Aleph 3 Upgrade

[juanitox]

 

[Zen Mod]

that cap is slightly relaxing danger of pumping DC offset from source

if you're sure that preceding stage is having none of it , you can short the cap , with amp output offset re-check

 

[juanitox]

have made the "aleph 3 J" feedbach change 10K /1K 220uf to 220K / 22K direct to ground .

it sound louder as this so i presume the feedbach have changed a bit

 

[Zen Mod]

can't be

it's 10:1 in both cases

 

[Blues]

have made the "aleph 3 J" feedbach change 10K /1K 220uf to 220K / 22K direct to ground .

it sound louder as this so i presume the feedbach have changed a bit

You are probably getting a slightly higher input voltage with the higher input impedance...

 

[juanitox]

at last ordered ZTX550 and ZTX450 and some new Res to end up with a full aleph J .... Zen contagious?

 

[Zen Mod]

in Aleph , these are easily changed with any Uni NPN and Uni PNP

 

[juanitox]

something scratching my head , with the aleph 3 the AC gain and bias resistor was 1K /47K for IRF244 and with aleph J it is 1K2 68K for IRF240

so my question is what setting to keep with my aleph J with IRF244 ?

 

[Zen Mod]

try both,keep what you like

 

[juanitox]

ok i will , so to resume increasing 47K to 68K i will get higher bias and increasing the AC gain resistor the AC will reduce the % of the CCS gain ?

 

[Zen Mod]

yup

 

[juanitox]

try both,keep what you like

i prefer 68K but more heat on the heatsink: i'v got 0,56V on the 0.47source resistor !

for the AC gain i put the trimmer to 50% of the ouptut but cant honestly tell the difference between 40 /50 or 60 %

 

[Zen Mod]

Sissy amp

 

[juanitox]

sissy amp yess but with hair on the balls

50% result in 650R for the AC resistor , PAPA 1K is a better match with tube amp

 

[juanitox]

Sissy amp

you want a real sissy, ALEPH JM !
yesterday i was so afraid with the heatsink temp ( can fry an egg) that i remove one stage of CCS and Power transistor.
and also the current and AC gain resistors and running it as pure CCS


and the sound is a fantasticmellowbuttered ..

the only problem with this PaPa amp is to choose one variant as all sounds marvellous in their ways.

 

[Zen Mod]

no more than 25W per device , and you're good

 

[juanitox]

that's a sissy advice

on the Mini J i'v got 23V X 1.25amp 29W on each Mosfet and the Alpeh 3 heatsink is a little colder than the full aleph with 0.8amp

is there a gain to change the source resistor from 0.47 to 0.33 on the Mini ?

danger robinson ?

 

[Zen Mod]

ok then - heatsink up to 55C

good now ?

 

[juanitox]

ok then - heatsink up to 55C

good now ?

for today !

 

[juanitox]

too many times without harrasing ZM

what is the gain of reducing source and output resistor from 0.47 to 0.33 ?
on the Aleph M or babblefish ?