Ampex AG-440B-8 Story...

[sweetbeats]

I don't think JFR has any more of those heads and if he did my guess is that the price of admission would be more (including the other stuff you'd need) than just getting a complete 440-8.

Places like Flux Magnetics could make the heads, but same deal there as far as cost. You'd need the 1/2 8-track heads, 4 more electronics modules, another 39VDC supply, special cabling to get the 120VAC to the second supply and to carry the bias tone from the first to the second (may have to mod the second supply to rid it of the bias oscillator unless you find one already that way), and the head connnectors and cabling, and of course the cabling to connect the second set of 4 electronics to their power supply. I just *happen* to have the power supply and ALL the cabling including the head connector box for 8-track operation (basically everything you'd need but the heads and the electronics) IF you were thinking of doing that , but again the heads would be $$$.

If you were to convert your transport to 1" operation you'd need the above stuff and of course the 1" heads and the 1" headblock or "nest", 1" flutter idler and center guide, reel idler roller/tensioner/flywheel, 1" takeup tension arm guide, 1" reel adapters, and to avoid having to help out your reel motors every time you FFWD or REW you'd need to mod your transport control box or find a 440-8 box in order to utilize the torque delay module and power boost assembly (and you'd have to find those too). Plus there's the first rotary guide in the center of the transport plate above the headblock...find the guide and drill the hole to mount it. Lifters...annnnnd the capstan motor.

I'll stop there. I'm sure you quit thinking about it somewhere in the second paragraph.

Obviously converting a 1/4" ~ 1/2" transport to 1/2" 8-track is a lot easier, but still a *project*.

 

[SteveM]

I'll stop there. I'm sure you quit thinking about it somewhere in the second paragraph.

Yeah, pretty much. I think I'd rather go with something all ready to go.

 

[sweetbeats]

I think I'd much rather SEE you go with something all ready to go.

 

[Muckelroy]

Your first house shouldn't be too much of a fixxer-upper, or you'll screw things up, be bitter, go broke trying to re-fix it correctly, and then sell it for less than you put into it, barely breaking even if you're lucky. Then it'll be that much harder to get into being a home owner again. (This I know.)

Same goes with your gear, I imagine.

 

[pmahern]

I love this thread. I just joined because of your work here. Would it be possible for you to give a part list for your PSU rebuild?

Best - Paul

 

[natrecstudio]

Ampex 440 brake straps

Hi,

Can anyone direct me to a source for brake straps for my 440-4?

Thanks!
Danny

 

[sweetbeats]

Hi there.

I would join the Ampex Mailing List and post something to that listserv and see if anybody knows of any NOS stores or means of repairing/restoring the bands. Another option is to find a parts transport for cheap that has serviceable brake bands intact.

Here's the recordist.com website that has a link to the Ampex Mailing List:

Ampex Virtual Museum and Ampex Mailing List

 

[13volt]

Hello - I was lucky to find your posts on rebuilding the Ampex 440.

We have had a 440/8 in the family for about 25 years. A while back, the transport became erratic, and it has sat unused for a few years.

I'm interested in getting back into service, so we traced the problem to the take-up side brake system: It seems that the one-way bearing (aka "pawl bearing," aka "sprag clutch") is bad. This bearing is pressed into the brake hub.

It appeared in one of your posts that you successfully pulled and replaced this bearing:
Ampex AG-440B-8 Story...

Would you have a source for the bearing itself? I see that the type and form factor used is readily available, but I'm not near the machine so I cannot measure the old part precisely.

Or are there refurbished or NOS brake drums available?

I thought I would make my own puller, but if you have any wisdom to share, it would be welcome!

Thanks again for the posts and any information is greatly appreciated!

Cheers, -Heath

 

[sweetbeats]

Greetings, Heath!

Pretty cool to have a 440-8 in the family for so long.

Unfortunately the bearings I refer to in that post were the motor shaft bearings, not the Sprague clutch bearings in the brake drums.

