First One - mosFET amplifier module

[meanman1964]

Look at Hypex , they still support the diy community

 

[Bassivus]

Interesting article. This explains why he dropped out of the DIY scene. I'm glad I built one back in the day. Best money I ever spent on a power amp build - without question. IMO the transparency and articulation of each and every note is so clear it's scary. Some people/engineers/designers are just born with a gift. I'm just glad he provided his First One modules to the DIY community. I know there many members sore he left us hanging with no support. Clearly, he was destined for greater audio ambitions.

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...

 

[Theodosis O.]

Hi @gabor.lorinc87 ,

did the module die by your fault ?

 

[redjr]

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.

 

[gabor.lorinc87]

Hi @gabor.lorinc87 ,

did the module die by your fault ?

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!

 

[Erlend Sæterdal]

No surprise

 

[Bassivus]

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!

Yeah... LC promised to many of us and than disappeared for good. Lame

 

[rawbas]

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?

 

[Erlend Sæterdal]

I sent it to Virtual Zero Audio. But they didn't manage.

 

[sonnya]

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

 

[sonnya]

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.

 

[stocktrader200]

You can make a good one following Bruno Putzeys design on the Phillips mosfet datasheet.

 

[Erlend Sæterdal]

I have some boards that I can find soon. But I don't think pictures will be alright taken from a smartphone.

 

[sonnya]

Ok, but you could try.

You are located in Denmark. So you could send me one defective module if you have one.

 

[Erlend Sæterdal]

I will look but not easy because I just moved to s new location.

 

[rawbas]

@Erlend, any updates?

 

[Erlend Sæterdal]

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.

 

[momomo67890]

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.

 

[Erlend Sæterdal]

Anybody remember wich voltage for the large modules?

 

[momomo67890]