Zen Mod Napisano Septembar 23, 2019 Share #1 Napisano Septembar 23, 2019 Babelfish ᄅſ Seeing some stones turned lately , I simply couldn't resist Babelfishing urge...... Though , as I already did some mild Babelfishing of our dear and beloved J2 , logically that this time I needed to do something ...... completely different due to constant demand and popularity mainly on Far and less Far East , schematic of original FW J2 is still generally unknown or - better said - none of circulating DIY schematics weren't blessed by Mighty Pa (pleonasm here , Pa is Mighty by 42) few things we all know , and these few things are good and plenty enough for basic postulates of variation of Jazz Standard Basic premises : 1. possibility of incorporating less critical ( for acquire) JFets for input LTP, by choice and must possible use of 1+1 , or 2+2 in same ; 2. possibility of incorporating various output devices , of lesser and bigger rarity and/or price 2a. possibility to avoid tearfully matched parts (outputs and other ) , while still easy settable both output offset and OS Iq in broad range of values I got it all ........ how: 1.easy peasy - use N channel JFets (choice is waste!) , lead them (currents) back to lower output gate via simple and effective current mirror ..... put few cascodes here and there to pet both JFets and fine CM parts (tiny JFets are always grateful for that, but high beta small BJTs like that too) ....... and while we are there - why not using fine emiter follower between CM final end and lower output's gate ....... 2. OK - trimpot in front of lower output's gate is trivial ; second part is feeding Optocoupler with CCS , with some current spare , and routing the same in loop around ( in parallel practically) said optocoupler , so we can set Iq of upper mosfet with ease and in broad range 2a.partly already covered above , just to add that output devices can be plain old IRFP150 , same as any boutique part you already have , value of Ugs is irrelevant - easily covered with change of ,say, two resistors 'nuff talking , time for schm (read notes on left side): Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #2 Napisano Septembar 23, 2019 while we at Eagle files , two more Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #3 Napisano Septembar 23, 2019 few days ago , I received 0 series pcbs , and did some stuffing Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #4 Napisano Septembar 23, 2019 then yesterday and today I put it in T-Bed , and did some final tweaking of some values for start , they're equipped with 1+1 Toshiba 2SK170BL in FE , Iq set at 10mA (5mA per tiny) and pair of goodoldsturdy IRFP150 are in OS Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #5 Napisano Septembar 23, 2019 power-on and power-off behavior is same polite and nice and gorgeous as ZM Might itself , so there is no any surprise now some measurements ....... being lazy and impatient , I didn't use recently acquired Quantasylum ( older , SE one ) but my old funny interface box and EMU1212 in PC , software is ARTA Iq set at 1A8 , rails more or less exactly 25Vdc first set of measurements at 8R load ; each graph is titled at bottom ; as always with my T-Bed and test setup - ignore everything left of 1K ...... plastic box for interface , old and crummy PSU incorporated in T-Bed blahblah mrcelavi je reagovao/la na ovo 1 Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #6 Napisano Septembar 23, 2019 so , set of measurements at 4R load , same Iq and rails as for previous test btw. I decided that clipping is at 1% THD , and that's exactly at 21W9 ...... though - it was tricky to set level pot to exact value (THD rising rapidly at that level!!) pretty good , if you ask Mighty Moi Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #7 Napisano Septembar 23, 2019 that's it , practically , for today tomorrow , I hope - same tests with 2+2 2SK2145BL in LTP , LTP current programmed to 5mA per tiny (20mA overall) , so it'll be nice and cozy 50mW for each will up a little current through EF , to be closer to 20mA than 15mA ........ after that will most probably leave 2SK2145BL in situ ( not crazy enough to remove them ) and try same battery of test with SJEP120R100whatever in lower output position .... will leave mighty IRFP150 in position of upper one ( mu or what-follower) , can't see what Semisouth could do better in same role .... ZM , Happy Camper this evening edit: Shade game not promptly ; first need to evaluate this one in long term listening test , to be able to value Shade after ..... I know it'll measure worse , but it could happen that my ears are happier with worse after all , I'm listening regularly one of crappiest amps by measurements and enjoying immensely Link to comment Podeli na ovim sajtovima More sharing options...