That post was 9.5 years ago and I parted that 440-8 out about 9 years ago...I can’t remember what I did about those one-way bearings...maybe just cleaned them well and re-lubricated? Or maybe I didn’t get that far in the refurb process to have done anything at all about them.

i do have a faint memory my goal was to find "solid" brake drums off of an original AG-440 (no one-way clutch bearings) and just do away with the clutch bearings all together.

Another faint memory: I vaguely recall finding what I thought might be suitable replacements at VXB.com. They have a pretty large selection of “one way bearings”:

One Way Bearings

I don’t know if any of those would work...I don’t have any way to find out the dimensions of the clutch bearings in the 440B/440C brake drums. Do you know what size they are?

 

[jOn_jOn]

Huh? Me or him? :???:

Steve...okay...we are on the same page as far as the transport. Don't know if you read earlier in thread but I had a laugh-out-loud moment when I realized there wasn't even a counter...talk about getting back to basics, but there is a real allure to that for me personally.

I figure I will eventually get around to replacing all the electrolytic capacitors, but for the time being I'm focusing on those most critical ones as advised by the folks at the Ampex List...It sounds like you have a really fine machine. You may have read I got a hold of a full nearly unused 'C' headblock and matching repro cards. The complete usage history is known and the block was used for two projects and that's it...John French gave his blessing on the assembly being in as-new condition. I'm excited.

I also plan on changing the electronics from NAB to CCIR eq...I haven't looked into the particulars on this yet though I know it involves some simple component swaps on the eq daughter boards...do you have any handy resources on what to change with what?

Mine has the AC capstan motor so I'm running 7.5/15...and I'm not looking to change it to servo. I don't know what the change to 30ips does to the frequency of the head bump or the LF knee point but I figure I'll be happy at 15ips anyway.

Yeah...the cost...I did a rough calculation of what it would cost new in today's dollars and I came up with about $70,000.

Hi Swwebeats,
This is my first post or reply, I am just entering here this question about the capstan solenoid because I am not sure where you mentioned and rebuild or options for replacement. Have you ever had any issues with this or any solenoid on the 440? And would you be able to suggest any options for solving my dead capstan solenoid problems? Thanks so much

 

[sweetbeats]

Never had any issue with the solenoids.

Describe your problem, and have you verified the power is getting to the solenoid and that it sustains under load? Measure the power at the solenoid cool when it is supposed to be energized. It should be at or close to +24VDC.

 

[Jonk]

I'm finally getting back into working on this 440-8 and thought I'd post here, revive this epic thread and ask a few questions.

For the middle roller guide, how do I take the cap off? Rubber pliers? Or do I remove it from the bottom? (hex screw) It needs to be shimmed up a tiny bit so my tape doesn't scrape the bottom of the guide right before the erase head. The supply reel needs to be shimmed up a tiny bit too. Is there a source for some ultra thin cork shims?

Also, my tape lifters are lazy, in FF and RW. From the manual, I gather this is the Solenoid perhaps. What is the voltage that I should read at the Solenoid associated with the lifters. Maybe it just needs to be cleaned. I haven't investigated that yet.

 

[sweetbeats]

I'm finally getting back into working on this 440-8 and thought I'd post here, revive this epic thread and ask a few questions.

For the middle roller guide, how do I take the cap off? Rubber pliers? Or do I remove it from the bottom? (hex screw) It needs to be shimmed up a tiny bit so my tape doesn't scrape the bottom of the guide right before the erase head. The supply reel needs to be shimmed up a tiny bit too. Is there a source for some ultra thin cork shims?

Also, my tape lifters are lazy, in FF and RW. From the manual, I gather this is the Solenoid perhaps. What is the voltage that I should read at the Solenoid associated with the lifters. Maybe it just needs to be cleaned. I haven't investigated that yet.

Hi there.

So I *think* I understand what you mean by “middle roller guide”…so from the supply reel the first thing the tape hits is the “rotary tape guide” right above the center of the head nest…is that what you’re talking about?



