Ampex MM-1000 Story...

Been getting the studio wired up and running tone to the MM-1000. 2 out of 8 channels were dead. One needed an amp card re-seat, the other has a bad repro card. Swapped out the bad card and now I've got needle deflection on all 8 channels. Yay. Problem is, I'm not getting any return to the board from channels 2 and 5. Not sure yet if it is a cabling or a hardware issue.
 
sweetbeats said:
Been getting the studio wired up and running tone to the MM-1000. 2 out of 8 channels were dead. One needed an amp card re-seat, the other has a bad repro card. Swapped out the bad card and now I've got needle deflection on all 8 channels. Yay. Problem is, I'm not getting any return to the board from channels 2 and 5. Not sure yet if it is a cabling or a hardware issue.
Click to expand...

Well, you're making some progress there, so that's cool!

I remember back when I had my MS-16 before I dished out over $1600 to a local technician to get everything working properly, and had "surprise" dead channels in every single recording session! It was frustrating but I'd console myself by admitting that its an older machine with a lot of miles on it and sh!t happens, and to just keep fighting the good fight of re-seating cards, jiggling umbilical cables and getting it working long enough to at least get through the session.

Short version: chin up!

Cheers! :)
 
Thanks, Jeff...yeah I'm not getting too worked up over it. Pretty much all of my restoration efforts on this machine have been centered on the transport. The electronics are 100% original right down to the electrolytic caps (except for one cap on the record cards that is a safety issue). I recapped and upgrade the 39V power supplies, but nothing in the electronics chassis have been touched...not even cleaning contacts. This machine is nearly 45 years old. I think it is amazing it can be powered up and pass signal at all, and there aren't even any "skritchies" from the level pots. Pretty incredible. It'll be a bit of a puzzle to chase down the source of the problem for the channel 2 and channel 5 returns since there are 6 steps in between the output jacks of the Ampex and the line in jacks on the mixer (1. internal XLR plug to XLR panel on the Ampex; 2. XLR to TRS snake; 3. TRS to TRS barrel couplers; 4. short TRS to XLR snake; 5. Tascam LA-40mkII; 6. RCA to RCA snake), and stuff is really hard to access due to the size of the room and the size of the gear, but I'll track it down. And eventually the electronics modules will be rebuilt vastly increasing reliability if such an issue exists now.
 
sweetbeats said:
Thanks, Jeff...yeah I'm not getting too worked up over it. Pretty much all of my restoration efforts on this machine have been centered on the transport. The electronics are 100% original right down to the electrolytic caps (except for one cap on the record cards that is a safety issue). I recapped and upgrade the 39V power supplies, but nothing in the electronics chassis have been touched...not even cleaning contacts. This machine is nearly 45 years old. I think it is amazing it can be powered up and pass signal at all, and there aren't even any "skritchies" from the level pots. Pretty incredible. It'll be a bit of a puzzle to chase down the source of the problem for the channel 2 and channel 5 returns since there are 6 steps in between the output jacks of the Ampex and the line in jacks on the mixer (1. internal XLR plug to XLR panel on the Ampex; 2. XLR to TRS snake; 3. TRS to TRS barrel couplers; 4. short TRS to XLR snake; 5. Tascam LA-40mkII; 6. RCA to RCA snake), and stuff is really hard to access due to the size of the room and the size of the gear, but I'll track it down. And eventually the electronics modules will be rebuilt vastly increasing reliability if such an issue exists now.
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Hi

Since I recap and sometimes modify my electronics and also notice that most Ampex owners stress to keep the electronics as original as possible. I would just like your thoughts on why this is so. Thanks.
 
Simply stated, at least as far as the AG-440 amplifier electronics are concerned (along with their descendants the MM-1000/1100/1200), they knew what they were doing and it was a good design. There is a short list of must-do items on the 440 electronics, but it is short and reasonable...
 
