Babelfish M2/SEF amp

[flocchini]

Should the new output be taken from the drain of Q2

and is the pinout looking down on Q2

G D S?

Thinking about doing the mod to my Toshiba M2

Thanks

Bob

 

[Zen Mod]

Should the new output be taken from the drain of Q2

and is the pinout looking down on Q2

G D S?

Thinking about doing the mod to my Toshiba M2

Thanks

Bob

nope Bubba

for SEF, output taken directly from source of IRFP9240 (that one in negative rail)

pinout , numbers looking at you , legs down , from left, is always G-D-S

 

[flocchini]

Thanks !!!

That why I have learned to ask

 

[flocchini]

Also I should have looked at posted pics a bit closer

 

[Zen Mod]

 

[flocchini]

Schaded M2 up and running

Using Schade 3.5k ohms.
Bias 1.4A
R6s 40k on one channel, 42k on the other

Wide and deep soundstage - tight bass - instruments well placed - smooth -very easy to listen with this amp.

Highly recommended if you don't have access to THF51s or 182s

Hats off to you ZM

 

[Dennis Hui]

Very nice Bob!

 

[flocchini]

Thanks Dennis - its fun amp - would be a great first amp for a diy'er

 

[indra1]

Schaded M2 up and running...

Bob, don't forget to try both speaker polarities.

 

[flocchini]

thanks for reminding me !!!!

 

[Zen Mod]

I like stone detail

I'm glad that you're glad

what's most important , besides fact that's one more iteration of already good amp , is confirmation that Schade can be implemented without too much penalty in linearity in upper part of spectrum

 

[flocchini]

Bob, don't forget to try both speaker polarities.

indra1

On my Tannoys changing polarities is interesting - there is a subtle difference - original polarity seems a bit warmer to me - sorry I am using a term that may be different for each individual - both are listenable - this may have to be integrated over more listening

Still say that this would be a great amp for a person new to diy

 

[flocchini]

After extended listening it is hard for me to select a preference - both connections are listenable - I went back to original set-up for now. Maybe it's my ear/brain combo. It's all about experimenting

 

[Zen Mod]

Tannoys are for Sissies

 

[indra1]

... both are listenable - this may have to be integrated over more listening

Of course Bob, each set of room-speaker interacts differently.

 

[Zen Mod]

only Picodumb is connecting his speakers in antiphase, simply because his ears are that way connected

 

[Attila I]

stumbled upon this old thread and as i chose the 10µFsilmic/1µFmkc version
there was an easy option for implementing Rsch.
thanks Ylab and of course ZM.

 

[Zen Mod]

N.B. that final development (well, up to my ability) is done in Babelfish M25/SET amp

today I'll do even that one slightly different, putting Schade to upper mosfet

though, only drawback, if it is drawback at all is that 2nd harmonic is positive ( when Schade is in lower rail) , so all you need is to flip speaker polarity to get negative one

construction wise, both cases are challenging in finding small mosfet ( for small Source follower, explained in mentioned thread) with lowish Ugs ; in case of Schade down, solved with TP2640, in case of Schade up, DN2540N5

post #20