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Old 18th September 2018, 04:31 PM   #1
Pascal Nguyen is offline Pascal Nguyen  Australia
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Location: Sydney
Default LateSit

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
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Old 18th September 2018, 06:21 PM   #2
WalterW is online now WalterW  Netherlands
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LateSit
nice!
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Old 18th September 2018, 06:22 PM   #3
Nelson Pass is offline Nelson Pass  United States
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LateSit
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.
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Old 22nd September 2018, 04:43 PM   #4
Pascal Nguyen is offline Pascal Nguyen  Australia
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@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

.
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Old 23rd September 2018, 07:36 AM   #5
nicoch58 is offline nicoch58  Europe
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great signal cable/connector
can you please tell the models?
tnx
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Old 23rd September 2018, 04:41 PM   #6
Pascal Nguyen is offline Pascal Nguyen  Australia
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Default SMA RF connnectors

Quote:
Originally Posted by nicoch58 View Post
great signal cable/connector
can you please tell the models?
tnx
Hi nicoch58,

They are SMA connectors, left over from an RF project.
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Old 23rd September 2018, 05:01 PM   #7
Pascal Nguyen is offline Pascal Nguyen  Australia
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Default DN2540 Driver

It is a classic DN2540 cascode driver, Ids = 70mA, will release circuit diagram when all settings are done.
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Old 24th September 2018, 02:39 AM   #8
Pascal Nguyen is offline Pascal Nguyen  Australia
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Default 6J1P driver

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


.
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Old 24th September 2018, 06:55 AM   #9
juanitox is offline juanitox  France
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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 ?
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Old 24th September 2018, 12:17 PM   #10
aspringv is offline aspringv  Australia
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LateSit
Quote:
Originally Posted by Pascal Nguyen View Post
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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