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Old 5th October 2018, 07:51 PM   #61
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Quote:
Originally Posted by juanitox View Post
Eureka , now it is as undersandable as a ZM circuit !
Hope you would not running nude !


Quote:
Originally Posted by Samuel Jayaraj View Post
U3 Drain is connected to GND and Supply Rail at the same time?
Yes, it does for having a reversal effect in H2 generation.


Quote:
Originally Posted by Zen Mod View Post
well, not to ZM

Juanitox meant that he will polish your circuit with sand paper.


Cheers all
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Old 6th October 2018, 12:34 AM   #62
Chul is offline Chul  South Korea
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Join Date: May 2003
Location: Pusan Korea
LateSit
Hi Pascal I think the actual work you are doing is not the same as the circuit...
Maybe I am too stupid to follow and good luck with your test..!
__________________
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Old 9th October 2018, 02:39 AM   #63
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
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” .

Received my second 6J1 kit, then a quick and dirty modification happened for a buffering purpose (google search “6J1 site:www.diyaudio.com”

Preliminary measurements taken for conceiving a LateSit version 3, will be interesting due to direct negative H2 generation from tube, then Sit and Late mosfet have to be non reversal to have negative H2 output.

Please note, the LateSit is my long term project for personal education and entertainment.

The 6J1 preamp and buffer are behaving within normal limit of an Au $9 each, delivered, please find attached my measurements taken.

Cheers


.
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File Type: jpeg 23FDB8AD-A534-4805-ABB5-350A0E7B31E9.jpeg (832.7 KB, 399 views)
File Type: jpeg 986DD757-4280-4F97-B2A6-AABF720D9513.jpeg (815.8 KB, 390 views)
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Old 11th October 2018, 02:09 PM   #64
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Default Reference Amplifier

So far I am successfully “LateSitted” the DefiSit(C) up to its transformer gain stage (without the pair K170 & J74).

The result is very impressive, due to high transconductance of the lateral BUZ905D and very low distortion of 1:4 transformer ( wire gain, hihi, I realised it when I built my Zeus amp).

Preliminary measurement recorded as a reference for later comparison with difference input gain and buffering driver circuit.

Clipping at 5Vp-p input, interesting at 4Vp-p input, the output H2 shifted from negative to positive phase.
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File Type: jpeg F15FD428-1208-4DCB-BA39-2407C9753703.jpeg (931.7 KB, 342 views)
File Type: jpeg 7F5B6FBC-8A6B-46F7-A8DD-282AED491427.jpeg (920.7 KB, 326 views)
File Type: jpeg 73EF8B09-6FBF-4E34-87FB-6053979BC6EC.jpeg (884.7 KB, 55 views)
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Old 11th October 2018, 02:19 PM   #65
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Default Preliminary test 6J1 buffer and preamp

The result is very poor, perhaps it does need a regulated and low noise power supply, the built in 12v tripler contributed a lot of noise to the circuit.
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File Type: jpg 10225C1C-32F8-41FA-8D9B-822CC0BAF911.jpg (873.1 KB, 72 views)
File Type: jpeg 9C726CF2-9A3D-4242-9807-C375608DA09A.jpeg (880.4 KB, 66 views)
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Old 12th October 2018, 11:36 AM   #66
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Default Chassis Day

The wicked fan cooling is working extremely well, able to sink 150W for both channels with minimum fan speed.

Only problem is the height is 1cm taller than the U3 case.
Well, the copper plate has to go under the chassis!
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Old 13th October 2018, 02:56 PM   #67
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Default Power Supply Day

Using CRC filtering with el cheapo caps, just to find out how long would they last to the ripple current.
Will see.

Won’t gaming with the ouput capacitors.




Cheers
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Old 28th October 2018, 03:37 AM   #68
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
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Quote:
Originally Posted by Pascal Nguyen View Post
Using CRC filtering with el cheapo caps, just to find out how long would they last to the ripple current...
My toroid 2 x 24Vac @ 150VA, provides around 32Vdc under load, needs to be wind back to 28~30 for CRC voltage safety margin.
Too lazy to remove few turns from secondary coils, I thought about using LCRC that I learnt from “Eduard & nagini262” with bifilar Ls in differential mode

Type of Choke for CLC?.

Empirically I found the secondary 2 x 12Vac 100VA toroid is my best candidate, it does reduced the output to 28Vdc under load with 0.01Vpp ripple.
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Old 29th October 2018, 04:55 PM   #69
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Quote:
Originally Posted by Pascal Nguyen View Post
...with el cheapo caps, just to find out how long would they last to the ripple current...
I had a look at the ripple V out of both circuits:

CRC (60mF - 0.5R - 60mF)
LCRC (dual 12Vac secondary coils - 60mF - 0.5R - 60mF)

Vripple are all 0.01Vpp on my CRO.
But at the input to the first capacitor, the difference is huge.

17Vpp before choke and 0.3Vpp after choke

These voltages reveal that ripple current is reduced to a safe margin for low cost capacitor or expensive “audio grade” one.


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File Type: jpeg 2DD0BDC7-991E-4A17-8689-7DD67F447E7C.jpeg (837.3 KB, 86 views)
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Old 31st October 2018, 07:19 AM   #70
Pascal Nguyen is offline Pascal Nguyen  Australia
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Join Date: Sep 2016
Location: Sydney
Quote:
Originally Posted by Pascal Nguyen View Post
...

These voltages reveal that ripple current is reduced to a safe margin for low cost capacitor or expensive “audio grade” one.


.
Another benefit of LC Filter is ripple energy is not wasted as heat, it is transformed to magnetic flux and regulated the the energy’s transfer without the need of excessive high VA for power transformer. It is surpassing the SMPS in this field to provide fast and punching characters.

Thermal and power supply tests been conducted in 48 hours continuously, a dollar 10mF/35V capacitor is helpfully stretched my wallet far beyond expectation.

LateSit amp with two 6J1 cards, preamp and buffer modified from cheap kits.

YouTube



Cheers
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