OK, so i’ve found a direct replacement for the NE5532 audio op amp chips in the summing stage of the busses that really make the whole console sound better and “resolve” much more like we want it to sound. Here’s a link to the before and after files so you can hear it for yourself. I’ve included mastered and unmastered versions of the mix for a better idea of the actual changes you get from this mod. The files with 5532 in the name are the original chips.
http://www.mediafire.com/?6tr4s9uf2t46u
This Mod requires no changes to power supplies and is very easy to perform. I ordered the 8 pin dip package version of the Burson audio Dual op amp. The replacement chips are actually discrete little pc boards (and not chips at all) and use matched transistors and 1% resistors.
The people at Burson have an amazing product here and have gone way above the call of duty each time i’ve interacted with them/I’m very impressed by their customer support.
http://bursonaudio.com/DIY_HD_Opamp.htm
You can literally just pull out the 5532 chips in your Summing cards and plug these into the existing chip socket (noting the little notch out on the chip socket and just putting it in the same way…. Incredibly easy) . Since the sockets are laying vertically however they have a tendency of wanting to let gravity have its way and want to just fall out of the sockets. I didnt like the idea of a socket going into another socket sonically either, So i opted to unsolder and remove the original chip sockets from the summing card and simply solder the (much nicer milled socket) burson Op amps directly onto the pc bord. Problem solved. Whole console sounds better. and we can brag about our discreet modded output of our console.
Incredibly affordable, great sound, super easy to do. Had to share it with you guys. Also note… i doubled the capacitance value of the original caps ( 220 uf to 470uf) and added a very high quality 1 uf poly film cap on top of each cap ( >400 Volts per microsec which is 40 times faster than a fast audio chip!) that allows the highs to pass through a little cleaner. The caps did make an additional difference for the better and was more of a pain in the butt to do then the swapping the chips.
Make sure you have a good solder sucker and a really small tip, temperature controlled soldering iron handy for this job. Or just call a good tech like Gwyen who does if you are uncomfortable with this.
Next project (which Jo is involved with as well) is getting a custom 16 channel passive discreet summing box finished with remote controlled (custom motorized 5 gang pot) parallel master buss. My wallet shivers everytime i think about it LOL.
With love and respect for my S12 brothers!
Shawn
 "Pin It")
Love and respect to you too for sharing! I'm downloading your mixes right now. Forgive me, but where is this summing card located?
The summing cards are located in the rear of your execution rack. Look directly above your "pat send & pat rtn 1-8" D sub connecters and you will be looking at the middle of the 8 channel summing card. Sum 1 and Sum 2 is your multitrack outs 1 and 2. The 5532 chips at the bottom are the ones i replaced with the Burson Audio op amps. You'll hear the results in the mix example files. I also intend on replacing all the program buss outs with the Bursons as well. Sonically i am only gaining and losing nothing with this mod, at least to my ears.
Shawn you're an inspiration!
Thanks Man!
I have another project brewing as well. i will probably be making some little pc boards to switch the gazillion coupling cap stages for the channel strips to DC servo . which means you can remove all dc blocking capacitors from the channel/signal path and replace with the DC servo circuit .
DC servo circuits balance the DC offset so your chips are running perfectly balanced instead of using blocking capacitors which just block the DC out like a filter. This will clean up the signal path immensely (GOD only know how many blocking caps there are in even one channel of the S12) Of course you can do some channels and leave others alone for different tones. If you are like me , you short load your console (dont run all of your channels) which means you could easily have 8-16 channels of dc servo channels and the rest stock or whatever you need, just plug in the ones you want for a particular project. Let me know if you guys are interested in this, because i can put a larger order in for the little custom designed pc boards. They wont be very expensive. I cant leave well enough alone!
After that i want to clean up the high band eq a bit (which maybe just replacing a chip with the discrete mod above) , i'll dig into that later.
Wow Shawn, I just realized that I had not seen this great great stuff!
Congrats for these mods, and huge thanks for sharing them with us, I'm definitely willing to try them !
Did you do the DC servo mod yet ?
Another very big upgrade for a S12 would be to replace the noisy switching PS by linear ones (I think only Paul's desk and Rainbow's desk have linear PS's), but that might not be so cheap, and of course there's the power consumption and heat! :-P
I havent done the DC servo mod yet, but i have a big post coming soon with a serious mod to the EQ section of the board which uses all poly styrene Caps (the best sounding caps there are for an EQ circuit. i found some almost impossible to find 20,000 pf, 8200, pf ( pico farad) 1960's' soviet mil spec stuff. Big difference in grain on the EQ, much smoother high end and no swoosh or whoosh phase sound when boosting and cutting lows and mids.
I've done 24 channels so far. Also i have recapped using Nichicon Muze KZ and Elna SILMIC II caps in some channels as well as used Wima film caps in parallel to bypass the Electrolytics. there are a large number of the Electrolytic caps ( probably like 100 or so on a channel! ) and many had to be bypassed. Transients are amazing now on the film cap bypassed channels, snares with more pop, overheads with much more accurate sounding resolve and transients. I thought that the chips were the limiting factor in this console and while i have had positive results with a few different chip swaps ( especially swapping 5532, & 33078 with the fabulous LME49720 chips in certain sections) the caps and bypassing some of them with small value film caps made a bigger difference.
the ELNA SILMIC II caps sound great in the coupling stages. i have a bunch of channels with Panasonic FM caps as well to compare, and while they ( the Panasonic FM's) sound very good, they are not in the same league as the SILMIC II caps.
I do have linear PS supplies with my console. Honestly , well designed switching supplies are not bad at all. Unless they dropped the ball on design, your switching i would leave them alone (or do a recap at the very least) .
Dont worry about the consumption of the linear supplies, its not that bad to be honest.