100W Ultimate Fidelity Amplifier

[bimo]

what is the role of 100 ohm input resistors at each opamp?

To improve stability when drive capacitive load.

 

[prasi]

See if this is useful to you, not tested. Although do read comments posted by sajti/ivanlukik.

regards
Prasi

here is something better to the quoted post.

 

[Yuriy64]

Configuring APEX FB3.1

Sf3.1

Hi, Mr. Mile.
Tell me please how to properly adjust the variable resistor 1K in this circuit

 

[maouna]

will something like this with an input filter,do the job?are there any extra resistors needed like R2,R5,R8,R11=100ohm shown on previous schematic??

 

[apexaudio]

Hi, Mr. Mile.
Tell me please how to properly adjust the variable resistor 1K in this circuit

With 1k set DC offset to 0V at the output

 

[Sunny22g]

Hello ,Respected Sir mile

 

[HIFI0101]

Hi I have a question. Which caps should i use for amplifier(a40) ? I mean what should be the tolerance level 10% or 20% ? and there are many kinds of caps of same config have a look which one i am looking for? lets say im searching for 1000uf then these categories show up!
>>

==>>

An externally hosted image should be here but it was not working when we last tested it.

 

[cesarin]

Signal audio splitter

here is something better to the quoted post.

I like this PCB. I prefer with Opamp and use volume control. Excellent Mr. Prasy, thank you very much.

 

[ikona]

Hi I have a question. Which caps should i use for amplifier(a40) ? I mean what should be the tolerance level 10% or 20% ? and there are many kinds of caps of same config have a look which one i am looking for? lets say im searching for 1000uf then these categories show up!
>>

==>>

An externally hosted image should be here but it was not working when we last tested it.

HIFI0101 You want to build A40 but you can not find correct capacitor? Funny

 

[HIFI0101]

Nah its not funny i know nothing about electronics thats why i was confused.

 

[prasi]

I like this PCB. I prefer with Opamp and use volume control. Excellent Mr. Prasy, thank you very much.

Hello Cesarin,
you are welcome. Do post here once you build it.
regards
prasi

 

[maouna]

Hello mouna,
some thing like this would work?
regards
Pasi

Hi Prasi,whats the purpose or R2 and R5 on your schematic?

 

[prasi]

Hi Prasi,whats the purpose or R2 and R5 on your schematic?

Hello maouna,
Its for RF immunity. I configured the buffer similar to ESP P88/ivanlukik schematic.
In fact ESP recommends it no less than 220 ohms.
regards
Prasi

 

[ivanlukic]

Input series resistor serves two functions.

1. RF immunity
2. Protective function. Most high performance opamps have back to back diodes at the input. If opamp is configured as unity gain buffer these diodes can conduct at turn on pulses. In that case input transistors can be destroyed or damaged. Series resistor provides protective function reducing the current. To be effective these resistors should have value between 500R and 1k.

 

[prasi]

The second one, I didnt know. thanks.
Need to update the schematic.

 

[Yuriy64]

F40 for fanatics

Hi, Mr. Mile.
I can not find the transistor 2SJ74 for the APEX F40 amplifier. Prompt his replacement. Or how can I replace the pair 2SK170 / 2SJ74?

 

[HIFI0101]

What is the max output of A40 btw? watt?

 

[Sunny22g]

Hi can I replace bc550 bc560. With mspa64.mspa13 in a40

 

[prasi]

here is something better to the quoted post.

Updated schematic.

 

[Bangla H]

single Rail FX4

Hello Fellas


Any time back Mile presented a FX4 Retro single Rail schematic.
For fun i have done a board and share it here.

Please takes a look over- is it ok?

If there is interesting i will create gerbers and share here too.


Regards