100W Ultimate Fidelity Amplifier

[apexaudio]

Unfortunately, specs quoted are of little relevance when these transistors are used in audio circuits. In fact, IRF540 fails frequently even in low power AB class circuits if Vbe multiplier is not implemented. Big heatsink is necessary!

Big heatsink is necessary, but with Vbe multiplier (thermal compensation) in class AB current can go to infinity if transistors are open, there is CCS in class A and current only can go to 1,5A independent of temperature.

 

[aliskamjad]

APEX AX14

Good Afternoon Mr.Mile,
Can I use C3856/A1492 instead of C5200/A1943, if yes then do i need to change anything using rail voltage +/-56V, and which will be better c5200 or c3856 in terms of sound qualtiy and stability.

 

[apexaudio]

Good Afternoon Mr.Mile,
Can I use C3856/A1492 instead of C5200/A1943, if yes then do i need to change anything using rail voltage +/-56V, and which will be better c5200 or c3856 in terms of sound qualtiy and stability.

Yes you can without changes.

 

[herimanana]

HI ALL !!! hI Apex,

Can I use darlington MJ11032 / MJ11033 with Apex B500 with 80 VDC ??

 

[apexaudio]

HI ALL !!! hI Apex,

Can I use darlington MJ11032 / MJ11033 with Apex B500 with 80 VDC ??

Yes

 

[herimanana]

thank you lord of loud !!! hihih

Thank you apex

 

[tuanndh]

Hello everyone,

I would like to build the FA9 amp as my first diy amp. I have some questions relate to prepare parts, could someone like to help me:

1. I have a pair heatsink with 18cm long as the photo, is it Ok for FA9?

2. For the power, PSU-5 with 2x10000uf + 2x22000uf is good for this amp? Or without PSU-5?

3. Transformers 2x18VAC@3.18A is enough for two channel?

Thank you!



Sent from my iPhone using Tapatalk

 

[apexaudio]

Hello everyone,

I would like to build the FA9 amp as my first diy amp. I have some questions relate to prepare parts, could someone like to help me:

1. I have a pair heatsink with 18cm long as the photo, is it Ok for FA9?

2. For the power, PSU-5 with 2x10000uf + 2x22000uf is good for this amp? Or without PSU-5?

3. Transformers 2x18VAC@3.18A is enough for two channel?

Thank you!



Sent from my iPhone using Tapatalk

This heatsinks can be use but with 0,8-0,9A bias. You need transformer 2x15V 5A for stereo or you can use 2x18V with PSU5 and set to +/-20V. 3,18A will be ok with 800mA bias.

 

[Hadighorbani]

hi dears
i need a fast protection for STK amp
it must cut out put under 0.3 S in short out
any one have any idea ?

 

[prasi]

Hi Prasi! Can post the pcb files in pdf format? Thanks!

here are the pdf and stuff guide.
regards
Prasi

 

[tuanndh]

This heatsinks can be use but with 0,8-0,9A bias. You need transformer 2x15V 5A for stereo or you can use 2x18V with PSU5 and set to +/-20V. 3,18A will be ok with 800mA bias.

Thank Mr. Mile, I will extend it to 6cm more and find the way to use chassis as heatsink.

One more question, do we need speaker protection for this amp?

 

[apexaudio]

Thank Mr. Mile, I will extend it to 6cm more and find the way to use chassis as heatsink.

One more question, do we need speaker protection for this amp?

Yes use DC protect with NE555 and NTC for thermal protect.

 

[tuanndh]

Yes use DC protect with NE555 and NTC for thermal protect.

Did you mean this one?

 

[I love the sound]

here are the pdf and stuff guide.
regards
Prasi

Thank you very much Prasi. You have a beer from my. All the best!

 

[prasi]

Thank you very much Prasi. You have a beer from my. All the best!

Do you have good beer in Romania? I have had German beer, it tastes too good!
sorry Mr. Mile for OT!, just couldn't resist!

 

[prasi]

Mr. Mile,
I have added rail decoupling near the o/p device and also ground lift.
Is it recommended?
+some reduced the PCB size to 68mmx75mm

reg
Prasi
PS; many revisions, but i want to make it as good as possible.

edit: the black jumper is optional jumper to reduce the trace length from C7 to C of T6.

Hi Bob53,
here are the pdf for rev3 Apex AA9. All views are from component side.
regards
Prasi

 

[AdeS]

Thanks. prasi!
Can you indicate a power supply to use with this amp AA9 or FA9? +/-20V

 

[prasi]

A CRC PSU implemented either on a PCB or a point to point like xrk971 does, would be a good option,
Mr. Mile if has a design in mind would be better.
Or can Apex regulated supply using 2sc5200 work here?

 

[I love the sound]

Do you have good beer in Romania? I have had German beer, it tastes too good!
sorry Mr. Mile for OT!, just couldn't resist!

Romanian beer is very good! Come in Romania and try the beer, you will not be sorry! All the best!

 

[44250]

every country has it's own good,I have tried it many(Romania,Hungary, Croatia, Serbia,Slovenia,Bosnia and Herzegovina, Austria, Germany times xy) ... but let's not spoil thread. sorry moderators...