AB100 Class AB Power Amplifier

[jimk04]

Thanks Prasi. Stuffing boards today and its all going nicely. Nice boards to solder

 

[prasi]

Great ; check , measure twice , and solder only once... don't depend on labels by mouser, etc

 

[jimk04]

Wise advice my friend

 

[flamethrower1]

I need to build a summer amp, so here is my plan with parts I have on hand
Each heat sink is 6"H x 7 1/4" long or 152.4 mm x 184.15.
The only thing that makes me nervous is the seam in the sinks and if that is going to create a hot spot and be problematic.

This is what I was referring to pic didnt make it the first time

 

[jimk04]

I would think if you but them up tight and maybe a little thermal compound you will be good.

Regarding the BC transistors....is the grade important. I seem to have ordered 'A' but generally I am seeing C grade. Dont know why I ordered A?!

 

[rollingtube]

1% MFR tolerance itself is +/-0.22kOhm for 22kOhm nominal value, so there is no problem using 22k

Given how often I see these 22.1k resistors in Mr. Pass‘ designs I‘m rather suspecting that he once got a bargain offer for 2 metric tons of this resistor value and is using them ever since.

I at least always use 22k resistors from my own stash in those positions 🙂

 

[Mark Johnson]

221 is an E96 international standard resistor value: (wonderful table here)

It wouldn't surprise me at all to learn that Pass Labs has decided its stockroom will only inventory resistors from the E96 standard series. Thus if you work at Pass labs, and if you want a resistor around 22K ohms or so, the closest you can get from the stockroom is 22.1K. An E96 standard value.

BTW those Vishay Dale resistors with printed resistance values instead of colored bands, which diyAudio members love, Love, LOVE (RN55, RN60, CMF55) . . . . are only available in E96 standard values.

 

[RickRay]

Finally got around to building this amp. I had a Proton D1200 that self destructed so I gutted it and installed the AB100 boards instead. I cut the meter driver portion off the old circuit board and made a small power supply to drive those. It sounds great, but not nearly as authoritative as the original.

 

[vdi_nenna]

Looks real nice.

I haven't heard the AB100 myself, but more than a few have said the AB100 has a solid bass response.
Do you hear that it's lacking punch?

 

[RickRay]

No, it has solid bass response, hard to compete with a +6dB dynamic power. That D1200 will put out 1200 watts into a 2ohm load for about 200mS. It's rated at 100 watts into 8 ohms and will put out 400 watts into 8ohms for 200mS.

 

[flamethrower1]

Nice build.
What are you running your rails at and what kind of temps are you seeing?

 

[Abx74]

Hi everyone,


could you tell me what is the lowest voltage rail supply we could use ?


Damien

 

[prasi]

Hello Damien,

AB100 Class AB Power Amplifier

i couldnnt find the actual post which mentions this , i think Jan is correct in his post.
regards

 

[osscar]

comment from NP regarding lower voltage:



Nelson,

Do you see any problem if the rails of the amplifier go down to +/- 25V ?

thanks in advance
George


Nelson Pass:



If it get noisy, you can reduce R8 to 3.3K, but probably not needed.

And lower rails gives opportunity for higher OS bias.

 

[Abx74]

Ok great. higher OS bias is not wanted, 30W will be enough I think, just want an amp for summer...

Damien

 

[RickRay]

Nice build.
What are you running your rails at and what kind of temps are you seeing?

I'm running +-50VDC rails and haven't measured temps because it doesn't get hot enough to be concerned with music.

 

[flamethrower1]

Thanks, 50 it is

 

[fredeb]

I ordered my last necessary parts from my supplier in SA last week , can't wait to get it started .

 

[jk556]

Board Question

Hi All,


I had a question if someone knows something about the design of the board maybe Prasi can help.


I am trying to get heatsinks pre drilled and tapped for the Prasi PCB, but they need a DXF Cad file:


I was wondering if someone has any experience on how to make this from the gerber files? I tried using Eagle but I couldn't get it to work. Does anybody have any ideas?

Prasi do you maybe have a file like this for your boards? I really only need the holes for the PCB mounts and the Tranistors.


Any help greatly appreciated

 

[prasi]

Hi jk556,
I can provide the dxf file , no problem.
please inform or link the post number of the pcb design.

regards
prasi