Tascam 22 - Low freq. bump questions

Update-

My test tape and demag unit have not arrived yet. I am suspecting analogkid is on target with the demag. The more I listen, the more I hear diminished high feq., rather than increased lows.

I could be wrong, it's just what I think I hear. The heads are clean, btw.

Hopefully the stuff will get here soon I and can continue checking it out.
 
Ok. Got the Handi-Mag and MRL test tape.

Demaged as per instructions, cleaned the heads again, then ran the test tape. Here's the response from the test tape:

32 +4
63 +2
125 +0.5
250 0
500 0
1000 0
2000 -1
4000 -2
8000 -3
10000 -3
12500 -3.5
16000 -4
20000 -4

So it appears the head bump is not so bad, but the HF loss seems out of spec. above 12.5khz. I was hearing HF loss and not LF bump...

I need to run the test again recording the tones from my PC the way I did before as well. Maybe it's my DA conversion, or the Tascam recording is different than the playback.

I will test my other Tascam 22 later tonight and see how different it is too.
 
That is a really...um...really solid low-end response...that curve...it must drop off really steep after 32.5Hz...:eek:

I'm not as concerned about the HF drop, especially not knowing what condition your heads are in.

Does it look like the wrap is correct (the centerline of the head is perpendicular to the tape path)?

Does the 22 have reproduce eq trimmers for low and hi frequency? I'm betting it is hi frequency only, but if you increase that so that you are -2 ~ -3 in the 16 ~ 20kHz range that may actually pull your level up at the 1kHz mark, and then when you drop the repro level trimmer to pull the 1kHz tone back to 0VU it will also drop your low-end head bump a bit essentially flattening things out across the spectrum.

Leddy, can you find the part number for your amp card?

I agree that you have some HF loss there, at least according to my experience...more importantly, you heard it before you saw it. And I still maintain that you have an unsavory head bump there.

Your 22 is the 2-track model right? Looking again at the factory response spec it shous +/- 3dB from 40Hz ~ 22kHz...you are running about +/- 4dB in that range, but that is not telling the full picture, because usually the response is dropping off at both ends of the spectrum...yours looks like its still headed uphill at the low end, unless, like I said, it drops off steeply after 32.5Hz...which it might very well do.

Check your manual...there should be a picture of a rec/play amp card in the maintenance section that shows what each trimmer does. If you can find that, can you list what trimmers you have?

And tell us more about what the tape path looks like, wear patterns etc....better yet, put up some pictures...1000 words and all that.
 
Herm, I guess my impetus for saying anything is the fact that the deck is down 3dB by the time it hits 8kHz...that's probably what leddy is hearing (or not hearing as it were). And then its starting to crawl up by 125Hz...He's saying it doesn't sound right and the response curve explains maybe why.

BTW, I can't hear 16K either, at least on the right side for sure...I blame the ride cymbal...:D
 
Lol. The specs on Tascam 22 number two are worse.

32 3
63 2
125 1
250 1
500 1
1000 0
2000 -1
4000 -3
8000 -6
10000 -8
12500 -9
16000 -12
20000 -13

I tested before and after demaging and nothing changed.
 
That is a really...um...really solid low-end response...that curve...it must drop off really steep after 32.5Hz...:eek:

I'm not as concerned about the HF drop, especially not knowing what condition your heads are in.

Does it look like the wrap is correct (the centerline of the head is perpendicular to the tape path)?

Does the 22 have reproduce eq trimmers for low and hi frequency? I'm betting it is hi frequency only, but if you increase that so that you are -2 ~ -3 in the 16 ~ 20kHz range that may actually pull your level up at the 1kHz mark, and then when you drop the repro level trimmer to pull the 1kHz tone back to 0VU it will also drop your low-end head bump a bit essentially flattening things out across the spectrum.

Leddy, can you find the part number for your amp card?

I agree that you have some HF loss there, at least according to my experience...more importantly, you heard it before you saw it. And I still maintain that you have an unsavory head bump there.

Your 22 is the 2-track model right? Looking again at the factory response spec it shous +/- 3dB from 40Hz ~ 22kHz...you are running about +/- 4dB in that range, but that is not telling the full picture, because usually the response is dropping off at both ends of the spectrum...yours looks like its still headed uphill at the low end, unless, like I said, it drops off steeply after 32.5Hz...which it might very well do.

Check your manual...there should be a picture of a rec/play amp card in the maintenance section that shows what each trimmer does. If you can find that, can you list what trimmers you have?

