I have been working on this amp for a while it works great and has a great sound to it. My neighbor has a pair of klipschorns and wow.
Here is the schematic of the amp + power supply and speaker detection circuit. http://byrne.isa-geek.com/brendan/amp.bmp
Here is the schematic of the amp + power supply and speaker detection circuit. http://byrne.isa-geek.com/brendan/amp.bmp
What a Silly Design!
If I am correct then you have
one NPN differential[you dont even know how to draw a differential pair for easy reading]
Then again NPN differential connected to a PNP differential[but where are collector resistors for NPN differential 2NA410] which inturns connected to Vas followed by EF and then output stage, but why 180ohms for base resistors, it should be like 2.2 ohms or 4.7 ohms max..
Is is really working in reallity....??
IrishboyM4 said:
If I am correct then you have
one NPN differential[you dont even know how to draw a differential pair for easy reading]
Then again NPN differential connected to a PNP differential[but where are collector resistors for NPN differential 2NA410] which inturns connected to Vas followed by EF and then output stage, but why 180ohms for base resistors, it should be like 2.2 ohms or 4.7 ohms max..
Is is really working in reallity....??
The amp works great. It is currently driving a 4Ohm load to considerable volume as i am typing this. Please note that i use two of the NTE2328-NTE2329 pairs for more current handling. Yes its overkill, but it keeps everything running cool. I know i need to work on my schematic drawing. The extra differentials are for signal conditioning and getting the negative feedback correct.
Pictures please Irishboy.... i would be happy to take a look at it
Internally, externally, rigth side, left side,vision from up..back panel, supply, wiring, general vision, details, the speakers, the listening room, the house, your car, dog, the fleas..everything.
Others wants too..but they want only the board.
ahahahha
Please....images man!
regards,
Carlos
Internally, externally, rigth side, left side,vision from up..back panel, supply, wiring, general vision, details, the speakers, the listening room, the house, your car, dog, the fleas..everything.
Others wants too..but they want only the board.
ahahahha
Please....images man!
regards,
Carlos
Here it is. Yes I know its all laid out and that will do heck to the distortion, but for some reason when tested its below .02 (Best the oscilloscope can do. The speakers are JVC SP-97WD. If anyone has specs for these let me know because I need them.
http://byrne.isa-geek.com/brendan/images/1.jpg
http://byrne.isa-geek.com/brendan/images/2.jpg
http://byrne.isa-geek.com/brendan/images/3.jpg
And here is my dog. LOL
http://byrne.isa-geek.com/images/lucy.jpg
Well that was her, she is bigger now.
http://byrne.isa-geek.com/brendan/images/1.jpg
http://byrne.isa-geek.com/brendan/images/2.jpg
http://byrne.isa-geek.com/brendan/images/3.jpg
And here is my dog. LOL
http://byrne.isa-geek.com/images/lucy.jpg
Well that was her, she is bigger now.
IrishboyM4 said:
Well, if it works fine then it is different from the schematic you posted above. That 180 ohms will limit severely the available base drive for the outputs. It will work, but only for low levels especially in 4 ohms load.
For full power in 4 ohms at 30V peak you need 7.5A output current. Assume the output transistors have a gain of 50 at that current means 150mA base current. That would mean 27V across the 180 ohms. Where does that come from?
Jan Didden
You have made my day Irishboy....all that stuff shows me you are a real constructor
And this would be your name in place of Irish boy.....thank you as you have shared with me your images, in special your nice dog.
There are so many "simulators" doing electronics...... also so many people that cannot do simple things, only perfect boards with perfect brand new parts, needing to buy transformers, cases and all stuff to do something that you made me smile deep inside my heart, because so simple and nice your are.
You have that good passion for audio., not a snobish need to show your work as pretty...a very rare folk.
You have a friend on me.
Current to the bases are very small to the drivers...if your 180 ohms stop resistors were place into the drivers base, for sure will work better there, as output base current, beeing larger, will bave biggers losses with 180 ohms resistance....... 18 ohms would be better, 1.8 ohms will be perfect....also will work fine if you replace that one (those 180 ohms) with a wire jumper.
Your standard 180 ohms will produce nice sonics into treble...result may be magic...but will make you loose some power too.
From now on i will be watching your posts...you have a friend in me.
regards,
Carlos
And this would be your name in place of Irish boy.....thank you as you have shared with me your images, in special your nice dog.
There are so many "simulators" doing electronics...... also so many people that cannot do simple things, only perfect boards with perfect brand new parts, needing to buy transformers, cases and all stuff to do something that you made me smile deep inside my heart, because so simple and nice your are.
You have that good passion for audio., not a snobish need to show your work as pretty...a very rare folk.
You have a friend on me.
