Mastodawn

#hainbach #eurorack #modularsynth

I speculate that is has some number of channels (4? 8? More?) and uses something like FM recording to allow recording DC signal levels. While it would hardly be practical for data acquisition anymore in 2026, I hope to apply it to something whimsical like Eurorack modular analog synthesizer control voltage (CV) stuff. Will it Hainbach?

Decades ago, I had a 1/2" open reel instrumentation recorder which sadly went to scrap a smaller number of decades ago. As I recall, it was a 7-track recorder with a mix of FM channel cards for DC coupled recording, and some other channel cards that may have been AC coupled. I think it was older than this Ampex rig.

The current owner of this rig says it weighs 95 pounds. I'll bring Ibuprofen when I go pick it up tomorrow. 🤪

I have found very scant information about this recorder online so far. Mostly just eBay auctions for 1-page magazine ads with Ampex showing it off, not including any specifications or details. Also, it looks like the owner may have some other weird monitor thing that came from the same place. This could get fun. #fun

https://www.ebay.com/itm/122412229484

Here is an eBay listing I found for an Ampex PR-2230. I don’t know how it differs from the PR-2200 that I’ll be buying/adopting, but it gives a hint about what the rear panel might be like. Maybe they differ in tape width and channel count or something like that? Anyway, y’all might like the photos in this listing.

AMPEX PR-2230 Reel To Reel Tape recorder | eBay

ABQ Electronics is committed to keeping computers and other electronics in use and out of the landfill.

eBay

Looks like the deal is falling through. The fellow who posted on Reddit wanted to give it away for free along with some fascinating CRT monitorstrosity, but apparently his dad decided they're made of gold. At least I found out before I started the 2 hour drive. 🤷🏻‍♂️

Anyway, based on very sparse information I found online, I think that tape drive may have a rotating head and record one telemetry channel in each stripe, possibly with one or more linear tracks for timing and/or voice annotations.

Now maybe the deal's back on? Time for me to shut up and drive. 😁

Target acquired for an acceptably cheap price. A little under two hours south of me near San Diego, driving in lovely weather through the pretty green hills. Now stopping for some food before I head back home.

So you know what time it is now… PHOTO THREAD TIME!

I think this is 1/2” tape.

Let’s look behind these access panels

There is some reference info silkscreened inside the panels

I think this used to be a rubberized drive capstan. Now it’s a new restoration skill for me to learn before I move tape. I think I see fixed heads for linear tracks. I don’t understand yet why this stuff all looks a lot wider than the tape in the machine.

Some controls under a door on top, and a place for your favorite narrator to plug in their microphone

Time for me to head home. I’ll resume with photos of the back side in a couple of hours.

Home again! Ok, let’s look at the back of this Ampex PR-2200. It appears to be configured for 8 channels of telemetry.

However, peeking at the cards in the front, it appears that only enough cards are plugged in for 2 out of 8 channels. Maybe this unit became a parts donor at some point? These look like the FM cards shown by the silkscreened reference, so I assume they would support signals from DC through some modest upper frequency. I assume the direct recording cards would support much higher frequencies, but could not record DC or sub-audio signals.

Back to the back, here is the nameplate.

The rear panel opens easily to show the innards. It appears that there is room to install guts for an additional 8 channels, but I don’t think that would be a field installable modification.

It looks like the hubs can accept 1/2” or 1” reels.

The tape path looks like it’s wide enough for 1” tape, but it is assembled with guide rollers for 1/2” tape. I speculate that 16 channel versions of this recorder would be assembled with different heads, 1” wide guide rollers, and additional electronics for the second 8 channels.

That's all for now. I need to figure out what to do about that decomposed capstan rubber before I try moving tape through this chonky boy.

Update: Power applied. Something popped.

The power supply hinges out, and now we can see the hub motors.

Davide Bucci Jan 26

@NF6X well, it’s a fantastic beast! 😍 Would it be suitable/adaptabe for multitrack audio recording?

@davbucci Not really, but I do hope to be able to misuse it for modular analog synthesizer fun. I don't think it has the capability to record only some tracks; it's all or none, so that eliminates usual multitrack recording use.

@davbucci But on the other hand, this one appears to be set up with FM modulation channel cards, which should be able to record signals all the way down to DC... so maybe it can record and play back control voltage (CV) signals for synthesizers!

Davide Bucci Jan 26

@NF6X that will be terrific, indeed. Maybe you’ll find a way to record both CV and audio at the same time. Amazing find!

@davbucci I hope I can find more channels cards for it, both FM and direct recording. This could turn into a rabbit hole of designing my own...

Davide Bucci Jan 26

@NF6X magnetic recording is quite of a rabbit hole, indeed. Two years ago I restored a Revox B77 R2R recorder and I utterly love it. Getting new tapes is expensive though, but the quality with DBX is outstanding: davbucci.chez-alice.fr/index.php?argument=varie/revoxb77/revoxb77.inc