FINALLY I modified it

[hugobross]

Yieeeeeeeehhhhhhaaa

At least the amp sound as I wanted!!!

The sound is normal with 0.47 µF, and warm with 1µF; so I'll took the 1µF of course (😉); for higher sounds use 0.25µF.

I think I will use these three values with a switch, so you can adjust the amp to your speakers with the switch.

Hey, do I hear CCR 'live' in my hobby-room 🙂 ???

HB.

 

[hugobross]

Now, I've got even better sound with the 0.47µF input cap (1µF was too heavy with some songs), and a 100µF placed over the biasing circuit.

Tomorrow I will add the MJ15003/15004 transistors to the circuit, how many should I place in parallel to play with 4 ohm load (or bridged 8ohm)??

HB.

 

[e96mlo]

You would probably manage with 2 transistors for a long time but to be on the safe side, use 3 in parallel.

/Marcus

 

[hugobross]

I'm think to use 4 PCB's in total with each 4 transistors
So, that will make 16 transistors in total, and the acht plastic ones, for the bridged stereo-version, which can will drive 8 ohm load.
woooh, I've made that heatsink + fans already, and have also the necessary supplies and the caps, so I only need to make 3 another PCB's. That will take about two or three weeks to make that PA-amplifier I always wanted.

I will publish some pictures if it is so far...

HB.

 

[hugobross]

I'm just wondering how many watts I can drive with my eight transformers: 8 x 120VA (30V (220V) 34V(230V)).
I calculated 250W (x 2 => stereo). I'm just wondering if I can get more out those transformers or not?

HB.

 

[palesha]

Dear Hugobross,
Congratulations! U might have finalised all the component values of the amp till now. Can u kindly publish final circuit and it's pcb layout for those who are interested. I am one of them.
Mahendra Palesha

 

[hugobross]

hey thanks,

the amp works fine but I want to change some things ( 😉 ).
As I've told the TIP142/147 are not enough (they blew again when I made a little mistake with setting up the bias...).
So, I think I'll get me some new components thursday or friday.

This is what I've got in mind to change:

*)when I have my new TIP's I can add the Mj15003/15004's too
*)change the bootstrapping thing (R9-R8-C5) into a current source
*)change the bias diodes and the potmeter by a fixed resistor; I will try to make the current of the current source depending of the temperature with some diodes (and a resistor) in front of the base of the current source (transistor)
*)so I have to make a new pcb too

I will publish the whole new schematic as soon as possible...

HB.

 

[hugobross]

so the global view of the new schematic will be something like this:
-D2 and D3 are in thermal contact with the output transistors

-right values and pcb will be added

-any comments welcome, sorry for the unclear picture.

HB.

 

[HarryHaller]

the global view of the new schematic

I think you are missing something that should be connected to Q3 and Q5. Think what they do in the circuit......... No help from the audience please!

H.H.

 

[mlloyd1]

Re: the global view of the new schematic

Harry:
Very important point. Got your ruler ready to rap some knuckles?😀

I think you are missing something .....

😀

 

[Nelson Pass]

What do you mean? The function of Q3 and 5 here is
clearly to implement smoke generation, very popular
with many DJ's.

 

[mlloyd1]

smoke generation - I love it, heh, heh, heh. You guys are brutal 🙂

... The function of Q3 and 5 here is
clearly to implement smoke generation....

 

[hugobross]

hey thanks (for laughing with me 😉 ),

how about this one? should I keep Q4 or just leave it away?

HB.

 

[HarryHaller]

to implement smoke generation

Hey don't antagonize the newbies or you will upset someone.....
By the way, I'm only a part time saint.

H.H.

 

[hugobross]

Hey don't worry, I laughed too with that 😛

HB.