Yeah...it's a little bit of a kludge because the mixer actually outputs unbalanced -10dBv OR +4dBu...switchable per channel on the buss outs on the back. And naturally the Ampex will accept unbalanced signals, but the level-bumping circuitry in the LA-40 is cleaner than the mixer's, and I'm going balanced for now since the overall cable run is about 25 feet and I've got the highest power AM radio station in my state less than 0.1 miles from my house. The TRS barrel connectors to the short TRS - XLR snake is temporary...the snake between the Ampex and the LA-40s used to be XLR - TRS, and 8 of the TRS ends have been converted to XLRF for the sends to the Ampex (so it connects right up to the outputs of the LA-40s), but the other 8 are still TRS and I have the barrel connectors and that short TRS to XLRM snake...so it's hooked up. Eventually I'll buy more XLRM connectors and convert the other 8 channels and get rid of the adapters and the short snake.
 
Sweetbeats,

Radio station makes sense,otherwise Ampex can be calibrated for any level and balanced to unbalanced can
be taken care of in the cable.Could eliminate all the stuff in between.
I was just curious.

Gary
 
sweetbeats said:
Simply stated, at least as far as the AG-440 amplifier electronics are concerned (along with their descendants the MM-1000/1100/1200), they knew what they were doing and it was a good design. There is a short list of must-do items on the 440 electronics, but it is short and reasonable...
Click to expand...

Next to IBM,Ampex holds the most U.S. patents,so yes they knew what they were doing. Some want museum pieces,I want the best sound possible and I use the original circuit and values.

Roger
 
sasquatch said:
Sweetbeats,

Radio station makes sense,otherwise Ampex can be calibrated for any level and balanced to unbalanced can
be taken care of in the cable.Could eliminate all the stuff in between.
I was just curious.

Gary
Click to expand...

Yeah, were it not for the radio station I might just make up an unbalanced XLR to RCA snake, but for now I'm keeping it balanced with the LA-40mkIIs.

And while the Ampex can accomodate -10dBv, it was *designed* for +4 or +8dBu and there is a noise floor advantage by sticking with the intended nominal level. So that's the logic. Good question.
 
FAST996 said:
Next to IBM,Ampex holds the most U.S. patents,so yes they knew what they were doing. Some want museum pieces,I want the best sound possible and I use the original circuit and values.

Roger
Click to expand...

Yeah, I don't care for a museum piece, but I'd be a fool not to live with and get accustomed to the machine stock before modifying stuff. Eventually the 'lytics will be replaced with equivalent low ESR modern parts, adjusting values where advised (which includes an increase in the voltage rating of C32 on the Record PWA, increase in capacitance of the output coupling cap which is probably the BEST bang-for-the-buck improvement, and slight increase in the local supply filter...). I WON'T be replacing the multi-section electrolytic caps unless there is a functional problem because those deal with timing delays...they don't handle audio. Also bypassing the 5uF cap on the octal socket as I won't be using the plug in mic transformers there. And I think upgrading of the electronics power supplies is key which I have done for the first two supplies; I used Mallory computer grade caps for the main and secondary filters (with an upgrade in voltage and capacitance on the main filter cap), and replaced the rectifiers with new 1N4008 parts...also replaced the bleed resistor and bypassed the main filter cap with a small value cap. Outside of that I likely won't be doing much more secondary to the curve of diminishing returns compared to cost. There are people that insist on replacing all the electrolytics on the PWAs with huge expensive film caps, and bypassing the transformers, etc. I know that's not what you are going for necessarily, but my anchor is something that Steve Puntolillo said to me a couple years ago..."Replace that output coupling cap and the local filter, change out the electrolytics on the amp cards, and set it up at 15ips NAB and it'll sound like an Ampex." That's what I want. Then if I decide its NOT what I want after living with it awhile as is, I can tinker or go a completely different route, but at some point its lipstick on a pig (not that the MM-1000 is a pig by any means...the "pig" represents *anything* that is in discord with what you want or need). You can change all the tants and film caps out for higher quality films, bypass all the larger value lytics...replace all the carbon comp resistors with metal film, blahblahblah...but I've heard some GREAT recordings come off of stock MM-1000s. And the fact that the amplifier circuit is little changed from the AG-440 all the way through the MM-1200. I mean, there are plenty of folks that don't and/or didn't consider the MM-1200 as the go-to machine, but they weren't after what it offered and still does...the MM-1200 was definitely and remains a top choice, and it was one of the kings in an age when everything was going to IC opamps and transformerless topology to pursue "transparency", and yet the MM-1200 is all transformer coupled and discrete class A circuitry. Antiquated, right. Bleh. If I want transparent I can use my digital rig.
 
