help with upgrading a allen and heath sr416 mixer

[doulos24]

ok guys I just picked up a allen and heath sr416 and everything works on it, but i'd like to see what i can do to make it the best it can be. I've never worked on anything this large. The boards look good ,theres a lot of room in the case to work with and I have all the schematics cept the power supply. the board is full of tl072's without and I'm looking for a good replacment that won't draw to much current diffrence, but be of lower noise. I'd like to keep the eq sound, but I'm afraid it's not posible since the first tl072 is used for the pre and the first stage of the eq I'd hate to have one eq sound on the low and diffrent sound on high and mids would a dual mono opamp adapter work here? also the faders are stiff 90mm 5k type I'd either like to replace them or bypass them for unity gain fixed resistors and use it as a 16 channel front end and summing mixer

 

[tchgtr]

  I used to own one of these, and it was a nice sounding mixer. My best advice is to leave the ICs alone. They are all soldered in, and it would be quite a job to replace them, not to mention the fact that there is no replacement for the 072 that draws the same or less power, and sounds better.
  Perhaps change the ICs on the buss and output channels to something faster, but why take a chance on messing up a board, and over-taxing the PSU?
  Perhaps look into changing the caps on the EQs, but the EQ can be left out of the input channels, so I wouldn't do that unless you planned on using it for some serious mixing.
    If yours has no xlr outs on the mains, you might think about adding those. That was why I got rid of mine, but I used it for some recordings and the pres sound good on that mixer.
  Your best efforts would be spent in swapping out all the electros with new, starting with the PSU, IMHO.
Didn't mean to burst your bubble, but I have played with chips in mixers a lot and used to own one of these. Maybe you got my old one!
Enjoy!
 

 

[doulos24]

kind of what I was afraid of. If i had the psu schematics i could beef it up, but I dont so thats why I care about getting a close ic. The tl07s draws 3ma of current per chip which is really low compared to newer low noise chips I guess I'll look to just recap it then how about 90mm faders anyone know where i can find 90mm 5k faders?

 

[doulos24]

ok so im going to start re capping the psu and getting some fader lube and see what i have to work with from there

 

[analogguru]

ok so im going to start re capping the psu....

Are the caps blown ?

... and getting some fader lube

Use WD40 or Sonax MoS2 for the faders.  It´s the best for faders - tested - and doesn´t destroy them like contakt cleaners do.  Put a small amount at the top, middle and bottom and move the fader 20 or 30 times up and down.

analogguru

 

[doulos24]

no the caps arn't blown but this board is quite old and I've got some money into it so I'd like to put a lil bit of work in it so it lasts me awhile

 

[sodderboy]

I would not use WD-40 anywhere near electronic equipment except on the door locks!!!  Not even the hinges.
It is a petroleum based compound and it does murder on plastic parts when it gasses in a warm enviornment.
The only chemicals good for faders are P&G fader oil(conductive plastic) or Caig fader/pot conditioner(plastic or corbon).
I have replaced plastic parts in many a piece of outboard because of pikers with WD-40.
Mike

 

[doulos24]

I kind of agree that's why I'm going to use fader lube, but I had an alternative I wanted to ask about what do you guys think if I try to retrofit new 100mm 10k faders in place of the 90mm 5k and add a trim pot and set the top of the travel maxed at 5k? I mix with everything close to unity so I doubt I'd push it past + 10 on the fader the extra .40 inch wouldn't kill me to lose and I think theres enough space the only problem is making a bracket to hold the other screw in place or a strong glue to bind it together thoughts? 

 

[doulos24]

thought I'd give you all an update I've finished recapping the psu and everything works now I'm ready to pull a few channels and look them over

 

[nickeveslage]

Just curious as to why you replaced those caps in the PSU...thought everything was working fine.

 

[doulos24]

it was working fine, but I picked better quality caps I wanted less noise from the psu and since I plan on modding the board it seemed like a good place to start

Your best efforts would be spent in swapping out all the electros with new, starting with the PSU, IMHO

now when I dig in the boad if there is something going on I can't be like well maybe it's the power supply cause I know for a fact the psu is working correctly and has brand new caps throughout