500W PA amplifier with Limiter

[TonyTecson]

gains for hifi amps are about x20, while professional/PA amps start at x40, i even saw a design with gains of x70....

 

[wattaniya]

hi apex sir,
can i use c5171,a1930 or c4793,a1837 instead mje340,mje350 for pre driver section.
if its ok so is it need small heatsink or no need heatsink.

 

[apexaudio]

hi apex sir,
can i use c5171,a1930 or c4793,a1837 instead mje340,mje350 for pre driver section.
if its ok so is it need small heatsink or no need heatsink.

Yes, and use very small heatsink.

 

[wattaniya]

Yes, and use very small heatsink.

thanks sir for the reply.

 

[comasus]

Replace R2, use 1k instead 10k and gain will increase.

If R22(680) decreased bias decreases or not?

Can I use 3mm led in place of NSL32?

 

[apexaudio]

If R22(680) decreased bias decreases or not?

Can I use 3mm led in place of NSL32?

Yes and yes, you have 'clip' led and amp without limiter.

 

[comasus]

Yes and yes, you have 'clip' led and amp without limiter.

Thank you sir for your reply

 

[yohnsee]

@ JOHN BALI:

Very nice design! I also wanted to build my B500 with TTA and TTC transistors, but they are unavaiable here
I like to get my hands on those trannies, their advantage is that their case is full plastic (even their heatsink side)

 

[JOHN BALI]

@ JOHN BALI:

Very nice design! I also wanted to build my B500 with TTA and TTC transistors, but they are unavaiable here
I like to get my hands on those trannies, their advantage is that their case is full plastic (even their heatsink side)

But finally I made it with 2SA & 2SC
I keep those TTA & TTC because maybe it not as good 2SA & 2SC
note that TTA & TTC is new product, maybe replacement for 2SA & 2SC
the back of those TTA & TTC are metals, not full plastic case
that make a little doubt, maybe it fake or not that good older version

I'm also happy if I can find full plastic case, so we can mount it easier

Btw thanks, my PCB is not good there are miss-route on it
on it IC's pin 1 & 3, sorry not fix that yet

Regards

 

[irvynejay]

Hello mile can i ask if it is possible to use 85vdc+/- on B500 do i have to change anything any modification?

 

[apexaudio]

Hello mile can i ask if it is possible to use 85vdc+/- on B500 do i have to change anything any modification?

No change for 8R speaker, but for 4R better add 2 pairs of outputs and use large heatsink.

 

[irvynejay]

ok i have plan to change my bose1800 2 channel just blow up and parts are hard to get so ill make B500 with 6 pairs

 

[MATSAZILIN]

sir, if I may want to ask your permission to use your invention. many of my friends want to have this amp. If possible I would like to sell to them. especially B500 with 10 transistors.

 

[comasus]

What happens if i dont use 47k resistor instead of LDR

When the sound of B500 is compared with AX-14 the treble of B500 is low and has more bass

How can i increase the brightness of the sound?

When clip LED glows does it indicates that the amp has reached to its maximum power???

 

[apexaudio]

What happens if i dont use 47k resistor instead of LDR

When the sound of B500 is compared with AX-14 the treble of B500 is low and has more bass

How can i increase the brightness of the sound?

When clip LED glows does it indicates that the amp has reached to its maximum power???

Nothing happens without 47k resistor. Increase bias to 25mA per outputs for better treble. Clip LED glows about 10V before hard clip (about 80% power).

 

[smblite]

Hi Apex,

Just wanted to try your amp. But I have a question, can I used 2sc2240 and 2sa970 instead of 2n5551 and 2n5401?

regards,
smbl

 

[TonyTecson]

Hi Apex,

Just wanted to try your amp. But I have a question, can I used 2sc2240 and 2sa970 instead of 2n5551 and 2n5401?

regards,
smbl

afaik, those japanese trannies are better in terms of hfe's....

2sc2240

hFE
(Note)
VCE  6 V, IC  2 mA 200  700

2n5401

DC Current Gain
(IC = 1.0 mAdc, VCE = 5.0 Vdc)
(IC = 10 mAdc, VCE = 5.0 Vdc)
(IC = 50 mAdc, VCE = 5.0 Vdc)
hFE
50
60
50
−
240

 

[smblite]

A few question before I go to build this amp. I'm Just trying to understand the circuit, I been notice that Q1 and Q2 is in position of common collector biasing, correct me if I'm wrong, so the main signal path going through R15 and R16 and that time Q1, Q2 will saturate depend on the signal. now question again how it works D3, D4, D5 and D6.

Sorry for this ignorant question, Just wanted to know the behavior of intire ckt.

regards,
smb,

 

[TonyTecson]

A few question before I go to build this amp. I'm Just trying to understand the circuit, I been notice that Q1 and Q2 is in position of common collector biasing, correct me if I'm wrong, so the main signal path going through R15 and R16 and that time Q1, Q2 will saturate depend on the signal. now question again how it works D3, D4, D5 and D6.

Sorry for this ignorant question, Just wanted to know the behavior of intire ckt.

regards,
smb,

The output of the op amp is fed to the emitters of Q1/Q2 via R15 and R16, actually Q1, Q2 are common base circuits, not common collector as you think...please look at the schematics again....

Diodes D3, D4, D5 and D6 biases Q1 and Q2, so that about 0.6mA runs thru these trannies.....

 

[apexaudio]

A few question before I go to build this amp. I'm Just trying to understand the circuit, I been notice that Q1 and Q2 is in position of common collector biasing, correct me if I'm wrong, so the main signal path going through R15 and R16 and that time Q1, Q2 will saturate depend on the signal. now question again how it works D3, D4, D5 and D6.

Sorry for this ignorant question, Just wanted to know the behavior of intire ckt.

regards,
smb,

Go to http://www.diyaudio.com/forums/solid-state/164093-100w-ultimate-fidelity-amplifier-94.html post 934,
Regards