100W Ultimate Fidelity Amplifier

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#4,482
still4given said:
Am I missing something? It is called an fet preamp but it is all bjt.
Click to expand...

Maybe he forgot to change the name because I also have the FET schematic

Regards
Juan
 

Attachments

  • APEX FET PREAMP.jpg
    APEX FET PREAMP.jpg
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#4,485
MATSAZILIN said:
PDF for this PCB. Thank You Sir.
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I'm going to be honest, I'm not an expert or circuit designer 🙂 I only try to do my best way possible I will leave the files here it came out too big but is better because the traces are a bit thicker than what I usually do that is 1.5 mm this are 1.75 to 1.80 mm I have already simulated and it came out 1.5Vp on the output please if some one see an error let me know 😎

Regards
Juan
 

Attachments

#4,487
vargasmongo3435 said:
I'm going to be honest, I'm not an expert or circuit designer 🙂 I only try to do my best way possible I will leave the files here it came out too big but is better because the traces are a bit thicker than what I usually do that is 1.5 mm this are 1.75 to 1.80 mm I have already simulated and it came out 1.5Vp on the output please if some one see an error let me know 😎

Regards
Juan
Click to expand...

What is size of pcb?
 
#4,488
apexaudio said:
What is size of pcb?
Click to expand...

is quite large mister Mile, is 289 mm x 99.5 mm I just make a fast PCB because my layout are sometimes too small I mean on the traces thickness

a common A4 paper sizes is 297 mm x 210 mm maybe I might split the PCB and have separate power supply and preamp separate, you think might be better like that ? 🙂

About the A33, today I was checking the simulation of A33 an I have to change only one of the resistors that is controlling the bias R35 from 1K to 470R so now I can get about 30mA = 10 mV reading from one of the emitter resistors,

question, 30mA will be ok to have it set the standby current ?

Regards
Juan
 

Attachments

  • R35 from 1K to 470R.PNG
    R35 from 1K to 470R.PNG
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  • bias 10mV 30mA.PNG
    bias 10mV 30mA.PNG
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  • layout sizes.jpg
    layout sizes.jpg
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Last edited:
#4,489
vargasmongo3435 said:
is quite large mister Mile, is 289 mm x 99.5 mm I just make a fast PCB because my layout are sometimes too small I mean on the traces thickness

a common A4 paper sizes is 297 mm x 210 mm maybe I might split the PCB and have separate power supply and preamp separate, you think might be better like that ? 🙂

About the A33, today I was checking the simulation of A33 an I have to change only one of the resistors that is controlling the bias R35 from 1K to 470R so now I can get about 30mA = 10 mV reading from one of the emitter resistors,

question, 30mA will be ok to have it set the standby current ?

Regards
Juan
Click to expand...

30mA is OK
Regards
 
#4,490
Board Size

vargasmongo3435 said:
is quite large mister Mile, is 289 mm x 99.5 mm I just make a fast PCB because my layout are sometimes too small I mean on the traces thickness

a common A4 paper sizes is 297 mm x 210 mm maybe I might split the PCB and have separate power supply and preamp separate, you think might be better like that ? 🙂


Regards
Juan
Click to expand...

I think if you split it, could it be 140mm X 99.5.? That way it fits on an 8" X 11" (203.2 X 279.4) PCB, and we can get Both boards from 1 PCB.😀
 
#4,493
Hello last post of the day 🙂

seen now that the bias is set correctly now in simulation from software the I check the square wave to see how it looks now and there is a nice curve on the top at 20KHz and 30KHz, and with sine wave simulation at low volume example 5W of audio "example" the THD is 0.001% of course this is only simulation 🙄, I hope all goes smoothly after I order a few PCB to test, I already change R35 to 470R instead of 1K, the trim pot I changed to 1K I'm confidence that this will be a great build for this topology that is unique :up:🙂

Regards
Juan
 

Attachments

  • 1KHz.PNG
    1KHz.PNG
    192.4 KB · Views: 1,605
  • 20KHz.PNG
    20KHz.PNG
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  • 30KHz.PNG
    30KHz.PNG
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  • A33 R35 to 470Rs.jpg
    A33 R35 to 470Rs.jpg
    683.4 KB · Views: 1,554
#4,494
vargasmongo3435 said:
Hello last post of the day 🙂

seen now that the bias is set correctly now in simulation from software the I check the square wave to see how it looks now and there is a nice curve on the top at 20KHz and 30KHz, and with sine wave simulation at low volume example 5W of audio "example" the THD is 0.001% of course this is only simulation 🙄, I hope all goes smoothly after I order a few PCB to test, I already change R35 to 470R instead of 1K, the trim pot I changed to 1K I'm confidence that this will be a great build for this topology that is unique :up:🙂

Regards
Juan
Click to expand...

Nice simulation
Regards
 
#4,496
still4given said:
Today I mounted the boards on heatsinks so I could give them a good test. The amp sounds very good but the thermal compensation is not affective. The hotter the amp gets the higher the bias goes. Something need to change there. As I said before, the scale is a little small so the devices are pretty tight together but I would think that would make the comp sensors more affective. The other thing is thebias is very unstable. As the amp heats up the offset can climb pretty high.
Click to expand...
Hallo @still4given, the problems with bias and offset are resolved? Thank you.http://ro-en.gsp.ro/index.php?d=e&q=Thank+you!
 
#4,497
platon.rado said:
good work,when the test pcb ???
Click to expand...

Hello sir yes the PCB is completed and by next month I will order just a few for testing let say even if I order new PCB they will be call it "prototype" for now, if all goes well I let you know guys this is my first two layout PCB and it does take more time, like I say I'm gonna risk my own money if all goes wrong it will be me that will have the error and not you guys that is way I did not share the files for now if all goes well, I will share file but please only for personal use 🙂



Regards
Juan
 
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