MCI JH-416 Story...

  • Thread starter Thread starter sweetbeats
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That's nice. Thank you.

Its possible that I may impress again in the future, if I have indeed done that in the past. It is, however gauranteed I'll be an ignoramous again sometime...heheh.

Place your bets!!!
 
Its possible that I may impress again in the future,
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You just did. On the M-1000 thread. Absolutely astounding what you are doing. Hey, I just thought of something you might be interested in. I have about 25-30, Dialight momentary push button switches from some kind of pro mixer. I bought them on ebay, but don't really have a use for them. The dress covers are square, but the switch bodys are round.
Anyway, let me know if your interested. Some yellow, some red, some green..er I think. I'd have to look. Oh, one other thing. I still have that parts chassi from an Ampex 440. Has one motor, some electronics, some inner brake hardware etc, and the transport switch panel..oh, some relays and chassi tape path stuff too. You can have it if you need it. Later.
 
I"m new around here, but I've read through all of your MM1000 Story and now this MCI Story. Very impressed with your work. I love old gear that needs help too! I'm hoping to get an Ampex very soon, but I mainly wanted to say that I have 2 of those empty server cases similar to what you got to put your power supplies in. You can have them both but I'm in Texas and not sure what shipping would cost. Mine are empty so they are not too heavy. Power supplies and motherboards are long gone. These are white and not the same color as the one you found but they are here if you want them. I have a great shipping place and I do a lot of web design for them so maybe I could get them to you cheap if you want. Cross you fingers for me running into an Ampex. I looked at an MM1000 here in Texas about 10 years ago but it was rough and the guy wanted $1100. All I had at the time was $800 and he wouldn't take it. Good luck and I'll keep reading about your restorations for sure!
 
Hey kids! Here's one for the "update from out of nowhere" crowd...fabricating the "legs" and a rear cross-member to tie the legs together. These three pieces will make up what is missing as far as the mixer frame goes, transforming it back into a true mixing "desk". I got the measurements for the legs some time back from cadde. The original legs aren't solid...it was easier for me to make them solid...and I don't believe there is a cross-member with the factory frame, but having one will make the frame more sturdy.

I made the sections out of surplus solid-core doors with either 1/8" reject panel or 1/4" plywood to make them about 1.95" thick, which will make them 2" thick with the laminate just like the factory pieces.

I haven't decided yet if I'm going to try my hand and putting laminate on myself or paying the local flooring/countertop shop to do it. What I DO know is that I'm going to use good 'ol early 70's walnut grain laminate...I'm going for a stock look.

Anyway, here they are cut to size...just need to sand them and install some T-nuts and they'll be ready for laminate.

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Cool beans, Cory! :)

Glad to see you working on your studio gear again! ;)

Perhaps MCI went without the cross member piece out of acoustic reflective issues that might be had from studio monitors seeing that as a reflective surface in larger control rooms where the console would be further into the room?

Cheers! :)
 
Not sure if this is helpful or not but I was digging around the web earlier this evening and found a number of images of the 416 mixer where the leg section was an open square design.

See image below:



View attachment 81044

I didn't see any where it was a solid piece but wasn't sure if you were aware of this so I figured I'd mention it here.

Cheers! :)
 
Yeah, Jeff, that's what I was saying...I know they were open in factory form and its just easier to make them solid. You can see they attach it the top and then tag to the bottom of the frame's side panel via that 'L' bracket. I'm sure they were adequately sturdy as-is, but I believe solid form will be even more sturdy, and with a cross-member in the back along the floor it should be VERY sturdy.

I honestly don't think there was any particular reason acoustic or otherwise outside of mayerial cost-saving MCI designed the legs the way they did. The JH-416 was literally one of the very first mass-produced mixing desks and there were decisions made to manage the price point. Using opamp technology was one of them. Up until that time most mixing desks or consoles were custom built in the studio, right? We're talking early 1970's.

Jeff, where did you find that picture of the leg ?!? Please feel free to attach ANY JH-416 related pics to this thread.
 
Yeah, I can definitely see the solid side piece as being more sturdy then the open frame design. I made mention of it only because you had mentioned something about wanting to keep things "stock"...though that was in reference to the walnut veneer.

