Hello Apex,
Yeah I did use red LED, the green one is only for testing.
Test procedures made with red LED/LDR assembly:
1. Resistance when LED is off roughly it's @ 800K - 1M.
2. Resistance when LED is on it's @ 300 Ohms.
I have seen lots of post for the step driver circuit and some have corrections. I wonder what's the correct circuit to use and the proper wiring for the said circuit. Can you post the right ones please?
Thank you once again!
Regards,
Blueice23
![APEXaudio%20B500%20PCBMON[2].JPG](/community/data/attachments/190/190101-f2475b1fe37daec3359168e1e6ebea9a.jpg)
apex,
please make i.c resistor stabilizer guide,we know this value change according to PSU,different volt if possible
please help thanks
markedin blue
I suggest minimum 30mA for 15V zeners. Resistor value R is HV-15/0,03. For +/-80V rail R is about 2k2/2W, if you want 50mA use 5W resistor or two 2W resistors in parallel.
![APEXaudio%20B500%20PCBMON[2].JPG](/community/data/attachments/191/191462-f2475b1fe37daec3359168e1e6ebea9a.jpg)
Hi, Apex.
I have some minor problems with your B500 amp:
1. When I connect +/-63V, there is about 50mV on output.
2. 400mV on input.
3. Resistor 22ohm is little darken, but no change in resistance.
I had used 2 pairs of output transistors 2SC5200/2SA1943, and MJE15030/15031, 4K7/2W resistors.
ZD12V and TL072 are only changes. And I didn't have 33pF capacitor, so I put 47pF.
Can you help me to locate source of the problem? Please sir.
Regards
I have some minor problems with your B500 amp:
1. When I connect +/-63V, there is about 50mV on output.
2. 400mV on input.
3. Resistor 22ohm is little darken, but no change in resistance.
I had used 2 pairs of output transistors 2SC5200/2SA1943, and MJE15030/15031, 4K7/2W resistors.
ZD12V and TL072 are only changes. And I didn't have 33pF capacitor, so I put 47pF.
Can you help me to locate source of the problem? Please sir.
Regards
B500 in the finish line
Hy Apex! Thank you again for this great amplifier, I made tests during the weekend, it worked with 2 15"+1" 300W 2-way speakers, and it ran for 7 hours at the speakers' top volume. The amplifier was only about 30°C, the caps and the transformer performed also very well. The supply voltage was 2x76VDC before use, and after 4 hours of continous use it only dropped 1,5V, and it was smooth, not dropped even at the hardest beat. Now I disassembled it, because the casing will be painted, and then I make pictures of it, and share on this forum.
Thanks, bye!
Hy Apex! Thank you again for this great amplifier, I made tests during the weekend, it worked with 2 15"+1" 300W 2-way speakers, and it ran for 7 hours at the speakers' top volume. The amplifier was only about 30°C, the caps and the transformer performed also very well. The supply voltage was 2x76VDC before use, and after 4 hours of continous use it only dropped 1,5V, and it was smooth, not dropped even at the hardest beat. Now I disassembled it, because the casing will be painted, and then I make pictures of it, and share on this forum.
Thanks, bye!
did u check the amp at the full volume for 7hours in indoor or outdoor with speaker.
Hy! The amp wasn't at full volume (I guess) because the speakers couldn't handle that output. It was indoor, and was really warm (120 people danced on a 200m2 dancefloor)
Bye
how much ampere transformer do u use and the core size, bobbin size.
for stereo one transformer or two?
It was a room with 10 meters x 20 meters (200 square meters) - and full of people
Well, I bought the transformer. I use 1 transformer, but as I am limited with the space I can use (because of the casing) it is a 1500VA, has 2x55VAC+2x18VAC secondaries. I don't know the exact inner parameters (core, bobbin)
I hope I could help.
Bye
If it is a toroid, you can easily wind down a few turns...and get about 2x55V, as I tested the amp, it was the best for it.
Bye