After the rotary tape guide tape wraps around the reel idler roller and tensioner, and then it hits the stationary tape guide at the entrance of the head nest, then the erase head etc.

If you’re talking about how you get the cap off the rotary tape guide, I’ll tell you, but then I’m going to caution you not to jump to shimming or messing with that. The cap is just a steel hole plug like this:




I always use a dull putty knife, spudger or similar to go around and lever the cap off…it is just a spring-loaded friction-fit.

There are socket-head set screws on the bottom of the guide in the base for adjustment, but please don’t jump in and mess with that. All of these components were set at the factory for proper tape handling. I bet you dollars to doughnuts the root-cause of your problem is worn and compressed reel table corks. You need to get new ones. It is a special thickness cork with a specific type and thickness fabric backing. You can buy them from David Dintenfass at Full Track Productions:

https://fulltrackproductions.com/subdirectory1/turntable_pads.html

The corks are for a 1/4” to 1/2” machines, so you have to trim them into the rings that go on the 440-8 tables. I have a pictorial guide earlier in this thread for how I did it. But I think this is the first thing you should do and see where things are at.

 

[sweetbeats]

Regarding the lifters, you have the service manual, right?

Looks like the lifter solenoid is energized by +30V. You definitely want to measure the voltage when the solenoid is energized to measure for voltage drop. And you can remove the lifter assembly and make sure it’s not bound up…clean, lubricate….
And while that’s out also check and make sure the solenoid plunger can freely move. You shouldn’t need to lubricate that. So if it’s bound up at all I’d make sure the plunger and plunger bore are nice and clean.

 

[Jonk]

Sweetbeats,

Thanks so much for the info. There is a bit of play in the rotary tape guide anyway, maybe enough, so I'll start with the cork. The amount the tape needs to go north is a tiny bit, less than a mm. A guy on the ampex list said he shimmed his 440-8 reel table cork with industrial steel shim stock.

Anyway, thanks for the tape lifter info as well.

Sweetbeats, I think it is you who has a big MM1000, is that correct? This is another question I'm going to need answered at some point, maybe you've come across a version of these machines that is set up for a remote in between the heads and the electronics? I have these electronics and they need to have a bypass in some way in order to get all the functions going properly without the remote. As I remember, (a long time ago) I was shown a bypass on one of the back plugs (J14), that enables almost normal operation. Let me explain further. I can monitor in input,fine, and even monitor in repro, while recording. But I can't monitor off the sync head for overdubbing. There's nothing coming through. I'll need to open up the electronics and get down into it more after the transport get's (sort of) smooth. But my inclination is there is one more bypass somwhere around J14 that needs to be made to enable monitoring in sync.

Another couple interesting things. I believe my motor is actually 15/30 ips. (I guess this would translate to using the "low speed" pots on the cards during alignment for 15ips??? hmmm) I can't imagine running this thing at 30ips though. Also, I see now my reel idler tensioner is rotated about 90 degrees from where it should be. No wonder that wasn't making sense. Duh. (Might have something to do with my issues)

Btw, this is one of those machines that's been put away for years, that I never got fully running when I bought it, so it's past is a little fuzzy. I've been good about letting it run and oiling the capstan motor. And every once in awhile I'd have another go at it. All the cards are recapped, and the electronics too (except the big silver cans) No power supply recap yet either, but they checked out at 39V last time I checked.

 

[sweetbeats]

Thanks so much for the info. There is a bit of play in the rotary tape guide anyway, maybe enough, so I'll start with the cork. The amount the tape needs to go north is a tiny bit, less than a mm. A guy on the ampex list said he shimmed his 440-8 reel table cork with industrial steel shim stock.

No disrespect to any Ampex List members, but that seems like a strange solution when we know the original cork aged out probably decades ago, and new correct material is available…and for really cheap! Dave Dintenfass is *still* only charging $12 for a pair of the corks.

