Audio mixer fix...

[DrWho]

Wow, looks like a lot of fun. So what's happening to these consoles after you finish with them?

[Daddy Dee]

Very cool, Marvel.

Thanks for documenting the fixup.

[colterphoto1]

Groovy fixes Bruce- dig the crazy grommet thingies! Very nice job on restoring some electronics. We're going to have to get you some gigs!

That 4 band with PEQ is extra special. Check the wiring if you use any channel inserts as I know Allen & Heath (another Limey board) are wired BACKWARDS of the standard TRS configuration.

Now you going to start collecting some Klipsch PRO and amps?

Michael

[Marvel]

Not sure what I'll do with them. I'm a bit of an equipment junkie, but have been trying to simpify my life. The smaller mixer I will probably keep, just to have on hand. Sort of wanting to have smallish P.A. fur use with my acoustic, but I'm not exactly giging anywhere. THe larger one I might try out on my ADAT. Or the smaller one too. They both have direct outs, and the smaller lets you switch between a mix out of sub groups, effectively making it a four buss mixer.

The inserts on these are wired exactly the same as my Alesis mixer according to the manuals. Also checked on some Yamahas, and they are all consistent. I'll just have to try plugging in an external piece and see how the work. Always nice to know BEFORE a gig or people come over.

[Professor Thump]

Nice Work Marvel! It sounds like you fixed some design flaws in the power supply connection.

Are those 100 mm Alps faders on the boards?

[Marvel]

PT,

Thanks! I'm not sure the connection is a design flaw or student workers abusing it. Although I have some mic cables I made over 20 years ago that still look new, and I used them all the time. I just didn't let anyone else coil them up at the end of a gig.

They could be Alps faders. Definitely 100mm, which is a plus. Our A/V guy at work hated them, but it certainly makes it easier to move a group of them at one time (if they aren't feeding a sub group, of course). They are very smooth. I should have paid more attention to them when I had it opened up. I'm not too inclined to pull off all the knobs and remove the screws again if I don't need to. [:|]

It's really quiet. It would be a pain to service with the single board and surface mount ICs.

Bruce

[DrWho]

I've mixed on that console a few times and felt the same way about those "slippery" faders...we used to flick the faders to see if we could get them to land at unity (while it's muted of course). They're so loose, you can get them to bounce off the top and come back down. The newer A&H boards are still real smooth, but I remember that particular board being a bit harder to mix on because of it. Though part of it might have been the fact that the band I practiced with was using a Mackie at the time, which is totally the complete opposite.

The mindset at shure is that it's a design flaw if someone, or some monkey, can find a way to break it...I think your new power jack is gonna last a whole heck of a lot longer than the stock one.[Y] Heck, you could probably hang your mixer from the power cable now []

[Marvel]

The LX7 got replaced by an A&H PA series for th eroom where the drama dept. has productions and a Mackie 1604 was replaced with a GL2200 24 input went into our chapel. The chapel gets used for other shows and larger performances. It's an asymetrical cavern that seats about 800 (not sure exactly what the seating is).The Allen & Heath equipment is pretty nice. We still have a 32 input Yamaha in a case somewhere. New hires seem to always want something else, insead of learning how something works.

I plugged the LX7 into my system with the LaScalas last night. With all the input gains up, all faders at 0, routers to one of th eoutput groups, sitting on my couch I can't tell it's on. Newer gear should be even quieter. Missing one knob and the pot for the talkback level feels loose.The Spirit SX is just as quiet.

[Don Richard]

Great work! Soundcraft is known for making fine sounding boards, and the ones you have were certainly worth salvaging[Y]

[Marvel]

Thanks, Don. ALL I can find wrong with the LX7 is one knob missing, and one other rotary pot (for the talkback level feels a little wiggly, but it still works fine and there is no noise from it. I think this boils down to... It's old, and newer is better... I haven't read the manual to learn how it really works so it sounds like cr@p... I really want to get some newer toys in here.

One of the students who works for this av guy told me that the mic preamps were worn out. I almost couldn't keep a straight face. The input gain controls are fine. He said they had to turn the controls all the way up to get enough gain out of the wireless mic's. Perhaps they could have also adjusted the output of the receivers, but I wasn't going to tell him that. This is the same guy who said that the silk dome on his tweeters covered the actual diaphragm [*-)] and that tube mic's work by the vibration of an element in the tube. [:#] Whew! Some stuff he does really well, and his mixes are usually fine, but his actual understanding of how this stuff works just baffles me sometimes.

Now... if I could just find a Fostex E-16 for the same price and in as good a shape, that would be cool.

[DrWho]

lol, you're way too nice Marvel....someone should find that kid a good book - either to hit him over the head with or learn him something new []

[The Dude]

I like the fact your able to go in a figure out your self what the problem was. I am recently trying to figure out a problem on a harman/kardon 2 channel power amp, which i am stumped on but I also dont have the experiance you do either. You showed a pic of the caps I have a hard time making out which one has the top blown off. Im thinking caps could be the possible problem with the amp but don't have fancy volt meter that reads ufs to help me figure out which ones are bad. As old as the amp is it probably would'nt hurt to replace all, but would like to make sure what the problem is before dumping money into. Like how the first thing you did was replace the power supply, I can't believe that for such a big item they used such a small plug. Nice choice of connectors, Ive used that style on amp to speaker connection for pro audio never thought to use it for power.

nick

[Marvel]

I have a hard time making out which one has the top blown off.

The pic I showed already had the cap replaced. I should have posted a pic of the bad cap. It was rather obvious who the culprit was. I would have a harder time with many of the other components on these guys, as they are mostly surface mount. I have replaced surface mount parts before, but it is a little tricky with my small iron I use.

I can't believe that for such a big item they used such a small plug. Nice choice of connectors, Ive used that style on amp to speaker connection for pro audio never thought to use it for power.

It is low voltage and pretty low current, so the small connector itself isn't that much of a problem.

The Neutriks for POWER are the bright blue, and called Powercons instead of Speakons. This is to help keep people from plugging power into their speakers. [:|]

I used to diagnose and work on 3 phase motor controllers for the textile industry.

EDIT: Looks like I'll have to be taking it apart after all. The mutes are acting up. Could be they've been messed with too much, but it may be part of the mute circuit that is causing them to mute at inopportune times. Probably something in the circuit as I can't believe all 16 mute buttons are messed up.

[whamo]

Good job. Very nice. I have a cheesy little Stanton 4 channel DJ mixer that I bought new and it has an annoying little hum to it. Not too much hum but it bothers me. I've heard that the problem may be that the grounds on the XLR connectors maybe soldered to the circuit board instead of going to the chasis. I need to open it up and check it out soon. Mark

[Marvel]

Mark,

Thanks... One would hope that the board ground is also tied to the chassis. Not too likely that they floated the whole board. That would be a fairly simple one to check out, once you open it up.

Spent most of yesterday taking apart the 16 channel mixer, pulling out the three boards and PS module. 268 knobs and as over 50 nuts for the rear jack panel and lots of screws. Cleaned all the board interconnects, and reassembled. Dang... still have the mutes acting up. I guess it could be the mute switches. The PS checks good, and actually has indicator L.E.D.s on the front panel indicating power supply rails are good. I'd like to get this one fixed for sure. Other than THAT problem, it's good.

Bruce