B1 with Korg Triode

[KevinHeem]

and see if I have the cojones to attempt, and accept the possibility of abject failure.

No matter their size (or whether you have than at all for that matter) I’m sure you can tackle that project.

 

[R-K Rønningstad]

All three are single-ended buffers, that is to say an N channel Jfet
follower which is biased by a constant current source.

The follower fet is a 2SK170, LSK170, or 2SK370 (same chip different
package) in the B1 and Korg. In those two, the current source is simply
the same part operated at Idss by connecting Gate and Source together.

Ideally the follower and CCS use the Jfets selected so that they are
either matched or for slightly lower Idss on the CCS.

In the LXmini buffer, we use J113's, with the CCS current set by the value
of Idss and the resistor to operate the follower at slightly less than it's
Idss figure.

We do this in order to avoid using the very expensive / unavailable
Jfets seen on the two other circuits. There is not doubt that the 2SK170
types are better, but in this application we can get similar performance
from selected J113's, - thd around 0.002% at 1V into 10 Kohm, with
negligible noise.

Thank you. The creative DIYer could use the J113 for the CCS and the 174 part for the follower part of the design.

 

[cubicincher]

to dtaylo3 #1988

Hello dtaylo3,


this is my CAD design I did with the software from SCHAEFFER AG /
front panel express for the NUTUBE front panel.
The case is a modushop Galaxy Maggiorato GX287 (230mm x 170mm)
with 10mm thick front plate. Top and base is 2mm aluminum. Back is 3mm
aluminum.

Price is 44 € (plus shipping and tax)



Greets
Dirk

 

[carsten.witt]

@cubicincher (Dirk),
you attached pic will not shown but in the notification of a new post vial email there is it attached and also not shown.

 

[cubicincher]

to CarstenWitt

Ah, I see. Doesn't open.
Made a screen shot but doesn't load up as expected. Will try later again.
Thanks for the hint.
Dirk

 

[Zen Mod]

nope

still no go

 

[cubicincher]

Can't work. Filetype is .dxf
Greets
Dirk

 

[cubicincher]

I made a foto from 'frontplattendesigner'. I can't convert to JPEG or other filetype
supported by the uploader.
So, only a foto from the screen.
Dirk

 

[Rewind]

I think the front plate designer is a great tip. I have been looking for a nice chassis for a month now.the Chinese sellers at Ebay and Aliexpress wants €70 in shipping, and the nice designs cost €280. Hifi2000 in Italy are ok, but a bit boring looking. So my options in Europe is Hifi2000, or Chinese which is surprisingly expensive.

 

[carsten.witt]

@cubicincher,
can you send me the dxf file, will try to convert it (if it done, i will post it here, mail to: diyaudio.com@wittnet.de)?

 

[cubicincher]

to CarstenWitt

Hello Carsten,


I tried to send you the data. Please check e-mail.


Greets
Dirk

 

[tubesguy]

I really like this idea of cubicincher to have the display window. It saves money, too - no costly led needed to show that it is on.

 

[Rewind]

Yeah, I am getting one with a window. I will add some acrylic glass in the window and paint it black around the Nutube.

 

[Hadox]

2SK170 JFET matching

All three are single-ended buffers, that is to say an N channel Jfet
follower which is biased by a constant current source.

The follower fet is a 2SK170, LSK170, or 2SK370 (same chip different
package) in the B1 and Korg. In those two, the current source is simply
the same part operated at Idss by connecting Gate and Source together.

Ideally the follower and CCS use the Jfets selected so that they are
either matched or for slightly lower Idss on the CCS.

Can someone help my understanding; on my annotated schematic, is it A and B that need matching, or A and C?

 

[Zen Mod]

A with B , C with D

 

[Mrshazbot]

I had Modushop cut my plexiglass and the front panel and it fit perfectly. I think they only charged like $20 for it and it was worth it since I couldn't have possibly done a better job and it would have taken me hours to do a worse job.

I don't think I ever posted the final picture with the plexiglass inserts.

 

[cubicincher]

to mrshazbot

Nice B1 NUTUBE-Preamp!


Modushop in Italy as well Schaeffer AG in Germany can cut aluminum (CNC)
as well acrylic glass.
Both also offer printing and engraving.


Greets
Dirk

 

[Hadox]

Thought so, ZM, thanks.

 

[wdecho]

I had Modushop cut my plexiglass and the front panel and it fit perfectly. I think they only charged like $20 for it and it was worth it since I couldn't have possibly done a better job and it would have taken me hours to do a worse job.

I don't think I ever posted the final picture with the plexiglass inserts.

Very nice added touch making your build look extremely nice.

 

[cubicincher]

NUTUBE FRONTPLATE CAD converted to JPEG

This is my CAD datas converted to JPEG.


Greets
Dirk