Hi i intend to make a 200-600W pure Class A amp.
My limited knowledge has limited to ouput device matching.
My best shot is a stock of 2SC5200 transistors.
Is there any simple design for class A pull push type using only NPN in output stage?
Reason:available 5200 transitors, 48 of them and no dismilarity in turn-0n turn off time associated with complimentary pair.
regards
My limited knowledge has limited to ouput device matching.
My best shot is a stock of 2SC5200 transistors.
Is there any simple design for class A pull push type using only NPN in output stage?
Reason:available 5200 transitors, 48 of them and no dismilarity in turn-0n turn off time associated with complimentary pair.
regards
Hi i intend to make a 200-600W pure Class A amp.
Is there any simple design for class A pull push type using only NPN in output stage?
regards
It is perfectly possible to make a push-pull Class A amp with only NPN output devices. You simply use a quasi-complementary output stage, preferably with a Baxandall diode to reduce distortion.
You will find more info in my power amplifier book, (5th edition) page309.
The Audio Power Amplifier Design Handbook
That'll be a fabulous room heater.Hi i intend to make a 200-600W pure Class A amp.
Not to mention exceptionally big and heavy.
Here's an output stage variation for the Leach amp:My limited knowledge has limited to ouput device matching.
My best shot is a stock of 2SC5200 transistors.
Is there any simple design for class A pull push type using only NPN in output stage?
Reason:available 5200 transitors, 48 of them and no dismilarity in turn-0n turn off time associated with complimentary pair.
... as discussed here.
Q14/15 would be medium power, Q16/17 5200s, and Q18/19 plus corresponding Rs would be replicated in parallel, again with 5200s. Not sure how many you can realistically drive, 4 or 5 pairs seem common - maybe twice that max.
Any schmematics , minimal parts, only symmetry CLASS A. ?
If you are going to use only NPN output devices, then the "symmetry" bit is going to be real challenge.
Symmetrical is not necessarily good.
Hi i intend to make a 200-600W pure Class A amp.
For 600 W output power (8 ohms), your push pull amplifier will dissipate more than 1200W, have a quiescent current of more than 6 Amperes, and the power supply rails will be more than plus/minus 100 Volts. I really look forward to see your well-sounding oven....
this is something like what a 600W Class A amplifier will look like, if you are lucky =)
Dimensions : 19" Rack Mountable 5U high (220mm / 8.7")
Overall Depth : 545mm (21.4")
Front Panel & Handles : 75mm (3")
Rear Handles : 40mm (1.6")
Amplifier Body : 430mm (16.9")
Weight : 40kg approx.
this is a 4 way amp though, with crossover and is 850w
Specifications
Output Power (RMS) :
HF: 100 Watts into 6 ohms
MF: 200 Watts into 16 ohms
LF: 275 Watts x 2 into 8 ohms
An externally hosted image should be here but it was not working when we last tested it.
Dimensions : 19" Rack Mountable 5U high (220mm / 8.7")
Overall Depth : 545mm (21.4")
Front Panel & Handles : 75mm (3")
Rear Handles : 40mm (1.6")
Amplifier Body : 430mm (16.9")
Weight : 40kg approx.
this is a 4 way amp though, with crossover and is 850w
Specifications
Output Power (RMS) :
HF: 100 Watts into 6 ohms
MF: 200 Watts into 16 ohms
LF: 275 Watts x 2 into 8 ohms
i'm curious too, my guess is hes not aware of exactly what the implications of that is, thus my including a picture of 1 channelThis one (19" - 5U)
I am curious why, and for what purpose, people intend to make a 200-600 watt class A amplifier.
I guess the OT means class A/B
perhaps hes building something like these?
An externally hosted image should be here but it was not working when we last tested it.
perhaps hes building something like these?
An externally hosted image should be here but it was not working when we last tested it.
Insane
But large speakers can be high efficient and play great music with low power tube amps...
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my gosh, those are speakers.
I agree with Doug, symmetrical is not what I'd be aiming for if I were looking at all NPN outputs.
Have you considered a JLH style amplifier ?
You may find this a useful link: The Class-A Amplifier Site
and you can get PCB's for it from ebay etc.
You can scale it up using multiple outputs - but I would suggest that 40W would be reasonable. If you really want 200W plus then using up existing output transistors is the least of your challenges - you'll need a humongous heatsink, a huge power transformer, a soft start circuit, thermal protection etc.
