| senicz |
| Best sound, best power, super low price. |
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| PierreG |
Very intersting.
Did you try it? |
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| zafira1981 |
I tried the same output stage but with a lm1875. I had lot of oscillation problems, but I made it work.
What I couldnt make work was the same but bridged.
the output transistors were 2n3055 / mj2955
good luck!! :D |
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| Bazukaz |
What is the reason to do this ? You won't be able to use > +-40V rails anyway.Using two LMs in parralel would give better reliability / easier to build.
Also i think that 2SA1491 have too low power dissipation for reliable operation. |
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| senicz |
I made this project exlusively for Hi-End speakers manufacturer "EDYTON".
For the high power output you should use 2X2SA1491/2SC2580. |
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| Tim__x |
| Are those darlingtons? If not your bias current is going to be very high, Iq(3886)*Hfe(Q2). |
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| steven344 |
| Have you ever tried this circuit |
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| zafira1981 |
| quote: | Originally posted by steven344
Have you ever tried this circuit |
wow.. that's a strange circuit... do you have the explanation of how it works? I cant figure out..
thanks |
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| steven344 |
| This is right from the national lm12 app notes,The zeners set up a regulated power supply to the lm12 as the audio increases the series pass transistors increase the voltage to to lm12,there is always no more then 39 volts between what the lm12 is putting out and the power supply rails feeding it ,its a tracking power supply,I have not tried it yet but I wonder if it would work with lm3875 or lm3886.As an example if the lm12 was putting out + 30 volt peak the + supply would increase to approx 69 volts and the negitive supply would decrease to about -9 keeping the lm12 within soa |
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| zafira1981 |
| quote: | Originally posted by steven344
This is right from the national lm12 app notes,The zeners set up a regulated power supply to the lm12 as the audio increases the series pass transistors increase the voltage to to lm12,there is always no more then 39 volts between what the lm12 is putting out and the power supply rails feeding it ,its a tracking power supply,I have not tried it yet but I wonder if it would work with lm3875 or lm3886.As an example if the lm12 was putting out + 30 volt peak the + supply would increase to approx 69 volts and the negitive supply would decrease to about -9 keeping the lm12 within soa |
thanks I will look at the APP notes. |
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| steven344 |
| Im always looking for ways to increase the capacity of gainclones I prefer the Lm12 for sub amp the lm3875 or lm3886 is good for highs and mids |
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| senicz |
| measurenent raport |
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| senicz |
| sorry! Rout=0.00025 (0.25milliohm) no 2.5milliohm |
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| lgreen |
senicz,
nice project, I have been waiting years to see something like that posted here. |
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| steven344 |
| Just wanted to know if you had a good pcb layout for this,Im going to try to breadboard this first,Will this circuit work using 2 chips and output transistors in a bridge configuration |
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| Nicks |
what ever happened with this design?
Anyone tried it?
BR
Nicks |
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| Leolabs |
| It should be able to work,since both transistors are just switches,act when reaching certain operating point,depend on the base resistors.Put less stress on the IC esp driving difficult load at high power level. |
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