Can I modify a Teac 3340 reel deck to run at 2340 speeds?

Has anyone here ever converted/modified a Teac 3340 deck, which is a 15/7.5ips machine, to run at the 2340's 7.5/3.75ips instead?  Probably by replacing the capstan/flywheel assembly?  Anyone know how feasible this is, or what it would take to do it?  How similar the mechanical parts are amongst the various models?  Any other gotchas/hints?

Or is this just a really dumb idea?

Thanks,
-clintfan


...still here, and still not doing much audio, pending a solution to our furniture problem!

I think you'd have a lot of difficulty with this, because you'd have to change the capstan for a smaller one - no chance of a sleeve. And being a japanese machine, I doubt whether a retrofit was ever available. Then you have to sort out the EQ...

Is this just a playback problem you've got, or do you actually want to record on it?

I wouldn't do it.

I think you'd be better off searching for a machine of the spec you require, rather than getting involved in a complicated mod like this.  

Alternatively - since it would seem what you really want is the 3 3/4 ips speed - there might be some other options open to you.  However, this depends on whether you are recording or just playing and also whether you need the four track capability, etc.

As ever, full details of the problem to be solved will result in a better selection of options.

...I think you'd be better off searching for a machine of the spec you require, rather than getting involved in a complicated mod like this...

Yeah, what he said!
I know for sure that the Otari MX55 had a switch internally. You just unscrewed the back cover, and flipped the switch between its 2 positions to select between 3.25/7.5 ips and 7.5/15 ips.
Have no idea what they'd be worth second hand these days, but maybe worth having a hunt around.
Good luck.

http://www.broadcastworks.com/equipment.htm

Scroll down to the list of reel to reel machines about half way down the page....

You didn't tell us why you would want to do that. The whole point of recording at the higher speed is to get a better quality recording. So I'm guessing you have on of two reasons for doing this, One, you're really cheap and want to save money on tape, or two, you have some 4 track recordings that were recorded at the slower speed, and want to play them back.  If that's the case, you may be able to transfer them at the higher speed into Audition and then slow them down in the program, instead of ruining a classic, vintage tape recorder.

I had a few of those 3 3/4 speed reels of tape myself, as I had a 2340, and used to record 4 hour shows. To save money on tape, we used to record at the slower speed, and still got fairly good live recordings.

Luckily, I bumped into a guy a few years ago that had another 2340, and he let me borrow it long enough, to transfer my tapes to HI-8 using a DA-88. They're getting hard to find though.

....you may be able to transfer them at the higher speed into Audition and then slow them down in the program, instead of ruining a classic, vintage tape recorder.

Just in case you've ever found some acceptable EQ compensation using the software, I (and probably others) would love to have that information...    Can you post it here?

Also, I'd think that some serious physical tape/transport problems would get exacerbated by slowing down these fast-recorded tracks on the computer - at least, that's the experience I've had on a quick try, a few years ago. Of course we immediately decided to hire-in the proper gear for the job.    

Best... -Jon

EQ compensation ??  Now you're talking out of my league, as I haven't actually tried dojng this, it was just a suggetstion to try to save some old recordings without destroying the 3340. You may go thru the problems of converting to 3-3/4 only to find there's nothing worthwhile on the tape anyhow. If it was recorded at 3-3/4, it must not have been considered a critical recording at the time. So in the meantime, I would try everything possible, before tampering with the 3340. Once you start making alterations to it, it may never be the same again, and another classic, vintage recording machine bites the dust. It's doubtful they'll ever be made again, so what units out there, should be taken care of , not altered, in my opinion.

I recently had a 1/4" 1/4-track tape in which had a live theatre recording (circa 1973) on it - in stereo. Part one (on side one) ran at 1 7/8 IPS, whereas part two (on side two) ran at 3 3/8 IPS. I was poised to dig out my old Akai M8 to deal with the slower side but (having already transfered side two and got the azimuth spot on) I gave side one a quick go at double-speed on the Revox B77, sampling at 88200k.

After I'd adjusted the sample rate I found it quite easy to get a match between the two sides. With additional tweaking in Ozone required anyway I don't suppose anyone's going to notice any difference. Certainly it's far and away the best 1 7/8 recording I've heard away from my Nakamichi cassette deck, and that usually needs Mr. Dolby's assistance...

So - give it a try at the higher speed and see where it gets you. If you're going to fiddle around with it afterwards you might just get away with it. If it is critical, borrow or buy (briefly) a machine that'll help. Good luck!

(Digs out and dons old nostalgia hat)
I remember playing stuff at twice the speed on one machine set to its minimum speed and recording it at the higest speed on another one. Then just drop to a lower speed on the second machine...

Yes, it used to sound dreadful - but not unusable. The thing to remember about a lot of these old 3 3/4" recordings is that the EQ was frequently shot to hell anyway - and the chances are that you wouldn't even lose a significant amount of treble (if any at all) by playing the tape at twice the speed and using CEP/AA to slow it down. And there's enough EQ to straighten out just about anything. Heck, you can even get rid of most of  the tape noise!

If it's old material that you have no idea about, and you don't yet know whether you actually want it or not, just be grateful that by recording it into the PC at twice its correct running speed, you will actually have saved yourself quite a bit of recording time!

If the situation ever presents itself again (dubious, but not an impossibility), I'll give it another whirl. Thanks for the info, guys.  

Best... -Jon

Hi everyone, and thanks for your inputs!  I didn't mention why I wanted to do it, because I just wanted to keep the original post short and sweet, not be a whole long dissertation.

It is as I expected... no one here has tried it, and it is not a very good idea.  Yes I do have many old 3-3/4 tapes which it would have been nice to play on this, for dubbing purposes, but I probably won't.  

The trick about doubling the sample rate for double-speed playback dubbing was a detail I hadn't thought of... makes plenty of sense, I just hadn't thought of it, so thank you for that Andrew.

I actually probably have the necessary mechanical parts, but the EQ is one thing I was worried about.  I wasn't sure the deck had such or not;  I'll assume it has at least some EQ in it.  

But I will probably leave the 3340 as-is, and either give it away or keep it in case I want to do some 4-track recording.  Space is the main issue, so having it go away is the more likely path.

Now, as to the "why"...

As some of you may recall my uncle had accumulated well over a dozen decks.  I was forced to literally dump most of these this past September, and I wrote a thread about that.  But we had held onto 4 for himself (plus I found a few more in his garage last week).  As his cancer has progressed, he was unable to keep even the 3 he had chosen for his own personal use, so to lessen his pain I came away with the 3340S, and also a 2-track 2300 he'd had completely rebuilt.

So, painful as it might seem, my casual thought was to do surgery on both decks to transplant the capstan/flywheen from the 2300 into the 3340;  it's not at all beyond my capabilities.  And based on rudimentary flashlight inspection, this would probably work, the mechanicals look very similar, which is as we might expect from a product-line perspective.  But this fails to consider EQ differences, and so in the end it's probably not worth it for the sudio results, not to mention winding up with a mod'ed deck probably no one else would ever want after I'm done with it.

I guess if I ever really want a 2340, they can be had regularly on Ebay where I picked up my X300R (ugh!) a couple years back.  Should'a got a 2340 then, I just thought it was too old and too huge.  Didn't realize the X300R auto-reverse would muck up the tape path so much, and the heads are poor, but it recorded some voice-overs OK last year.

Anyway, thanks everyone...

-clintfan