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

[generg]

What shall we do now?Hu,hu,hu,hu..........

[Zen Mod]

relax ?:rofl:Brunhildr ?

[generg]

Martina.....

[Tea-Bag]

Okay, so here are some observations. Only somewhat based in reality, as all systems are different, and my BJ2 is not built anymore to spec.Listening MaterialHerbie Hancock - Possibilities - Track with Paul SimonHerbie Hancock - Gershwins World - SummertimeHerbie Hancock - Joni Letters - The Jungle Line (sung by leonard cohen)Alison Krauss - A collection - Get me through DecemberAlison Krauss - A collection - Jakobs dream.AmpsF2J, per Nelsons recommendations, Biased at 12vBj2 - specs aboveI listened to the same tracks on both amps, trying to be objective about the whole thing. These albums seem decently recorded to my ears, and are not produced to sound too warm like some T. Bone Burnett stuff.BJ2:Pros: Wide, precise soundstage, dynamic. Really smooth upper end of female voices like Alisons. No midrange bloom, but I think this is a good thing. It does not sound like a tube amp. It sounds like R100 in other circuits in general. Clean mids and top end. (below 120hz, another amp.). This amp might be a hair mellow only if comparing to F5 amp.Cons: Soundstage depth is a bit 2D, or missing a bit of front to back location of sounds. I think the F5 did this better.F2J: Pros: excels at detail, more depth to soundstage, but 'imaging' or where stuff is, is more vague and sounds more like two speakers at times , - but this is relative to BJ2. Imaging is not bad, just not as good.You can pick up say guitar plucks and decay with a bit more precision on the F2J.Cons: Well, you got to play with the sideways notch filter. Less wide soundstage, and less dynamic punch. The ambient detail seems to be less. If you want more precise detail, this may be the amp. Things will jump out at you. Is you listen at 90db like I often do, then it loses steam and distorts. Top and Bottom are not as refined. Not as silky as the BJ2.Conclusions: well, I might change my mind later - so that's not a good way to start it.The F2J is supringly easy on the ears. I didn't suspect this. The inner detail at times is great. It's flaw is soundstage precision and range of punch over the whole spectrum isn't the same as BJ2. The BJ2's statement sound in this configuration is great vocals. Best I have heard. It has a broad paintbrush and uses it to it's advantage to give a good musical performance. The way I like the R100's to sound is clean, and not bloomy or fat. It's not these things. If you want it to sound like a old dynaco, or super-warm - this isn't the way to go. These amps are both crisp and detailed and fun to listen to.

[sp300b]

Thanks Tea-Bag for very detailed expressions sharing :clapping:Conclusion: we all made Good Amp

[Tea-Bag]

The BJ2 is supringly easy on the ears. I didn't suspect this

Should be F2J.

edited your previous post according to that

ZM

btw . YGM

[generg]

hi tea-bag, happy to hear that you finished your Babel J2 successfully!and thanks for the detailed comparison with F2J, which speakers did you use, your precious Lowthers?

[Tea-Bag]

hi tea-bag, happy to hear that you finished your Babel J2 successfully!and thanks for the detailed comparison with F2J, which speakers did you use, your precious Lowthers?

I had some help! and thanks!Yes, Lowthers in Open Baffles, 200hz on up I guess, ran them without a low-pass x-over. This time I was using the DX4's (not PM5As) which are a bit more clinical, and harder to tame. No added Tweeter which I normally use.People may not like lowthers, but they are all I know since started using them in 1998. I liked the fact back then they made your ears bleed when Miles blows his horn. They are a bit tamer now. The PM5As need no notch filter. They have no hi-ferric and copper voice coils. I got them, used, and they didn't come without problems.I've done open baffle for 2-3 years. Before that BLH, but it couldn't fill room well in Living/Dining area room 35 x 20. I have no listening room. In old house I did, but in USA, everyone was buying selling houses in the last decade - making or losing lot's of money.

