Malotron said:
Not pretty... could running the j109 Vds at -10v permit a higher bias?
connecting R1 to intersection of R9 and R10 ?
anyway- why not higher bias , keep it hot 😉 but-do not burn it.....
Yep, Papa had his reasons for choosing Toshiba's (again!!)😀 Well, its publicly known that Toshiba J-fets are the best for audio purposes, as far as I am concerned🙂
Steen🙂
steenoe said:
just on my mind.........I'll not tell that I know that from first hand,but I remember BillWW's J version of A30..........in Salt Lake shootouts they sez that this version is best Aleph for their knowledge;
he use sheeeeeeeeeety chopper dedicated J176 as input ones.......
not a fact against Toshibas audio jfets ( hehe-"audio") ,but certainly is a fact that some other types are more than useful........
anyway-give me some computer toobz , and don't worry for me
even if they are not for audio
This needs to be investigated... I think I'll try j103 and 2n5462.
Unrelated question:
Would a zener based CCS for input pair lower the turn off thump?
Unrelated question:
Would a zener based CCS for input pair lower the turn off thump?
cviller said:
two bjt CCS have pretty nice tempco , and that is important for achieving lesser initial offset...........
besides that- thump isn't big really?
anyway- use spk protection with delay,so thump can't be problem
I must confess that I'm paranoic regarding my spks
The turn ON thump is hardly noticable, but the OFF thump is louder. I don't know of any universal reference I can compare it to.
I have been thinking about speaker protection too, perhaps I should surf the forum for a nice solution.
Yeah, I you're probably right. Do you use it for your babbel?
I think I'll mod it for some ta7317p I have in the drawer....
I think I'll mod it for some ta7317p I have in the drawer....
cviller said:
you can always buy few mosfets and resistors,if something goes south.....but if you have rare ,or just expensive, speakers ......going south is major trouble .
because of this,I know that I'm right 😉
I tried this schmtc on breadboard . pcbs are in drawer (Oly is magician,as always) ,but I'm kinda short with time.
because of same reason , my Babelfish is still in pieces ; frankly- ALL pieces.......but still not in one piece.
but-who cares when I always have musak producing gadgets .
Babelfish was nice trip , something new to me (learning how to understand making of SS amp), and I know it works (good).........
who knows-maybe I don't need it now......journey is so often more important to me than destination (hehe nothing new under the sun)
My usual supplier threw the towel in! Meaning that I wont be able to get Toshiba's at a good price
SK370 and pal, is what I talk about! Sorry....
Steen.
SK370 and pal, is what I talk about! Sorry....Steen.
How much are people generally spending on 2SJ109s when they find them. I want to know if I'm being taken...
BrianDonegan said:
they aren't listed anymore even on Borbely's site ;
I have few dozens stashed and I also have some offerings for ~7,25E.........not from any official vendor,but privately
say that I have solved my Paypal issues
say that I have 12 (6 stereo pairs) pcbs from first batch in this very moment ; purchasing more is easy and quick
say that you can - if you have any interest after F4 -contact me via PM for pcbs availability
say that I didn't yet received promised 2SJ109BLs......😡
so-choice is yours
say that I have 12 (6 stereo pairs) pcbs from first batch in this very moment ; purchasing more is easy and quick
say that you can - if you have any interest after F4 -contact me via PM for pcbs availability
say that I didn't yet received promised 2SJ109BLs......😡
so-choice is yours
hehe
ZM ........happy camper......
now I have 10 pairs (20 pieces) of 2SJ109BL.............ready to go with pcbs
ZM ........happy camper......
now I have 10 pairs (20 pieces) of 2SJ109BL.............ready to go with pcbs
The Babelfish is still a safe bet, with or without the F4!! All you people loving your preamp, should choose the B-fish🙂 Those wanting to build a heavygain preamp for the F4, should go that way🙂 Its actually as simple as that!Zen Mod said:
Steen🙂
Okay, this is the manual for finding J-Fets:BrianDonegan said:
I payed 4,2 Euro a piece, for the last batch I ordered (last week). Just in case that would be usefull? I am not sure if you US guys really do contact the shops that pops up now and then, here on DIYA?? I have no trouble getting the Toshiba J-Fets! I even secured for myself a dozen of those elusive 2SK369V's! I dont even know if I will ever need them, but they should be considerably better than 2SK170V's, regarding noise. They are meant for MC headamps. Search, search, and search some more😉 Another good hint: buy them when you can! I am sure ppl are reluctant when it comes to stowing away
You shouldnt be, it will only cause you greef later😉 I started on this DIY thing about 3 years ago, and I have a healthy supply of J-fets allready🙂 Makes me wonder why the average DIY'er doesn't here on this board?Steen🙂
steenoe said:
now you can bet that in a month I'll have tested construction and ready pcbs for "Steen's JFET preamp" .....not Bastardized BOSOZ.............other one 😉
with ultra cheap jfets
Just let me know if I can help out, maybe with some SJ109's? I would be happy to! ZM, you do give a lot to this board! I mean A LOT!!! I will send you the J-fets for the cost I have to pay🙂 They will never end up ultracheap though😀 Just let me know.Zen Mod said:
now you can bet that in a month I'll have tested construction and ready pcbs for "Steen's JFET preamp" .....not Bastardized BOSOZ.............other one 😉
with ultra cheap jfets
Steen🙂
steenoe said:
where you see 2SJ109?
and-after you demanded 389 ..........
you'll be beta beta tester
I'll be beta 😉
An externally hosted image should be here but it was not working when we last tested it.
you can help me answering on few Q :
what footprint for 4U7~10UF outputs and- is it vise to implement +/- shunt regs ditto on pcb?
pcbs will be one/channel
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