O
ofajen
Daddy-O Daddy-O Baby
I recently fired up the old 3M M-23 1/4" 2-track for the first time ever since collecting the pieces a few years back.
I'm kind of amazed, but the transport is working quite well, and the electronics is at least working on playback and signal input. I haven't had time to test the record function, nor to do any calibration. One capacitor blew up on one of the channel power meter cards, but that's it so far and it wasn't hard to replace.
For those who are unfamiliar, the M-23 (400 series) was the first series of 3M machine (after the initial set of about six Dynatrack machines were sold to a few big studios). 3M shot Dynatrack in the foot by introducing the Scotch 200 series of low noise tape about the same time. Studios decided to opt for the new tape and not bother with the complicated electronics of Dynatrack, which worked well, but took two tape tracks per audio channel. Most of the M-23 machines sold were standard NAB machines. The electronics can be easily modified to yield proper IEC1 eq at 15 ips (which is what I do) and AES eq at 30 ips if the machine runs at that speed.
Anyway, the M-23 series uses an old rim drive capstan mechanism to drive the capstan. The capstan motor shaft clunks onto the rubber tire on the outer edge of the capstan flywheel a few seconds after the machine starts up, but the tape is only driven when you push play and the pinch rollers push the tape into contact with the capstan. It's a lot better than you might think from that description, though they did move to a belt drive system with the M-64/M-56 machines (500 series). Mine is a 7.5/15 ips rim drive, but I have the parts to convert it to the later 15/30 ips belt drive at some point.
The M-23 tape drive is the same basic Isoloop used in all the other later 3Ms, where the 2" diameter capstan drives both the incoming and outgoing tape on the loop, using a differential capstan and pinch roller to create tension within the loop.
The M-23 is the best looking of the 3M machines, with chrome-plated trim parts around the Isoloop path, instead of the dull grey of the later machines. Mine is not quite as pretty as it will be, since the transport is still unmounted. I'm going to make custom portable plywood cases for the transport and electronics and paint them black. It also uses the old "one big rack per audio channel" style of electronics and happens to have big 4 1/2" wide Weston VU meters on each channel. Those are true VU spec meters and a delight to use.
Now that this machine seems to be coming together, I've also located a second M-23 2-track machine and the parts that would let me build it up as a portable 1/2" 4-track. I don't have the desire to have a whole house full of tape machines, but I still need to have a few around and I have been wishing I had a portable 4-track M-23 for many years. Mitch Easter has one but has finally decided he will never sell it, so I'm going to have to find another way, and I think I found it this week. Cool!
Having worked some with a digital audio rig for the first time for the last year or so, I still find that I prefer to do a lot of my initial recording on tape. I don't think that's ever going to change, so I'm certainly one who hopes that someone continues to make good tape for sale! The biggest hurdle I have with the digital rig for initial creative work is that it SO wants to put stuff on a grid, while tape has no desire to force me into beat slavery.
Cheers,
Otto
I'm kind of amazed, but the transport is working quite well, and the electronics is at least working on playback and signal input. I haven't had time to test the record function, nor to do any calibration. One capacitor blew up on one of the channel power meter cards, but that's it so far and it wasn't hard to replace.
For those who are unfamiliar, the M-23 (400 series) was the first series of 3M machine (after the initial set of about six Dynatrack machines were sold to a few big studios). 3M shot Dynatrack in the foot by introducing the Scotch 200 series of low noise tape about the same time. Studios decided to opt for the new tape and not bother with the complicated electronics of Dynatrack, which worked well, but took two tape tracks per audio channel. Most of the M-23 machines sold were standard NAB machines. The electronics can be easily modified to yield proper IEC1 eq at 15 ips (which is what I do) and AES eq at 30 ips if the machine runs at that speed.
Anyway, the M-23 series uses an old rim drive capstan mechanism to drive the capstan. The capstan motor shaft clunks onto the rubber tire on the outer edge of the capstan flywheel a few seconds after the machine starts up, but the tape is only driven when you push play and the pinch rollers push the tape into contact with the capstan. It's a lot better than you might think from that description, though they did move to a belt drive system with the M-64/M-56 machines (500 series). Mine is a 7.5/15 ips rim drive, but I have the parts to convert it to the later 15/30 ips belt drive at some point.
The M-23 tape drive is the same basic Isoloop used in all the other later 3Ms, where the 2" diameter capstan drives both the incoming and outgoing tape on the loop, using a differential capstan and pinch roller to create tension within the loop.
The M-23 is the best looking of the 3M machines, with chrome-plated trim parts around the Isoloop path, instead of the dull grey of the later machines. Mine is not quite as pretty as it will be, since the transport is still unmounted. I'm going to make custom portable plywood cases for the transport and electronics and paint them black. It also uses the old "one big rack per audio channel" style of electronics and happens to have big 4 1/2" wide Weston VU meters on each channel. Those are true VU spec meters and a delight to use.
Now that this machine seems to be coming together, I've also located a second M-23 2-track machine and the parts that would let me build it up as a portable 1/2" 4-track. I don't have the desire to have a whole house full of tape machines, but I still need to have a few around and I have been wishing I had a portable 4-track M-23 for many years. Mitch Easter has one but has finally decided he will never sell it, so I'm going to have to find another way, and I think I found it this week. Cool!
Having worked some with a digital audio rig for the first time for the last year or so, I still find that I prefer to do a lot of my initial recording on tape. I don't think that's ever going to change, so I'm certainly one who hopes that someone continues to make good tape for sale! The biggest hurdle I have with the digital rig for initial creative work is that it SO wants to put stuff on a grid, while tape has no desire to force me into beat slavery.
Cheers,
Otto
