Helios 2128 + 22113 Module Pics

[Hansblooey Ribbon]

Hello All.
Anyone have pics of the backside of either of these modules? Would like to etch a couple and might as well keep the component layout the same.
Thanks
-ahb

 

[Whoops]

this is what I have in my archives, can't find any photo of the backside

 

[Hansblooey Ribbon]

Thanks Whoops.
Those are great shots. Maybe I'll have to buy an actual module.

 

[Whoops]

Thanks Whoops.
Those are great shots.

Maybe I'll have to buy an actual module.

Are you sure?
One original Helios module alone will cost you between 4000€ to 10000€

Would like to etch a couple and might as well keep the component layout the same.

The circuits are so simple that even an inexperienced person can design a pcb layout for these in Kicad, it's easy, just a matter of wanting to do it and watching some youtube tutorials, the circuit is that simple.

So that's my advice, just do your own PCB for it

 

[Hansblooey Ribbon]

Thanks Whoop$. Not the whole Pre/ EQ Just the 2128 I traced it out but of course some of it makes little sense. The 22113 is even worse.
I use Inkscape to make PCB layouts, mostly 4 & 5U modular stuff.

 

[Whoops]

I traced it out but of course some of it makes little sense. The 22113 is even worse.

You don't need to trace it out, the schematics for those circuits are well known and available.

sorry, I'm not getting it, what doesn't make sense?

I use Inkscape to make PCB layouts, mostly 4 & 5U modular stuff.

That's great,
so these circuits will be really easy for you

 

[JMan]

I have to agree with Whoops, just search up the schematics (easily available here on the forum or elsewhere on the internet). A number of folks, myself included, have made their own pcb layouts for one or both of these circuits. If you want yours to be a copy of the original card, well, between the schematic and the photos of the layout provided above, you should be able to get a very nice result!

 

[Hansblooey Ribbon]

Hello Helios Hellions.
Found the backside of a 2128 amp card. Thank You Reverb. There's a discrepancy between this board and all the schematics we have here. In the schematics the signal returns from the 0-40-80 filter switch where it connects to a 180K resistor and 1.5uF cap The 180K goes to 0V and the cap goes to the divider/ Q4 base. The board shows the resistor and cap in series to the divider/ Q4 base. Probably no big deal.
Cheers
-ahb

 

[Whoops]

 

[Whoops]

22113

 

[ubxf]

Hopefully this can help

 

[Hansblooey Ribbon]

Thanks for the pics Whoops & Uxbf. The last 2 are from that Reverb sale. I’ll probably draw my pcb so the return input can be wired either way.
Cheers
-ahb

 

[ruffrecords]

Thanks for the pics Whoops & Uxbf. The last 2 are from that Reverb sale. I’ll probably draw my pcb so the return input can be wired either way.
Cheers
-ahb

The way the emitter follower section of the 2128 is wired to the filter does not make sense to me. The emitter follower output is in phase with its input but the output appears to be connected to the centre of the filter via a 4K7 resistor and also to a 22K to ground and then to the output. I would have expected the filter to be entirely passive with the emitter follower acting only as a unity gain buffer. I am sure I have seen it drawn this way somewhere.