Ampex MM-1000 Story...

[Muckelroy]

Well hell, it's about the size of a mid-size sedan engine, so it does not surprise me that it has measurable, sealed chambers where fluid is housed, much like transmission fluid or transfer case fluid on a vehicle!

 

[sweetbeats]

Biting the proverbial bullet...

Looks like there is some debate about the viscosity of the reel idler flywheel fluid...not going to worry about it as mine seems to be working good, but I definitely need to get something for the motion sensor switch actuator housing (the paddle). May see if I can get a sample of the 10,000cst fluid and see if it is similar to what came out...10,000cst is roughly equivalent to Karo Syrup which sounds about right for what I intuitively think should be in there. I did find a source of small quantities of Dow Corning 200 fluid...

Brief sidenote...the mounting panel for the two additional 39V regulated power supplies for channel 9~16 electronics will be on its way here in the near future as well as another remote carcass. Between my exisiting carcass and the second one soon coming I hope to make a complete remote...noticed recently that the remote cable and connector on the remote are not the same as the one on the MM-1000 chassis. This supports that my MM-1000 may have originally been an 8-track. The one on the console is smaller...not sure what I'm going to do about this but I can't really be concerned about it at this point. Anyway, all that's needed for conversion to 16-track after those parts arrive is the missing harnessing. Hoping a source for that will come to my attention.

I had my machinist friend make up a set of reel spacers for precision reels. They are identical to the four I have but are 0.050" thinner. This is what I calculated would be needed in order to have the lower inside flange surface of a precision reel at the same height as a standard reel. Here is a standard spacer on the left and the new special ones on the right. This will take care of my problem of tape rubbing on the lower flange when using precision reels:

I'm also having my machinist friend make up a spacer so I can use the rotary guide off of a 440-8 as the incoming guide to the headcover, and a special base for a standard 1" guide so I can replace the static guide just ahead of the erase head with a rolling guide. I'll have to drill the headblock platform for the guide but that'll be easy, and it should reduce flutter.

Got the pinch roller off again tonight to prep it for shipment to Terry Witt to have it rebuilt.

Also I......removed the capstan motor and shaft assembly. Wowwww is what I have to say first. Second, it was pretty easy to remove. My wife helped with the last part so I could just hold the assembly and she removed the last two bolts so I could keep the assembly steady in case there were any shims installed. There weren't, but better safe than sorry.

It took less than 20 minutes to remove the assembly.

First you remove the headcover which requires a 7/64" hex-socket wrench (or allen wrench) for 5 hex socket head cap screws. Here it is without the head cover:

Then you remove the headblock which just requires a 5/32" hex-socket wrench for four bolts...and of course don't forget to unplug the heads!

Then go underneath and remove the captive barrier strip wire terminal from the terminal block as well as the two wires going to the start capacitor:

That leaves the four 5/32" hex socket cap screws for the capstan assembly exposed. You can remove two and then get your helper to remove the other two while you hold the assembly steady from below...and don't forget to wrap the capstan shaft with masking tape or similar to protect it! Here it is ready to be removed:

Poof! Its out...

And here it is...I put an AA battery on it for scale. When't the last time you saw one of these?

That aluminum plate with the four screws covers the motor pulley and the belt...its been a big mystery to me what that mylar belt actually looks like...do I open it up???

OF COURSE!!

Check this out...indeed it is a mylar belt. I had always pictured it as a composite but nope...just...mylar. Amazing.

The main reason I wanted to take this assembly out is to assess the bearings, but you know what? Even though the thing makes a racket in the machine when powered up, it is smooth as velvet when out of the machine...I've heard Ampex quad VTR's in a couple of youtube videos and their capstans sound the same, so I'm likely to leave it alone...I do want to check the belt tension and clean up what I can get to, but I'm thinking I shall leave well enough alone since it really is easy to get this assembly out and back in should something arise in the future.

 

[cjacek]

I'm itching to comment on the marvelous descriptions (in words and photos) of the inner workings of a genius machine. I've been inside many TEAC / TASCAM machines, a Revox etc.... but NEVER seen the type of precision engineering and sheer overbuilt nature of a tape deck like this. You guys should really appreciate this thread (as many of the others Cory opened up) 'cause this is quite possibly once in a lifetime opportunity to delve inside one of those beasts, in detail probably never to be seen again. Thanks Cory! This is really a treat of the highest order.

