Recalibrating Cassette Format Portastudios to use Type I Normal Bias Tapes

Illsidgus

Desiccated Member
I not sure if this is the right forum for this post or if the Tascam forum is, so first I will post here, and if I don't get any results then I'll try the Tascam forum. I have a Tascam 244 which I have owned since 1984/85. The Type II High Bias tapes that it is calibrated for are hard to find and when found are very expensive. So I was wondering, has anyone ever recalibrated a 244 or other machine set to use Type II cassettes to use Type I? Does anyone know if it can even be done? At least you can still buy new stock Type I tapes at a fairly reasonable price.

May you all have a lovely day.
 
I've never heard of that being done, successfully or otherwise and considering the time and expense to do a proper recalibration, you'd quickly eat up any savings in tape costs if you have to go out and get a normal bias calibration tape and a meter and scope to test for azimuth.

Plus, you might also have to recalibrate the internal dbx circuitry on top of all that.

As well, you'd also lose some precious high frequency response and lose a bit of distortion headroom as type I cassettes were more designed for voice quality. They also shed oxide more rapidly so it means more frequent head and pinch roller cleaning too.

All things considered, probably not the smartest idea.

Besides, type II cassettes shouldn't be that expensive? Maybe 3 or 4 bucks a tape for 22 minutes on a C-90 cassette. Way cheaper then reel to reel tape for sure!

Cheers! :)
 
Yes it could be done but very expensive as it would be custom work which most techs wouldnt want to touch. These days you might be struggling to find an experienced tech to do normal service and repair on one of those, let alone custom mods. Price wise you'd be at the mercy of maybe that one guy who was prepared to take it on.

Dont get me wrong. After the proper mods, a good quality Type I cassette would work fine. Type I tapes had very few oxide shedding problems and the dbx wouldnt need recalibrating.
Many, many good quality cassette decks were designed for Type I, II and IV tapes so technically it wasnt a big expense at the manufacturing stage, but the retrofit would indeed be pricey. If you had the skills you could do it as a labour of love.

I agree with Ghost. Better to source some hard to find new Type II tapes, even good condition used ones. People throw the latter out.
 
Thanks guys, it was just a thought. I had read in other threads about people recalibrating Tascam 38-8s and 388s for different bias tapes and thought maybe it could be easily done for the 244. As an example of the cost of Type II cassettes, I can order through Amazon 10 TDK PRO SM60 Professional High Bias Audio Tape (60 min) for $89.80. For someone living on retirement income, that is quite a lot.
 
You can recalibrate for type I, but as already pointed out the expense is prohibitive and probably not something you would want to do yourself. And IMO the results would disappoint. Machines like the 244 were built around type II tape, so that's going to be what you want to feed them. I regularly find good deals on high bias tape on eBay. The links below are my customized eBay searches for the type II tapes I look for. Be my guest and feel free to use them. Good tape at good prices is out there if you know how to search.

For Maxell
maxell 35-90, 35-90b, xl, xli, xl1, xlii -battery | eBay

For TDK SA and SA-X
tdk sa | eBay

For General High Bias
| eBay

There will be some overlap in these searches because of key words sellers use, but they each target something different.

P.S. Try to stick with 60 and 90-minute tapes. Anything longer than 90-minute is not recommend because it's very thin.
 
As someone who has re biased many a cassette and O/R machine I will agree it could be costly and yes, difficult to find a good tech'.

Since the machine is that old my first check would be to see if the heads were worn. This can be done by recording some tones, 333Hz* at 0vu then at -20 then 5kHz, 10kHz and (maybe!) 15kHz. I suspect you do not have a good audio generator or mV meter so the easiest way is to generate the tones in Audacity and check the levels back on the computer.

If the response is more than a dB or so down at 10k you probably should retire the unit.

TDK-SA tapes I found very quickly from Amazon at $21.25 for 5 and $31.60 for 8. SA gives splendid results on my Sony Dolby S machine.

*Does the machine run at 3.3/4ips? If so the baseline frequency can be 1kHz I could not find an owners manual with out selling my computers' soul to a trojan! It is also quite possible that the internals of the Tascam are not adjustable and that factory setting were made by selecting resistors/caps and therefore a PITA to re calibrate.

Dave.
 