Aleks Napisano Septembar 23, 2019 Share #8 Napisano Septembar 23, 2019 Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #9 Napisano Septembar 23, 2019 Mikum ga mrko pogledao i ovaj jado odmah mora da navija Link to comment Podeli na ovim sajtovima More sharing options...
Aleks Napisano Septembar 23, 2019 Share #10 Napisano Septembar 23, 2019 Kao BJ fan rezerviram unaprijed par pcbsova, da se zna... Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 23, 2019 Autor Share #11 Napisano Septembar 23, 2019 eto, ovaj nema ono ckupo gvozdje i nema one ckupe current sense chips i nema one ckupe tokine sinko,ovaj sinko - imas li ti ostali hardware ...... to uvek kosta isto ....... Link to comment Podeli na ovim sajtovima More sharing options...
Aleks Napisano Septembar 24, 2019 Share #12 Napisano Septembar 24, 2019 Ma to za u arhivu. Začas mi ćune da se napakuje Babel, ako duša ište. Obećo sam sebi, jerbo sam prodo onog. Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 24, 2019 Autor Share #13 Napisano Septembar 24, 2019 as I promised (to my self , in first place ) , today I did change pair of 2SK170BL in input LTP position , for 2+2 pcs of 2SK2145BL previous idea was to up LTP current from 10mA to 20mA , resulting in healthy 50mW per tiny bugger , but later decided to try Papa's approach , of doubling input JFets , while Iq keeping at same level as for single pair that way - due to increased combined xconductance , OLG is rising , and without change of NFB network , NFB is rising , so we can expect lower level of THD is it good thing or not - sound wise , who cares ...... I have all the time left to humanity to try that ...... later Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 24, 2019 Autor Share #14 Napisano Septembar 24, 2019 now the real stuff ...... I mean - hard data (observe how I finally switched two cells On , so removed confusing unnecessary part of graph ) each graph is having title in bottom so , THD indeed goes down , comparing to yesterdays measurements , with pair of Toshiba 2SK170BL in FE load 8R Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 24, 2019 Autor Share #15 Napisano Septembar 24, 2019 same , load 4R Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 24, 2019 Autor Share #16 Napisano Septembar 24, 2019 tomorrow - Semisouth SJEP in bottom position , 2SK2145BL will stay in , no reason to change them anymore it just came to my (precious!) mind - I can try Pass SIT-1 there , too...... naah , too complicated , involving depletion part ..... Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 25, 2019 Autor Share #17 Napisano Septembar 25, 2019 surprise !!!! Semisouth SJEP120R100 u donjoj poziciji , 8R load Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 25, 2019 Autor Share #18 Napisano Septembar 25, 2019 (izmenjeno) Semisouth SJEP120R100 u donjoj poziciji , 4R load Izmenjeno Septembar 25, 2019 od Zen Mod Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 25, 2019 Autor Share #19 Napisano Septembar 25, 2019 ima li ko komentar - priroda ampa sa oba IRFP u izlazu , priroda ampa sa Semisouth dole , IRFP gore ? Link to comment Podeli na ovim sajtovima More sharing options...
Aleks Napisano Septembar 25, 2019 Share #20 Napisano Septembar 25, 2019 Sjep sa manjim izobličenjima, treba staviti 2 kom (i gore i dole) da bi dobili 2nd? Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Septembar 25, 2019 Autor Share #21 Napisano Septembar 25, 2019 rekoh - priroda , , ne citanje postotaka sve moze arbitrarno da se promeni , odnosom vrednosti MOX otpora u izlaznoj vertikali Link to comment Podeli na ovim sajtovima More sharing options...
mutayu Napisano Septembar 25, 2019 Share #22 Napisano Septembar 25, 2019 Semisouth SJEP120R100 u donjoj poziciji , 8R load Treci, a i ostali neparni harmonici, podigli glavu? Link to comment Podeli na ovim sajtovima More sharing options...
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