Zen Mod

Graphs , 4R load, BFR=510R
everything same as previous, load changed to 4R

I did planned before to make it, but finally made T-Bed 2 , as proper cradle for prototyping this
from one of pics, you can clearly see that ZM is Chicken , executing first power up and settings with IRFP240/9140 and 2A fuses in rails...... did it with smallish Iq, and later - when I was happy camper, changed to Biguns

Now, for clarity sake, there is edited schm, parts needed for SIT iteration omitted
few more funny pics, too

prepis sa Big DiyA
no way da kucam ponovo, zato copy-paste
 
///////////////////////////////////////////////////////////////////////////////////
Few years ago, we had enormous fun in funny named thread : F4 Beast Builders : https://www.diyaudio.com/forums/pass-labs/300233-f4-beast-builders.html
Well, you can call it Group of Hysteric Housewives Brainstorming 
Result of that was that I have myriad of back of napkin sketches, and after these I started simulating ...... and simulating ... and simulating
After myriad of these ( out of sheer enthusiasm I even made pcb files for some of iterations), I finally had made nice smallish channel pcbs, containing OS having different-ish approach to biasing than Papa's original XA25 is having, while FE was in principle same as Papa's, but with few beautiful quirks, of which I was damn proud (yup, Mighty ZM reinventing Da Wheel, time and time again)
And they were sitting, populated, on my shelf ........ always being pushing to bottom of list; I knew they would work, but somehow I wasn't content with overall picture
Now, recently - besides revising biasing mechanismus for SissySIT ( resulting in R.3) and few other amps, I also made FE called Plethora of Pinjatas ( or just Plethora, short) and found interesting to combine it in sitting Babelfish XA25 project
Plethora Fe having both SE and Bal inputs as matter of choice, called to adding another "2" in name , so result is Babelfish XA252
Plan is also to have iteration of DEF OS ( real SIT, no emulation in form of Schaded Mosfet), thus addition of "SIT" in name, so Babelfish XA252 / SIT
Find enclosed cumulative schematic, and will do edits of this post, if and when needed
OK1-OK2-TH1 .......... 10A limiting circuit, Savior of Our Souls, blatantly stolen from Pa 
 

nista od Wolija
on prelazi na D klasu
kaze, ovo mu previse greje dnevni boravci

Graphs , 4R load, BFR=510R
everything same as previous, load changed to 4R

Graphs , 8R load, BFR=510R
Everything the same, but BFR changed to 510R, that being opposite extreme to 22R - practically lowest OLG which I considered

Graphs , 4R load, BFR=22R
everything the same, load 4R

Graphs , 8R load, BFR=22R
 
FE is made as more or less basic LTP thingy; though, I did wanted to have possibility of altering THD level by changing OLG in simple and predictable way - which I made in also basic way - tearing LTP halves ( each halve having own CCS) and introducing common degeneration resistor ( practically changing length of effective Tail of LTP) , which I then named as Beauty Factor Resistor, short BFR
as you will see, changing value of that resistor is chhanging OLG, thus changing amount of overall NFB, and as result we have lesser or higher THD level
Luckily, Spectra is not changing, and that was a goal 
now - set of measurements with highest possible OLG - BFR s 22R
Rails are 30Vdc ( amp projected to work with rails of 30-35Vdc with no changes)
Iq 1A7
DC offset and Iq practically not changing in temperature domain
While varying mains voltage (nominal 230Vac) between 200Vac and 255Vac - DC offset is changing some 20mV, while Iq is practically not changing
Good enough for me 
Load for these graphs is 8R; each graph is having title captured, so you can see what/how much
due to 30Vdc rails, clipping smidge above 40W
with 35Vdc rails, clip near 55W
who needs that ?
 

I did planned before to make it, but finally made T-Bed 2 , as proper cradle for prototyping this
from one of pics, you can clearly see that ZM is Chicken , executing first power up and settings with IRFP240/9140 and 2A fuses in rails...... did it with smallish Iq, and later - when I was happy camper, changed to Biguns

Now, for clarity sake, there is edited schm, parts needed for SIT iteration omitted
few more funny pics, too

Graphs , 4R load, BFR=510R
everything same as previous, load changed to 4R

prepis sa Big DiyA
no way da kucam ponovo, zato copy-paste
 
///////////////////////////////////////////////////////////////////////////////////
Few years ago, we had enormous fun in funny named thread : F4 Beast Builders : https://www.diyaudio.com/forums/pass-labs/300233-f4-beast-builders.html
Well, you can call it Group of Hysteric Housewives Brainstorming 
Result of that was that I have myriad of back of napkin sketches, and after these I started simulating ...... and simulating ... and simulating
After myriad of these ( out of sheer enthusiasm I even made pcb files for some of iterations), I finally had made nice smallish channel pcbs, containing OS having different-ish approach to biasing than Papa's original XA25 is having, while FE was in principle same as Papa's, but with few beautiful quirks, of which I was damn proud (yup, Mighty ZM reinventing Da Wheel, time and time again)
And they were sitting, populated, on my shelf ........ always being pushing to bottom of list; I knew they would work, but somehow I wasn't content with overall picture
Now, recently - besides revising biasing mechanismus for SissySIT ( resulting in R.3) and few other amps, I also made FE called Plethora of Pinjatas ( or just Plethora, short) and found interesting to combine it in sitting Babelfish XA25 project
Plethora Fe having both SE and Bal inputs as matter of choice, called to adding another "2" in name , so result is Babelfish XA252
Plan is also to have iteration of DEF OS ( real SIT, no emulation in form of Schaded Mosfet), thus addition of "SIT" in name, so Babelfish XA252 / SIT
Find enclosed cumulative schematic, and will do edits of this post, if and when needed
OK1-OK2-TH1 .......... 10A limiting circuit, Savior of Our Souls, blatantly stolen from Pa 
 

da ne bude da samo shonne radi nesto

Now, for clarity sake, there is edited schm, parts needed for SIT iteration omitted
few more funny pics, too

nema potrebe
samo sebe stavim na zabranu citanja (foruma) 5 dana i eto lepote
 
 

lako vam je mene zaebavati

ma ovo super ladno pojacalo
vako kako je , smali mosfeti, 1A1 Iq  - dissipacija 66W/ch a klip na 40W/8R
sutra pucks na mesto

da ne bude da samo shonne radi nesto

eh
kuj trazi taj  i nadje
naleteo na KP, Garant - 15E
ce ga prestelujemo za M4 i dosta moment opreme
usput uzeo za 1K i zuti kompletak, da se nadje
 
sto rece Edi Marfi - kad sam bio mali, morao sam da prdim u kadi, to have this

nema potrebe
samo sebe stavim na zabranu citanja (foruma) 5 dana i eto lepote
 
 

nema potrebe
samo sebe stavim na zabranu citanja (foruma) 5 dana i eto lepote
 
 

nema potrebe
samo sebe stavim na zabranu citanja (foruma) 5 dana i eto lepote
 
 

eh
kuj trazi taj  i nadje
naleteo na KP, Garant - 15E
ce ga prestelujemo za M4 i dosta moment opreme
usput uzeo za 1K i zuti kompletak, da se nadje
 
sto rece Edi Marfi - kad sam bio mali, morao sam da prdim u kadi, to have this

nema potrebe
samo sebe stavim na zabranu citanja (foruma) 5 dana i eto lepote