And tell us more about what the tape path looks like, wear patterns etc....better yet, put up some pictures...1000 words and all that.

Tape paths look ok. Both machines are 2-track.

I will explore the manual and look for the trimmers. I will try to get some good pictures as well. It will probably take a day or two - I've got a pretty busy day tomorrow.

As always, thanks for the help.
 
What is the model number of the MRL tape you bought?

21J205

It's an NAB, 250 nWb/m tape, which is what they recommended to me on the phone. (That makes the 1kHz reference +3. So I basically subtracted 3 from each of the numbers).
 
I also found the pages in the manual on adjusting frequency response. I need to find the controls that get adjusted.
 
Wow. The PC board that appears to have the controls for frequency response is really not easy to get to. I don't see how I can get to it while being able to operate the machine to run the test tape. Anyone have a Tascam 22 that knows this stuff? I'll try to post a pic soon.
 
I dont know that much about it. But tascam list the specs on the 22 for 185 tape. Then when you get to the 30 series machines the machines are calibrated for 250.
Im not sure but wouldnt that make a differance:confused:

Ah sorry I just read your post above again and you made adjustments for that. (I think)
 
21J205

It's an NAB, 250 nWb/m tape, which is what they recommended to me on the phone. (That makes the 1kHz reference +3. So I basically subtracted 3 from each of the numbers).

That tape will be fine and you can setup the 22-2 for 250 nWb/m without worrying about compensating. I have one of my 22-2's calibrated to 250 @ 0VU.

The setup section in the 22-2 manual is really lacking compared to other Tascam decks. I've been meaning to write up a better procedure, but haven't had time. I use the procedure from the 32 manual, which is more complete. Of course you have to translate the 32’s adjustment points into those of the 22-2.

I can’t find the 32 manual on the Tascam site… they keep movin’ stuff around, but here’s the one that used to be at tascamcontractor.com

http://web.archive.org/web/20021120....com/ftp_resources/files/manual/32_manual.pdf

The 22-2 was originally marketed to the small home/project studio, but it’s much more capable than how it’s set at the factory. The reason they chose 185 nWb/m was so people could use standard (at the time) Hi-Fi tapes from the local stereo shop or K-Mart. Back in the day there was more of a split in marketing… consumer vs. pro. People bought TDK, Maxell and Radio Shack brand tapes for their home Hi-Fi decks and that’s what Tascam expected people would use on the 22-2.

The listed specs for the 22-2 are poorer than they would be had they used a better blank tape for the tests. The tape itself affects the S/N, distortion, etc. I’m not sure exactly what kind of tape YTT-8013 (blank tape) is, but it’s not a modern high output tape.

So use something like Quantegy 407/457, 3M/Scotch 207 or RMGI LPR35 with the 22-2 calibrated to 250 nWb/m, 1kHz @ 0VU and you’ll have performance on par with the Tascam 32. Even 200 nWb/m would be a good setting if using Quantegy 407, 3M 207 or Maxell XLI 35-90B.

When you’re using a cal tape with a higher flux level than you want the machine set for, for example you want the machine at 200 nWb/m, but have a 250 nWb/m cal tape, you should adjust the meter needle up by 2VU from 0VU (+2) while playing the 1kHz test tone from the cal tape.

I’ll try to whip something up shortly that makes calibrating more straight-forward… as soon as I dig myself out of this list of things I have to do – fix car, fix lawnmower, paint mom’s house, etc. I haven’t had a lot of time lately for the bbs…

I’ll Be Back

:)
 
Thanks Beck. Whenever you have time - I appreciate the help. :)

My main concern at the moment is being able to identify the controls to make any adjustments, and can I access them without having to take the thing apart too much.

I'm wondering if the 22 was not designed to be adjusted much outside the factory...
 
I don't know if I mentioned this before, and you commented at the very beginning of this thread but it is possible that you will need to recalibrate the bias for the tape you are using - if you haven't done so already.



AK
 
22-2 tape use

For future readers and those that want to know from a Teac Technician. The flux density of most Tascam 1/2 track decks is 250nWb/M and the old 185 standard can not be obtained anymore so I use 200 when 185 is needed. The 1/2 track format and machines running at 15 IPS can tale 250 nWb/M and have no problem with good tape like SM911 or SM900 or ATR Master.
I never heard of YTT1044 until lately and they did not have it around when I worked there.
We used MRL tapes for the 250nWb/M tape as I have the one here that Teac Chicago used to use.
 
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