This can be done by recording some tones, 333Hz* at 0vu then at -20 then 5kHz, 10kHz and (maybe!) 15kHz.
*Does the machine run at 3.3/4ips? If so the baseline frequency can be 1kHz I could not find an owners manual with out selling my computers' soul to a trojan! It is also quite possible that the internals of the Tascam are not adjustable and that factory setting were made by selecting resistors/caps and therefore a PITA to re calibrate.

Dave.

Like I said earlier it was just a thought, I am not going to try to recalibrate the bias. I am not to worried about the heads. After about 20 hours of use, I put the 244 away for 25 years, busy with my military career, then busy for another five years getting my BA in Anthropology. The machine is almost like new. Just for your info the service manual says to generate a 400 Hz, -10db (0.3 v)reference input.

I have 8 or 10 Type II tapes that I will erase then record over. If all goes well with that then I will buy some new tapes.

Thanks you all for your help.
 
Yes, would be 400Hz over there and for DBX. England went for 333Hz for Dolby and other reasons.

Neg 10 would be the mid band reference but at HF that would still squash I think and I would still run response tests at neg 20.

Dave.
 
Musician's friend has Trutone type 2's for roughly $1.30 each.

I thought about that but most of the reviews I have read about those Trutone tapes indicates that they have sloppy tracking mechanisms and there is a lot of trouble with the tapes breaking. Having said that I will probably try a couple of them to check them out for myself.

Thanks
 
Type II tapes aren't too difficult to find, they're still out there.

Here's a few links:
TDK SA-90min. High Bias Audio Cassette Tapes 2-pack [TDKSA90] - $3.80 : DVD, CD Blank Discs, Blank Cassettes, Media, Blu Ray and More | Tapes.com
Tape.Com: Cassette Tape: TDK SA90 High Bias Cassettes (5-Pack)
High Bias Bulk Loaded Audio Cassette Tapes Audio Cassette Tape Stock at Markertek.com
High Bias Cassette Tape - Compare Prices, Reviews and Buy at Nextag - Price - Review

It's a real shame that you can't simply go to Best Buy, Radio Shack, or even the local drug store to buy them, but they're still out there if you work Google hard enough ;)
 
I always thought that they were calibrated to high bias tapes?? and I know with my experience that every tascam cassette machine I had ,sounded much better with high bias tape ;))
 
It’s been boggling my mind lately how much excellent NOS name brand cassette high bias tape has been selling for peanuts on eBay. I don’t know if eBay has just become too convoluted to search for the average person or what (Which it certainly has compared to years past), but man lately I’ve been watching boxes and boxes of new Maxell XLII almost given away because no one is bidding. The 60 and 90-minute lengths are the best for portastudios. 60-minute is usually a bit harder to find. I’ve been getting incredible deals, but I just had to pass on the last couple even though they were steals. As tough as it is to watch these things go, I’m on the verge of needing to rent a storage building if I don’t stop buying cassettes. I’ve got so much sealed NOS Maxell, TDK and Fuji at this point I’ll be leaving it to my kids in my will. :)

Check these out:

Seven New Maxell XLII 90 for less than $13.00 including shipping. (1 bid)
Maxell High Bias XLII Audio Cassette 90 Minutes Black Magnetite 7 Pack Sealed | eBay

Ten New Maxell XLII 90 for just under $19.00 including shipping. (2 bids)
MAXELL XLII 90 AUDIO CASSETTES | eBay

Ten New Maxell XLII 90 for less than $15.00 including shipping. (3 bids)
Maxell XL II 90-minute cassette tapes (10-pack!!!) | eBay

And here’s the craziest one of all… and it even ran the duration, not Buy-it-Now
20 New sealed Maxell XLII 60 for $15.49, including shipping (only 3 bids)
That’s 77 cents per tape… Holy Crap!
MAXELL High Bias XL11 Sealed Audio Cassette Tape 20 Lot New Sealed 60 Minutes | eBay

I see a lot of people complaining about not being able to find type II tape, but you guys are just asleep at the wheel. And sure there’s the usual crazy high priced enemies of analog sellers who should be shot :p but you just have to wade through those assholes and you’ll find plenty of good reasonably priced tape. All the above is the last of the Maxell XLII before they stopped making it, but the tape is made in Japan, the cassette shells made in USA and assembled in Mexico. I have great results with it. No complaints at all.
 
