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Sound Workshop 1280b DIY upgrades

 
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soundnerd
audio school graduate


Joined: 14 Jan 2004
Posts: 15
Location: DC

PostPosted: Sun May 09, 2010 12:47 am    Post subject: Sound Workshop 1280b DIY upgrades Reply with quote

I just read a post in the sale column for a Sound Workshop 1280b console for sale. I've have a 1280b for around 8 years, and am a big fan of it. I'd love to know of any DIY upgrades that I do to the console to improve the sound. The for sale article mentions upgraded chips, power supply, outputs, etc. Does anyone know where I can find info on upgrading this console? Much appreciated!

Mike
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themagicmanmdt
george martin


Joined: 14 Nov 2006
Posts: 1339
Location: home on the range

PostPosted: Mon May 10, 2010 1:18 pm    Post subject: Re: Sound Workshop 1280b DIY upgrades Reply with quote

There's a Yahoo! group that's the source of many of SW's original designers and head techs that still post there. Just search the Yahoo groups for sound_workshop -!

Otherwise -

Swap out all 4741 chips to TL074's. Faster slew rate chips can be installed, but require not only an upgraded PSU but also some bypass caps to stop oscillations. I find the TL074's plenty fast, clear and hi-fi.

Recap the board. Big difference.

Add balanced line input transformers to the line input jacks. 10k:10k steel sounds awesome.

The mic pres are most probably wired pin 3 hot, pin 2 not. They need to be switched.

New power supply, especially after rechipping.

Add balancing transformers to the buss outputs, or at least the mixdown outputs. 600:600.

Others I never got to yet - phase switches for each channel, a dedicated '2 mix' switch (instead of just relying on buss 7/8, since the circuitry is there) -


Overall, it's a board stuck somewhere inbetween a Neotek and an API. If you leave the transformers off, it's very clean and neutral. Add them, and it's hi-fi mojo city. Get some transformers that saturate early!
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soundnerd
audio school graduate


Joined: 14 Jan 2004
Posts: 15
Location: DC

PostPosted: Mon May 10, 2010 5:05 pm    Post subject: Re: Sound Workshop 1280b DIY upgrades Reply with quote

Thanks for the advice. I have a pair of API's and a pair of OSA's (as well as Vintech's, etc...), but I really love this console - especially the eq. I'm in the middle of upgrading a bunch of stuff at my studio, and purchased a pair of UTC transformers with the intention of wiring them into my patch bay to give me the option of using them before tape on the direct outs. I'll definitely rechip the board, as I'm aware that it can have a major impact on the sound.

Good luck with your new adventures & thanks again for the advice.

-Mike
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Jim Williams
buyin' a studio


Joined: 03 Jun 2006
Posts: 991
Location: beautiful Carlsbad, CA

PostPosted: Thu May 13, 2010 11:14 am    Post subject: Re: Sound Workshop 1280b DIY upgrades Reply with quote

Superior quads include the LT1359, LME49740, OPA1644 and AD8513. 074's are the chips that drive up the prices for discrete English consoles...
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Jim Williams
Audio Upgrades
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boriscrispin
alignin' 24-trk


Joined: 13 Oct 2008
Posts: 66

PostPosted: Mon Sep 27, 2010 11:44 am    Post subject: Re: Sound Workshop 1280b DIY upgrades Reply with quote

Quote:
Superior quads include the LT1359, LME49740, OPA1644 and AD8513. 074's are the chips that drive up the prices for discrete English consoles...


Jim, sorry to revive this if it's old news, but I am planning changing the op-amps on my 1280b, it has a modded external power supply.

You list those iC's as superior to the (cheaper and readily available) 074's, can you possibly tell me how each of those are better? and which one would you go for? if pushed!
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Jim Williams
buyin' a studio


Joined: 03 Jun 2006
Posts: 991
Location: beautiful Carlsbad, CA

PostPosted: Mon Sep 27, 2010 6:24 pm    Post subject: Re: Sound Workshop 1280b DIY upgrades Reply with quote

All of them are much lower noise and THD. You may need local psu bypass caps added and feedback caps across feedback resistors if they are missing.

The other benefit is they are all low offset precision opamps. You can check the DC on the outputs, if below 2 mv, short out the electrolytic coupling caps. That really fixes the sonics and low end.

The BB and AD parts are surface mount, a Brown Dog or Aries header is needed. If used for summing, use the LME part, it has the highest open loop gain.
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