I found that image while doing a ebay search for all things "MCI", a couple of nights ago. The original image also has a 416 side panel in the image with both pieces laying flat on a slab of concrete. I cut out the leg and straightened it up. ;)

Cheers! :)
 
That open design that Ghost found would be very easy to cut on a table saw - using the slabs you have already cut. As a cabinet maker I would just layout the square on the door slab - say 6 inches in. Set your table saw fence to that inboard measurement less the blade width - usually 1/8". Lay the slab on the saw against the fence with the blade end above blade the and gently lower the slab into the blade. Just back up to the front corner mark and when you reach the front corner push the piece into the blade as you normally would and continue to the mark nearest you. You will have a 1" or so overcut on the bottom but it will not matter because you are going to laminate the parts. Be sure you STOP the saw before lifting the slab up off the saw AFTER EACH CUT. Looks like you are using 1 3/4" slabs. Don't know if you have solid core or hollow. If hollow, just rip up some clean 2x4 stock to the proper inside width and glue them inside the slab core. Use masking tape every few inches to put some pressure on the glue up. It will be a piece of cake.

If you need help doing the laminate work, let me know.
 
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Jeff, can you put up a link to the auction on eBay that had the panel pics? I have a saved search on eBay for "MCI" but somehow missed that!

Danny, it's all solid core from 70's vintage plain solid core doors. Good stuff. The doors were 1.7" to 1.8" thick. I used plywood or reject panel to scab them up to about 1.95" so the finished panels will be just about 2" thick with the laminate just like the factory panels on the mixer frame. I think I want to keep them solid...visually the solid panels integrate with the solid slab side panels of the mixer frame, and then there is the structural benefit; after all this is a unit that weighs about 500lbs.
 
Oh my goodness...THAT listing...totally forgot about that one. The seller has been trying to sell that producer's desk for, like, a year. Started at $600 I think.
 
Do those "start" and "stop" buttons actually control any tape machines? Or are they signals for some other machine operator?

Seems like one of these...
Screen Shot 2013-07-27 at 10.51.56 AM.webp
 
Well, I have to say my recent work on the support structure for the frame has re-ignited some interest in the old JH-416. I was working on those pieces for the legs of the frame because the totally awesome table saw that has been in my shop for the last several years goes back to its owner soon...and since I was doing some cleaning up in the shop and putting stuff on the burn pile it was a good time to take some of that scrap and turn it into something useful before the saw wasn't located so conveniently close to me.

Other things that I'm sort of working on at this point with this console:

