Project 500 EQ from Soundcraft Series One / Two

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L´Andratté

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:D
Ok, concerning Series One, the preamps are a little flawed imo, full gain with
attenuator in front, still sounds nice but noisy, the eq is sounding sweet but has fixed frequency
points not very flexible, could be made switchable for 2-3 freq. points?

There are two versions of Series Two ::), one with opamps and one discrete, which is
close to Serie One, but has much quiter preamps, the eq points and circuit is also
a little different, but also fixed frequencies

At least two different types of transformers on Series One, don´t know about Two...

Runs at 40V, but can be used at 48V (comfortably) with the chunky transistors used.
2sa970 and 2sc2240 are good replacement types

For 500 style module one should think about how to implement balanced i/o.

 

Menno1000

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Dec 9, 2014
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mjrippe said:
The Series One console was famously used by dub reggae pioneer Lee Scratch Perry.  I had a pair of channel strips at one point and they included Sowter input transformers and an all discrete preamp.  Sounded very nice and as you say, the eq is smooth and hard to make offensive.  I racked them and sold them to a fellow who was supposed to be working with Perry on a project.  Perhaps you can name yours the LSP 500  ;)

Hi, yes thanks for your reply. I also was thinking about racking them. LSP 500 indeed a great name!
 

Timjag

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Jun 23, 2016
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Actually scratch had a 16x4x2 which was the precursor to the series 1, I know because I've got the other one! seriously though they only made a few of them before the series one and they're pretty much the same, in fact I thought it was a series 1 until Andy Brown at Soundcraft corrected me, I've got the schematic for it if you need. It had a crappy PSU basically a massive Toroidal transformer and 1 filter cap! Eventually they'd dry out and you'd get an almighty hum!

The EQ is fun if limited - although that makes the fun! The preamp stage isn't exactly inspired - single darlington from a 1:7 sowter transformer. In those days that was the cheap way to do it! Expensive now though!

Anyhow, I've attached the stuff I have from Andy plus a photo of my old girl that's still waiting restoration! lots of nice sowter transformers!
 

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  • Series 1 UG.pdf
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Timjag

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Jun 23, 2016
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157
Great info, dubheadz want to know!
Is your model a different schematic than the one posted (which is series 1)?
Yeah it’s a series 1 schematic they really were the same, they rebranded it series 1 for marketing purposes. Soon after, they released the series 1s which was Opamp designed - Tlo72 I think. I have the schematic for that too I’ve uploaded it, I don’t think it’s anything special tbh the 16/4/2 and series 1 had all the sowter transformer and baxendall magic.

I bought mine 30 years ago when I was 18 it blew my mind how good it sounded next to this sansui mixer/6 track I had
 

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L´Andratté

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I think 1s actually came after series 2, which is like series 1 with better preamp circuit, postfade buffer and a little different eq frequencies as well as highpass filter.
Very nice you are actually the original owner!
 

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  • Series-Two standard-channel.png
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