If this level of power is a 'must' then I would recommend ClassAB instead. There are many good approaches. Doug has published a few
I agree with Doug, symmetrical is not what I'd be aiming for if I were looking at all NPN outputs.
Have you considered a JLH style amplifier ?
You may find this a useful link: The Class-A Amplifier Site
and you can get PCB's for it from ebay etc.
You can scale it up using multiple outputs - but I would suggest that 40W would be reasonable. If you really want 200W plus then using up existing output transistors is the least of your challenges - you'll need a humongous heatsink, a huge power transformer, a soft start circuit, thermal protection etc.
If this level of power is a 'must' then I would recommend ClassAB instead. There are many good approaches. Doug has published a few
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i'm curious too, my guess is hes not aware of exactly what the implications of that is, thus my including a picture of 1 channel
perhaps hes building something like these?
An externally hosted image should be here but it was not working when we last tested it.
I would expect that room to smell like burning carpet.
Hi i intend to make a 200-600W pure Class A amp.
regards
It is worth bearing in mind that with a real musical signal, as opposed to sinewaves, the maximum efficiency will be around 1% at full throttle. (Just clipping) It will be essentially a 1200W room heater.
I do not encourage people to build large Class-A amplifiers. They are grotesquely inefficient, and that offends my engineering sensibilities.
Assuming a multi-driver system, at that level an active crossover must be considered. There are few single drivers that require that much power except for subs. I don't require class-A subs. But I digress. What I wanted to suggest for those transistors, if you really love class-a, is making many amp channels of smaller wattage. You can tri-amp, or you can use redundant drivers each with its own amp, or perhaps someday use them for home theater surround. At the least, the improved efficiency from using an active crossover makes the idle current draw more reasonable.
What say DouglasSelf to increasing the bias to class A on the lower ±V rails on a class G amplifier for hi-fi?
Nelson Pass has a patent (expired) on something related (see fig.3):
Patent US5343166 - Efficient high fidelity audio power amplifier - Google Patents
Nelson Pass has a patent (expired) on something related (see fig.3):
Patent US5343166 - Efficient high fidelity audio power amplifier - Google Patents
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Weight : 40kg approx.
Alternitive use.....and anvil? Just don't drop it on your toe!
Strange to me why someone would build a solid state amplifier with more iron than a 1970 Crystler Imperial.
I would at least go with SMPS supply...
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Maybe a circlotron like Sumo nine? Or a BJT Aleph X.Class A amp with fully symmetric design using only NPN output transistor
ok dears.
I have a very good focal car amplifier. To save the hastle i am going to use the amp output to drive a high bias Class A output stage using 2SC5200 and 2SA1943 10 pairs.
the amplifier is a car amplifier and for output stage i have a +/-50 V invtrter off 12 Volt. my target is 2000 W Class A.
Now i have an amp for which i intend to separate the pull push output stage ground the emitters of NPN and PNP output transistors with 10K resistors to ground for feedback, and feed the 8 pull push pairs at +/- 50 V rail (10 pairs of 2SC5200 and 2SA1943) with the out put devices of the amplifier which incidently are also the same pair)
Questions:
What should be be the base resitance feeding the output transistors
Is 2 Amp Quisescent Ic enough for the Class A operation per device
for paralleling devices i intend to use 0.2Ohm 5 watt resistor in emitters.
Is any feed back from this output stage required?
Regards. Its just an intersting attempt just to add to the output stage of an existing high end car amplifier.
Regards
I have a very good focal car amplifier. To save the hastle i am going to use the amp output to drive a high bias Class A output stage using 2SC5200 and 2SA1943 10 pairs.
the amplifier is a car amplifier and for output stage i have a +/-50 V invtrter off 12 Volt. my target is 2000 W Class A.
Now i have an amp for which i intend to separate the pull push output stage ground the emitters of NPN and PNP output transistors with 10K resistors to ground for feedback, and feed the 8 pull push pairs at +/- 50 V rail (10 pairs of 2SC5200 and 2SA1943) with the out put devices of the amplifier which incidently are also the same pair)
Questions:
What should be be the base resitance feeding the output transistors
Is 2 Amp Quisescent Ic enough for the Class A operation per device
for paralleling devices i intend to use 0.2Ohm 5 watt resistor in emitters.
Is any feed back from this output stage required?
Regards. Its just an intersting attempt just to add to the output stage of an existing high end car amplifier.
Regards
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