[sp300b]

Original Power Resistors values used in J2, can be seen here :

Take a look at rev.1 of the J2 at Issue 34 – Magazine | TONEAudio MAGAZINE page 175 (in the High Resolution Version) (taken from here)

[generg]

Hi guys, I can continue the reviews about Semisouth implemented amps, Tea-bag started with his comparison of Babelfish J2 and FW2J you can read above.Because I changed finally to Lowther ( there was a very cheap offer I could not resist, only 9 months old, standing like written beer at the merchant, nobody wanted it), I can now use all First Watt amps. I still had in the basement F1J variant so I started comparing........The Babel J2 has the most lovely voices and a kind of being fluent, marvelous! Compared in this range the F1J is sharper and less spectacular.The F1J has more precision in the rest of the spectrum, he shows every detail more closely. J2 is more veiling details outside the lovely midrange.Babel J2 is more painting the colors, F1J is more painting the details.Not to forget, the F1j is an transconductance amp, it made of course a deeper bass, following the impedance curve. j2 had the smaller bass.Lowther shouting was no problem with Babel J2, the treble is soft and the voices have much body that compensates really the shouting.With F1J I had to use a small notch filter ( 10Ohm in series with 3uF parallel to the output)Most of you know F1J has 3rd grade distortion dominant and J2, as Nelson says, has the 2nd grade distortion dominant.Same Semisouths inside and such big differences in sound only by changing the circuit still unbelievable for me...To be continued with my impressions of F2J, only 5 Watt , hu,hu.........!

[Zen Mod]

if you want more bass with J2 - just put series resistor in line with speaker find your prefered valuecan we see some pics , please ?

[generg]

Hi Zen Mod, What a nice idea, the vice versa of damping the F1J........Pictures will come, I have to remount BJ2 in the case ..... But I did a very deep movement in tai chi chuan and tried to become a master....... Pain in the right back side ......three days.......I will no more want to became a master I stay better normal......Till later!:

[sp300b]

Hi all,

I was playing again today, now with Panasonic MOX resistors (3W).

Last change is like this :

2 x 0,68 Ohm = 0,34 (R22, R29)

2x (2 x 0,68 Ohm in serial) = 0,68 (R30, R36)

2 x 0,47 Ohm = 0,235 (R31, R37)

Seems like game over :-)

[Daudio]

.......

Seems like game over :-)

Never say never

[sp300b]

Never say never

Just seems like

[generg]

Hi guys, :Viannen_loungelizard: I think I have finished my journey through Semisouth amplifiers......I have heard the last days F1J, F2j, J2. Some wordsF1J: incredible defined sound, best bass but to harsh with Lowther, and the different notch filters took too much away from the qualities Lowther has.F2J: more mellow, good bass, good defined, did not need a notch filter with my PM6A, would be the best solution with Lowthers, if notJ2 had these lovely unbeatable medium area with the most tricky and maniac voices, smallest bass unfortunately. Introducing an resistor in series, I took 4,7 Ohm, did nor really better the bass.Result I go with J2 and will look or a good bassdriver and drive both with a small network.......later! :sarcastic_hand: :sarcastic_hand:

[Tea-Bag]

Hi guys, :Viannen_loungelizard: I think I have finished my journey through Semisouth amplifiers......J2 had these lovely unbeatable medium area with the most tricky and maniac voices, smallest bass unfortunately. Introducing an resistor in series, I took 4,7 Ohm, did nor really better the bass.Result I go with J2 and will look or a good bassdriver and drive both with a small network.......later! :sarcastic_hand: :sarcastic_hand:

No way, you cant really finish....Was J2 rev0, rev1, BJ2?My Brain is thinking about F3 likeish amp, without cascode, for R085.ZM - did you drop Susy SemiSouth idea?

[Zen Mod]

no - I didn't drop that idea - just need bloody time to try and polish my (last) Donut concept

[generg]

Hi tea-bag,This time it was j2 rev1, but Zens type of optocoupler....Ah forgot I managed to have no humming with the boards of Peter and I understand you that you like f2j really, it is also a very fine choice with Lowther.......

[Tea-Bag]

I've gotten more mileage on the F2J lately, the sound stage is much more solid now, and the setup very relaxed. I am liking it.BJ2 is sorta on the bench, trying to make revA alterations, but have been away from the bench for a bit.

[Zen Mod]

..... but have been away from the bench for a bit.

that's good or not ?

[Tea-Bag]

that's good or not ?

It's okay I guess. Health is okay, just work and housework have been over the top lately.Alway's want to do more than I have time or energy for.