Soundcraft 1600/800B

[Slrstcs]

First post here! So glad to be a member of this group. I’m new to DIY- have tackled some pedal kits, was planning on moving on to mic preamps, but was suddenly sidelined by a crazy opportunity. Would greatly appreciate any advice or guidance as I figure out how to approach this! Pardon the long post!

The other week, I stumbled into a deal that made my jaw drop for a 24-channel Soundcraft 1600 AND a 32-channel 800B. I am hoping to get at least one of these boards optimized and operational. I already have outboard preamps, so I would probably be mixing more than tracking with this board. 

I would really love to hear from people who have modified these boards- suggestions on op-amps, adding transformers, new caps, etc, all would be tremendous. Routing tricks would be cool too- how are people using the separate monitor and tape returns?  any general info about these boards or ideas for refurbishment would be wonderful.

Additionally- I have some specific issues that I’m trying to understand, so I can jump into fixing the board. Any advice would be amazing. Step 1 is rebuilding the power supply, but I think I should have a better understand the big picture of the project first

First-
If you look around online, Jim Williams/Audio Upgrades  and Creation Audio Labs (and their extensive
Op Amp swaps) come up often—however, after reading extensively here, I’m not sure swapping op amps is really necessary.  Should this be a priority? Have people had good luck swapping op amps in these boards, or is some of the prevalence of these swaps just marketing hype? Sorta overwhelmed by the conflicting information. I don’t have the know-how to revise the circuit to accommodate wider band op amps (decoupling, etc) and I recognize for some op amps, the power supply would need to be significantly altered. At the same time, I’m up for the challenge if it’s worth it, even if only on a few channels. Any recommendations on what to do? I basically just know the opa2143, 990, etc- so I’m not really sure which op amps to use if I were to replace them.

Next-
transformers! I see people add transformers to individual channels, subgroups, and the master buss. Is this to balance the output, or more to add color? Are people adding input,
output transformers, or both? What would be suitable choices? Are 1:1 transformers going to add much color?

Some master buss/summing questions —-
I’m really inclined to find a way to add the option of big color on the master buss or when summing- maybe transformers or something, with a toggle switch? I would really appreciate any advice on this. It seems like the console tends to be pretty clean, and I’m fine with having nice transparency for mixing, but I love the idea of being able to add color. For summing- is there any idea what to do to make the most of the board? I’ve seen people successfully add a CAPI 2-aca-bo to these- is that the best option?

I also need to figure out a desk or stand- any suggestions?

I have a friend who can help me learn some of this stuff to get me started- I think he can help demonstrate recapping, rebuilding the power supply - as well as options like hot rodding the summing and master buss, adding transformers, or swapping op amps. I think I’d need a parts list and a good idea of what I’m doing first, so we are on the same page. The goal is to get this thing sounding sweet, reliable and solid for as long as I can maintain it. I’m open to anything, and I greatly appreciate any guidance or suggestions anyone has to offer.  Thanks!

 

[TwentyTrees]

Congrats on your find, and welcome to the board! With a project like this / these it's really easy to disappear down the rabbit hole, I'd concentrate on getting it up and running first and see how it sounds to you. If there's anything you think isn't quite right, you've then got a solid baseline to start experimenting with things like op amps (bearing in mind any PSU constraints), transformers, etc.

Good luck!

 

[abbey road d enfer]

Stay away from these high speed opamps.
Make a good recap, because after all these years they have started to dry; new ones are much better than the originals. Don't try to increase the value (capacitance). In the same physical format you can put new ones with higher voltage rating and higher temperature rating; use nothing less than 105°C.
The only place where it makes sense to roll opamps is in the summing amps. You can replace the summing opamps (5534) with AD797 (beware: expensive).
Forget about transformers on this mixer! Unless you're experienced enough to completely redesign the output stages, you'll be disappointed.
If you want colour, there are many outboard that deliver; don't play havoc with the delicate balance of a large mixer.

 

[Rob Flinn]

Congrats on your find, and welcome to the board! With a project like this / these it's really easy to disappear down the rabbit hole, I'd concentrate on getting it up and running first and see how it sounds to you. If there's anything you think isn't quite right, you've then got a solid baseline to start experimenting with things like op amps (bearing in mind any PSU constraints), transformers, etc.

+1

 

[JW]

I agree with the above sentiment. I went hog wild once replacing TLO71 opamps in a Trident console with whatever the Jim Williams recommended replacements were and in the end, it sounded different, but not better. A waste of money, but not time fortunately since they were socketed.

I'd recap the 'lytics and listen. Compare the direct outs of the input strips to the full path through the master bus. If something seems lacking or dull, maybe then  look into replacing some chips in the masters for a small improvement.

The CAPI API summing bus project on this forum might be something to eventually look into. It can use the same power supply as the rest of of either of those boards I think?  It takes some time to figure out how to implement, but worth it probably.

