f4 parts substitution

slr 5000 · 10th July 2010, 10:42 PM

hi
i would like to use my 2sj109 in my diy f4 but i notice it has seven legs as oposed to six when using the normal combination of 108/ 389
what is this extra leg ?

i have not got the output devices yet are there any options here that would drop in and be an improvement on the originals ,toshiba or semisouth perhaps ?

thanks in advance for any help or advice

regards sheafer

Zen Mod · 10th July 2010, 11:09 PM

google for 2SJ109 ; pdf file

7-th ( middle ) pin is substrat ....... in fact - nothing .

btw- I don't know where in F4 you'll use 2SJ109 ?

you mean using pairs for both input Jfets , meaning on 2SJ109 and 2SK389 ?

slr 5000 · 11th July 2010, 02:35 AM

hi zen mod
seems i must have buggered up as usual

i thought i could replace the 108 and 389 with a single j109 per channel
as i have heaps of j109 and canot find anywhere the 389 or 108
what alternatives do i have ?

regards sheafer

Zen Mod · 11th July 2010, 07:52 AM

you can't do this
2SJ109 is nothing else than 2pcs of 2SJ74 in one case

same polarity jfets ........ and you need one of each polarity

slr 5000 · 14th July 2010, 08:40 AM

thanks zen mod
now i understand ,
so i need the opposite polarity to the or 2sj74

its a shame as i have 8 new 2sj109 bl here doing nothing

i have an aleph 2 clone that is running on high bias 7.2 a and low voltage (25/0/25 sec) for my esl speakers ,perhaps i could convert it to jfet input using the 2sj109

cheers

Zen Mod · 14th July 2010, 08:52 AM

Quote:

Originally Posted by slr 5000

......

i have an aleph 2 clone that is running on high bias 7.2 a and low voltage (25/0/25 sec) for my esl speakers ,perhaps i could convert it to jfet input using the 2sj109

cheers

yes , you can ;

post exact schematic of your Aleph 2 and I'll draw needed changes for you ......

slr 5000 · 14th July 2010, 10:18 AM

thank you zen mod

it is built from the kkk pcb boards
i will get the schematic tommorow and post it

many thanks
sheafer

slr 5000 · 15th July 2010, 07:21 AM

hi zen mod
here you go regards sheafer

Zen Mod · 15th July 2010, 09:19 AM

will you manage with this ?

Jfet input for Aleph 60?

slr 5000 · 15th July 2010, 11:12 AM

hi zen mod
i think so ,i should replace the 4x 2sj74 with 2x 2sj109 yes
also does mucho mean remove ?

regards sheafer

10th July 2010, 10:42 PM	#1
slr 5000 diyAudio Member Join Date: Oct 2007 Location: melbourne	f4 parts substitution hi i would like to use my 2sj109 in my diy f4 but i notice it has seven legs as oposed to six when using the normal combination of 108/ 389 what is this extra leg ? i have not got the output devices yet are there any options here that would drop in and be an improvement on the originals ,toshiba or semisouth perhaps ? thanks in advance for any help or advice regards sheafer

10th July 2010, 11:09 PM	#2
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	google for 2SJ109 ; pdf file 7-th ( middle ) pin is substrat ....... in fact - nothing . btw- I don't know where in F4 you'll use 2SJ109 ? you mean using pairs for both input Jfets , meaning on 2SJ109 and 2SK389 ? __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

11th July 2010, 07:52 AM	#4
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	you can't do this 2SJ109 is nothing else than 2pcs of 2SJ74 in one case same polarity jfets ........ and you need one of each polarity __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

15th July 2010, 09:19 AM	#9
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	will you manage with this ? Jfet input for Aleph 60? __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

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11th July 2010, 02:35 AM	#3
slr 5000 diyAudio Member Join Date: Oct 2007 Location: melbourne	hi zen mod seems i must have buggered up as usual i thought i could replace the 108 and 389 with a single j109 per channel as i have heaps of j109 and canot find anywhere the 389 or 108 what alternatives do i have ? regards sheafer

14th July 2010, 08:40 AM	#5
slr 5000 diyAudio Member Join Date: Oct 2007 Location: melbourne	thanks zen mod now i understand , so i need the opposite polarity to the or 2sj74 its a shame as i have 8 new 2sj109 bl here doing nothing i have an aleph 2 clone that is running on high bias 7.2 a and low voltage (25/0/25 sec) for my esl speakers ,perhaps i could convert it to jfet input using the 2sj109 cheers

14th July 2010, 10:18 AM	#7
slr 5000 diyAudio Member Join Date: Oct 2007 Location: melbourne	thank you zen mod it is built from the kkk pcb boards i will get the schematic tommorow and post it many thanks sheafer

15th July 2010, 11:12 AM	#10
slr 5000 diyAudio Member Join Date: Oct 2007 Location: melbourne	hi zen mod i think so ,i should replace the 4x 2sj74 with 2x 2sj109 yes also does mucho mean remove ? regards sheafer

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