The "Varanda"...the balcony, if the place the wind enters my home.
If i install those heaters there, the first will die will be Satelite Receiver (Thomsom, already very, very, very hot..has not upper holes for ventilation)... and them will go my Television... and the last will be me..coocked.
Camera returned... i said do not want them to fix... they have asked 150 dollares...replacement of Optical unit..ahahahah..the whole camera, as it costs less than that for them...so..disposable things... to use for small time.
I have it back and will produce images with strips.... they are even better than my Kodak...a pitty, those folks at Canon..better camera, worst philosophy.
regards,
Carlos
If i install those heaters there, the first will die will be Satelite Receiver (Thomsom, already very, very, very hot..has not upper holes for ventilation)... and them will go my Television... and the last will be me..coocked.
Camera returned... i said do not want them to fix... they have asked 150 dollares...replacement of Optical unit..ahahahah..the whole camera, as it costs less than that for them...so..disposable things... to use for small time.
I have it back and will produce images with strips.... they are even better than my Kodak...a pitty, those folks at Canon..better camera, worst philosophy.
regards,
Carlos
Hi, Carlos,
You don't like classA? Maybe this X-amp is suitable for you :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99&highlight=
But you have to modify the output stage to quasi complementary mosfets.
If you decide to make classA, this one is already quasi complementary mosfets
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3748&highlight=
You don't like classA? Maybe this X-amp is suitable for you :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99&highlight=
But you have to modify the output stage to quasi complementary mosfets.
If you decide to make classA, this one is already quasi complementary mosfets
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3748&highlight=
Re: I have others... do not know what to make with them
You can repair (or make) a lot of car audio amplifiers and 12V DC to 120/230V AC inverters with these parts
You could do a 2x800W@4ohm class D amplifier with SMPS with those IRFP450 and FQA34N20 too, although this is quite challenging (even for me because these parts are a bit dated and don't perform as good as latest generation ones).
destroyer X said:
You can repair (or make) a lot of car audio amplifiers and 12V DC to 120/230V AC inverters with these parts
You could do a 2x800W@4ohm class D amplifier with SMPS with those IRFP450 and FQA34N20 too, although this is quite challenging (even for me because these parts are a bit dated and don't perform as good as latest generation ones).
Thank you Lumanauw... the Aleph is executable
Eva
I am not able to produce Switching supplies...i am very stupid related those things.
When i hold Fets i feel they can bite me, i do not even know if they are "animal" or "vegetable"
Thank you, but i feel will be very hard to use those folks.... i am not addicted because i have not knowledge...or...i have not knowledge because not addicted to them...i believe into the second option.
I will search for local friens to make some negotiation with them..they can give me BGTs and i can supply them with Fets.
regards,
Carlos
........................................................................................................
Nordic.
If those parts are so bad this way..that some electrostatic energy can kill them..better to be killed into my hands then me loosing hours constructing to see them burn.
regards,
Carlos
Eva
I am not able to produce Switching supplies...i am very stupid related those things.
When i hold Fets i feel they can bite me, i do not even know if they are "animal" or "vegetable"
Thank you, but i feel will be very hard to use those folks.... i am not addicted because i have not knowledge...or...i have not knowledge because not addicted to them...i believe into the second option.
I will search for local friens to make some negotiation with them..they can give me BGTs and i can supply them with Fets.
regards,
Carlos
........................................................................................................
Nordic.
If those parts are so bad this way..that some electrostatic energy can kill them..better to be killed into my hands then me loosing hours constructing to see them burn.
regards,
Carlos
I will send yo usome nice headphone circuits when i find them again... will teach you the basic working of mosfets...
Pretty simple realy.... but yes there are safer and less safe ways of handling them...
In the meantime start here, Mr. read my 4600 post thread....
http://passdiy.com/amps.htm start at part 1
Pretty simple realy.... but yes there are safer and less safe ways of handling them...
In the meantime start here, Mr. read my 4600 post thread....
http://passdiy.com/amps.htm start at part 1
Negative dear nephew.... headphone i use coupled into the amplifier output... i make
it loaded by 8 ohms and them i pick a resistance in series with the headphone..only passive!.. nothing to create distortions....no amplifier to me.... i do not use them...no pre amplifier and no headphone amplifier.
But i thank you by the nice intention...but i am running out from more stages to kill my sonics.
One stage is all i want when needing some headphone low impedance buffer, or impedance adapting stage....but unfortunattelly do not produce high power....i mean...one transistor each channel only....class A and headphone in series with the colector...this is the best i could listen ever.
Was a 1976 Senheiser headphone that used microphone cartridges as drivers to sound... impedance was around 400 ohms...i have made an amplifier powered using 9 volts batteries, one BC109 each channel (low noise, general use..standard..alike 2SC945.... now a days 2SC1815) with the headphone coil in series with the colector, class A and sounding wonderfull...i could not listen better sound alike that one i have listened down the seventies...audio came from an Akai open reel... Demonstration tape, stereo demonstration, having trains, Russian Roulet and things alike.... headphone output from Akai into this single transistor stage.
I am still searching for that quality i have lost there.... no noise... the open reel had Dolby noise reduction.
Yeah..it is possible that listening again i perceive that thing awfull compared to now a days standards, but i doubt that, because we had ever the real sound as reference to evaluate fidelity.
regards,
Carlos
it loaded by 8 ohms and them i pick a resistance in series with the headphone..only passive!.. nothing to create distortions....no amplifier to me.... i do not use them...no pre amplifier and no headphone amplifier.