sweetbeats said:
Yeah, I don't care for a museum piece, but I'd be a fool not to live with and get accustomed to the machine stock before modifying stuff. Eventually the 'lytics will be replaced with equivalent low ESR modern parts, adjusting values where advised (which includes an increase in the voltage rating of C32 on the Record PWA, increase in capacitance of the output coupling cap which is probably the BEST bang-for-the-buck improvement, and slight increase in the local supply filter...). I WON'T be replacing the multi-section electrolytic caps unless there is a functional problem because those deal with timing delays...they don't handle audio. Also bypassing the 5uF cap on the octal socket as I won't be using the plug in mic transformers there. And I think upgrading of the electronics power supplies is key which I have done for the first two supplies; I used Mallory computer grade caps for the main and secondary filters (with an upgrade in voltage and capacitance on the main filter cap), and replaced the rectifiers with new 1N4008 parts...also replaced the bleed resistor and bypassed the main filter cap with a small value cap. Outside of that I likely won't be doing much more secondary to the curve of diminishing returns compared to cost. There are people that insist on replacing all the electrolytics on the PWAs with huge expensive film caps, and bypassing the transformers, etc. I know that's not what you are going for necessarily, but my anchor is something that Steve Puntolillo said to me a couple years ago..."Replace that output coupling cap and the local filter, change out the electrolytics on the amp cards, and set it up at 15ips NAB and it'll sound like an Ampex." That's what I want. Then if I decide its NOT what I want after living with it awhile as is, I can tinker or go a completely different route, but at some point its lipstick on a pig (not that the MM-1000 is a pig by any means...the "pig" represents *anything* that is in discord with what you want or need). You can change all the tants and film caps out for higher quality films, bypass all the larger value lytics...replace all the carbon comp resistors with metal film, blahblahblah...but I've heard some GREAT recordings come off of stock MM-1000s. And the fact that the amplifier circuit is little changed from the AG-440 all the way through the MM-1200. I mean, there are plenty of folks that don't and/or didn't consider the MM-1200 as the go-to machine, but they weren't after what it offered and still does...the MM-1200 was definitely and remains a top choice, and it was one of the kings in an age when everything was going to IC opamps and transformerless topology to pursue "transparency", and yet the MM-1200 is all transformer coupled and discrete class A circuitry. Antiquated, right. Bleh. If I want transparent I can use my digital rig.
Click to expand...

I never thought the RTZ sounded like a Ampex fwiw. I agree totally that if it doesn't sound like a Ampex,well then buy a Studer. My point was that I do so well with the REV B electronics and that's because the circuit is so clean I think these can sound amazing. I can appreciate living with the machine and tweaking later. Just wanted your opinion. Cory you do an amazing job and your threads are very informative.
 
Thanks, man...that means a lot to me.

Yeah I really like the 440 "A" or B electronics. It's a good design...they simply sound great, and it IS valuable to note they CAN be transformed into a very transparent circuit...just to to sonicraft.com...Steve knows Ampexes. His business depends on transparency. And at the same time the guy has oodles of experience working with a whole host of machines in a studio scenario. But he chose Ampex machines as his primary for his analog to digital transfer business.
 
I should have known it wasn't the Ampex (causing trouble with signal on some of the returns getting back to the mixer). It's several of the cheapey Rean TRS barrel connectors.

