Pioneer std-334 and std-331 test tapes

R

rbonvino

Active Member
Hi all,
I am going to service an about 50 years old ct-f9191 tape deck by pioneer. I think it will need the belts replaced, so I gave a look to the service manual and all the electrical adjustment need at least the std-334 test tape. I made some search and found out they're really expensive. Is there anyway to make those tapes on my own? Thanks
 
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There are modern equivalent choices that are less expensive than some other vendors, but quality reference test tapes were, and are still are, expensive. One cannot make a reference tape themselves.
 
oldvinyldude said:
There are modern equivalent choices that are less expensive than some other vendors, but quality reference test tapes were, and are still are, expensive. One cannot make a reference tape themselves.
Click to expand...
Thank you. Would you mind suggesting me some equivalent test tapes and where to buy? Thanks
 
Other possible sources of cassette calibration tapes are discussed in this thread.

Buying test cassettes in the EU

Recently I've come to the conclusion that the Denon DR-M2 serving as my primary tape deck could use some adjustment to make sure things are in spec, so I consulted the manual and found that if I want to go through the entire procedure, I'd need a whole suite of test tapes. The manual only lists...
www.tapeheads.net
 
Hi. Actually I do have a dual channel oscilloscope (120 MHz bandwidth). It features the XY mode to use the Lissajous figures. In order to tune the speed and the azimuth I think I need a 3 kHz tone test tape. Do you think these two would be suitable for the most part of the tests?
P.S. To "estimate" the W&F you could use an oscilloscope or an FFT meter (I have this as well) giving an eye to the frequency modulation of the test tone. This of course could just give you an idea of the W&F.
 
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rbonvino said:
Do you think these two would be suitable for the most part of the tests?
Click to expand...

Not sure, there is not enough detail in the text. Most e-bay 'alignment' cassettes these days are home-brew with a stereo head, making them actually useless for real alignment work, despite the makers' claims.

Apart from speed and track registration an alignment tape has to be full-track, meaning magnetised over the full surface. Only this allows one to decouple mechanical from electronical alignment errors, so that the correction can be applied in the right place with the right method.

Hanspeter Roth in Germany makes and sells full-track tapes, next to ANT in the UK and Gennlab in New Zealand. HPR's tapes are the cheapest, by far, but still of useful quality. https://www.ebay.de/usr/hanspeterroth

You won't find direct Pioneer equivalents, so you will have to do some math to recalculate target voltages from fluxes.
 
In your case it will be quite easy, as the Pioneer SM manual calls for a 250nWb/m tape for setting output level (section 5 of SM). The HPR tape set includes a 250nWb/m tape.

For azimuth the actual level does not matter. HPR includes a 10kHz tape. You can use that. Alternatively (as there are many slightly different azimuth tapes in rotation), you could use a selection of high-quality pre-recorded cassettes, and align by listening, with headphones, in mono, for the highest amount of treble. The average setting of these tapes is also valid azimuth (hopefully agreeing with the HPR tape). Warning: if there is a wear groove in the head then changing azimuth may make things worse, as the tape edge will ride on the groove edge, impairing head contact.

For section 6, playback equaliser, the HPR set is infinitely better than STD-341: it includes a very high quality tape with frequency bursts from 30Hz up to 18kHz. First you align azimuth to one of the 10kHz bursts on this tape, then you run a sequence from 30Hz to 18kHz while measuring and graphing each frequency's level L and R. Ideally the resulting graph is flat. (I record into Audition or Audacity, analyse the levels off-line, then graph in Excel. Example here https://audiochrome.blogspot.com/2022/10/restoring-nad-6340-cassette-deck.html.)
Afterwards don't forget to re-align azimuth!