Those Soundcrafts have nice eq's. Congrats.

 

[JW]

"Next-
transformers! I see people add transformers to individual channels, subgroups, and the master buss. Is this to balance the output, or more to add color? Are people adding input,
output transformers, or both? What would be suitable choices? Are 1:1 transformers going to add much color?"

I also agree that transformers are probably only going to "benefit" the situation if you can get rid of the balancing ic opamps as a result. (And even then?)  Which is probably not hard. But I wouldn't spend a bunch of money on lots of channels of Xformers unless you find some too hard to pass up deal for the perfect Xformer. Experiment w/ the master outs first? (???) 1:1 Xformers contribute the least color vs step up/down is what I've heard.

That said, in my console I have a mixture of all kinds of 1:1 600 ohm transformers and they definitely contribute their own sound. The Carnhill 600:600 sounds soft and smooth, the UTC A20 sounds more clean and open to me, my console's original Tamuras somewhere inbetween. But very good as well. They will make some sort of difference, but only you will be able to tell if they're an improvement.

 

[abbey road d enfer]

The CAPI API summing bus project on this forum might be something to eventually look into. It can use the same power supply as the rest of of either of those boards I think?  It takes some time to figure out how to implement, but worth it probably.

As a summing amp, a 2520 is not better than the 5534's that are in this position. A 990 would be better.

 

[abbey road d enfer]

1:1 Xformers contribute the least color vs step up/down is what I've heard.

Any one who said that is strongly misinformed. Turn ratio has nothing to do with saturatin/distortion, which is the essence of transformer sound.
What counts is the induction. Increasing the induction increases artefacts. In order to increase induction, for a given level, one can use a smaller core or less turns (or both), or change the composition of laminations.

 

[Slrstcs]

Thanks to everyone for chiming in- I was really hoping that by now I’d have the board in hand so I could start contributing to the discussion in some way  ;D turns out, I’ve just landed a new job that is going to be moving me out of state, and so instead of refurbishing the console, I’m traveling all over while getting the family ready for a move. It is a really exciting time, but also kind of a bummer to have this project just sitting. I do think I’ll have the board here next week.

Glad to hear I don’t need to change chips across the whole board! That’s a relief. Changing stuff just for the sake of making changes doesn’t seem worth the effort. Plus, totally agree with the sentiment that I should get this working before worrying about going nuts with modifications. The thought to get it working and then just listen and compare seems perfect.

As far as recap goes- Should I just plan on recapping the entire board?

I’d love to meet my tech, and make some sort of rough plan for adding iron somewhere in the path. I guess I’m leaning towards keeping the channels fairly simple, but using iron on the master- Any ideas on a good transformer to use? I also love that idea of using 990s on the summing buss.  Does anyone have a good suggestion on how to implement that? I’m guessing my tech would have some ideas, but I’d love to understand as much as I possibly can before I talk to him. In the end I will end up doing a lot of the work myself, hopefully developing some chops/knowledge in the process. Thank you guys for all your comments!

 

[abbey road d enfer]

As far as recap goes- Should I just plan on recapping the entire board?

You don't want one of the caps leak and ruin a large area of the PCB. Change 'em all.

I also love that idea of using 990s on the summing buss.  Does anyone have a good suggestion on how to implement that?

That should be fairly simple. the biggest trouble will be finding a place to install them, not too far from the actual position of the 5534's, because you want short wires. An important factor is where to connect the non-inverting input. Connecting it to the non-inverting position of the 5534 (pin 2) is safe enough but there may be a better position that would improve noise. It's not trivial to optimize. Another consideration is where to connect the 990's ground pin (which does not exist on the 5534). It takes some experimenting to find the best position.

 

[Rocinante]

Jeff at CAPI-GEAR makes pcb's called the 2-ACA-BO (the help thread is on this website and located under this category of mixers/monitors) that utilize the 2520/990 footprint and feature wonderful transformers that will definitely have an excellent effect on your console. I used these pcb's on a Soundcraft Ghost and the difference was night and day. I went the 2520 route and was very pleased with the results.
Also as someone warned it is very tempting to run down a rabbit hole and the best bet is just to take it slow and do one thing at a time.

 

[fazer]

Jeff at CAPI-GEAR makes pcb's called the 2-ACA-BO (the help thread is on this website and located under this category of mixers/monitors) that utilize the 2520/990 footprint and feature wonderful transformers that will definitely have an excellent effect on your console. I used these pcb's on a Soundcraft Ghost and the difference was night and day. I went the 2520 route and was very pleased with the results.
Also as someone warned it is very tempting to run down a rabbit hole and the best bet is just to take it slow and do one thing at a time.

