Babelfish ᄅſ....or FW J2 on Steroids .... or Not your Father's J2!

[res07njc]

Where is Generg with all his previous listening efforts.... it's all a re-hash

 

[Zen Mod]

I'm in constant , even if sometimes rarefied, correspondence with my Bruder Generg ;

he's , as usual , having same problems - too many good things , to choose from

and all of that , by his own making*



*in last few years , most of his fun is cloning , but properly - in private, for personal pleasure

 

[res07njc]

ah yes that Generg... in Vahalla.

 

[indra1]

...However after Sissy I will wait for the Fish XA25 ...

Actually Bob, there is this very interesting US5343166 patent by Papa Pass which cite US4115739 that potentially surpass any ouput stage using lowly IRFP240/9240 pair. I currently put everything else on hold in favor of exploring this.

 

[Zen Mod]

yeah , interesting , and we know that Pa pursued that in F5T ..... if you attention is on source located diodes diodes ?

I'm, personally, not especially interested in higher power amps , even if I made/"made" few of them in one way or another

 

[indra1]

My exploration is not about higher power. When a pair of complementary mosfet is used as follower, the Miller stray caps are the ones to dominate. When cascoded there is no more Miller effect which gives rise to virtually flat phase shift and distortion from 20-20k.

 

[Zen Mod]

aha

so not diodes , but cascodes

 

[indra1]

Yup, me greedy boy, spooky, grainless, silky smooth with all the good sparkle still intact is what I'm after.

 

[Zen Mod]

that reminds me , I had once ( intrigued by same thing ) Hitachi HA5300

it sounded much, much better than it's schematic (plenty of stages , numerous caps in signal path) and physical execution had you expect

after some thinking and looking at other comparable schematics , I realized that difference is solely in OS

sorry , no better file , there is a complete pdf at Hitachi HA-5300 - Manual - Stereo Integrated Amplifier - HiFi Engine

 

[flocchini]

Actually Bob, there is this very interesting US5343166 patent by Papa Pass which cite US4115739 that potentially surpass any ouput stage using lowly IRFP240/9240 pair. I currently put everything else on hold in favor of exploring this.

Thanks indra I will check this out

 

[Itsmee]

... When a pair of complementary mosfet is used as follower, the Miller stray caps are the ones to dominate. When cascoded there is no more Miller effect...

Assume the input signal will never drive into the higher cascode voltage, then all the drive current could come from the low voltage PSU.
If the cascode transistors are turned into a CCS, set to a lowish current, would this have the same effect on miller?

 

[Zen Mod]

cascode must conduct full current of cascoded device, practically being fully opened all the time, also floated in a way that cascoded device is working in constant voltage regime

exception could be modulated cascode , but that's another subject

that would be answer, if I properly understood what your idea is

 

[Itsmee]

To put it another way, how much current must the ccs provide to overcome the miller capacitance?

I think the penny has dropped, ccs won't work.

 

[Zen Mod]

as said - proper cascode is not acting as brake to cascoded device

 

[Zen Mod]

More Sugar for Greedy Semisouthworshiping Boyz

just to state - I have no intention to play with MOX values in output vertical , to invoke 2nd harmonic above 3rd ; I have what I intended with poor man's iteration and that's it

oh, yeah ....... temptation was simply to big that ZM can resist .......

so , if you want to compare , look back in thread , at graphs , iteration with Semisouth down ( both 4R & 8R load) and iteration with Semisouth both (both 4R & 8R load)

so .......... tadadada:

 

[Zen Mod]

Semisouth down , MOX changed , 8R load

see two red dotted resistors ; comparing to previous sch. , these two resistors are swapped

so , looking at graphs and THD levels - still Pin(g)point Machine , more mellow

 

[Zen Mod]

Semisouth down , MOX changed , 4R load

max power graph for 1% THD .......

 

[Zen Mod]

Semisouth both , MOX changed , 8R load

schematic same as previous , ignore IRFP150 title on upper output critter

this one even more mellow than "SS down"

 

[Zen Mod]

Semisouth both , MOX changed , 4R load

max power graph for 1% THD .......

 

[Zen Mod]

I enjoyed listening all- IRFP iteration more than 6 hrs today ....... typical (part of) long term test, listening while working

finishing my own SissySIT , so pleasure was ..... quadrupled

what can I say , without straining in FiFi vocabulary ....... let's say it as - didn't found sole thing to complain

details , dynamics .... and bass is super-layered ....

after few days of listening , I have nothing to add , except that my green is not around my entire head ...... now it is twice around my entire head , all that with full IRFP150 output

someone said - who needs Semisouths ?



as shown , if you have them, at least 3 similar but different enough amps are possible ; for someone having SSouths , I personally believe that iteration with SS down is most interesting , under condition of having sweet enough speakers per se

for Moi , even if having SSouths , full IRFP is still most fun

Hasta La Vista .... Make my day, Punk ....... Family is everything .... I Love the Smell of Napalm in the Morning ...... I'll be back ....... and I'm done with this amp.




now is really a time to populate Babelfish M2/SEF amp pcbs and test ...... it's also going to be either major fun .... or major flop , applicable for SEF