UA LA-610 Schematic

[kingkorg]

Does anyone have it?

Here's the deal, i used to own one of these. I wasn't crazy about that pre, nor the compression section.

However, that EQ could be the simplest and sweetest sounding eq i ever laid my hands on. You could not do anything wrong with it. It changed the sound obviously, but even at extreme settings it sounded just right. I really miss it, but i dont think i'd buy another one just because of it.

I am wondering if someone knows if there's something similar to it? I would like to make one. Or obviously original schematic of any version with eq.

 

[Bo Deadly]

I don't know about the schem but the eq are just hi/lo shelving filters. It's probably not all that different from what you would get with a baxandall eq. Except a baxandall would perform "better" in that it would have a sharper Q. But this last bit is wild speculation on my part (the 610 could use bootstrapping to sharpen up the response).

 

[shot]

I don't know if it helps, but here's a photo I took many years ago when I popped up the hood on my 2-610.
It was with a phone camera of that era so it's very grainy.



Left of the psu there are two vertical boards. That's the filter.
Obviously it's a simple R-C network.
Of two boards, left one has only switches for frequency and on the right one is rc network

If I remember correctly, someone said to me that this eq is on mic level, before the gain makeup.
But I was not into electronics then, so I never bothered to take a closer look into it.

If you don't find better schemo, maybe I can pull it out of the rack and take closer photos...



Luka

 

[Bo Deadly]

Actually that looks like a 4 pole switch. So it can't be that simple.

 

[kingkorg]

Thanks Luka!

Here's the 610A revision schematic, however it has fewer EQ options. I would still like to see what's going on in B revision.

Squarewave i think you might be right about Baxandal eq. I just downloaded a couple of free Baxandal vsts. They seem to do that "non invasive/any position sounds good" thing. Especially Kuassa basiQ.  So that might be the way to go.