nope , secret one is Babelfish J2 , still not revealed 
this one is (just) Babelfish J , sort of V2
pretty much soon to evolve in Babelfish JX , with some twists
this one is (just) Babelfish J , sort of V2
pretty much soon to evolve in Babelfish JX , with some twists
Hello Zen!
As always... a hard worker!
This summer I was thinking to mount trim pots in my Aleph Js so I can lower a little bit the bias of the Aleph CCS, because with 30C room temp the amps were getting quite hot and to null the output offset.
Now that I see the new front end of the Babelfish J I am very curious to try it in my Aleph Js.
Since in my Js I have some j74bl with 10ma idss I would like to use these, can I reach with them the 10ma setting that you reccommend? At what helps increasing current in the ltp?
At what current do you run the mmbf ccs? I Ask because I also have at hand some k117gr that I want to use also.
Thanks !
As always... a hard worker!
This summer I was thinking to mount trim pots in my Aleph Js so I can lower a little bit the bias of the Aleph CCS, because with 30C room temp the amps were getting quite hot and to null the output offset.
Now that I see the new front end of the Babelfish J I am very curious to try it in my Aleph Js.
Since in my Js I have some j74bl with 10ma idss I would like to use these, can I reach with them the 10ma setting that you reccommend? At what helps increasing current in the ltp?
At what current do you run the mmbf ccs? I Ask because I also have at hand some k117gr that I want to use also.
Thanks !
whatever JFets you have for input LTP , only important is that they're having Idss above targeted 5mA (per LTP half)
so , 10mA are good ones , being in most practical BL grade (6-12mA) and 10mA CCS will take care of their Iq
LED string thingy is fed with anything between 3-5mA ; it can be resistor or MMBF JFet , but I like 3mm greenies combined with JFet CCS sponginess
regarding JFet LTP current - keep them at 5mA per side - that way you're having most practical values of xconductance , drain resistor value , small source degeneration (few ohms) ...... resulting in most practical OLG/CLG/NFB ratio
if you're in mood for more ballsy mosfet's gate drive , either put 2+2 JFets in LTP (doubling current to 20mA and halving drain resistor) or put emiter follower (20-25mA Iq) in between
that would give ~6db THD decrease
edit - regarding summer and heatsinks - don't be skimpy - just make Babysitter for amp
so , 10mA are good ones , being in most practical BL grade (6-12mA) and 10mA CCS will take care of their Iq
LED string thingy is fed with anything between 3-5mA ; it can be resistor or MMBF JFet , but I like 3mm greenies combined with JFet CCS sponginess
regarding JFet LTP current - keep them at 5mA per side - that way you're having most practical values of xconductance , drain resistor value , small source degeneration (few ohms) ...... resulting in most practical OLG/CLG/NFB ratio
if you're in mood for more ballsy mosfet's gate drive , either put 2+2 JFets in LTP (doubling current to 20mA and halving drain resistor) or put emiter follower (20-25mA Iq) in between
that would give ~6db THD decrease
edit - regarding summer and heatsinks - don't be skimpy
- just make Babysitter for amp
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It`s a nice ideea and I thought about it some time ago but what are the chances that used with monoblocks it could finish with different temps for each amp ?
When you say ~6db THD decrease you are talking about entire amp or ltp?
If I paralell input devices how much would input impedance decrease?
What would be the input impedance of the V2 with a single pair of j74 ?
When you say ~6db THD decrease you are talking about entire amp or ltp?
If I paralell input devices how much would input impedance decrease?
What would be the input impedance of the V2 with a single pair of j74 ?
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just piggyback additional JFets , double current though LTP , halve drain resistor
input impedance will stay the same , being dominated with values of input/CLG defining resistors
though , it's best that each LTP JFet is having own gate stopper resitor
~6db THD decrease for entire amp , at least when using (emiter follower) buffer in between LTP and mosfet gate(s)
input impedance will stay the same , being dominated with values of input/CLG defining resistors
though , it's best that each LTP JFet is having own gate stopper resitor
~6db THD decrease for entire amp , at least when using (emiter follower) buffer in between LTP and mosfet gate(s)
I am very tempted to try the iterations of the first stage you done but I still want to connect the collector of Q6 to -V as the original schematic.
I have to find a way to stuff all on a very small proto board that I will fit on top of PD board without doing a big ratsnest.
Thanks Zen for the patience!
I have to find a way to stuff all on a very small proto board that I will fit on top of PD board without doing a big ratsnest.
Thanks Zen for the patience!
collector of Q6 ; it's fluffy fun residue from past , slightly ewffective in a good way only when JFets aren't cascoded (see it as anti-cascoding move 
)
it stays as is mostly from fun , and in case someone won't use cascoding bjts , to spice things a little bit
so - detail pretty much irrelevant for your intention , just ignore it and connect Q6c to -V
btw- that thingie with small daughterboard and Aleph J-fication is already done several times
but , I can't remember by whom and in which threads exactly
)it stays as is mostly from fun , and in case someone won't use cascoding bjts , to spice things a little bit
so - detail pretty much irrelevant for your intention , just ignore it and connect Q6c to -V
btw- that thingie with small daughterboard and Aleph J-fication is already done several times
but , I can't remember by whom and in which threads exactly
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Good to know that is already done so with a little help from google I can get some ideeas first that I would start to mess arround.
As for cascoding input fets what kind of benefits does it yeld? Others than greater rail voltage.
Thanks!
As for cascoding input fets what kind of benefits does it yeld? Others than greater rail voltage.
Thanks!
lesser distortion , but ..... matter of taste what you'll prefer
some can't even hear difference
some can't even hear difference
Ok Zen Mod
What's the deal? Are we talking pcbs?
Do you have schematic? Or is it only available to people who buy pcbs?
Too lazy to read.
What's the deal? Are we talking pcbs?
Do you have schematic? Or is it only available to people who buy pcbs?
Too lazy to read.
#1,#49,#80
Attachments
Looks pretty good.
Have you had a chance to build it and listen? How does it compare with Aleph J?
What features do you like about your version?
Have you had a chance to build it and listen? How does it compare with Aleph J?
What features do you like about your version?
I know
besides working in my little service , I'm breathing old school speakers and wakoo amps , Papamps being bigger part of those in last decade
so - I did listen ; comparable to Papa's FW original , certainly not being worse
this particular one made to be scalable , covering almost entire range of (previous, non-J) Aleph stable , bringing J-fication to that
besides that , easily set ........ though demanding some use of brain**
**but , I simply couldn't avoid that