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Aleph J illustrated build guide
Aleph J illustrated build guide
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Old 29th July 2019, 01:47 PM   #3671
6L6 is offline 6L6  United States
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Aleph J illustrated build guide
Quote:
Originally Posted by astromo View Post
Q5 and Q6
Q7 and Q8
Correct. 5&6 should be a pair, 7&8 should be a pair.
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Old 29th July 2019, 01:53 PM   #3672
astromo is offline astromo  Australia
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Originally Posted by 6L6 View Post
Correct. 5&6 should be a pair, 7&8 should be a pair.

Bravo and thanks for the quick reply.
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Old 29th July 2019, 01:57 PM   #3673
6L6 is offline 6L6  United States
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Aleph J illustrated build guide
5&6 are the transistors for the Constant Current Source, so they need to be matched so there's equal current though both, and one doesn't turn on a bit sooner and hog the current while the other just sits there.

7&8 are the output transistors. The same reasoning as above applies.

The pairs don't need to be matched to each other.
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Old 29th July 2019, 01:59 PM   #3674
Dennis Hui is offline Dennis Hui  Canada
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Aleph J illustrated build guide
You need to match Q5 to Q6, and separately Q7 to Q8.

Hope that helps.

Dennis

Edit: Jim answered already.
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Old 3rd August 2019, 06:14 AM   #3675
marantzfan is offline marantzfan  United States
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Quote:
Originally Posted by 6L6 View Post
Thats and odd mixup, the Aleph J transistor kit should only ever come with a 9.1v Zener.

The 5.1v and 6.1v selections are for an entirely different amplifier... the F6
Odd as this was... it happened again in the Aleph J transistor kit I bought.

I already had the correct 9.1v Zener from Mouser, but was scratching my head as to what the 5.1v and 6.1v were for?.. Now I know.
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Old 7th August 2019, 04:24 PM   #3676
astromo is offline astromo  Australia
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Not the tidiest wiring job ever but it's finally finished and most importantly it works. I'll do a tidy up in due course (maybe never?).



Thanks to Nelson, 6L6, didiet, diyAS and everyone else for their help along the way.


Got the big fella biased at 450 mV and the heat sinks are registering 43 - 45 C. That's the advantage of the modushop 5U chassis..
Attached Images
File Type: jpg 20190808_Aleph J Back View.jpg (656.8 KB, 273 views)
File Type: jpg 20190808_Aleph J Front View.jpg (691.7 KB, 278 views)
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Old 8th August 2019, 12:05 PM   #3677
escucalin is offline escucalin
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Quote:
Originally Posted by marantzfan View Post
Odd as this was... it happened again in the Aleph J transistor kit I bought.

I already had the correct 9.1v Zener from Mouser, but was scratching my head as to what the 5.1v and 6.1v were for?.. Now I know.

May I ask where did you bought such a kit?
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Old 8th August 2019, 12:21 PM   #3678
astromo is offline astromo  Australia
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Quote:
Originally Posted by escucalin View Post
May I ask where did you bought such a kit?

From the store:
The diyAudio Store - DIY amplifier kits, chassis, and parts


The Aleph J kit is sold out currently, as are the P channel JFETs. They don't have a long shelf life. Too much demand.
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Old 12th August 2019, 11:32 AM   #3679
astromo is offline astromo  Australia
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Quote:
Originally Posted by astromo View Post
Not the tidiest wiring job ever but it's finally finished and most importantly it works. I'll do a tidy up in due course (maybe never?).



Thanks to Nelson, 6L6, didiet, diyAS and everyone else for their help along the way.


Got the big fella biased at 450 mV and the heat sinks are registering 43 - 45 C. That's the advantage of the modushop 5U chassis..

Set the emissivity of my IR thermo-gun unit to a more sensible 0.85, so those temps are more 45 - 47 C down the bottom of the heat sink. Just getting a quick audition (a bit hard with a 4yo - not me - in the house ) of the Aleph J with my main system (includes floor standing speakers with 92 dB/W/m) ... noice mate, noice !
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Old 15th August 2019, 11:58 AM   #3680
K i n g p i n is offline K i n g p i n  Netherlands
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For my winter project i'm planning to build an amplifier.
As pre i will use my Naim UnitiQute 2 (for now).

After a lot of reading i got my attention to the FirstWatt designs because my first requirements are - Pure Class A - Single Ended - Fets.

Finaly i think the Aleph-J will suits most of my requirements so i am planning to build one .. yeah!

I need a lot of reading as i see so many threads about this amp and the different 'settings'.
Planning is to build the Aleph-J according the following items:

- PCB v2

- BOM Rev. C for now .. i know there is a Rev. D but i need a lot of reading

- J74/J74 Stereo Differential Kit when available

- Aleph J Transistor Kit (i think the items are not complete .. zener?)

- Universal Power Supply

I hope these items and heat dissipation will fit into this chassis ?

Click the image to open in full size.


To be continued ...
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