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