Current to the bases are very small to the drivers...if your 180 ohms stop resistors were place into the drivers base, for sure will work better there, as output base current, beeing larger, will bave biggers losses with 180 ohms resistance....... 18 ohms would be better, 1.8 ohms will be perfect....also will work fine if you replace that one (those 180 ohms) with a wire jumper.
Your standard 180 ohms will produce nice sonics into treble...result may be magic...but will make you loose some power too.
From now on i will be watching your posts...you have a friend in me.
regards,
Carlos
Attachments
Hi IrishboyM4,
Sorry friend, but about that 180 Ohms. I take it they are at least 10W jobs? Just to make sure you have the values right - and pardon us for asking, because if arithmetic is followed the circuit can only give 20W out.
If the NTE 2328 has a B of 30 (reasonable assumption) then arithmetic would show 13V over the 4 ohm load, i.e. 3.5A . For that Ib would be 3.5/30 = 120mA. 120mA through 180 ohm gives 21V, the rest of your h.t., allowing for 1V drop across the emitter 0.33 Ohm. So please see our problem.
I am not a buzzard sitting just waiting for bait, but it would also seem that your input impedance is about 0.5 ohm at 1 KHz - you are driving at the virtual earth point of a feedback circuit. What are you driving with, if this works?
So please bear with us if we seem dubious about certain component values!
Regards
Sorry friend, but about that 180 Ohms. I take it they are at least 10W jobs? Just to make sure you have the values right - and pardon us for asking, because if arithmetic is followed the circuit can only give 20W out.
If the NTE 2328 has a B of 30 (reasonable assumption) then arithmetic would show 13V over the 4 ohm load, i.e. 3.5A . For that Ib would be 3.5/30 = 120mA. 120mA through 180 ohm gives 21V, the rest of your h.t., allowing for 1V drop across the emitter 0.33 Ohm. So please see our problem.
I am not a buzzard sitting just waiting for bait, but it would also seem that your input impedance is about 0.5 ohm at 1 KHz - you are driving at the virtual earth point of a feedback circuit. What are you driving with, if this works?
So please bear with us if we seem dubious about certain component values!
Regards
The 180Ohm resistors are only .5watt and they don't even get warm. The gain of the NTE2328 is 55 minimum. Well I just took them out and it doesn't seem to make a huge difference but it does seem that it has more gain. The idle current is also higher and I need to adjust it. There does seem to be a little more power, but not huge. With the 180 Ohm resistors the amp would come to within 2 volts of the rail, without them it comes within .5V and that is when its driving the load.
By the way I'm only 15 so i haven't been doing this for very long.
Here is the updated schematic.schemaichttp://byrne.isa-geek.com/brendan/amp.bmp
By the way I'm only 15 so i haven't been doing this for very long.
Here is the updated schematic.schemaichttp://byrne.isa-geek.com/brendan/amp.bmp
Oh dear!
Now we do have a problem. If I follow correctly, you say that with a 4 ohm load connected, the output will go to within 2V of the 35V rail? (Small differences ignored.) Investigating that would mean that there is less than 1V remaining between NTE2328 base and the rail. Say 1V drop across the 180 ohm, that will give a max. base current of 5.6mA. On the other hand, about 34V across the 4 ohm load means 8.5A of load current. That would mean that the NTE2328 needs to have a gain of 8.5A/5.6mA = almost 1500. That can clearly not be the case!
Also, as per my previous calculations the NTE should saturate with 21V over the 180 ohm. That would be a dissipation of almost 2.5W, which I assure you would make it quite hot.
So I hope you see from this arithmetic (using simple Ohm's Law), that something must be quite wrong somewhere - and only you can work that out. My first suggestion would be that those 180 ohm resistors are actually much lower, though you might think they are 180 ohm. I hope you see the problem here.
Regards.
Now we do have a problem. If I follow correctly, you say that with a 4 ohm load connected, the output will go to within 2V of the 35V rail? (Small differences ignored.) Investigating that would mean that there is less than 1V remaining between NTE2328 base and the rail. Say 1V drop across the 180 ohm, that will give a max. base current of 5.6mA. On the other hand, about 34V across the 4 ohm load means 8.5A of load current. That would mean that the NTE2328 needs to have a gain of 8.5A/5.6mA = almost 1500. That can clearly not be the case!
Also, as per my previous calculations the NTE should saturate with 21V over the 180 ohm. That would be a dissipation of almost 2.5W, which I assure you would make it quite hot.
So I hope you see from this arithmetic (using simple Ohm's Law), that something must be quite wrong somewhere - and only you can work that out. My first suggestion would be that those 180 ohm resistors are actually much lower, though you might think they are 180 ohm. I hope you see the problem here.
Regards.
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