  1. There is an idea that was put up by another JH-400 owner on an MCI forum to bypass all of the relay functions on the board. The relays provide global mode switching of the input modules between tracking, overdubbing and mixdown modes. The relays are an issue because they are problematic with age, replacements either aren't cheap, and/or are difficult to retrofit to the modules. What this owner found is that by doing his mod (which is pretty simple and easily reversible), he bypassed a couple amp stages and avoided audio going through the relays at all and he asserts it sounds much better. The downside is there is some reduced functionality, but not significant. So I want to try this out when my console is working, but first I have to see if the mod translates to my specific model (the mod was done on a JH-428), and if it doesn't directly translate, to come up with a translation and then see if the impact is the same as far as function limitation. It may turn out it is impractical, but I'm curious to find out from a paper/logic standpoint first. So I'm working on that. After the paper study I need to power at least one module sans power to the relay buss and test the theory out, so I'm getting ready to decide if I build a simple test-jig for a module, or go the more risky and labor intensive route of powering the entire frame. This will be the first time I hear audio through one of the input modules. If I do the test jig option the test will not include the transformers, and I understand this has a significant impact on the character of the sound. So anyway...
  3. I'm also working on a VERY exciting little project. I've mentioned in this thread somewhere along the way that early JH-416 consoles were 100% discrete...no opamps or integrated circuits of any kind. There were only a few made like this. I know of one person who has one of these consoles, and another that has a number of discrete modules in his JH-416B frame. I always hoped to get some good pictures of the component side and solder side of these modules to see if I could reverse-engineer the discrete amp, but the pics I was able to get proved challenging because there was no way to identify the transistor parts. 4 of the 6 transistors were "blob-tops" that are difficult to identify...the other 2 were metal cans but the owner of the modules was hard to get ahold of to get the p/n's off of the cans. Life happened, the JH-416 project went to the WAYYYY back burner...so I revisit the MCI forum recently and lo' and behold somebody found a set of schematics for the early consoles and put up a jpeg of the input module schematic. The schematic was still created when the IC opamp-based boards were in production, but it has a "Standard Amplifier Block" schematics for two different amps and one is discrete with the label "Used Only On Early Models"l. Shazam. Parts references and everything. So I'm in process of confirming the schematic with the actual module, and working with a friend to determine suitable replacements for the unobtanium or $$$ and hard-to-find transistors. It looks like the pics I have of a discrete module are of one that has been significantly modified, so I'm skeptical of its integrity as far as parts present on the assembly; some stuff ain't lining up. I have been in contact this last week with the very helpful and friendly owner of the full discrete console (of which he came into possession while I was on hiatus from the project). He's going to get me some pics of his modules soon, and since his console is really "glitchy" (with typical age-related glitches) I think it is pretty original (i.e. hasn't been gone-through/upgraded/tweaked...I suspect it is quite original). Bottom line is I'm planning on getting some proto board and parts to build 10 discrete opamps and try them out on a couple channels. The parts would cost well under $4 per amp, and that's for good parts...2% metal film resistors, good quality C0G caps, and robust transistors.
  5. I also discovered that my console is fitted with the optional Cue Boost amps...the JH-416 console input modules are fitted with 5 amps on each module, with an optional 6th for the Cue circuit. I don't know how many consoles were made with this option fitted...maybe it became a fairly standard feature to be fitted...but it simply means my console was fully loaded and it also means I have more spare MCI2001 opamps considering I won't likely fully load the frame, AND even more so if I bypass the relay functionality noted above and negate the need for 2 amps. I don't know how I missed the presence of those amps before; funny. Its not like the input module PCBs are densely loaded. The presence of this option is part and parcel to what I'm finding as far as other options and/or mods on my modules; they are well outfitted as far as JH-416A modules go (i.e. my mid eq circuit is boost AND cut...stock JH-416A modules were boost only and I think mine may have been factory modified to include the cut function; the frequency shift for the hi and low eq bands...early JH-416A modules do not have a switchable frequency center function for the hi and low eq bands but mine does; lastly the mix buss assignment functionality on my board which has modules 1~16 assignable to busses 1~16, and modules 17~24 assignable to busses 9~24...early JH-416A's had modules 1~16 assignable to busses 1~16, and modules 17~24 only directly assignable to their corresponding buss, i.e. module 17 to buss 17, module 18 to buss 18, etc.).


ANYway...this big ol' mixer has an allure.
 
Oooooo...

Sweetbeats hears audio through a JH-416 module for the first time...

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photo%20(1).JPG
 
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Like I expected...terrible.

Caveats:

*It's a device that's over 40 years old.
*The caps are all original and were not good quality from the start.
*It may have been decades since any of it has been powered.
*It was in a storage unit for some years and is FILTHY.
*I've done nothing as far as...anything...lots of metal-to-metal contacts that haven't been even touched, and the sealed relays are THE known Achilles heel of these consoles and I'm sure the contacts are in dire need of service or likely replacement (or bypassing as I plan to do). Didn't even re-seat the opamps.

So the mic amp was clipping well before the top of the gain range, and the further along the signal chain I tapped the output the more distorted or truncated the output became...and I didn't have the relays powered so no way to even exercise the relay contacts.

BUT...that all being said, holy smokes I have NEVER worked with any audio device with the kind of oomph I'm experiencing. This console is +4dBu all the way through the chain. And I was shocked and surprised at how low the noise floor is...it was quiet, and not like for "old and crusty" quiet, it was quiet-quiet. And the quality and type of components fitted...well I would generally expect lots of scratchiness in the pots and in the channel fader...nothing. Clean. And I wasn't expecting the mic amp to have the HF clarity and presence I heard. One of the critical comments of these consoles is the high end. I don't think it's going to be an issue. And keep in mind I was monitoring the output pre output transformer...the trafos will be interesting to experience. But what I'm hearing has me really excited. Recapping and servicing controls/contacts, bypassing the relays and experimenting with building discrete amps...I feel like I found gold. Yes, the feature set is limited by today's standards, but I think this thing is going to sound awesome, and negate the need for all kinds of "stuff" that's in my rack. The signal path of these modules is so simple and clean, and the high power rails...there is no substitute.
 
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