So this is most likely in the wrong area, but this is where I've gotten a lot of help with the same types of questions as I'm asking now.
Soundcraft 200 Delta Mixer. Bought it from Craigslist and once researching, I realize after a full recap (Nichicon and Wima's, about 1,000 of them), this can be a studio quality mixer. I also read up about some Jim Williams mods. But since those are $150 a channel, no one says what they are. (Which is good, that's the guys job!) So, since I have 24 channels to mess with, I thought I'd ask here for circuit opinions.
Stable op amp upgrades would be very nice to know, I have some ideas, but again, I'd like to have input. The power supply is a CP450, recap and new rectifiers are on the docket.
Here's a thread with the (maybe) correct schematics. It combines Delta, Venue, and Delta Theatre so I'm not quite sure.
Soundcraft 200 Delta Mixer. Bought it from Craigslist and once researching, I realize after a full recap (Nichicon and Wima's, about 1,000 of them), this can be a studio quality mixer. I also read up about some Jim Williams mods. But since those are $150 a channel, no one says what they are. (Which is good, that's the guys job!) So, since I have 24 channels to mess with, I thought I'd ask here for circuit opinions.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Stable op amp upgrades would be very nice to know, I have some ideas, but again, I'd like to have input. The power supply is a CP450, recap and new rectifiers are on the docket.
Here's a thread with the (maybe) correct schematics. It combines Delta, Venue, and Delta Theatre so I'm not quite sure.
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Looks like quite a sensible circuit overall (schematics are hard to read though).
What are the supply voltages like? Could be anything from +/-12 to +/-18 V.
That's a whole bunch of faders likely in need of some TLC. I hope you are prepared for this.
I'd say you could probably do better than TL072s for the input and EQ nowadays. IC1 should be something suitable for medium-high source impedances (3-10k), with either FET input or some kind of input bias current cancellation, good CMRR, and half-decent output driving. Medium-low current consumption preferred. IC2 similar but with low input impedance nonlinearity. Hmm. LM4562 seems close but its current noise isn't terribly low. Doesn't anyone make a dual with cascoded FET input?
BTW, I wouldn't trust the circuit to give symmetric input impedance with the gain adjustment like this. That's just a hunch though, and would have to be verified by simulation.
The balanced output amps could use something even beefier than the trusty NE5532... LM4562/LME49720/LME49860-ish.
What are the supply voltages like? Could be anything from +/-12 to +/-18 V.
That's a whole bunch of faders likely in need of some TLC. I hope you are prepared for this.
I'd say you could probably do better than TL072s for the input and EQ nowadays. IC1 should be something suitable for medium-high source impedances (3-10k), with either FET input or some kind of input bias current cancellation, good CMRR, and half-decent output driving. Medium-low current consumption preferred. IC2 similar but with low input impedance nonlinearity. Hmm. LM4562 seems close but its current noise isn't terribly low. Doesn't anyone make a dual with cascoded FET input?
BTW, I wouldn't trust the circuit to give symmetric input impedance with the gain adjustment like this. That's just a hunch though, and would have to be verified by simulation.
The balanced output amps could use something even beefier than the trusty NE5532... LM4562/LME49720/LME49860-ish.
Sorry about the schematics. The PDF link I put in seems to have disappeared.....
Rails are -\+ 17V. I am ready as I ever will be for the faders, worth it! I'll do some simming with it, thanks for the idea, not sure why I didn't think of that.
I have a boatload of TI op amp samples, most of which you recommended. I'll probably go with LME49720 for outputs, I've had good experiences with it. Thanks!
got any pic's of your new bundle of joy.
i liked the delta i had use of for the better part of 12 years i miss it...
i used it for live sound applications as well as some recording projects worked great in both circumstances.
only problem i ever had was assignment buttons sticking but that was in a heavy touring season with no time in the schedule for maintenance even the crew was hard pressed to find shower time(stinky tour as i recall...)
i liked the delta i had use of for the better part of 12 years i miss it...
i used it for live sound applications as well as some recording projects worked great in both circumstances.
only problem i ever had was assignment buttons sticking but that was in a heavy touring season with no time in the schedule for maintenance even the crew was hard pressed to find shower time(stinky tour as i recall...)
