UDNeSS, or You don't need Semisouth's

[Andreas60di]

hello patrik I intend to build your UDNeSS project but I was intrigued by the diagram you published TOPIC: first watt J2 post 1312 page 132 which I report below
Now I ask can I get SIMILAR results using that scheme or is it better to do the UDNeSS as it is Default

The "J1014" And that's just me having fun.
I'm sure people remember the Zen V9 with a LU1014 triode cell.
So why not use it here instead of the Semisouths?

Here's how it might work.
A little more complicated, but now you can easily change the open loop gain.
This allows it to adapt to different speaker loads or NFB level.

Does Nelson still have 4k of those to give away?


Health,
Patrick

.

 

[EUVL]

As already mentioned here :
Pictures of a >>GENUINE<< Lovoltech LU1014D Wanted!
The J1014 schematics has only been simulated and not built.
So build at your own risk.

The UDNeSS has been successfully built by multiple people, as you can read here.


Patrick

 

[Andreas60di]

ok thanks for the prompt reply, i will make the UDNeSS with my own PCB as i like to design single sided PCBs inspired by your PCB If you have nothing against it as soon as I make the drawing I would like to publish it
it's possible?

 

[EUVL]

You are free to do what you want.

But for those who intend to build the UDNeSS, I still recommend using our proven design.
The Gerber has already been published.


Cheers,
Patrick

 

[damon1983]

But the time of 2SK170+2SJ74 is over, where are you finding them?..

 

[petoluk]

If only there was some interconnected network of computers where one could search for stuff...

But really:

1. The diyAudio Store right here sells the current-production Linear Systems equivalents.
2. Several trusted sellers of genuine Toshiba parts have been brought up time and again in multiple threads especially in the Pass Labs section (alweit, NicMac, punkydawgs, ...).
3. If you put your mind to the task, you can still find thousands of these in stock at various suppliers all around the world - *real* suppliers of *real* parts, so the *real* price may not be to everyone’s liking (check e.g. NAC Semi in Florida).

 

[EUVL]

> But the time of 2SK170+2SJ74 is over ....

Where did you see 2SK170 / 2SJ74 on the UDNeSS schematics ?

The J1014 has nothing to do with the UDNeSS; different thread if you wouldn't mind.
https://www.diyaudio.com/forums/pass-labs/151909-firstwatt-j2-27.html#post5895263


Cheers,
Patrick

 

[damon1983]

Aaaah. never mind.

 

[EUVL]

The UDNeSS was designed with the very purpose of avoiding any unobtanium devices.
The J1014, which was posted at the Pass J2 thread, was a pure simulation exercise, for fun.

Just to make that clear to anyone interested in building either ot them.


Cheers,
Patrick

 

[Andreas60di]

I buy most of the components on AliExpress I also took the j74 and J170 BL which in the selection phase instead of giving me 10 or 12 mA gave me between 6 and 7 mA. I got them from sellers who cost a little more than the others but guarantee the original the only problem is that you have to wait between 50 and sometimes 65 days to receive the material

 

[Andreas60di]

hello Patrik returning to the UDNeSS discussion I would like to know if I can do without the servo and then create the pcb without a servo
As it is often mentioned in the forum that good offset results are achieved without the aid of the servo
But inserting it can somehow affect listening

 

[EUVL]

A PCB with the DC servo gives you all options.
You can just leave out those components, like Morde did, if you are happy with the DC drift.


Patrick

 

[damon1983]

I buy most of the components on AliExpress I also took the j74 and J170 BL which in the selection phase instead of giving me 10 or 12 mA gave me between 6 and 7 mA. I got them from sellers who cost a little more than the others but guarantee the original the only problem is that you have to wait between 50 and sometimes 65 days to receive the material

I'm never buying electric parts on Ali, cause 99% - a big crap. Only on official dealers.

 

[mareli]

I found on Digikey UJ3N065080K3S from UnitedSIC N-channel SIC JFET.
Will those be suitable for a J2 ?

 

[EUVL]

> I found on Digikey UJ3N065080K3S from UnitedSIC N-channel SIC JFET.
> Will those be suitable for a J2 ?

Wrong thread. Please ask at Pass forum.


Patrick

 

[EUVL]

Someone asked here :
FirstWatt J2

> Will the circuit ProUDNESS with 2 pairs of output transistors work?

Yes in principle, but have not tried myself.
So build at own risk.

> I need more power and will it work from +/-32V rails?

To work with 32V rails, you will need an octet (8 pieces) of output MOSFETs.
Each MOSFET should be biased to 0.9A, and dissipates ~30W.
Not for beginners.


Patrick

 

[mareli]

Why so many output pairs? F5turbo for example will work from 32V with only 2 output pairs.

 

[EUVL]

F5 Turbo is 32V 2A bias.
Max output voltage ~28V; max. output current ~4A.
So optimum for 7R load.

ProUDneSS is designed for 4R load.
So max. output current should be 7A; which means bias 3.5A.
I design for 30W per MOSFET.
So 32V 0.9A, which means one Octet per channel.

But you are free to do what suits you best.


Cheers,
Patrick

 

[mareli]

I have 8 ohm speakers so 2A bias is enough with 32V i only need 4 transistors per channel for 16w dissipation per device

 

[umut1001]

Hi.I have hundreds of 2sk209gr and IRFP9140.How can i build one with them?Same schematic works?