I just thought I'd add to this thread with some thoughts I've had for a while.

I tried a type I cassette in my Tascam 244 when I first bought it 34 years ago and was surprised that it didn't sound too awful. Just lately I refurbished my old deck with new rubber and adjusted the bias for best results with my mid 80's TDK SA C90 cassettes and I've since bought 2 more decks for spares - at least I thought so but I couldn't resist refurbishing these and they all sound as good as new. The response is pretty flat from 40Hz to 16kHz even recording at 0dB (-2dB at 40Hz and -3dB at 16kHz when zeroed at 400Hz). I appreciate tests should really be done at -10dB or less but I prefer to work 0dB. Because Type II cassettes are getting pretty hard to find in the UK and even the Type II tapes on eBay are mostly late formulations which don't always work too well I've tried a few type I cassettes again - Maxell UR C90 being one as it is easily available and pretty cheap. I must say I'm amazed how good they sound but I have a few questions. Output at 400 Hz at 0dB record is at least 3dB up from the level with SA - how can this be if the tape is, presumably, pretty much overbiased? Output at 10kHz is down by 3dB, explaining the slightly dull sound but by setting the high end eq to the 3 o clock position at 8KHz this is flattened and response is OK-ish to 14kHz and beyond. Acoustic guitar and vocals sound great at this setting and the record replay is very reliable - none of strange dropouts I sometimes get even with top of the range type IIs. I'm wondering if the distortion is less with the overbiased tape? The S/N is so great with the dbx that there is no noise issue with eq setting. I might try to re-bias one machine for Type 1 for a definitive answer but wonder if anyone has a take on this?
 
Hi Findlay, can't really help with the level anomaly except to say, it does not seem as if you have any means of measuring distortion?

If you don't know the THD you are pushing the tapes to I cannot see how you can make valid comparisons?

There is of course free software that can do THD (RightMark is one) but a quick an dirty hardware solution if you have a decent (1mv FSD) AC voltmeter is a parallel T filter with an op amp with bootstrapping to sharpen up the notch. Google should be your friend, also try J Lyndsley Hood..

The device is pretty crude by modern standards but since you are not looking at 0.0002%THD but around 3% it will do!

Where in the world are you? I have a stash of old cassettes, once recorded. Have you tried/can find TDK AD? Was a very good high bias T1.

Dave.
 
Hi Dave,

Thanks for this. I'll look into the software and maybe try your other ideas for THD if I get the courage!

I'm in the UK - I have a few TDK AD tapes so will try them too. I seem to remember they sounded quite bright on a normal deck due to slight underbias so they may be less overbiased on the 244 at.

I guess I was thinking that the distortion levels for Type 1 on the 244 could be lower because of the overbias. I think I am right in saying that distortion goes down with overbias - up to a point at which it start to rise again. I can't find much info about the specifics for this sort of situation. And because the output is so high for the type 1 on the 244 for the same recording level it would always be possible to record at lower levels to reduce it further I guess. But to my ear the recordings sound pretty clean anyway! - at odds a bit with the "dull and dirty" expectations.
 
I love that you brought this thread back to life. I stumbled on it last summer while researching the best tape to use with my then new 244. Since then, I also refurbished a couple 246's, and also a NOS 246 that I bought off a guy in Westchester NY. It was still in plastic inside the cardboard box. I couldn't believe it. He was swearing up and down hat it would run since he'd never used it, but I knew it would need new rubber. He bought it back in the late 80's for his then studio and said that he had gotten into a terrible car accident and never finished setting up the rest. Weird right?

It was in his attic all these years until he saw an ad I placed in craigslist about repairing 4-tracks and contacted me. I'm still in shock that there was a 30 year old piece of gear out there like that. I bought some TDK SM-X 30 tapes for it and I was blown away by how real vocals can sound on it when I push it. I love recording on these things. So inspiring!
 
Have you noticed what's "railroading" with older TDK type II's? I heard about it a while back over at Tapeheads and checked out a SA 60 I have from the early 80's and sure enough, it had the tracks all on the tape. I've read that it affects older TDK's from 80-90 or something like that. Pretty much across the board too, which sucks. I have some SA's from 1979 and they have minor railroad marks butI don't notice it affecting the sound at all. Then again, I'm no audiophile so...
 
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