And on the rotary guide there should be no okay. Get a new set of bearings, get Nachi, SKF or the like…good quality…and pre-load them by installing a small rubber O-ring at the base of the spindle. There will be no play, and it’ll spin like glass.

Sweetbeats, I think it is you who has a big MM1000, is that correct? This is another question I'm going to need answered at some point, maybe you've come across a version of these machines that is set up for a remote in between the heads and the electronics? I have these electronics and they need to have a bypass in some way in order to get all the functions going properly without the remote. As I remember, (a long time ago) I was shown a bypass on one of the back plugs (J14), that enables almost normal operation. Let me explain further. I can monitor in input,fine, and even monitor in repro, while recording. But I can't monitor off the sync head for overdubbing. There's nothing coming through. I'll need to open up the electronics and get down into it more after the transport get's (sort of) smooth. But my inclination is there is one more bypass somwhere around J14 that needs to be made to enable monitoring in sync.

What version is your AG-440-8? It’s a ‘B’ right?

If so, yeah from the factory the ‘B’ versions came fitted with a jumper plug in J14. You have the service manual right? The jumper plug is diagramed on the page with the schematic for the signal electronics chassis circuits…if you can’t find that let me know. And, yes, there was an optional Sel-Sync remote control starting with the ‘B’ version…not common. I have the manual. So the remote plugged into J14 among other things so the mode switching and indicator lamp status could be extended to the remote. The MM-1000 uses this functionality to extend those functions from the signal electronics modules to the control panel.

Another couple interesting things. I believe my motor is actually 15/30 ips. (I guess this would translate to using the "low speed" pots on the cards during alignment for 15ips??? hmmm) I can't imagine running this thing at 30ips though. Also, I see now my reel idler tensioner is rotated about 90 degrees from where it should be. No wonder that wasn't making sense. Duh. (Might have something to do with my issues)

Can you post a pic of your reel idler assembly? I want to see what you’re talking about. And does your machine have the servo capstan then? Or a sleeve on the capstan shaft? Post pics of your capstan shaft and the back of the console behind the transport if you can. Presumably if your machine is factory 15/30 then the EQ daughter boards on your amp cards are fitted with the correct components for correct EQ at those speeds. You can cross reference with the ‘C’ manual for that to see what’s what. If it is NOT factory 15/30 then who’s to say the EQ boards are correct. But it’s pretty easy to check. The daughter boards have a part number suffix…a two-digit revision number that correspond with the machine specs (7.5/15…15/30, etc).

I’ve never messed with 30ips on an AG-440 or MM-1000. All I know is my MM-1000 has the AC hysteresis sync capstan, is 7.5/15, and I’m not changing it. Somebody I trust very much offered the opinion “cal it up using NAB and 15ips and it’ll sound like an Ampex”, and that was a very favorable comment…like the goal was to have it sound like it should.

Btw, this is one of those machines that's been put away for years, that I never got fully running when I bought it, so it's past is a little fuzzy. I've been good about letting it run and oiling the capstan motor. And every once in awhile I'd have another go at it. All the cards are recapped, and the electronics too (except the big silver cans) No power supply recap yet either, but they checked out at 39V last time I checked.

If you have the DC servo capstan I don’t think you’re supposed to oil it. The AC capstan has a bronze sleeve bearing at the nose and a felt oiling washer, and yes that should be periodically inspected and lubricated.

Output voltage on a regulated DC supply is no indicator of whether or not it’s time to recap. If we’re talking about filter caps, given the bridge rectifier is good, a bad filter cap will allow too much AC ripple through at the output. So the first thing to do is always scope the output. If it looks clean, generally on the supplies with the old huge computer grade caps it’s okay to leave them alone. If you want to dig deeper you pull the cap and measure the ESR and capacitance spec. If either are out of spec then it’s not a bad idea to replace, but always start with scoping the output. If it’s clean under load, there’s no reason to jump at a recap. I replaced mine with new 2,000uF 80V Mallory computer grade caps and Nichicon PW parts for the smaller caps. Replaced the bridge diodes, added a bleed resistor to the main filter and also a small value film bypass to the main filter for better HF filtering. All these things were probably just PM…noise floor might be improved.