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Buyer is in Vegas, so I don't have the mixer quite yet unfortunately so no pictures except for these uninteresting ones sent by seller.
Something odd however, the first two inputs are not DLX, then 18 are, then another 4 aren't. No dual inputs and they all have only four auxes, maybe slowly I'll look on the bay for the full input modules.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Something odd however, the first two inputs are not DLX, then 18 are, then another 4 aren't. No dual inputs and they all have only four auxes, maybe slowly I'll look on the bay for the full input modules.
so it's a 24 channel mainframe mine or i should say the one i had was a 32.
i hope it comes with a roadcase.
it looks like this one has some corrosion forming on it.
i hope it comes with a roadcase.
it looks like this one has some corrosion forming on it.
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Yeah, wish it was a 32. I think that corrosion might just be residue from something (hopefully). It doesn't come with a road case, but I'm happy the power supply included is rack mountable!
as long as it doesn't get shipped in a cardboard box all should be well.
i once purchased a TAC Scorpion console (used) that arrived with a 1/3 of the controls sheered off because the supply was in the same box.
i once purchased a TAC Scorpion console (used) that arrived with a 1/3 of the controls sheered off because the supply was in the same box.
*Seller in Vegas
Very sorry. That must have made no sense. I'm in Minnesota and should've picking it up Saturday sometime.
https://www.gearslutz.com/board/gee...lta-200-series-service-manual-schematics.html
Post 7
Wondering about a input transformer.
Post 7
Wondering about a input transformer.
are you asking whether an input x-former would be an upgrade?
i liked the performance of the front end gain stage. it would have to be one heck of a good x-former
price + added weight =??? i really can't say if the improvement (if any) would be worth it.
i liked the performance of the front end gain stage. it would have to be one heck of a good x-former
price + added weight =??? i really can't say if the improvement (if any) would be worth it.
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I agree with your points, and I most likely won't, but I know where to get them if I ever do.
http://www.jensen-transformers.com/transformers/mic-input/
Very expensive, but very good.
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An externally hosted image should be here but it was not working when we last tested it.
Here she is!
An externally hosted image should be here but it was not working when we last tested it.
With the beefier CPS 450/B PSU.
looks like it's in good shape!
no shipping damage.
now i'm sad i miss that Delta 32
(i think i got a leftover of scotch somewhere...)
no shipping damage.
now i'm sad i miss that Delta 32
(i think i got a leftover of scotch somewhere...)
Since there are very few pictures online of the modules:
DLX:
One channel only works when I push down on it. I don't like that at all.
Needs to be in use right now, so no more fun with it until Wednesday.
An externally hosted image should be here but it was not working when we last tested it.
DLX:
An externally hosted image should be here but it was not working when we last tested it.
One channel only works when I push down on it. I don't like that at all.
Needs to be in use right now, so no more fun with it until Wednesday.
An another goal, there is a evident hiss with all channels off and masters at zero. To get rid of that, is that grounding? Op amps? Old caps?
with the channel that only works when you press down on it breakout the magnifying glass and inspect it for cracked solder joints.
the hiss is most likely supply decoupling caps in the master section.does this go away with channels routed directly to master?
if you have a scope check the supply lines for high frequency oscillations.
the original supplies had an issue with the regulators for the 17 V lines but if you have the "B"it should be upgraded.
the hiss is most likely supply decoupling caps in the master section.does this go away with channels routed directly to master?
if you have a scope check the supply lines for high frequency oscillations.
the original supplies had an issue with the regulators for the 17 V lines but if you have the "B"it should be upgraded.
No the hiss stays. Do you think I should add more 0.1uF's to the opamps? Or just replacing the electrolytic ones?
Will do. Maybe a silly question, but is the strip with the white boxes indicating the channel number at the bottom....are those dry erase? I used to use magnets to ID channels, but that can't happen now.
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