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

[generg]

Hi Zen Mod,

I am happy you got georgous mono at least!!!

When you have stereo you will see the panoramic stage offered by Babelfish 2!

Schuro got very slow the last weeks!

Because of the completely different sound of Babelfish 2 I start new with the pre amplification.

I try again passive solutions, they seem to keep the qualities of the output stage more than the active solutions I have.

And 20 db amplification is seductive to try this!

Happy evening for you! ( of course I am just hearing babefish2)

[gaggia]

Ma nist ti ne verujem...dok to Sloba ne sastavi i protrese. Tek onda pravim.

Dakle..g Slobo, dajte malo vasu gusicu nama radoznalima na uvid

[sp300b]

Dakle..g Slobo, dajte malo vasu gusicu nama radoznalima na uvid

Zen je obecao poslati mi paket pre mesec dana,Od tog obecanja je proslo 3 meseca

[Aleksandar Car]

... Ako paket ne bude u subotu... zapalicu vam forum

[gaggia]

Zen je obecao poslati mi paket pre mesec dana,Od tog obecanja je proslo 3 meseca

Dakle..g DEDA, dajte malo vasu gusicu nama radoznalima na uvid !! sa`ce deda da se samolansira

[generg]

Hi everybody,Hearing a longer time with Babelfish J2 I prefer to rise the source resistors from 22 Ohm to about 100 ohm. When you have read my few lines about sound you know my joy about this amplifier, I spoke about the bass, the highs, the panoramic sound. :Viannen_loungelizard: the precision, the lightness it moves.....But it did not speak about the medium frequencies, they were praised in the reviews of J2. I could not praise them...... they were just ok.Maybe because I used the cheapest parts for my chaotic build or maybe the J74 aren' t matched close enough .....Maybe my speaker tends to emphasize these region...... But I had one hope the source resistors ...... I know F 1J has 22 Ohm only, it sounded fine, but already with my BA-1 variant I had to go back to 100 Ohm. My wife came in and said what a harsh sound..... , (22 ohm).Ok play with it ....... Lovely medium region now!

[gaggia]

... Ako paket ne bude u subotu... zapalicu vam forum

ti onda da pocistis pepeo !

[Zen Mod]

......Ok play with it ....... Lovely medium region now!

tnx for tip !!I still didn't reach that level of finesse in construction of that amp

[sp300b]

Hi everybody,

Hearing a longer time with Babelfish J2 I prefer to rise the source resistors from 22 Ohm to about 100 ohm.

...

Ok play with it ....... Lovely medium region now!

And what about the bass, the highs, the panoramic sound right NOW ?

[Daudio]

[Sipi]

... the panoramic sound ...

I would go straight for ellipically orbital

[generg]

Yes I prefer panoramic and ellipically orbital sound and I wish you could hear it!

[Zen Mod]

shhhhhhSipi is one of those who can hear up to 100 KHz !

[generg]

Happy man! Sipi must keep 22 Ohm for the gate resistor! I hear down to 10 kHz I can take 100 Ohm.

[Sipi]

Yes I prefer panoramic and ellipically orbital sound and I wish you could hear it!

I'm glad you enjoy your amp that much

[generg]

Thx Sipi,otherwise I had tried your version of F5 .....

[Tea-Bag]

After much hassle fro Generg, I replaced LED in both BJ2 boards.Still one board biases too high.I measured around against working channel to look for differences. Here they are. I didn't compare everything.Q3 - OV on bad unit 9V on good unit.Q8 - 0.3V on bad, ~19v on good unit. Both measured on From Collector to Emitter. I am inclined to think one of them is toasted.Too tired to replace them to see if that works. I need to dig around for more PNPs.I think the solder connections across R23,24 are all good. Q3 doesn't seem to be too close here, so not sure why both measure 0v.Lazy American looking for ideas

[Zen Mod]

will dig tomorrow through schematic with your values ....now I'm going to catch few hours sleep

[Tea-Bag]

will dig tomorrow through schematic with your values ....now I'm going to catch few hours sleep

No hurry.I replaced Q3, Q8, still same results for them, 0v.Hmmm, must be something else Will measure some cold resistance values and continuity on both unit's see if something's amiss there, although it feals like a transistor failure somewhere.

[generg]

I looked what I could have done wrong, polarity of C1 and C2 correct? You set the jumpers J1 and J2. Q5 orientation?good luck?

[Zen Mod]

.....

compare with this

best - open this pic in some editor ( MS Paint good enough) and write your values in other color

also - let me know what is Ugs of Jfets you put in ; I presume you also match them at 2A

edit : schm deleted by ZM

[Tea-Bag]

compare with this

best - open this pic in some editor ( MS Paint good enough) and write your values in other color

also - let me know what is Ugs of Jfets you put in ; I presume you also match them at 2A

I made some progress last night. I measured everything at voltage, good and bad. For better or worse, Q14 on bad channel sputtered and blew out white smoke like a steam engine and blew fuse. Repalced it with a mismatched vgs one, and offset is bad, Q8 still no voltage (I checkd CNY17, both channels are the same). Q14 still runs hot at start as well, so worried it might blow. I measured voltages and continuity in the R23,27, 26 area, all looks good. I am using 60.4R on R23. Maybe my bad or from old schematic. Anyway's hope these look good.

edit : schm deleted by ZM