MCI JH-636 Story

[janob75]

It is in the spirit of perfection that I am thinking of doing sweeps so that all the modules sound exactly the same.

 

[janob75]

What about the -18V rail?

For bench testing purposes you really don’t need to modify the +15V supply to +18. The additional +3V is only going to provide a little additional headroom which is not necessary for function testing.

Can you not do sweeps and other tests with the modules in the frame?

+ and - 18V at 6A of course.

 

[janob75]

It's much more complicated in the framework. We break our backs and handling is more difficult with the module on the extension catre. I don't trust.

 

[man-bot]

Well - I'll get in on the fun too!

Been a while since I have been on the board - still using my MS16 and Soundcraft Series Two... but I took the plunge and purchased an JH-636 about a month ago.

It came out of a studio close to me (that uses a 500 series now) - and was restored and maintained by a well regarded local tech - so I imagine it should be in pretty good shape and run quite well. Just need to get my studio space redone and then I can move it in. Will likely sit at my warehouse for the next 3 months - but then I'll get it installed.

Gives me time to clean the channels, restore the wood end panels, recover the arm rest and get soldering wiring to Tuchels... fun times ahead!

 

[sweetbeats]

Nice!

I like the pre-Sony JH-600 consoles…looks like a nice straight desk. Any Vari-Q modules? Do you know if the power supplies have been serviced? What will become of the Soundcraft?

 

[man-bot]

There were 2 Vari-Q modules included. The desk has 36 channels, but only 2 digitizer boards - so the final 4 channels have had the faders modded to operate - but no SIP or mutes. The rest are the standard EQs. Would love to find some Troisi EQ modules to try as well. Once I get the beast up and running I'll see how much of a difference the Vari-Q makes and decide from there if I want to try and buy more modules.

PS has been serviced yep, board was recapped 10 years ago and all board functions have been checked in the last 6 months. I imagine there will be a few gremlins, and I will check each channel thoroughly on installation (mic pre, EQ sweeps, routing etc...) but I don't think I'll have a ton of work outside of the initial cleaning and some cosmetic cleanup.

The Soundcraft I am hanging on to - I purchased it about 15 years ago dead and have put a lot of love into it. Its a cool board, runs off a 40v supply, fully discrete, transformer based mic pres, P & G faders. A little limited in the EQ dept (the parametric EQs are OK, but IC based - whereas the fixed EQ is all discrete), the molex connectors are forever causing issues... but I just like it.

Eventually the MCI will move off to a commercial space/creative clubhouse (likely in the next 5-7 years) if/when I wind down my business and then the Soundcraft will remain my board at home (or maybe the cottage). Thats kind of the plan for now!

 

[sweetbeats]

Sounds like a good set of plans…couple of nice consoles. I was just curious about the Vari-Q modules; not any sort of deal-breaker.

On your Series Two is it modified? According to the schematics the mic amp does have a discrete front-end using six transistors, but that goes into an OPA275, so it’s only partially discrete…and no transformer. I don’t even see a transformer option. Granted that is probably a well-performing mic amp. And the EQ…nothing discrete there either as far as amp stages…all TL072-based, each filter. And it looks like the audio power is 34V not 40V (+/-17V)?

 

[man-bot]

Soundcraft had some silly console nomenclature. My series two is from 1978 - they had a later model called the series 2 as well….

Mike is like this:

 

[sweetbeats]

Soundcraft had some silly console nomenclature. My series two is from 1978 - they had a later model called the series 2 as well….

Mike is like this:

I can’t see anything but ohhhhhhkayyyy that explains it…pre-Harman. I’ll have to see if I can find out more about that. At any rate very cool.

 

[sweetbeats]

Now I can see the pic. I also did some reading in the meantime. Very, very cool. Thanks for being gracious with my ignorance.

 

[man-bot]

All good man - zero ignorance! I think with the quality of posts you bring to this forum its easy to see you don't approach things in a negative light - so was definitely not taken that way.

Was posting form mobile so the image was being a bit funky!

Anyhow - its a fun mixing desk, I had zero idea about it when I bought it... thought it looked cool and was the right price. Turned out to have some nice features and sound.

 

[man-bot]

Finally powered the MCI desk up yesterday. Has all but 2 of the channels removed, but master channel and faders installed and.... faders lit up for about 2 mins and then they went out and its not passing audio.

I know the desk was in proper working condition prior to the move... so will start tracing the 18v feed from the automation power supply to see why the faders not longer have power. I am assuming a fuse somewhere, and perhaps the automation boards in the belly pan need to be reseated...

Unfortunately its at my warehouse/office - so I don't have immediate access when at home - so have to bring the multimeter over and start looking for fuses

 

[man-bot]

Well - got to poke around a bit and it looks like the PSUs both need some work. The 8v console automation is blowing fuses and one of the +18v supply keeps popping a fuse. This is without anything connected to the console. So next steps are a bit of a rebuild and get voltages correct and then we’ll go from there.

 

[man-bot]

Just a followup - the past month flew by!

The person I bought the board form kindly offered to repair the supply - so I am good there!

I had to do some serious teardown to get the board into my basement studio (remove meterbridge, end panel, faders and fader frame)... and did so - and it just fit. Gave me a chance to refinish all of the wood as well.

Now I am just testing everything - a few dead preamps, one fader isn't working correct, but all in all its pretty badass

I'll have my band over in about a week and will run a quick live session and see how it goes!