 

[Jonk]

Thanks Sweetbeats.

Okay, I'll get the corks. Regarding the rotary guide, a false memory I had I believe. Just checked it, and there is no play at all. Hmmmm. So I'll start with the corks.

Attached some more pics. The capstan is AC. This is a 440B.

I have 7.5/15ips repro daughter cards (-01 suffix) so I guess I'm actually stuck at 15 anyway, if I wanna align properly. I'm guessing this means the speed on the transport is set to low, but the "high" pots are the ones I'm aligning with, and I can forget about both 7.5 and 30ips.

When I bought this machine, it was from a guy named Phil (can't remember last name) in Oakland, claimed to have worked with Foreigner, had fallen on his head off of a ladder, had a near death experience, and afterward, had a craving for dairy products. He was drinking Yoo-hoos a lot when I was picking it up. Anyway, he had to clear a whole ton of gear in a storage area and everything took forever. During the process I think he had asked me something like 'do you want the 7.5/15ips or the 15/30 motor?' and made a last minute swap when I said, hell 15/30ips with stars in my eyes. I didn't know enough at the time but were it these days, I would have picked the other one.

I attached a pic of the (booster? circuit)

Another pic shows the only cable that I can't figure where it would plug in. (I'm guessing the missing remote)

 

[Jonk]

So, the slot that the idler tensioner moves in. Should that be at around 10:00 to 2:00, or more like 12:00 to 3:00? Mine is between 9:00 and 12:00 which doesn't seem right.

 

[sweetbeats]

Attached some more pics. The capstan is AC. This is a 440B.

Okay. I’ll ask again, you have the manual right? It’s a well-written manual, and essential if you have an Ampex. For the AG-440B-8 there are actually two manuals…the standard 1/4”~1/2” manual, and the 36-page AG-440B-8 supplement to the standard manual. If you don’t have them, you can find them at the link below. I believe my scans are the best and most complete…tabloid pages scanned in one shot…not broken up, etc.:

https://www.torridheatstudios.com/Ampex/Ampex AG-440/Ampex AG-440B/

I have 7.5/15ips repro daughter cards (-01 suffix) so I guess I'm actually stuck at 15 anyway, if I wanna align properly. I'm guessing this means the speed on the transport is set to low, but the "high" pots are the ones I'm aligning with, and I can forget about both 7.5 and 30ips.

You can update your -01 revision daughter boards to match the 15/30 spec. Just compare schematics between the two. And this is what you’ll want to do. Or check and see if it’s been done already. The reason is because, yes, if you want to run at 15ips, you’ll set the transport speed to low, but the signal will be going through low speed signal pathway, and the components for 7.5ips EQ. The “high” trimmers won’t adjust things when the transport is in low speed and vice-versa. Does that make sense?

When I bought this machine, it was from a guy named Phil…he had asked me something like 'do you want the 7.5/15ips or the 15/30 motor?' and made a last minute swap when I said, hell 15/30ips with stars in my eyes. I didn't know enough at the time but were it these days, I would have picked the other one.

Well, I hate to say it, but I might have too. The reason is, and I suspected this was the case and the picture you posted confirms my suspicion, you don’t have a “15/30ips” motor. You have a 7.5/15ips motor with a sleeve on the shaft to increase the circumference of the shaft, so when the motor is spinning at a given speed the tape is driven at twice the ips rate of the stock motor. This was a relatively cheap way to mod a capstan shaft for higher speeds, but it is not necessarily preferred. There were varying degrees of quality as far as the sleeve and the install, and I think a common problem is flutter issues if the sleeve isn’t perfect. If that motor was running on that machine then you really want to see if the EQ daughter boards were already modified. They should have been. If they weren’t then it really was a back-alley “upgrade”. If you want to convert it back to stock I think there are places that can do the work. You might even be able to get the sleeve off, but you’d likely need some sort of puller, and you’d want to cool the whole motor down, and then warm the sleeve up with a propane torch. You’d want to be careful not to heat the original shaft too much and take great care not to bend it. It’s probably best to send it to somebody if you want to do this. But if your EQ boards were already revised to match the modified capstan shaft, then you can just set the transport speed to low, and use the low speed trimmers. And if you have access to a flutter meter you can check if you have issues. Or just listen to some different test tones and that will reveal bad flutter or wow issues.