Speed and wow&flutter. You can use the dedicated HPR tape, but it is known that some have been subject to magnetic fields and now contain LF garbage. Play the tape with a high-pass filter between deck and W&F analyser. Here is a free (and very good) W&F program for PC:
http://www.ant-audio.co.uk/index.php?cat=post&qry=library

Section 7, meter adjustment: play the HPR 250nWb/m tape. Adjust voltage to 412*250/160 = 644mV. Adjust meter needle to +4dB.
 
a dual channel oscilloscope (120 MHz bandwidth). It features the XY mode to use the Lissajous figures.
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XY is a make-do for single-channel scopes. With two channels you simply display both audio channels, then adjust azimuth first for maximal signal strength, and then (ideally) for zero inter-channel phase, i.e. both sine traces on top of each other (but there will be some wander, this is inevitable).

Of course you may conclude that this is all not worth it, with that 9191 being ancient and likely too worn to perform at a high level again. In that case you could use one of those ebay tapes, knowing that the deck is perhaps-sort-of-approximately-aligned. But if you expect to refurbish other decks again, then you do need decent tapes.

Two more tips:

http://audiotester.de/

http://www.anaxwaves.com/NAKT100/
 
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WernerO said:
In your case it will be quite easy, as the Pioneer SM manual calls for a 250nWb/m tape for setting output level (section 5 of SM). The HPR tape set includes a 250nWb/m tape.

For azimuth the actual level does not matter. HPR includes a 10kHz tape. You can use that. Alternatively (as there are many slightly different azimuth tapes in rotation), you could use a selection of high-quality pre-recorded cassettes, and align by listening, with headphones, in mono, for the highest amount of treble. The average setting of these tapes is also valid azimuth (hopefully agreeing with the HPR tape). Warning: if there is a wear groove in the head then changing azimuth may make things worse, as the tape edge will ride on the groove edge, impairing head contact.

For section 6, playback equaliser, the HPR set is infinitely better than STD-341: it includes a very high quality tape with frequency bursts from 30Hz up to 18kHz. First you align azimuth to one of the 10kHz bursts on this tape, then you run a sequence from 30Hz to 18kHz while measuring and graphing each frequency's level L and R. Ideally the resulting graph is flat. (I record into Audition or Audacity, analyse the levels off-line, then graph in Excel. Example here https://audiochrome.blogspot.com/2022/10/restoring-nad-6340-cassette-deck.html.)
Afterwards don't forget to re-align azimuth!

Speed and wow&flutter. You can use the dedicated HPR tape, but it is known that some have been subject to magnetic fields and now contain LF garbage. Play the tape with a high-pass filter between deck and W&F analyser. Here is a free (and very good) W&F program for PC:
http://www.ant-audio.co.uk/index.php?cat=post&qry=library

Section 7, meter adjustment: play the HPR 250nWb/m tape. Adjust voltage to 412*250/160 = 644mV. Adjust meter needle to +4dB.
Click to expand...
Thank you. I yet emailed HPR to discuss the topic
 
WernerO said:
In your case it will be quite easy, as the Pioneer SM manual calls for a 250nWb/m tape for setting output level (section 5 of SM). The HPR tape set includes a 250nWb/m tape.

For azimuth the actual level does not matter. HPR includes a 10kHz tape. You can use that. Alternatively (as there are many slightly different azimuth tapes in rotation), you could use a selection of high-quality pre-recorded cassettes, and align by listening, with headphones, in mono, for the highest amount of treble. The average setting of these tapes is also valid azimuth (hopefully agreeing with the HPR tape). Warning: if there is a wear groove in the head then changing azimuth may make things worse, as the tape edge will ride on the groove edge, impairing head contact.

For section 6, playback equaliser, the HPR set is infinitely better than STD-341: it includes a very high quality tape with frequency bursts from 30Hz up to 18kHz. First you align azimuth to one of the 10kHz bursts on this tape, then you run a sequence from 30Hz to 18kHz while measuring and graphing each frequency's level L and R. Ideally the resulting graph is flat. (I record into Audition or Audacity, analyse the levels off-line, then graph in Excel. Example here https://audiochrome.blogspot.com/2022/10/restoring-nad-6340-cassette-deck.html.)
Afterwards don't forget to re-align azimuth!