:mad:

Can't figure out how to open them up to dicker with them. Probably should just invest in the XLR-M connectors I need to do away with the barrel connectors and the short TRS - XLR snake.

Bleh.
 
That's it. Ordered a set of matching XLR-M connectors to do away with the Rean TRS-TRS barrel adapters and the short TRS-XLR snake. 5 of the 8 barrel adapters are not conducting on one of the signal conductors and these are barely used. Not impressed/happy. I could get past it if I could disassemble and repair/improve the adapters, but they are not threaded. They are all metal (Switchcraft knock-offs), but it's not clear to me how they assemble. I'm going to destroy one to find out though.
 
Every connector in a system reduces reliability of said system. That coming from the director of Engineering at a connector company, seriously. Obviously we cant operate very well without them in our home endeavors. But eliminating as many as possible, especially adaptors will go a long way.
 
Yes, all excellent points, and just to clarify the use of the adapters and the short snake was just a temp cobble to get things hooked up...using what I had on-hand with the intent of modifying the main snake to/from the Ampex when able...well, I'm suddenly able.

:D
 
Forget your favorite exercise program...just crawl around under my mixer table for a couple hours. I'm beat. Seriously. But the TRS barrel adapters are gone, as is the short TRS - XLR snake...got all XLR connectors on both ends of the 16 channel (8 send, 8 return) snake to/from the MM-1000, and while I was down under the table I decided to calibrate the Tascam LA-40mkII bump boxes...I'm glad I did. Never have gotten around to doing that and some of the levels were WAY off. I calibrated all three of my units which entails setting trimmers to adjust the level bump from the -10dBv unbalanced inputs to the +4dBu balanced outputs, and then setting trimmers to adjust the level going the other way (i.e. from balanced +4dBu to unbalanced -10dBv). Since each unit has 4 channels one way and 4 channels the other way, and since I have 3 units, that's 24 trimmers. And I did it using Y cables so connections were loaded via termination into the actual devices they are routinely connected for the most true adjustment...anyway, there was quite a range of variance in where somebody has set those trimmers in the past. All ship-shape now, and resolved a couple other connection issues as well...In the end I've got 8 channels successfully going to and from the MM-1000 and the mixer now.

Time to get some sleep, but the next step is to clean up in the room...cables and tools ALL over the floor. It's a mess.

image.jpg
 
I tried tracking to the MM-1000 earlier tonight...didn't work...quickly discovered it helps if you have the R/P heads plugged into the right sockets...heheh.

Haven't had a chance to take another crack at it yet but I just thought y'all would like to know. I don't expect much out of the quality of the recording; there's still work to do to finish setting up the transport, and then NONE of the electronics have been calibrated...I'm sure it's nowhere near biased for the 499, etc., but it was encouraging to not have to jury-rig something to get signal into it...I did what I should be able to do which is plug my bass into my preferred instrument preamp (Presonus Digimax FS) which is normalled to a line in on the Tascam mixer, dial up the right level, buss it to the desired track, arm the track and let 'er rip. This...could be fun.

And I can do all of it even though my DAW PC is on the fritz with a failed hard drive. :p :D

Back to folding laundry.

Oh...and MAN that thing is noisy...the Ampex...mechanically-speaking. I mean, it's no louder than its always been but the capstan seems 10x louder when I'm tracking. It's going to be something with which I'm going to have to contend. I love the sound of it and everything but its just...loud. There is an MM-1000 I did a service assessment on a couple years ago up in Portland and its capstan was MUCH quieter. I'm wondering if the bearings are tired on mine, though I've seen a video of an Ampex quad VTR in action and it sounds just like mine. The bearings are NOT a simple matter to replace on the MM-1000 capstan shaft...they're in there like Fort Knox by design in order to provide stable accurate tape drive. I have a lead on another capstan assembly...hoping it might be in better shape. Anyway, no surprises here, just becoming faced with the reality I guess.
 
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