 

[sweetbeats]

More capstan stuff

Looks like something of this capstan assembly was serviced or rebuilt by Ampex, yes? This is a sticker on one of the coverplates:

It runs very smooth, appears to have been serviced at some point, and check now I understand why the manual says (more or less) "There is nothing you can do to service the capstan outside of tensioning the belt. Leave it alone or pay the price!" That flywheel is pressed onto the capstan shaft in a mighty-mighty way...I'm not EVEN going to consider removing it...plus its balanced...nope. I usually cast the "no user serviceable parts inside" warnings to the wind but I think I better heed this one. If I ever get desperate I betcha the shop press could get it apart but its working well and looks scary. Same thing on the motor flywheel...its balanced and fixed to the motor shaft with two set-screws and looks so nice and smooth when it spins. I'll clean the stuff up and put it back in. Done with that. Here's the underside of the capstan flywheel:

And here's a video of the two flywheels and that mylar belt in action:

YouTube

Also, I went ahead and pulled the viscous flywheel out again. I've been dialoging with somebody that has experience with these things and they said that (based on my video of the inner workings of the flywheel) it appears to be functioning correctly but the bearing really should be submerged in the fluid...helps to diminish noise and enhance the damping effect. Do it right, do it once. Its been bugging me, my impression that the fluid level is low. It looks as though the fluid viscosity may be something more like 200cst vs. 50,000. I'm going to do some subjective testing to narrow in on what grade it might be. Plus I have an email out to a Dow Corning 200 fluid retailer to ask if I need to get every trace of the 80/90 gear oil out of the motion sensor actuator housing before filling it with the silicone fluid. Hope I don't. I'm sure I can get it apart but I'd rather not mess with it.

ALSO...the pinch roller is on its way to Terry Witt for a rebuild.

Git 'er dun.

 

[dodgeaspen]

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

Looks like there is some debate about the viscosity of the reel idler flywheel fluid...not going to worry about it as mine seems to be working good, but I definitely need to get something for the motion sensor switch actuator housing (the paddle). May see if I can get a sample of the 10,000cst fluid and see if it is similar to what came out...10,000cst is roughly equivalent to Karo Syrup which sounds about right for what I intuitively think should be in there. I did find a source of small quantities of Dow Corning 200 fluid...

I was thinking the fluid that comes out might be a little lighter then the new because of the age and the years of the change in temperature. Or am I totally off the mark on this one?

 

[sweetbeats]

I'm itching to comment on the marvelous descriptions (in words and photos) of the inner workings of a genius machine. I've been inside many TEAC / TASCAM machines, a Revox etc.... but NEVER seen the type of precision engineering and sheer overbuilt nature of a tape deck like this. You guys should really appreciate this thread (as many of the others Cory opened up) 'cause this is quite possibly once in a lifetime opportunity to delve inside one of those beasts, in detail probably never to be seen again. Thanks Cory! This is really a treat of the highest order.

I'm glad some of that impact is coming through because its an experience for sure on my end. Some thing for me. Been all through the Tascam 48, 58, 388...spent plenty of time with my BR-20T too...and those have LOVELY precision parts and they take up a little less space and are refined performers...impressive in their own way for sure...I really love the to-scale size of the precision parts on the 388. Fantastic stuff, but this Ampex beas is a really unique experience...if I had a nickel for every time I've muttered "aw no way..." as I go through this thing.

I was thinking the fluid that comes out might be a little lighter then the new because of the age and the years of the change in temperature. Or am I totally off the mark on this one?

Dodge, the reason the silicone fluid was chosen is precisely because it doesn't break down over time and has extremely stable performance regardless of temperature. It does what it does because it just does.

[EDIT]

I have it on authority from Jay McKnight that Ampex snarfed the idea of the viscous flywheel from the film industry...motion picture cameras had been using these viscous flywheels on the soundheads for many decades prior to Ampex incorporating them into their VTR and ATR transports.

