I'd like to be able to look that positive... To me it looks more like that LC intentionally used DIY community as a free debugging grounds. For eg. Nelson Pass never left his DIY family hanging...
One thing I’ve learned hanging around here for 10 yrs is there are no guarantees. I don’t expect DIY offerings to be backed up and supported like a commercial product would be. It’s a rare exception when they are. It’s simply the nature of the hobby. There are a couple of members here, that offer commercial grade products I’ve been interested in over the years, that do provide excellent support though.
Hi,
I don't think so, the engineer assembled the amplifier and during the testing phase one of the modules did not work under load. It was difficult to reach the seller but he answered and I sent the two modules back to him to fix them, but he still hasn't sent them back and he doesn't answer my email! That was about 1-1.5 years ago!
Sorry, too lazy to back read. Been away for too long.
Did anyone managed to reverse engineer the board to get the circuit so we can debug the issues?
Did anyone managed to reverse engineer the board to get the circuit so we can debug the issues?
take pictures of the board and the transistors/diodes.. There are markings on top. That part i can help you guys with to translate to transistor model.
Current feedback gives very high currents in the input pair. If BC850 and BC860 is used, Then I would replace them with SMMBT2907AL and SMMBT2222AL at least. The current rating is 6 times higher. Still the SOT23-3 is just to small a case. If you are subject it to DC on the input they can burn just because the power dissipation. After all they are normally only 250 to 300mW.
It is hard learning also for me.
I would also pull the bandwidth down from the 1.5MHz to the half to avoid too much oscillation. Most likely two capacitors that needs double value.
- Sonny
Current feedback gives very high currents in the input pair. If BC850 and BC860 is used, Then I would replace them with SMMBT2907AL and SMMBT2222AL at least. The current rating is 6 times higher. Still the SOT23-3 is just to small a case. If you are subject it to DC on the input they can burn just because the power dissipation. After all they are normally only 250 to 300mW.
It is hard learning also for me.
I would also pull the bandwidth down from the 1.5MHz to the half to avoid too much oscillation. Most likely two capacitors that needs double value.
- Sonny
Any close up picture of The board and traces would be very helpfull. Resistor values and capacitors.
I pretty sure , that I have an idea of how it is made. Then I can do reverse engineering of the board.
I pretty sure , that I have an idea of how it is made. Then I can do reverse engineering of the board.
I have some boards that I can find soon. But I don't think pictures will be alright taken from a smartphone.
Ok, but you could try.
You are located in Denmark. So you could send me one defective module if you have one.
You are located in Denmark. So you could send me one defective module if you have one.
Within a week I will take a picture. Now I know where they are. I think about using a Smps. What voltage do you recommend. I don't remember.
I have a few of these I never used if you want pics of the 1.4m I think it was I can take some.
