The marriage

[Zen Mod]

DN2540 is used as level shifter for Schade - triodizing enhanced part ( positive Ugs)

IRF510 is used as level shifter for depletion parts - negative Ugs

find entire presentation where I explained logic of this biasing ..... I forgot where it is

 

[schultzsch]

These days it’s a luxury to remember everything I read

 

[twitchie]

It's in the SissySIT R3 thread

 

[schultzsch]

thanks @twitchie

 

[schultzsch]

 

[Zen Mod]

 

[schultzsch]

Slowly but almost there.

I hoped that this day will never come but here I am that I have to drill and tap 4 new holes in the heatsinks.

 

[Zen Mod]

 

[twitchie]

Do we call that Boo-Lu now? 🤔 👍 🤣

 

[Zen Mod]

 

[schultzsch]

For me it’s a complete version of the Boo 😁

If anyone is interested to play with their Lu fets I can share the gerbers for r1 here or in a pm.

I have also 4 pcbs of r0 that I can donate. They have the wrong tracks cut, you only need to place some wires to do the correct bridges and some cleaning.

 

[Pars]

What are those connectors you are using for the Vcc's and the Out? Look almost like some sort of BNC.

 

[schultzsch]

Those are rc bullet connectors, very cheap. I use some between the amps and speakers without problems for many years.

 

[schultzsch]

2 more holes to drill and tap and I’m ready 😎

 

[Lvandoorn]

I would like to have the gerbers for r1 version!

 

[schultzsch]

the 1st half of a channel is heating up. I have 0.5r resistors in the crc filter of the ps so I have 500mV for 1a bias, the offset is close to 0mV. I set the vds of the lu at 2.4v

 

[Zen Mod]

...........

 

[schultzsch]

Oh boy, both amps are now playing music. It was easier than expected to setup everything.
Thanks ZM

 

[Zen Mod]

first impressions?

 

[schultzsch]

I am listening Coleman Hawkins tonight.
At 50mW that go to the speakers at this hour I can say it’s very good. What I noticed is that it does better at low level details compared to the mosfet version.

I mostly don’t like to do this type of comments because every new amp sounds better than the old one … you know how it is.
I am curious to play with the Vds of the LU. I think it can be done while you listen to music 😁
This is the part that implies a lot of fun.