Speed and wow&flutter. You can use the dedicated HPR tape, but it is known that some have been subject to magnetic fields and now contain LF garbage. Play the tape with a high-pass filter between deck and W&F analyser. Here is a free (and very good) W&F program for PC:
http://www.ant-audio.co.uk/index.php?cat=post&qry=library

Section 7, meter adjustment: play the HPR 250nWb/m tape. Adjust voltage to 412*250/160 = 644mV. Adjust meter needle to +4dB.
Click to expand...
The 250nWb/m tape is recorded with a 315 Hz tone as far as I can see while the SM says to use a 333 Hz tone. Is it ok anyway?
I agree on the second point. A good 10 kHz tape and an oscilloscope will be enough.
For the section 6 I think a tone near the two stated would do the job as the output frequency response is expected to be flat over all the bandwidth.
The meter adjustment should be done searching for -4 dBv, shouldn't it?
 
as the output frequency response is expected to be flat over all the bandwidth.
Click to expand...

But it likely won't be. Once you have such a good response tape as HPR's it would be a shame not to use it.

The meter adjustment should be done searching for -4 dBv, shouldn't it?
Click to expand...

644mV, see above (is close to -4dBV). Needle at +4dB.
 
Why? I didn't get it...
Regarding the frequency response test tape:

FG frequency response (Revival) Teac FG-MTT-356U 31.5 Hz to 18kHz -20 dB full track Crom

Full track = recorded with Studer A80 and Saki Spezial head 4mm.

There's the note:
The Fg can only work with Cr equalization, the others are for Fe and Cr.

Hence, is it OK to skip the frequency response test without the cr equalization?
 
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I don't get what your problem is.

All of HPR's tapes are made to be replayed at 70us, i.e. chrome / type II position. They are not compatible with 120us.

For most of these tapes this does not really matter, i.e they are good enough at 120us, but for the response tape it is of course critical.
 
WernerO said:
I don't get what your problem is.

All of HPR's tapes are made to be replayed at 70us, i.e. chrome / type II position. They are not compatible with 120us.

For most of these tapes this does not really matter, i.e they are good enough at 120us, but for the response tape it is of course critical.
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Hi Werner,

my concern is about the 6 section of the SM. It states to adjust the output while beeing in the STD mode and confirm the levels in the chrome mode while I see that the HPR's response tape can of course be used just with the CR equalization being the 70us far critical in this test. It looks like the SM does not care too much about this. Did I understand well or am I getting something wrong?
 
The SM sees type I ('STD') as standard, and builds Type II ('CR') on top of that.

Given that the Roth tape is 70us you can only test in Type II/CR position, and have to assume that Type I also will be correct.
That is the same, but in reverse. Normally, if one is good, the other also will be good.

At any rate, after having done the 70us test (aiming at flatness), you can run the same tape at 120us, aiming for the deviation from flatness as predicted by the theoretical difference between 120us and 70us filters. But again, there is no need to do this.


Once you do the 70us test you will likely see that the resulting frequency curve is not flat at all. That will be the result of two things: 1) manufacturers in the 70s did not quite obey the standards, and often built decks with rolled-off treble in playback. This allowed them to artificially boost the SNR specs. It also allowed for buyer-lock-in, making that a recording made on brand A only sounded at its best on a deck from brand A, and not B. And 2) head wear. Depending on the shape of the curve you will have to decide what to do next.
 
Ok, now's all crystal clear. A few more question before starting in the next days:
  • Is this kit suitable or could you recommend a good European seller? I haven't yet give an eye to the belts, but I assume the tape deck needs the belt changed cause it is silent since about nineties;
  • Which points to lubricate and what oil/grease to use?
  • Do you recommend the demagnetization of the head as well?
 
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