But i thank you by the nice intention...but i am running out from more stages to kill my sonics.
One stage is all i want when needing some headphone low impedance buffer, or impedance adapting stage....but unfortunattelly do not produce high power....i mean...one transistor each channel only....class A and headphone in series with the colector...this is the best i could listen ever.
Was a 1976 Senheiser headphone that used microphone cartridges as drivers to sound... impedance was around 400 ohms...i have made an amplifier powered using 9 volts batteries, one BC109 each channel (low noise, general use..standard..alike 2SC945.... now a days 2SC1815) with the headphone coil in series with the colector, class A and sounding wonderfull...i could not listen better sound alike that one i have listened down the seventies...audio came from an Akai open reel... Demonstration tape, stereo demonstration, having trains, Russian Roulet and things alike.... headphone output from Akai into this single transistor stage.
I am still searching for that quality i have lost there.... no noise... the open reel had Dolby noise reduction.
Yeah..it is possible that listening again i perceive that thing awfull compared to now a days standards, but i doubt that, because we had ever the real sound as reference to evaluate fidelity.
regards,
Carlos
Attachments
It is simply to learn from uncle charly... not to beat anything...
Once you see the diffirences between fets and bjts you should be able to come up with some clever stuff... hybrids etc...
Some of the best amps I have heard are mosfet hybrids... with valves on the input side....
Now Carlos says " buta wea don'ta have de valves in Brasil"
In the meantime, did you start looking at that pss labs link?
Once you see the diffirences between fets and bjts you should be able to come up with some clever stuff... hybrids etc...
Some of the best amps I have heard are mosfet hybrids... with valves on the input side....
Now Carlos says " buta wea don'ta have de valves in Brasil"
In the meantime, did you start looking at that pss labs link?
Yeah...have to read.... aaagh!... fets and fets and more fets
Sometimes MOS fets and Hexafets, lateral fets, crazy fets.
My God... i do not know how the simple fet works..imagine those big brothers!
Ahahahha!!!
But i have readed some....now i am less stupid.
I already know things about them.... good .... they have different threshold voltages.....hummmm., interesting.
regards,
Carlos
Sometimes MOS fets and Hexafets, lateral fets, crazy fets.
My God... i do not know how the simple fet works..imagine those big brothers!
Ahahahha!!!
But i have readed some....now i am less stupid.
I already know things about them.... good .... they have different threshold voltages.....hummmm., interesting.
regards,
Carlos
MOSFET may either operate as voltage controlled resistors or as voltage controlled current sources, it depends on the currents and voltages involved.
With some effort you could learn other technologies. We usually set our own limits.
Anyway, I'm going to propose you a simple N-channel MOSFET rail-to-rail output topology, see the attachment
With some effort you could learn other technologies. We usually set our own limits.
Anyway, I'm going to propose you a simple N-channel MOSFET rail-to-rail output topology, see the attachment
Attachments
Thank you Eva.... maybe better to start new technology with simple things
24 plus 24 will produce some work to me.... i understand that you use to do to automobile and trucks,... so... 24 volts batteries are available there.
I will have to use power regulators to reduce the voltage...but i can do it... because i have them assembled.
Of course... if 36 volts would be better to me....i have wonderfull supply..with huge capacitance (40000uf each rail) to face class A units too.... and if needed.
The input and feedback, can you please complete those parts...i know they are optional..but what is your option?
regards,
Carlos
24 plus 24 will produce some work to me.... i understand that you use to do to automobile and trucks,... so... 24 volts batteries are available there.
I will have to use power regulators to reduce the voltage...but i can do it... because i have them assembled.
Of course... if 36 volts would be better to me....i have wonderfull supply..with huge capacitance (40000uf each rail) to face class A units too.... and if needed.
The input and feedback, can you please complete those parts...i know they are optional..but what is your option?
regards,
Carlos
The schematic is purely conceptual, you should use whatever supply voltage that your transistors can handle, and you will have to add more parts (like the gate zeners) to get it working right. For example you could make low-part-count single-supply bridged amplifiers with all those low voltage high current MOSFETs.
The source with the "bias" label is actually an adjustable current source that is hand trimmed to set output bias current and is also controlled by heatsink temperature to compensate for changes in MOSFET Vgs "turn-on" threshold (similar to Vbe in bipolars).
It works like the Vbe multiplier in a traditional class AB emitter follower output stage. If heatsink becomes hotter, the current is reduced and Vgs becomes lower, and vice-versa. The proper slope has to be found by experimentation.
This may be achieved by coupling the current source main transistor (or diodes) to the heatsink very close to the output transistors, like a good old Vbe multiplier.
Vgs drift with themperature for HEXFETs is around -8mV/ºC but it changes depending on MOSFET model.
I can't give you much more help than this, I'm sorry but I'm really busy with projects.
The source with the "bias" label is actually an adjustable current source that is hand trimmed to set output bias current and is also controlled by heatsink temperature to compensate for changes in MOSFET Vgs "turn-on" threshold (similar to Vbe in bipolars).
It works like the Vbe multiplier in a traditional class AB emitter follower output stage. If heatsink becomes hotter, the current is reduced and Vgs becomes lower, and vice-versa. The proper slope has to be found by experimentation.
This may be achieved by coupling the current source main transistor (or diodes) to the heatsink very close to the output transistors, like a good old Vbe multiplier.
Vgs drift with themperature for HEXFETs is around -8mV/ºC but it changes depending on MOSFET model.
I can't give you much more help than this, I'm sorry but I'm really busy with projects.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.