The whole idea of 30ips on a first generation or second generation ‘B’ AG-440 makes no sense to me. The HF frequency response was relatively limited, and that’s what the higher speed does…shifts the response curve higher in the frequency spectrum up an octave, but if the heads aren’t up to the task of taking advantage of that, all you get is losing the Ampex head bump, and burning through tape faster. The 440C had different heads…the laminations were about 1/3 the thickness of the first gen and second gen ‘B’ heads. So it makes more sense on a C. But I still think 15ips is where it’s at, and there’s nothing wrong with the sound of the HF response on the earlier generations…it doesn’t look that great on paper comparatively speaking, but what’s on paper doesn’t always translate directly to real-world performance. It’s more complex than what is captured on a spec sheet.

I attached a pic of the (booster? circuit)

I can’t really tell what all I’m looking at in some of your pics because they don’t show enough of the context of what’s outside the picture frame. The 440-8 has a power boost assembly mounted on the underside of the transport where the signal electronics power supply sits on a standard 1/4”~1/2” AG-440. It plugs into the transport control box at J604S. Then there is also a torque delay module mounted on the rear of the console above the signal electronics power supplies. The schematic in the AG-440B-8 indicates it plugs into the transport control box at J608S. Now, I can’t see in the manual where that connector is physically located…haven’t had my hands on an AG-440-8 in 15 years. So I don’t know if it is a panel-mount connector or maybe cable-mount…but it appears to be a 6-pin Cinch Jones connector like the other ones on the transport control box.

Another pic shows the only cable that I can't figure where it would plug in. (I'm guessing the missing remote)

If you’re talking about the pic where you’re holding the cable with the round twist-lock connector, isn’t that just the mains power cord? Plugs into the round socket on the transport control box?

The transport remote control plugs into the transport control box at J605S. It is a 12-pin Cinch Jones connector. In absence of the remote there is a jumper plug that must be installed for the controls on the transport to function. I *think* yours is in place? Hard to tell from the pics. But the jumper plug straps pins 7, 8 & 12 together which are the STOP control, +30V ground and lifter cancel control respectively.

Your reel idler tensioner…so in the picture is the tensioner arm as far clockwise as it will go? Is the spring in place? Like is it spring-loaded? The AG-440B-8 supplement goes into good detail about transport component checks and adjustments.

 

[Jonk]

As per the idler tensioner, yes it's spring loaded and it is as far clockwise in it's slot as it will go. Thanks for the supplement manual. I already had the two track manual, but downloaded yours as well, as it does look like a better scan.

Modifying the daughter board eq modules is easy it appears. Acccording to here: http://www.uneeda-audio.com/ampex/ag440_equalizer_pwa.pdf

The difference between -01 and -03 is two caps. Actually turns out I have a pair of -03's and the rest are -01's.

Record card daughterboards don't need to be modified?

The supplement manual also makes obvious what the extra box I have is. It's a torque delay box.

That extra power plug is not the AC to the control box. It's a bit smaller than that.

I do have the Cinch Jones remote dummy plug with the correct pins shorted.

I should be honest about my intentions with this machine. The plan is to simply get it rolling tape like it's capable of, and recording on every channel, and then sell it. I hate to give up on it, but I found a MM1100 for a good deal, so planning to spend my time more on that machine. Just want to get it as least running for the next person who uses it.

The info you're giving me is much help. Thank you!