 

[cjacek]

Cory, can you see any (obvious) evidence that the guys who put together the MM-1000 cut corners to meet a price bracket or is this generally a "lets build the best tape deck, money is no object" project? Certainly looks that way. This is a bygone era and that's why this thread is so special, especially for those who appreciate engineering art. "aw no way..." is right.

 

[sweetbeats]

Cory, can you see any (obvious) evidence that the guys who put together the MM-1000 cut corners to meet a price bracket or is this generally a "lets build the best tape deck, money is no object" project? Certainly looks that way. This is a bygone era and that's why this thread is so special, especially for those who appreciate engineering art. "aw no way..." is right.

Hm...I don't know if there is a really straight-forward answer to that...

But let me see if I can spew enough conjecture and supposition to shed some light on it...my opinion is:

Machines like the MM-1000 were built before there really was such a thing as a "home studio". Products still had to be affordable, but Ampex's customer-base were large corporations as well as professional studios which, by in large, weren't project or home-based...and I believe Ampex moved a lot more video equipment than audio equipment but I may be wrong about that. My point is that I think on average what the customer wanted and needed was absolute reliability. When CBS ordered 'X' number of quad VTR's that absolutely had to run without a hitch 7 days a week there was a certain expectation that they would indeed do so with a minimum of fuss, and customers accepted that there was a price to pay to meet that need.

I argue that an increase in precision and engineering quality (whether mechanical or electrical in this case) will have a corresponding increase in reliability and performance...these are facets upon which the Ampex name rested and so it was of paramount concern for Ampex Corp. that when somebody needed something that would run and keep running like an Ampex, they could come to them to get what they expected. That high degree of reliability comes at a price and I have a sense that the market accepted that and, requiring that quality and reliability, demanded it and expected to pay accordingly for it.

I think, in general, when you look at engineering standards in any high-stakes arena you will find wider margins...for instance if the standard load is 'X' then the unit will be designed to operate at 2X, or maybe 3X or possibly even 4X before failure. But when the customer says I need 'X' and it must absolutely run then all the folks wearing labcoats at Ampex (and there were lots) determined the margins and the margins were big...there was just a different vantage point and market...it wasn't a matter of necessarily cutting corners to meet a price-point or antithetically neither was it a matter of going all-out to have the ultimate money-is-no-object machine of the day...I believe it was an application of period engineering standards appropriate to the product application and customer expectations. The priority was on non-stop performance and reliability rather than price-point and the market culture accepted as well as demanded those things, and, rather than compromise the margin to make products affordable it seems Ampex developed scalability into the product range...for instance the customer could get an MM-1000 8-track that could be upgraded to the 16-track version at a later date for a fraction of the initial buy-in as funds allowed. You'll see this with ANY of their professional open reel systems.

Ampex had many different product ranges though too, both consumer and professional. The MM-1000 was in the professional range of course, and the level of margin you are seeing here is similar to what you will find in their other professional lines throughout their history...the AG, MR, MM and ATR series machines...others as well like the VR and VPR video machines...the FR data machines...you get the point.

To muddy things I think it is important to include here, again, that the MM-1000 is a bit of a maverick machine. It is a juxtaposition to the picture of the "labcoat" Ampex since the MM-1000 is a converted quad VTR, but again the transport itself is very "labcoat" from an engineering standpoint, and the electronics are as well being from the very capable and popular 440 series which lived on in a very real way through the entire MM product run right on through the legendary MM-1200. Ampex audio was, as I understand it, very "labcoat" but also very "custom-shop", and there were also internal struggles between engineering and marketing (not unique), and that coupled with some controversial decisions of project management placement put, on many occasions, Ampex in a position of scrambling to keep up with competitors and, at times, rushing things to market that didn't have an integrated birth at the development level. This (again my opinion based on my understanding) is part of why the MM-1100 had issues initially. Again, these were worked out over time and typically the MM-1100 you find in operation today has had Ampex authorized mods executed...the same mods that were built into the MM-1200.

My point with that last bit is just to paint the picture that Ampex was a pretty unique company in that era both in how and why they developed the products they developed and the unique mixture of dynamics at play in those processes. In a way I see the MM-1000 as sort of representative of the excellence and the dysfunctionality...extreme excellence and "margin" can cover dysfunctionaility.

