Alesis X2: Everything from repair to upgrades!

[Svart]

Ok since I am the resident X2 guru( I think.. :green: ) and other members are interested about or have problems with their X2s, this thread is for you!

Post your problems with the greatest detail you can and we will figure it out!

I will also try to find links to any thread that has X2 information from myself or others.  I guess eventually it could be a Meta..

I will also post any tips or tricks with the console that I know about or figure out.

[Svart]

tip #1:

take the bus and master channels out of the console.  remove the section of back panel that contains the power inlet.  remove the jumper board connected to the power inlet/bulkhead and the wiring to the master channel.  this board has two connectors, remove them.  cut the connectors off the wires and solder the wires directly to the board.  replace the caps and add film bypasses while you are there.

reason:

these connectors are very prone to heating up due to small amounts of corrosion on the pin/socket and will burn up or lose contact and cause crazy problems which are usually intermittant.

[Svart]

Tip for buyers:

If you decide you want one of these consoles, look at a few of them, don't just buy the first one you come to unless you look inside first.  You want the older REV A boards.  You'll know these because they are a dark green.  The early REV B boards are a light green solder mask and the PCB is almost clear looking.  The later REV B board's PCBs are an opaque brown with very light green solder mask on the trace sides.

The REV A boards came with decent Xicon capacitors for all duties, decoupling and AC coupling.  They had Signetics 5532s and TI TL08x ICs.

The REV B boards came with no name capacitors(which leak like crazy..) for all duties and they had JRC 5532s and various manufacturers of TL08X parts.

I don't know who makes the pots as they are unmarked but the earlier ones seem to be more robust, the later ones have a cheaper feel.  I've not had either one wear out.  they both get scratchy if you don't turn them in some time.  They are typical 16(?)mm carbon pots with threaded metal collars and metal shafts(.25").



TIP for working with the PCBs:

The traces seem to lift really easily when working with parts on the PCBs.  While the boards are very easy to repair, be careful because the traces will break where the eyelets meet the trace and you WILL NOT see the break but the channel might not work.


TIP for troublshooting a channel that seems 6db low:

Check that you are getting a differential(balanced) signal from your source.  As with the tip above, I've found that after I bumped a board while getting it back into the chassis I broke a trace from the balanced ELCO input, MIC or line inputs and you are only getting one of the signal of the balanced signal.  This is usually located around an AC coupling cap that wasn't totally flat against the PCB when soldered.  I suggest you hot glue around their bases as well..



TIP for upgrading the opamps and capacitors:

I've found what I think sounds the best for opamps and capacitors in the signal path.  For the channel strips I found that the signetics 5532 in most applications sounds the best.  I used opa404 and opa2604 in the EQ filters sound pretty good.  I also found that the Nichicon bipolar Muse caps (the green ones) sound the best in ALL coupling applications even without the film bypassing.

[Svart]

Hello again.

I just thought I would drop in my own thread and mention a few things.

I changed out my gyrator opamps to the MC33078 and MC33079 types.  This gives me a smoother sound but it's not quite as detailed.  I find it's more like the older console sounds which helps keep the digital system from being too harsh.

I also changed the summing resistors to 15k from 3k and then bypassed the summing amps on the master channels with JFET front-end DOAs( I used the Big FET bloke/bloak).  You will get slightly worse crosstalk but your noisefloor will drop and you will get a much better freq response.  Once you do this you will need to have your channels switched to the master bus at all times or your impedances will change as you switch in/out channels.  I have found that this will cause your levels to rise/drop on the master bus.  It's a give/take situation.  It worked well for me but be forewarned.

[Svart]

I need to get more information up here since I keep getting so swamped with questions and requests for schematics that I can't keep up..




To recap the main signal chain:

C5,C6 phantom blocking caps

C2,3,13,14,18,21,22,23,30,31,41,42,49,50.  i replaced with 220uf 25v Nichicon Muse ES bipolars.




monitor signal chain:

C39,40,32,45,46.

-------------------------------------------------------------------------------------------


Adding bulk decoupling:

Replace C35, C39 with 1000uf 25v

Replace C37,26,12,11,25,36,33,34 with 100nf polypropylene caps.



Add local decoupling to opamps:

Quad opamp: add 100nf+ between pin 4 and gnd.  Add 100nf+ between pin 11 and gnd.

Dual opamp: add 100nf+ between pin 4 and gnd.  Add 100nf+ between pin 8 and gnd.


This is the minimum amount of decoupling that these channels can stand.  The original design did not have enough and the general sound will be much improved from stock.  I have added much more to the channels but it is not easy or straightforward.  I'll add pictures and such later.

[JoaT]

Came across this by accident.. But cool that there is actually a list of bulk decoupling with cap values in existence!

My x2 has had more and more of panpot scratching (the DC kind, not the normal wear kind), and I will take a shot at adding the decoupling as Svart listed above.

I have ample webspace at my disposal, so I will take some pictures and show the progress as I get to it.

as a token of my sincere intentions (just a hobby of mine, and the time is my primary issue in getting things done) here is the Alesis x2 reference manual as a pdf for everyone to download:

Alesis x2 reference manual, Adobe PDF

I also have a full service manual with all the schematics and modifications + some mails from Alesis to a service tech my board has had it's service back in the day. It has been my intention to get the manual in pdf form for a couple of years now, but I have not had the tools or a chance to use them to do a scan of this caliber (a few hundred pages total).

If I may, I would be very interested to know more about the master channel summing modification Svart has done for his own board.

[JoaT]

I did the decoupling upgrade according to Svart's brief replacement instructions above. I only changed the 10 caps listed on channels, but it did help me get rid of most of the scratching pot issues (a few still scratch, but it's clearly due to dirty pots which I intentionally didn't address now as I wanted to hear what the decoupling recap does). It's difficult to say, but I think the sound of individual channels improved a little too.

I have a photoset of the recap I did. Will put it online once I have documented it so it is useful for people attempting the same. Stay tuned!

I sent PM to Svart considering the opamp part of decoupling upgrade. Seems that he hasn't been logged in hear in months.

Also, I still dream about summing upgrade...

[J Uban]

I have a 95 X2 rev B and I have trying to hunt down some issues. My meter swithing does not work, so I went in to test I saw at one point the -17 had got hot but had been repaired. I have rails all thru the unit, but now all the meters stay lite, no audio and still no functions on the master strip. got any ideas of where to hunt ?

[cmuller0420]

Wondering if anyone can help me out...I am in need of schematics for the x2

Any help would be greatly appreciated!!

Thanks

[Fluff666]

Hi.
I just bought an old Alesis X2 (dont know what Rev
I have some faders (master and 2 busses) and some pots that are "scratchy"
And 1 channel strip there is sound coming in but nothing is coming out through the faders (busses, master, channelstrip) and 3 channels dont work (nothing is coming in)

Any ideas about how and what I should troubleshoot after?? What could it be?
Besides that the board sounds great.