersales service against BJT secondary breakdown failure
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Yes thats true, buts its expensiver to use mosfets for manufacturer,...profit first, reliable later
Well with the types of consumer protection laws popping up lately all over the world, that will change.
Normally Class D should be the final solution, but it isnt
good Class H amps and NMOS with about 100 V DC Rail kick 1500W Class D Amp out of the job, really
Class D amps from different manufacturer have much problems with low frequencies < 80 HZ
for subbass with big power not really good .....cant feel the big earthquake compare to analog amps
good Class H amps and NMOS with about 100 V DC Rail kick 1500W Class D Amp out of the job, really
Class D amps from different manufacturer have much problems with low frequencies < 80 HZ
for subbass with big power not really good .....cant feel the big earthquake compare to analog amps
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Hello! Anyone know what segnifica COUT1 the vertex. How do I connect to the scheme? Was that it?
An externally hosted image should be here but it was not working when we last tested it.
c out
hi kaylan
greetings cout is servo feedback connected to speaker out line
thanking you
andrew lebon
hi kaylan
greetings cout is servo feedback connected to speaker out line
thanking you
andrew lebon
a letter fro prof. leach about mosfet output stage,
The Leach Amp - Output Stage
I have been asked why I did not use MOSFETs in the output stage. The main reason is that the original amplifier was designed with BJTs. Because a lot of great things things have been said about MOSFETs, I did acquire a set of them which I intended to develop an output stage with. I was disappointed to find these devices plagued with parasitic oscillation problems.
The Leach Amp - Output Stage
I have been asked why I did not use MOSFETs in the output stage. The main reason is that the original amplifier was designed with BJTs. Because a lot of great things things have been said about MOSFETs, I did acquire a set of them which I intended to develop an output stage with. I was disappointed to find these devices plagued with parasitic oscillation problems.
the leach super amp is a high-fi amp....
for PA duties, mosfets are more rugged......
Nelson Pass, Bob Cordel are two designers who favor mosfets...
John Curl otoh favors BJT's....
i guess its horses for courses....
for PA duties, mosfets are more rugged......
Nelson Pass, Bob Cordel are two designers who favor mosfets...
John Curl otoh favors BJT's....
i guess its horses for courses....
I'm interested in this Nmos design
Hello! Is the attached schematic works, or is it only work-in-progress? Do you have PCB for it?
Thanks in advance!
Hello! Is the attached schematic works, or is it only work-in-progress? Do you have PCB for it?
Thanks in advance!
irvynejay
Do you think the H900 will work of Dc 136 68 0 68 136 or there is any few changes?
thanks
Do you think the H900 will work of Dc 136 68 0 68 136 or there is any few changes?
thanks
yes but you have to change 2sc5200.2Sa1943 to MJL4282/4302 and ic stabilizer for ne5532...
But better ask mile for sure,,, for me i have to stick on what voltage given to the amp and change 5200/1943 to mjl then higher the amperes of the trapo..
But better ask mile for sure,,, for me i have to stick on what voltage given to the amp and change 5200/1943 to mjl then higher the amperes of the trapo..
Yes but cost will increase for MJL4282/4302 x 4 /pcs.
have seen a lot of commercial amps... 150 - 170 V DC and 3 Step Class H with 5200/1943
and have seen commercial class AB amp 145 V DC and 5200/1943 output devices
well im not an expert im just DIYER it's up to you if you push it too hard,,it's not big problem ..all i just want is the safety margin of those trannies
"Some article posted by Rod Elliott"
There is always some
flexibility, but you must be very careful to make sure that transistor safe operating area (SOA) is not exceeded.
There is also a maximum voltage for any semiconductor, and devices must be selected to ensure they are used
within their ratings.
"Some article posted by Rod Elliott"
There is always some
flexibility, but you must be very careful to make sure that transistor safe operating area (SOA) is not exceeded.
There is also a maximum voltage for any semiconductor, and devices must be selected to ensure they are used
within their ratings.
if you want more power, then build yourself several amps.....why put all your eggs in one basket....
if your one big amp fails in the middle of a disco dance, then that would be a shame...
otoh, the chances of several amps failing all at once is very slim....
i have received several inquiries about modding amps to use higher rails.....and for me, this is one practice i would like to discourage.....😀
Nice work people and Hello.
Many thanks Apex for sharing with us, of course and others who are working hard on this project.
Whether someone may have tried this project?
Many thanks Apex for sharing with us, of course and others who are working hard on this project.
Whether someone may have tried this project?