Hopefully this doesn't offend anybody. It is all my opinion based on information I have absorbed as of today and it may be totally off since I was not there. Furthermore it is in no way meant to disrespect Ampex or the folks that designed and built these amazing machines. I'm very small and hold the makers of this stuff in very high regard. You can judge the plant by the fruit that it bears. This is very good fruit, but unique too and not without an idiosyncratic sheen which sets it apart gives it a personaility I like.

 

[cjacek]

Leave it to you, Cory, to write out a thesis based on a simple question. ... It's all good tho 'cause it all comes from a burning passion that you have for those things and it shows. Your explanations are intriguing and eye opening. Good stuff.

Yeah, my personal belief is that the MM-1000 and the likes of it represents an era that will never be. Who and which company, in their right mind, today, would seemingly go all out, sparing no expense, creating something which, in essence, all does is pull tape? OK, simplified, sure, but you get my drift. It's unreal, the machine you have. Initially, it just looked like a behemoth but then when you started peeling away the layers, well.... I can now see what you have there and it's indeed special. Keep at it my friend.

...

 

[sweetbeats]

Leave it to you, Cory, to write out a thesis based on a simple question. ... It's all good tho 'cause it all comes from a burning passion that you have for those things and it shows. Your explanations are intriguing and eye opening. Good stuff.

Yeah, my personal belief is that the MM-1000 and the likes of it represents an era that will never be. Who and which company, in their right mind, today, would seemingly go all out, sparing no expense, creating something which, in essence, all does is pull tape? OK, simplified, sure, but you get my drift. It's unreal, the machine you have. Initially, it just looked like a behemoth but then when you started peeling away the layers, well.... I can now see what you have there and it's indeed special. Keep at it my friend.

...

Well...heheh...you asked. And you know full-well that's the kind of crap swimming around in my brain all the time anyway.

The reality is that it was a niche market then...there are niche markets for everything, even within analog tape machines today. There was a gentleman on the Ampex List recently asking if there exist a source of master tapes for reproduction on his 1" halftrack deck.

I think that's what's been one of the most fun facets of working on the MM-1000 is peeling away the skin on these (by common present-day standards) grossly over-engineered bits...It DOES look somewhat crude at face-value and basic, and then you start going beneath the skin and up starts the "aw, no way" mutterings. Again, its not for everybody and there HAS been a learning curve with the Ampex machines. They require a different approach than my work with Tascam machines and it really took me awhile to get comfortable with the language used and the layout of the technical documents and then just to get comfortable with how the machines are built and what is really critical and what shouldn't be meesed with. I've found there is a much lower threshhold for going maverick. IOW on Tascam machines, for instance, there have been several "bro' I wouldn't do that" moments and I did them anyway...maybe not smart but in most cases I had confidence going into whatever it was and couldn't understand why people were afraid of it and the outcome was good. With the Ampex machines "bro' I wouldn't do that" just plain means "don't" and that's been a learning process for me. I guess its kind of like this: with a wider engineering margin comes a more narrow margin of how to treat that facet in order to maintain the performance or reliability factor gained by the wider margin. Its just different, and certainly I'm likely over-thinking it compared to the average person, but that's just me too.

 

[cjacek]

Well...heheh...you asked. And you know full-well that's the kind of crap swimming around in my brain all the time anyway.

Hey, at least you've got a healthy outlet here, on this forum and people appreciate it too!

The reality is that it was a niche market then...there are niche markets for everything..... even within analog tape machines today.

Very true but I doubt there's really something which matches the "grossly over-engineered" nature of the MM-1000, even what ATR Services comes up with. OK, maybe the electronics are more "advanced" but the sheer "balls" of it, I'd give it to the MM-1000. Maybe I'm wrong but that's my feel for it.

I think that's what's been one of the most fun facets of working on the MM-1000 is peeling away the skin on these (by common present-day standards) grossly over-engineered bits...It DOES look somewhat crude at face-value and basic, and then you start going beneath the skin and up starts the "aw, no way" mutterings.

