Beginner to build an Aleph30 needs some help

[Danger Mouse]

I know it's to late,

but i say build the BZLS (BOSOZ) stock schematic.

there's something really sweet in it's simplicity, and resistors doing the work of all those extra CCS parts...

and when you run it balanced to balanced it really shines. even when it's converting unbalanced to balanced.

i really don't think it's an inferior preamp... and i'm looking forward to comparing it to my
incoming Pass Labs X2.5

If you have your x2.5 i will be very interested in how it sounds for you compared to the Bosoz.
Because in past i think about buying a used X-preamp but think the difference to the old mosfet preamps is not so big, to spend so much money

 

[Zen Mod]

buy

and build

 

[cowneko]

Thanks Zen,

So 2X 21 steps smd commuted 10K pot with coupler added to BOM

 

[Zen Mod]

prior to pre stage , not post

 

[cowneko]

prior to pre stage , not post

You mean in place of P1 and P2 on the stock schematic? I thought Nelson suggested to put the pot on the output (P3 -P4)
On P1 P2, the pot is supposed to lower the input impedance to the pre right?

 

[cowneko]

Ok I see what you mean...I'm reading Nelson's article and he suggest 10K pot on P1 P2 (attenuator of input signal) and 5K on output (P3-P4)....however, it's quite difficult to find 5K pots.....

 

[Zen Mod]

P3 and P4 are optional - to directly decrease gain of circuit ; you must differentiate that from pot on input ( value of your choice , but better not higher then 10K ) , which is for attenuating input signal ...... working as normal volume pot

 

[cowneko]

So I just have to install the 10K pots on P1-P2 to adjust the volume, with nothing on the output?

 

[Zen Mod]

leave P3 and P4 out you don't need them
set gain with P5 (trimpot)

 

[cowneko]

I'll put a 1k trimpot on P5 (Nelson suggest 500R here, but a little margin won't hurt I guess)

 

[Zen Mod]

greater P5 value , less gain

 

[cowneko]

Ha..... right.....so 500R
more resistance=more resistance

 

[Zen Mod]

it doesn't matter ;

put whatever pot you have ; sum value of P5 (as set) and R15 is what counts

 

[cowneko]

I'll take note of all that for when I'll do the stock schematic Bosoz, although I don't know if it applies to the X CCS version (Kari's board)

 

[Zen Mod]

well - confusing me , talking about different schematics , is easy

but confusing your self is more critical




it can be applied also to CCs version , in same manner - slightly different for version with one (common for two halves) vs. version with two CCS-es (each half having own)

 

[cowneko]

Well, I'll take a little break to study the stock schematics and the Kari's board

 

[ClassC]

Can anyone please point me to the relevant thread/s for BOSOZ build with x-ccs? Ive searched so many threads that only discuss it but dont have any detail?? Id tear my hair out if I had any...

Im really keen on the BOSOZ line amp after reading Nelsons article on it and now having seen ccs mods that I thought would be great to experiment with...

TIA guys