TASCAM 244 speed adjust question

cjacek

Analogue Enthusiast
Hi,
I haven't posted for a looong while but wanted to ask my old analogue buddies or more recent members, those who are perhaps familiar with the old portastudios, if there is an adjustment pot inside the 244 which will allow to substantially lower the speed, like say to the standard 1-7/8 ips or thereabout? Thanks. :)
 
Hey, Daniel! :D

Just took a peek at the service manual for the 244. There's a section 6-4-8 Tape Speed describing a trimmer VR51 on the pitch control PCB. It won't get you to 1 7/8 ips though...probably only about 3 1/4 ips. I expect it may be possible to change the value of one or more components on the pitch control PCB to achieve 1 7/8 ips tape speed though...I'd have to dig deeper for that, but I'm sure it's possible.

Nice to "see" ya. Hope you are well!
 
For starters, if you want to try adjusting (a) component value(s) I would, assuming you have a frequency counter, record a 3kHz tone to tape, play back and verify the reproduce frequency, and then try replacing the 1.8 kohm resistor R585 on the pitch control PCB with 3.3 kohm and reproduce your 3kHz tone tape again and see what frequency reproduces. My hunch is it will be less than 3kHz. Depending on the result we could adjust the value if I'm right about that part being the key component in determining the capstan motor speed.
 
Hey Cory, missed you my friend! :) I had a feeling you'd be the one to reply and would offer your assistance (as you have always done) .. but there was really no need to dig deeper 'cause that's a bit beyond my expertise and comfort level.. I didn't know that it'd be more involved than turning a pot somewhere inside the unit but thanks anyway for explaining. Although I feel bad for taking your time like this.:( I'm doing alright, thanks for asking.. Feeling a bit older than my years sometimes but that's life I guess.. Still acquiring interesting gear on occasion, recently got a pair of SONY Nixon era "Watergate" open reel recorders :D that I'm cleaning up and using to record some simple piano / vocals on.. Yeah, more gear ... :facepalm: "when I thought I was out, they pull me back in" :D ..... ;) Hope you are alright my friend. Nice to "see" ya too! :)
 
:D :D :D

You should put up a a pic or two of those SONY machines...that's cool history!

Just to be clear on your 244 tape speed inquiry, there IS a trimmer to turn, but it won't get you to 1 7/8 ips.

There was a "234L" model that was sold...custom order I think. It was a 1 7/8 ips version of the 234. I'm selling some 234 parts on eBay and there was a fella interested in the pitch control assembly, but he has the 234L, and mine is off of the regular 234. I told him I'm sure I could modify my assembly to work with his machine, I just needed him to get me pics of the assembly in his so I could ID what part(s) is/are different. The circuit is the same between the 234 and 244, just some different values. If I ever close that loop with that guy I'll post the info here for you or whomever. It might be possible to modify the 234/244/246 to be dual speed without much trouble.

I'm doing better as time goes along after a fairly stormy half decade. I still have tapes you sent me of your music from way back when. :listeningmusic::thumbs up:
 
No worries my friend, will try to get some photos up (and thanks again for the info) .. Ah, those tapes, totally forgot about them if you hadn't reminded me.. :eek: ... :D
 
Just thought I'd mention that when you adjust the speed trimmer on the 244 from the central indent you may get increased w&f - Sweetbeats pointed this out to me a few months back when I was going for max speed. I liked the slightly enhanced top response at max speed (about 4.5 ips?) but found it after recording a track at top speed it was difficult to later match the pitch. so had to work a tad down from top speed to allow for this.

I guess it is obvious without me mentioning it, but you'll have to adjust the bias trim if you manage to mod for 1.7/8 ips and want to record - this might be tricky!
 
Thanks for the response Findlay.. Yeah, I saw that thread and Cory's responses.. Weren't you also trying to re-bias the 244 for the normal UR cassettes? I was reading up on that a few nights back but don't know if it was you or someone else who started talking about that.. Anyway, as far as the pitch control is concerned, yeah, I learned long ago to just leave that one alone. The slightly faster speed may at least on paper give better response (and perhaps some others' super sensitive ears) but in practice it's negligible and takes away the option of adjusting pitch if/when needed (but then again you know that already ;) ).. Actually I don't think bias would need to be adjusted if you're changing speed, unless you're also changing to a different [normal] tape. Bias doesn't care about speed just tape formulation (please correct me if I'm wrong). The EQ would need a readjust, for sure but not bias.. In any case, as I mentioned to Cory, that whole speed change thing (beyond the pitch/speed trimmer) is well beyond me right now so I'll pass.. In any case, thanks for chiming in guys. :) ... BTW, still working on those photos Cory, somewhat swamped with other things over here. :eek:
 
Hi Cjacek. Yes it was me re-biasing the 244 for Type I UR! Works magnificently.

As I understand it, bias does need some adjustment at different speeds as part of the compromise between freq response, output, dropouts etc. Pros refer to amount of overbias needed at different speeds and it can be about 9dB different at 7.5 ips compared to 30 ips. Maybe we should have a discussion about this on the forum?
 
:D :D :D

You should put up a a pic or two of those SONY machines...that's cool history!

Cory, here's a couple of those pics promised... They're the same model TC-800B, the one with reels on I'm almost done cleaning, need to recondition the roller and belts (though for 40+ year old rubber it's all still fine) and so too are the electronics! Those SONY's just keep going and going.. Worst thing is the foam from the battery compartment disintegrating to almost oil, need to clean up too. The felt head pressure pads still OK but need to replace one, on the other unit (found NOS pads on eBay). The other unit not yet cleaned up, it's a 220 Volt version (didn't know prior to purchase) but previous owner operated on our voltage which is strange... Initially I thought it may have been damaged using it this way but the Watts of these units are so low, just a tad more than a damn 9 volt battery, that it prob won't make any difference. This model is mid to late 60's I think, takes 5" reels and smaller, has 4 speeds 15/16 up to 7 1/2.., two settings for compression, internal, external mic or a combination of the two and it sounds great, half track mono AND the one feature it has is rather UNIQUE --- it has pitch control so it must be DC servo? Doesn't matter if it's fed 50 or 60 Hz, will keep speed accurate. No wonder Nixon was a fan. :D Never seen those features on such an early consumer open reel recorder. Also got a bunch of old tape with these units and original SONY mics (will try to get some pics up of these). Am thinking of using NU FINISH on these to clean 'em up and possibly restore them, especially the unknown dark back-coated ones.. Also ordered some Scotch 102 tape (some NOS sealed ones). Anyway, photos below (click on 'em for large version and then click again on the window that opens up for extra large version):

DSCF1746.JPGDSCF1745.JPG
 
Wayyyyyyyyy coooooool....!!!!!

I'm really curious if it is DC servo. I mean, that technology had been around, but packed in that thing? What year are these again?
 
Cory, it is from 1971 I believe, was an update to the earlier model 800 (without the "B") from the late 60's... Every doc that I was able to find, including the service manual (granted for the earlier 800 version) and also closely examining the unit, it definitely looks like indeed it has an electronically controlled DC motor, the speed seems to be controlled by the "built in frequency generator" (quote directly taken from the 800 service manual). So an early consumer tape deck with a DC motor with a frequency generator and capable of electronic pitch/speed control. Pretty cool. :)
 
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