Aleph J Schematic

[chinsettawong]

450VA as minimum for stereo PSU ;


CRCRC is certainly good enough , but don't go much above 0R22 per R

Thanks Zen Mod. Your answers help a lot.

Wachara C.

 

[chinsettawong]

Hello!

I'm just wondering - has any of you finished building this Aleph J? Which PCB design do you use?

Wachara C.

 

[traw]

made one, excellent. normal aleph board works fine, jumper away some of the 221's, twist n turn them little legs, the 4.75 ground seems ok - i used 2sj74's versus 109 though.

question - any caveats of triplet output 240's? besides heat etc...

 

[jacco vermeulen]

bandwidth ?

 

[EUVL]

> bandwidth ?

More likely to be limited by the first stage rather than the second.

Patrick

 

[chinsettawong]

Hello Friends,

I made a PCB based on the layout of HBarske. It was RC9 that I made as per http://www.hb001.de/alephjpcbbottom_rc9.pdf at http://www.diyaudio.com/forums/showthread.php?s=&threadid=111197&perpage=25&highlight=&pagenumber=9

I notice that the line from Collector of ZTX550 is going into the Sources of 2SJ109. Is this correct? Isn't it supposed to go into the drains of 2sj109 as per Mr. Pass's schematic diagram, or am I missing something?

Pins number 3 and 5 on 2sj109 are source1 and source2.

Wachara C.

 

[Nelson Pass]

ZTX550 is a pnp transistor used as a constant current source
for the JFET diff pair. That Collector does go to the Sources.

Perhaps you are thinking of the ZTX450 used as a current
limiter, whose collector does go to the Drain of one of the JFETs.

 

[chinsettawong]

Thanks Mr. Pass. I was really confused. Thanks again for your clarification.

Wachara C.

 

[zycomatique]

Hello Nelson,

Is there a previous date for the Aleph J official Manual???😀

 

[salesmonster]

2SJ109 Problems

I'm in the planning stages of an Aleph J build (my first Pass design!). I've been building the PC Board in Sprint as an exact copy of RC9 from HBarske.

It seems that there is a common thread with any Pass design I look into...there is always one part that us mere mortals can no longer easily put our hands on. Wow! Have I ever gotten an education about the 2sj109 from reading different threads!

Has anyone worked up an equivalent jfet input circuit that would be based on more common devices? Any tips on how to incorporate it into the board design? I'm a newbie at layout. I can copy someone else's design, but I just don't have the skills yet to translate schematic into physical layout.

Dave

 

[Zen Mod]

Re: 2SJ109 Problems

I'm in the planning stages of an Aleph J build (my first Pass design!). I've been building the PC Board in Sprint as an exact copy of RC9 from HBarske.

It seems that there is a common thread with any Pass design I look into...there is always one part that us mere mortals can no longer easily put our hands on. Wow! Have I ever gotten an education about the 2sj109 from reading different threads!

Has anyone worked up an equivalent jfet input circuit that would be based on more common devices? Any tips on how to incorporate it into the board design? I'm a newbie at layout. I can copy someone else's design, but I just don't have the skills yet to translate schematic into physical layout.

Dave

2SJ74 ; two of them are legal substitute for 2SJ109

both made in GR(een) , BL(ue) and V(iolet) range ;

nothing more than current divisions

you must look either for 2SJ74BL or V

look for jackinnj (member here ) if you want them in pairs ;

otherwise - you must buy them in dozens , to have several pairs

 

[jacco vermeulen]

Dave,

if that's you in the avatar pic i'll help you to a couple of J's for your Holger artwork, if you like.

 

[salesmonster]

Yep...that's me in the avatar

But only like 35 years ago! Wow, how time flies!

 

[salesmonster]

Here is my first try at rebuilding the circuit to use 2sj74s for the FET input

Any comments, critiques, reasons it will catch fire are welcome. Just be gentle, it's my first attempt at changing components around like this. It has been quite the brain exercise...hopefully I got all the sources and grains and dates in the right places! 😉

An externally hosted image should be here but it was not working when we last tested it.

Note that I placed both FETs together so I can use heatshrink to join them together. I slide a few parts over to the right just a bit to make things comfortable. Also, the blue traces are planned to be 2nd layer traces, but they could just as easily be wire jumpers.

Dave

 

[h_a]

Hi Dave, you can get completely rid of these jumpers as well - just another small brain exercise 😀

Have fun, Hannes

 

[ulanbatorr]

have a good job man!

 

[MEGA_amp]

I see that 2SJ74BL is a good replacement for 2SJ109. How do either of these compare to 2SJ103? The 2SJ103 can handle 50V but a little less dissipation. I do not have source for the 109, so the choice is between 103, and 74....any comments on these two?




**probably discussed ad nauseam somewhere but I couldn't find it.



regards,
John

 

[Zen Mod]

I see that 2SJ74BL is a good replacement for 2SJ109. How do either of these compare to 2SJ103? The 2SJ103 can handle 50V but a little less dissipation. I do not have source for the 109, so the choice is between 103, and 74....any comments on these two?




**probably discussed ad nauseam somewhere but I couldn't find it.



regards,
John

you need at least two 2sj103BL instead one 74BL .......... and you'll be still short in xconductance ;

click on jackinnj's www button

 

[Nelson Pass]

you need at least two 2sj103BL instead one 74BL

More like 6 of them if you go by the curves.

 

[MEGA_amp]

Thanks!!