BAF2022

[EUVL]

Slept with Papa Borbely papers month or so, in the end chickened both of White Cascode Follower ....

White follower = poor PSRR. I use Taylor Current Source (TCS) instead since 2008.
https://www.diyaudio.com/community/threads/b1-buffer-preamp.124889/post-1554969
https://www.diyaudio.com/community/threads/jfet-buffer-with-j113.318917/post-5344477
https://www.tubecad.com/2004/blog0023.htm


Patrick

 

[EUVL]

I asked Paul Norton of Linear Systems to start selling JFETs useful for bootstrapped cascode circuits.
You want a large |Vpinchoff| and a large Vdg_max and a large Vds_max for this application.

This self-biasing JFET cascode is what Erno Borbely & John Curl used extensively.

The most popular cascode device is 2SK246BL / 2SK103BL.
They are rated at 50V, and have max Idss of 14mA.
But if you would use them to cascode K170/J74BL running at Idss, you would end up with little or no Vds headroom.

So in the past I have used J111/J174 instead in the same position.
Disadvantage is much lower voltage rating.
J111 still can be had for a few cents, but J174 seems quite impossible now.
You may try your luck with J175 and select those with high enough Vp/Idss.
But again, limited to 30V.

We'll make available our stock of 2SK246BL / 2SJ103BL after matching.
Will take 6 months or so to match them all.


Patrick

 

[EUVL]

from laterals too

Love them to bits.
You don't know what you are missing. 😉


Patrick

 

[Zen Mod]

Still are. How many would you like?

Mighty Moi?

Naah, content with one sex tiny buggers

What could I do with complementary TO92, except making literal Papaknockouts?

 

[Zen Mod]

Love them to bits.
You don't know what you are missing. 😉


Patrick

Feel no need to be logical in all of my choices

Only feeling everlasting regret (luckily just slight one) for not playing with toobz more; but there are also logical reasons for that

 

[EUVL]

Nothing to do with logic.
If you have not try, you never know.


Cheers,
Patrick

 

[Zen Mod]

One thing important for proper existence of Forums in general is sharing information (hopefully from altruistic impulses, not any else)

Not that is your obligation to know circumstances of any member here, but one of these is that I'm always insisting in Greedy Boyz having informed choices, per se category directly depending of information

So, what gives you conclusion that my choice of not using laterals is not based on informed choice?

Even if I know nothing, I already grew enough in my Grown-up Syndrome, so why not indulging my own logical need to have opinion about everything?

 

[EUVL]

So to make it short, you tried, and think it is not worth your trouble ?
Or you have not tried ?

I tried. As said, love it to bits.


Cheers,
Patrick

 

[R-K Rønningstad]

With this control of cascode, you remind me of JC, he uploaded his JC2 schematic and put ??? on cascode control elements 🙂
I bet no body tried to find values 🙂

Pure JC!

 

[codyt]

Still are. How many would you like?

A beast’s worth…

 

[EUVL]

You can have them for a bargain price of 3.50 USD each. 😊
https://www.ebay.com/itm/255655422679?epid=5012072989&hash=item3b86402ad7:g:GEoAAOSwZSVi5xBB


Patrick

 

[generg]

I think you saw already the videos from BAF 2022 are online!
https://burningampfestival.com/videos/

:--))

So I looked for the new small pre and here is my Spice following the picture.

On the left side we have no value for C5/6 I took simply 220uF. Same is true for the RF cap in the input, Nelson gave no value I took simply a value that stops bandwidth with 3dB at 100kHz.
Irritating for me the distortion for 2V output and 1kHz is fairly high in Spice about 0.056%. That is too high I think so I must miss something.

 

[generg]

OH I see I did not replace the SK170 with the J113, but when I do it Spice refuses to work.....

Funny!

 

[mkc]

I think there might be a small mistake in the sim. As far as I know the ZTX550 is an NPN?

Edit: Sorry, my mistake. It's actually an PNP. I mistakenly thought it was diodes "copy" of BC550.

Mogens

 

[Mark Johnson]

Have a look at the simulation schematic in post #108 of Home --> Amplifiers --> Pass Labs --> BAF2022 SIT AMPS

It differs from your schematic in post #72 of this thread, in a few places. Scrutinize and review.

 

[Zen Mod]

Mein Bruder Generg is, besides known as originator of ZAP, also well known as

 

[generg]

Ha lhquam was faster....

:--))

I did not see this.

 

[generg]

I added the 100p cap at the PnP ZTX550 and

• Spice runs
• distortion is smaller from 0.056 to 0.16%

Indeed I forgot this cap at the ZTX550.

 

[generg]

Still the distortion pattern looks not good. I never saw this before in its fuzziness .....

 

[generg]

for comparison the same upper circuit with BJT CCSs down gives this result....and has 0.0013%