I agree the capi ACA  could help that console.  The mix bus could be improved.  Pulling the bus master down and driving it hard is a way to get color into the mix using the api ACA with transformers.  If you want a cleaner sound,  just push the master up and mix with less drive.  Also I would leave the fet amps in the eq.  I had a 400. And only replaced a 5534 on the line in if it’s got a TLO 71.  I also added direct outs which the 400 did not have.  Watch that the power supply can handle the load of any Opamps Changes you choose.  5534’s draw more power.  It may need to be replaced with a larger supply like an IR from Newark.    As Abby said ,  replace all the caps.  Lots of problems will go away with putting new caps in.  Clean all the pots and switches .  The 400 did a string of recordings from Red Rock Amphitheatre and nobody complained about the sound.  ZZ Top, 38 special , John Denver, And many many others. 

 

[Slrstcs]

Hey all!

I appreciate all the comments here- right after I bought the board, I relocated from Ohio to the DC area. It took me months to arrange for pickup of the Soundcraft boards, and I finally have them here. I've been swamped with work---  does anyone have a recommendation on someone fairly local to the DC area who can help me get this console in working order? I'd love to finally get this thing up-and-running, and ideally I could see someone work on it so I can tackle some of the work myself...

Thanks in advance

 

[mflemi]

I have a SC 600. I sent 2 input channels and the master to Audio Upgrades to get the Jim Williams treatment. The input channels are less noisy, lower distortion, improved frequency response and have wider sweeps on the eq. I can't really give a comparison between the old master and the upgraded one because I can't A/B them, but the design change choices are consistent with the input channels and I assume it's improved. FYI, the upgrade is more than just replacing the opamps and new caps. There's transistors, caps and resistor changes as well. I feel that the cost was worth it.
On the other channels, I am trying a design that bypasses the mic pre and adds a transformer to go from balanced line in to unbalanced directly to the EQ section. I realized that I really would prefer a line level mixer with inserts, EQ, sends, and summing. So it sounds like we are attempting some similar mods?

 

[buildafriend]

Hey I had an 800B that I got for 200 bucks. Probably the cheapest british designed console I would have ever had. Harman used to connect you with the service tech for these but they changed their phone network right around the same time that I had one and as ironically silly as it sounds they made it hard to reach the right person, but there is one tech in california who knows these desks pretty well still. the data is still laying around I think I actually have the schematics if you need them but I'll have to dig. My old boss was a tech at soundcraft in england when he was a kid so I got a pretty good run down. The 1600 was studio and the 800B was live. I would have preferred the 1600.

The pots in there are hard to replace. Id really advise getting a few spare channels for parts..

The largest improvement I know of after general maintenance is upgrading the power supply to some nice linear supplies by someone like International PSU. FWIW people often get less noise by omitting transformers for IC inputs and it ends up being a faster input but without the transformer sound and it's physically lighter and less expensive. That's another can of worms.. do you want specs or peoples or your own opinions? I won't fight for either. IIRC there was a ground mod as well.

If you lose signal press on the stepped pots and you'll often find the problem. The switches go bad pretty often as well. I'm yet to see one of the faders go bad. I think I only found one bad amp. While it's a cool desk, there is not a whole ton in there. It's still really cool.

enjoy  

 

[dbelousov]

Some of the next generations of Self's designs for Soundcraft are very good, but this one is just outdated. The Delta family and the S6000 are fine for sure.

The mic pres of the 1600 consoles are very basic. Any modern Behringer staff is better. You won't be able to upgrade them to any reasonable level. The line inputs are unbalanced, sometimes it matters.

I agree with Mr. Williams on the Deltas. They are the pinnacle of Self's mixing desk designs that I'm aware of. The next K series were simplified for the cost reduction.

 

[abbey road d enfer]

I have a SC 600. I sent 2 input channels and the master to Audio Upgrades to get the Jim Williams treatment.

The 600 is a totally different animal than the 800B/1600. Its circuitry lends itself to more experimentation just by changing some components. On teh 800B/1600, the circuits are basic and cannot be significantly improved without changing their topology.

 

[Matt Syson]

Swapping some of the op amps in a channel strip is a bit pointless as one of the principle issues with distortion is not the op amps themselves but the 'environment' for which a few cents worth of components, (and a spot of work) yield significant improvements unlike swapping a TL0 series chip for a fancy 'go faster' device.
As ever it depends on what you are really trying to achieve.
Matt S

 

[JohnRoberts]

My general advice when rehabbing old mixers is to benchmark channel performance as the first step (frequency response, noise floor, etc). Dried out caps will reveal themselves by their weak LF response. Replacing every single cap in a mixer is a massive effort with potential to make mistakes.

If/when you do find a bad cap or caps from measurements, replace all of the same value and voltage as they are from the same production batch as the faulty ones, so likely to suffer similar degradation.

JR

 

[Matt Syson]

Not disagreeing with John but to get completely 'nerdy' if you measure old removed caps you can spot trends like modules that are near bulkheads tend to have fewer 'failures' and even certain areas of the circuit boards. When shifting through 3000 or more caps you have to find something interesting to do!