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-   -   LateSit (https://www.diyaudio.com/forums/pass-labs/327580-latesit.html)

Pascal Nguyen 18th September 2018 04:31 PM

LateSit
 
4 Attachment(s)
Without Mr Pass and many contributors to the Pass Labs Forum, I wouldn’t have a clue what is concerning a class A SIT audio amplifier.
Those information helped me to build an SIT amp with a complementary lateral mosfet, my LATE - SIT

Point to point wiring I finished the power stage, which included an BUZ905D and an THF-51S.
The driver stage at the moment is an 8 dollars EBay 6J1 tube preamp, will be modified for best coupling to the gates.

YouTube

WalterW 18th September 2018 06:21 PM

nice!

Nelson Pass 18th September 2018 06:22 PM

I think that is an an interesting approach. The lower transconductance of
the Lateral Fet will demand more current swing from the VFET, and is
probably beneficial with high impedance loads.

Pascal Nguyen 22nd September 2018 04:43 PM

1 Attachment(s)
@Nelson Pass

Thanks for your comment,
I tried firsthand with IRFP9240, then ALF08P16 and realised that they perform poorly under 16 Ohm load.
The BUZ905D is much better from my third approach, the Vgs window from my ten samples varied between -2.95 to -3.05.
It has a margin about 2V from Vp pinch off of the THF-51S.

Thanks again

@WalterW

Hi,
Just finish the driver, will do all measurements by tomorrow, having all midnight oils burned.

Cheers

.

nicoch58 23rd September 2018 07:36 AM

great signal cable/connector :)
can you please tell the models?
tnx

Pascal Nguyen 23rd September 2018 04:41 PM

SMA RF connnectors
 
2 Attachment(s)
Quote:

Originally Posted by nicoch58 (https://www.diyaudio.com/forums/pass-labs/327580-latesit-post5553691.html#post5553691)
great signal cable/connector :)
can you please tell the models?
tnx

Hi nicoch58,

They are SMA connectors, left over from an RF project.

Pascal Nguyen 23rd September 2018 05:01 PM

DN2540 Driver
 
3 Attachment(s)
It is a classic DN2540 cascode driver, Ids = 70mA, will release circuit diagram when all settings are done.

Pascal Nguyen 24th September 2018 02:39 AM

6J1P driver
 
3 Attachment(s)
Mondayitis? Not really, back to 6J1P driver for a final decision.
In a crudely state this EBay preamp is full of noise from 12Vac doubler.
Her plate voltage and current are governed only by a resistor, no hated here, just seen it as an unpolished opal.
Will combined with DN2540 as CCS and perhaps another EBay order for an 6J1P preamp to be modified as buffer but within Mr Pass philosophy “simple and elegant” .

Cheers


.

juanitox 24th September 2018 06:55 AM

i try to be patient :)
do you need gain or just a buffer to drive the amp ?
what is the value of the two zener ?

aspringv 24th September 2018 12:17 PM

Quote:

Originally Posted by Pascal Nguyen (https://www.diyaudio.com/forums/pass-labs/327580-latesit-post5554658.html#post5554658)
Mondayitis? Not really, back to 6J1P driver for a final decision.
In a crudely state this EBay preamp is full of noise from 12Vac doubler.
Her plate voltage and current are governed only by a resistor, no hated here, just seen it as an unpolished opal.
Will combined with DN2540 as CCS and perhaps another EBay order for an 6J1P preamp to be modified as buffer but within Mr Pass philosophy “simple and elegant” .

Cheers


.

10/10 loving this just for the photos of your workbench.

The project looks pretty great too. ;)


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