Audio Precision Portable One Plus Audio Analyizer and Tone Generator

[Mike Lavigne]

working on learning to properly optimize my tapes, just bought this little toy. I have a local friend who will teach me how to use it. he has the same unit.

 

[Ron Resnick]

How will this analyzer help you optimize your tape machines?

 

[c1ferrari]

I had owned and used an optioned AP P1DD for years and had traded it to my Studer tech some five or so years ago. It's a great rig, but you'll need an older printer with Centronics (?) connector for hard copies of graphs and matrices. I have an optioned Rohde & Schwarz UPV, now, and it is nowhere near as user-friendly for tape folk; however, it is a much more capable instrument. Have fun!

If you're into tubes, you'll need a Tek 576 next with appropriate modules, of course!

 

[c1ferrari]

Did you drop by the AP suite at RMAF?

 

[Ron Resnick]

What operating parameters and functions of a tape machine did you use this device to maintain, Sam?

 

[Mike Lavigne]

How will this analyzer help you optimize your tape machines?

Ron,

if I could give you a chapter and verse answer to your question, I would not need the training I know I need. last week I watched as my friend (with an assist on Studer A-820 info from Ki Choi) calibrated all three of my A-820's for playback for 900 tape, 1/4" for 2 of the machines, and 1/2" for the other one. the 1/2" was calibrated for both 15" ips and 30 ips. this included azimuth adjustment. after these adjustments the playback for some specific tapes we had played was clearly better. this was just for playback for only one tape formula. if I were to have done recording I might have wanted to add test tones to the new tape. this machine can also do that. the decks themselves can do a rough tape calibration but not as well as this machine (the meters on the decks would need to be calibrated). the best decks and highest performance benefits most from the best calibration.

I do have 'fresh' MRL calibration tapes for 1/4" and 1/2" 15ips and 30ips.

clearly I only understand this on a rudimentary levels......I don't know what I don't know. watching the process, I could see I need to acquire the tool and learn about this so i'm comfortable doing this stuff myself.

here is a link to a tape project thread, scroll down and read post 9 and 10 which might give you a better understanding of some of the issues involved. I see this as the same type thing and learning curve involved in cartridge optimization.

https://tapeproject.com/smf/index.php?topic=1102.0

maybe there is a better link someone can post that is easier for a newbie to digest.

OTOH if you get your deck(s) optimized for one tape formulation and one source for recordings and it is always the same you can get by without any of this stuff. but I have lots of tapes from different sources using different tape formulations, many with test tones. and I do plan on making 1/4" and 1/2" dubs. so I have get my brain around this stuff.

 

[Ron Resnick]

Thank you very much for the background on this Mike.

I agree completely with you: if you are going to be this deep into tape you need to know this stuff. I am never going to be as deep into tape as you are, and I do not plan to get into dubbing, but I’ve already gotten myself deep enough that I have to learn some of this too.

 

[c1ferrari]

Hi Ron,

This machine will assist you in completing deck and audio alignments per the Studer manual. With that said, the manual furnished specs for tape stock which is no longer available. My pair of A-820/2CH decks (two 1/4" stacks and two 1/2" stacks) are lined-up for SM900 and ATR Magnetics tape stock. I like to mess around with test & measurement gear -- metrology is an interest of mine -- but I leave the deck and audio alignments to a Studer professional technician with bona fides. Particulary, in light of the second sentence avove.

Hth!

 

[microstrip]

Ron,

if I could give you a chapter and verse answer to your question, I would not need the training I know I need. last week I watched as my friend (with an assist on Studer A-820 info from Ki Choi) calibrated all three of my A-820's for playback for 900 tape, 1/4" for 2 of the machines, and 1/2" for the other one. the 1/2" was calibrated for both 15" ips and 30 ips. this included azimuth adjustment. after these adjustments the playback for some specific tapes we had played was clearly better. this was just for playback for only one tape formula. if I were to have done recording I might have wanted to add test tones to the new tape. this machine can also do that. the decks themselves can do a rough tape calibration but not as well as this machine (the meters on the decks would need to be calibrated). the best decks and highest performance benefits most from the best calibration.

I do have 'fresh' MRL calibration tapes for 1/4" and 1/2" 15ips and 30ips.

clearly I only understand this on a rudimentary levels......I don't know what I don't know. watching the process, I could see I need to acquire the tool and learn about this so i'm comfortable doing this stuff myself.

here is a link to a tape project thread, scroll down and read post 9 and 10 which might give you a better understanding of some of the issues involved. I see this as the same type thing and learning curve involved in cartridge optimization.

https://tapeproject.com/smf/index.php?topic=1102.0

maybe there is a better link someone can post that is easier for a newbie to digest.

OTOH if you get your deck(s) optimized for one tape formulation and one source for recordings and it is always the same you can get by without any of this stuff. but I have lots of tapes from different sources using different tape formulations, many with test tones. and I do plan on making 1/4" and 1/2" dubs. so I have get my brain around this stuff.

Mike,

I am curious concerning what kind of calibration was performed on your A820 - none of the procedures referred by Paul Stubblebine in the thread you refer needs an AP Audio Analyzer, just the test tapes, an oscilloscope and an accurate RMS voltmeter if we can not trust the oscilloscope calibration.

IMHO calibrating a tape machine is much easier than a cartridge - it is fully carried by logical adjustments and measurements, no subjective hearing at all! However, the AP will be probably very useful to calibrate the machine for recording.

 

[Tapetech]

I had owned and used an optioned AP P1DD for years and had traded it to my Studer tech some five or so years ago. It's a great rig, but you'll need an older printer with Centronics (?) connector for hard copies of graphs and matrices.

If you want FR (frequency response) graphs, you can use software programs to do that.

Here is a graph I made with AudioTester V3.0. It's a playback response curve (left and right channels) generated with an MRL sweep tape using my external tape preamp.

 

[ksalno]

Mike,

I am curious concerning what kind of calibration was performed on your A820 - none of the procedures referred by Paul Stubblebine in the thread you refer needs an AP Audio Analyzer, just the test tapes, an oscilloscope and an accurate RMS voltmeter if we can not trust the oscilloscope calibration.

I believe the AP generates the test tones that you would normally get from a test tape, so in that sense it replaces the test tape. It gives you flexibility to calibrate for different types or sizes of tape without needing to own a bunch of test tapes. Either one can do the job, so you don’t absolutely need an AP (or equivalent) to do a calibration. It is probably more of a pro oriented tool than the average hobbyist would need.

 

[microstrip]

I believe the AP generates the test tones that you would normally get from a test tape, so in that sense it replaces the test tape. It gives you flexibility to calibrate for different types or sizes of tape without needing to own a bunch of test tapes. Either one can do the job, so you don’t absolutely need an AP (or equivalent) to do a calibration. It is probably more of a pro oriented tool than the average hobbyist would need.

No, you can't replace the test tapes - they are the geometrical and absolute level references. It is an intrinsic limitation of reel to reel machine calibration - we can't be more accurate than our calibration tapes, except for azimuth where there are some complicated tricks to carry it without an absolute reference, as referred by Fred Thal in another thread.

If a recorded tape has test tones we should calibrate the machine using the tones recorded in the tape before playing it (I must confess I do not do it) . It could be an interesting exercise to compare the recorded test tones of several tape distributors.