Yup, that's precisely my thoughts too. At first it looks like a grossly overbuilt, industrial like, work-horse of a machine but then you go beneath and it's like "wow".

 

[sweetbeats]

Just ordered two grades of Dow Corning 200 fluid...might be a couple weeks before it gets here. When I get it I'll do some subjective tests to determine if I need to completely disassemble to motion sensor actuator and clean it of the other oils I put in there.

 

[cjacek]

If it needs to be disassembled and cleaned out, is it a complicated matter or pretty straight forward? I hope it's not a major setback?

 

[sweetbeats]

Well, first off let me just say I wasn't at peace with leaving well enough alone on this one...going to all the trouble to locate and purchase the fluid (which ain't cheap) and then to fill the assembly up and *maybe* have it not work out??? Naw...

It came apart pretty easy...more wow...pictures later. Not going to take apart the very last part which is the shaft and bearing inside the actuator housing but that assembly is out of the bi mounting bracket and the cap is off the actuator housing so I can see down in there. Its a decent-sized unshielded ball bearing like the one in the middle of the reel idler flywheel and I'd need a fancy set of c-clip pliers to get that one out just because of the tight access and relatively long throat. The bearings feels fine.

HERE'S THE TRICK...

Does anybody have a suggestion as to the best cleaner to use to dissolve and remove all the previous fluids?

I can fill the housing up with cleaner and mechanically rotate the shaft and bearing to really work all the old stuff out and there's no dirt/rust/stubborn stuff...just old silicon fluid, gear oil and turbine oil mixed together in a pungent slurry... Basically just "oil"...I know gasoline takes care of pretty much anything but I think that leaves quite a bit behind...thinner? Denatured alcohol?

 

[TheGuitarMan]

Well, first off let me just say I wasn't at peace with leaving well enough alone on this one...going to all the trouble to locate and purchase the fluid (which ain't cheap) and then to fill the assembly up and *maybe* have it not work out??? Naw...

It came apart pretty easy...more wow...pictures later. Not going to take apart the very last part which is the shaft and bearing inside the actuator housing but that assembly is out of the bi mounting bracket and the cap is off the actuator housing so I can see down in there. Its a decent-sized unshielded ball bearing like the one in the middle of the reel idler flywheel and I'd need a fancy set of c-clip pliers to get that one out just because of the tight access and relatively long throat. The bearings feels fine.

HERE'S THE TRICK...

Does anybody have a suggestion as to the best cleaner to use to dissolve and remove all the previous fluids?

I can fill the housing up with cleaner and mechanically rotate the shaft and bearing to really work all the old stuff out and there's no dirt/rust/stubborn stuff...just old silicon fluid, gear oil and turbine oil mixed together in a pungent slurry... Basically just "oil"...I know gasoline takes care of pretty much anything but I think that leaves quite a bit behind...thinner? Denatured alcohol?

If you can drain much of the fluid out then flush with mineral spirits, that might work. Might take a few flushes though.

 

[sweetbeats]

Most of the oil concoction has been drained for awhile now, ever since I realized my brew wasn't going to work...mineral spirits...is that the same as paint thinner?

 

[TheGuitarMan]

Most of the oil concoction has been drained for awhile now, ever since I realized my brew wasn't going to work...mineral spirits...is that the same as paint thinner?

It...can be. Mineral spirits is mineral spirits, but "paint thinner" can be made of 100% mineral spirits OR it can contain reclaimed solvent, i.e. used but filtered, and thinning agents. So paint thinner, while containing mostly mineral spirits, isn't necessarily that pure.

Maybe I'm paranoid, but I'd go for pure mineral spirits in such an application.

 

[cjacek]

Paint thinner is nasty sh*t. I wouldn't use it.

 

[sweetbeats]

Righty-o, gents...mineral sprirts it is then!

 

[sweetbeats]

I gots the fluid...

200 and 10,000 centistoke Dow Corning 200 silicone fluid. 8oz of the former and 4oz of the latter. Haven't opened the box yet...don't know when I will but I'm pretty curious to see if this is the right stuff to get the reel idler flywheel and motion sensor actuator up to snuff...gotta get some mineral spirits...