Ultrasimple SIT PP amp from BAF , or SIT Beast with a Thousand PSUs

[Zen Mod]

thread .

though - it needs Pa's confirmation - is it F7 , or just intermediate bone to Greedy Boyz Dogz




thread title edited , to not have any connection with F7 (Future Joy of Greedy Boyz , or Our Next Manna )

 

[Nelson Pass]

Intermediate bone.

 

[Zen Mod]

luckily , some Greedy Boyz are owned by real Dogz , so there is at least some intelligence ...........

(Mighty Moi included )

 

[Tea-Bag]

Uploaded initial pic stolen from Waveborne.

 

[PSz.]

I have already hacked up the design and managed to triple the parts count.

 

[Tea-Bag]

I have already hacked up the design and managed to triple the parts count.

based on my F6 trials, that Jfet front end will likely help.
Mine was motorboating without it.

So does the P channel SIT, the 7.4v is that a negative power supply?

 

[PKI]

I have already hacked up the design and managed to triple the parts count.

You should remove 10R to stay closer to the idea of only active components .

 

[PSz.]

That is only the beginning. I'm gonna really bastardise it so I can play with second harmonics too.

 

[buzz2]

Again hard to find and obsolete 2SK82 / 2SJ28. Fun for a small circle.

 

[PKI]

Is it possible to cool these TO-3 transistors passively? What are dissipations 60w/device...

 

[Zen Mod]

here it was , several months ago , in frenzy F6 thread : http://www.diyaudio.com/forums/pass-labs/216616-f6-amplifier-172.html#post3323995

I'm sure that Pa shouldawouldacoulda make it mucho simpler , with few voltage multipliers etc (taking in account appropriate RC constants for main vs. aux PSUs) ;

however , for really fast-finger-solder ones , Juma already made what's needed in his SIT PP thread


regarding SIT availability :

I had an exhausting but very good time at BAF yesterday.

Many thanks to all the people who were so helpful, particularly Jill (SWMBO),
Mark (not so much), Dana, and the two Pauls.

Apologies to Scott when my phone went off during his talk. I don't how to
work the thing...

Shortly I'll start posting the stuff I had.

In the meantime,

CircuitDIY Affortable Components for Hobbyists

sales@circuitdiy.com

is a reliable source for the Sony 2SK82 and 2SJ28. They have confirmed
that they have good quantities of these in the "E" rank, which I used,
and when those J's are depleted they have more J's in the "F" rank,
which should also work fine, just different Idss.

When they run out, you will have to start sending me bottles of Cab.

this is reputable seller , according to Greedy Boyz :

Vfet Sony's RARE 2SK82 and 2SJ28 Ke 33 Vfet 1 Pair | eBay

 

[Zen Mod]

Is it possible to cool these TO-3 transistors passively? What are dissipations 60w/device...

hear what Pa sez :

Keep AR2's photos handy when you watch this. I'm sure someone will post better video soon, but here is something for the greedy boys.
Pass at BA2013 - YouTube

tnx

in a meantime , here is real quickie SForged* audio from your Utoob :

https://dl.dropboxusercontent.com/u/20665608/DiyAudio/Pass at BA2013 - YouTube Sforged.mp3

*means - mono-ed , cleaned , Eq-ed , normalised , mp3-ed

 

[Soundhappy]

Sony CS XFRMR ultra minimal amplifier schematic by Nelson Pass

 

[OllBoll]

What if you have a balanced source already, would it be possible to do something like this and skip the transformer?

 

[Zen Mod]

yup

but , if you're able to do that (safely) , then you aren't in need to ask that sort of question

whatever - is there any benefit of introducing nasty caps instead of divine xformer ?

 

[PKI]

Didn't Pa say: cap is better than xformer, arguably ;-)

 

[Zen Mod]

should we call it ..... Mickey Mouse Amp ?

while Mighty ZM said - xformer , when used for several tasks in same time , is better than anything .....

Mickey Mouse Brave Little Tailor - Disney Classics Old Movies Songs Full Episodes Length Channel - YouTube



shhhhh

I'm expecting Buzz to chime in , with his 5-fillar xformer .....

 

[analog_sa]

whatever - is there any benefit of introducing nasty caps instead of divine xformer ?

What if the balanced source has already nasty output caps?

 

[2 picoDumbs]

Didn't Pa say: cap is better than xformer, arguably ;-)

Yeah I do remember him saying that, at least at the output, he might feel differently about it used as a voltage gain device driving high impedance.
Pa likes to play freely, there's no progress if you build stuff you already know works well.
Notice that in this amp he was able to select a transformer that gave a flat distortion vs frequency response curve.
I think the buffer front end will be almost mandatory for quite a few of us

 

[PKI]

He also used them coz he had them left from F6 amps ;-). What if you have an external buffer like B1, still need one in the front?