SemiSouth power Jfets .......... FW J2

[Tea-Bag]

:ok:Zen Mod,Did you use matched R100's per channel?

[Zen Mod]

:ok:Zen Mod,Did you use matched R100's per channel?

not exactly matched you can see their Vgs-es at 2A on pictures

[Tea-Bag]

: Thanks, do you think matching is needed or best practice here?

[Zen Mod]

just best practice

but - I didn't tried really mismatched ones ;

maybe I will , but not so soon ...... maybe because I don't have really mismatched ones

I know that they're everywhere from 1V2 to 1V9 , at 2A

in any case - I think that real and valid answer you can get only using THD meter , and comparing best and worst case

[Zen Mod]

Tea- just few thoughts ......

as you can always see from Papa's schematics - he always counts on selected parts ; same is here ;

value of drain resistor in input LTP is dependable of exact lower output Jfet Ugs value ;

same - value of resistance in paralell to CNY bjt is dependable of exact upper output Jfet Ugs value .

so - procedure for making functional Babelfish J2 is something as :

1. test and choose output Jfets ; according to their respective Ugs values -

2. preset input LTP resistance and CNY's parallel resistance

3.preset input LTP CCS at 20mA ;

then

4. solder outputs in place and proceed with proper power up procedure

#3 demands some tricks how to , with auxiliary PSU ...... or just setting programming resistance in CCS to ~ 0V65/20mA=32R5

more to come - with proper schematic , with parts nomenclature

[Vix]

lako vam je mene zekiti ........

Pa da, kad se ima za cega u'vatiti

Ma, glavno da igracka radi...samo da se ne pocne pusiti...

[Zen Mod]

Pa da, kad se ima za cega u'vatiti

Ma, glavno da igracka radi...samo da se ne pocne pusiti...

nece - ne boj se - ene je rastavljena

ce sledece pravimo Little Donut

[Tea-Bag]

Tea- just few thoughts ......

as you can always see from Papa's schematics - he always counts on selected parts ; same is here ;

value of drain resistor in input LTP is dependable of exact lower output Jfet Ugs value ;

same - value of resistance in paralell to CNY bjt is dependable of exact upper output Jfet Ugs value .

so - procedure for making functional Babelfish J2 is something as :

1. test and choose output Jfets ; according to their respective Ugs values -

2. preset input LTP resistance and CNY's parallel resistance

3.preset input LTP CCS at 20mA ;

then

4. solder outputs in place and proceed with proper power up procedure

#3 demands some tricks how to , with auxiliary PSU ...... or just setting programming resistance in CCS to ~ 0V65/20mA=32R5

more to come - with proper schematic , with parts nomenclature

Thanks for the applied science.

Let's see if I can dumb it down.

So it goes then match some R100's at 2A, find decent matched pair.

I'll assume that 1v6 was your vgs. #2 Set to get proper current to CNY pin 1 and across 200r pot. will guess that this pot affects offset.

Also, front end Jfets will need drain set with 100R pot (will also affect offset). #3, front end CCS may need to be fiddled with to get 20MA to girly JFETs, too much = white smoke. Does 22r pot help here, or should a pot be in series with 620R? (500r and 200r)

This sounds like the making of a Cookbook

Someone let me know if I can score good serbian pcb or gerber files. I got JFET's to trade.

[Zen Mod]

be patient day or two - then we'll have proper schematic with proper nomenclature , so explaining things will certainly be easier ;I'll make small batch of pcbs , so you can count on that ....... but be aware of possibility that someone on big DiyA came with closer approximation of real J2 .I intentionally didn't count parts in J2 , so I use it as general guide , really wanting to Babelfish it , not clone it .edit - all values of pots , along with dedicated series fixed resistors , are chosen to prevent any smoke scenario

[sp300b]

This seems to be the final revision...Checking still waiting to be done

[Manu]

Yummy Manu

[sp300b]

Yummy

Manu

Hi Manu, Your Pumpkin is completed or not ?

[generg]

compliment to Zen Mod and friends! It is very pleasant this forum exists and for my purposes its more productive and more open than the big brother at the moment! (everybody building F5) thank you all

[Zen Mod]

compliment to Zen Mod and friends! It is very pleasant this forum exists and for my purposes its more productive and more open than the big brother at the moment! (everybody building F5) thank you all

feel free to contribute whatever and whenever you want

[zocky]

This seems to be the final revision...Checking still waiting to be done

PCB rutirana ručno ili programski?

Ne tvrdim da bi se nešto dobilo rutiranjem pod uglom od 45 ali bi se izvestan broj vodova mogao skratiti time.

[Zen Mod]

ma pusti - da znas kad se u tokudana/noci radi - dobra je i predobra .u svakom slucaju dobra za nas :buehehe:znas i sam da za zadnje cinculacije u svakom programu treba najvise vremena ; evo vec 2 dana ne stizemo da chekiramo vodove

[Zen Mod]

lepsije li je ovakolije :

[Impuls]

Meni licno je ruzna stampa. Moze na njoj da se dokoriguje gomila sitnica. Evo d apocnem da je korigujem:- Q7 okrenuti za 180 stepeni- kond od 4u7 malo odmaci od njega i ti uglaviti R23- da bi se to omogucilo otpornik R35 staviti paralelno R15 zbog estetike a duzina vodova se ne menja- tranzistor levo od Q7 okrenuti za 180 stepeni- R13 i R14 da zamenu mesta a fet izmedju njih zarotirati za 180 stepeni- vod an bazi Q2 moze i bez vie ako se stvi sa gornje strane- na desnoj strani ima jos vise brljotina: vod od desnog kraja R6 ne mora da ide okolo sa dve vie kad moze kratko do fetaeto par korekcija pa posle ispravke nastavljamo

[Zen Mod]

ja to ne znam - za sve ove godine sam pogubio zivce za pcbs ...... jos iz doba kad se to nije radilo racunarima ....... odnosno - bar ja nisam imao para da kupim frizak 386 i da radim u Tangu

kasnije me nije to interesovalo ......... a nadam se i da nece morati

dakle - ostaje da Sloba ......... ako ima vremena ............

ne sumnjam da sve primedbe stoje , ali isto tako ne sumnjam da ce i ovako biti 100% funkcionalna

...... a mozda to cak i ja veceras uradim , sto si napisao ......

[Impuls]

ja za TO92 kuciste koristim komponentu sa malo razvucenim nogicama pa vod od srednje nogice lako prolazi kroz sredinu a ne menja bitno povrsinu za komponentu. A da ce biti funkcionalna i ovako ne znaci i da ce dobro svirati. Gomila nepotrebno isprepletenih vodova samo moze da preuzima smetnje i takve ih pojacava.Na primer imam Hamegove sonde za osciloskop a pored njih imam i kablove sa stipaljkom. Kabel sa stipaljkmo koji nema oklopljen kabel pokupi gomilu smetnji iz prostora i vise nemam informaciju o signalu. Apsurdno je koristiti vrhunske komponente, savrsene topologije a onda sve u***** lose projektovanom stampom. Kod nas u Backoj kazu: sta vredi sto krava daje 25 litara mleka kad se posle ritne i sve prospe.

[Zen Mod]

sreca pa ne zivim u Backoj

[sp300b]

O, Srbijo zemljo, otvori se

Ovde ništa ne fali i sve OK, a PCB- u nadjoste 100 mana.