Audio cassette alignment revisited

I doubt that those cheap adapters are even close to being in alignment. All they are, is a plastic shell, a tape head and a cord. They work by magnetically coupling the signal between the heads, and that doesn't require precision.

--
Anyone wanting to run for any political office in the US should have to 
have a DD214, and a honorable discharge.

But those adaptor gizmos do not have to consider alignment, in the sense of the lateral position of a piece of tape between guide pins or its azimuth, just vaguely one coil over one head and the other over the other head. As far as tape speed is concerned, I've moved over to correlation of the spindle diameter (x.y9mm diameter where x and y are integres) to capstan rotation speed, for pretty discerning listners, ie one classic music buff and another a railway sounds archiver

Here's a thought...

Do you have any commercially recorded cassettes? If so, use them check the head alignment with an XY (Lissajous) display on your scope. If they're close to each other, you can reasonably assume their alignment is absolute, or very close to it.

They are all high quality machines and work very well, but I know (particul arly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

nd/or what claims to be NOS, and Chinese new, but none of these are anythin g that I'd be willing to put any faith in. When I last looked there was a c ompany which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anythin g about either of these sources.

use. These alignment tapes used to be available from manufacturers like Son y and Nakamichi, and they were relatively inexpensive but unfortunately tho se have not been manufactured for many years.

to to properly align a machine.

They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a ca ssette unit I think. The adapter had a tape "head" of sorts and it had a ca ble coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of a n IPOD or whatever and the adapter's head would induce a signal onto the ca ssette players head. I guess this unit must have employed the NAB character istic curve because the ones I've heard always sounded pretty good to me.

generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for ali gnment purposes? That would totally eliminate the concerns with used tape o f stretching and high frequency roll off.

trying to use one of these run of the mill adapters, or any other high qual ity version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

s group for as long as I have already know that. And although I can no long er hear much above 8KHZ anymore, if you can appreciate it I just want to kn ow that it's there. I just like to transfer my music to cassette and be abl e to listen to it wherever. Thanks Lenny

Azimuth is not the issue. As you mentioned William I can use a commercially made tape and the scope to peak it for that. What I can't do is assure tha t every frequency that is being impressed into the head is being processed, amplified, and frequency compensated by the reproduce amplifier as to prod uce a flat signal output. For that the machine's head must see a finite lev el, either from a standard alignment tape or possibly this hair brained ada pter idea of mine.

Once the reproduce amplifier is flat, the record amplifier can be adjusted using the reproduce amplifier as the standard. Lenny

Hold on here, just what is the issue ? there is an amplifier, it applies a frequency response curve. That is that. Do you think the EQ network is faulty or what ?

[...]

There is a further problem that the original recordings may not have been correctly aligned, or the tapes have become distorted so that they no longer track through the playback machine correctly. You may find you have to replay a sample section of each tape to adjust the azimuth for that particular tape, then rewind it and begin the transfer process.

The alignment process is often a lot easier if you add the two channels to give mono, or if you can display them on an X-Y oscilloscope.

If you really want a proper alignment tape, you could ask Ted Kendall if he can still supply them:

--
~ Adrian Tuddenham ~ 
(Remove the ".invalid"s and add ".co.uk" to reply) 
www.poppyrecords.co.uk

A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.

Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way to to properly align a machine.

I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.

I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.

I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny

As has been pointed out, one of those adaptors will not help in the physical alignment of the head. But, that method will help you to check the EQ of the playback preamplifier. Basically all you need is a single turn loop of wire in the proximity of the head, or put the loop inside of a cassettes shell. Put a resistor between the loop and your generator, like 600 ohm , 50 ohm, whatever your generator needs for a termination. The current through the loop will be constant at all audio frequencies provided the generator is flat too. Then you plot the frequency response at the output of the deck. The response you get is a 6db per octave rolloff starting at nearly DC. Then at 1326 hz there should be a 3db boost added to the 6db rolloff. This is a

120usec EQ. There are also EQ's for 70usec and perhaps 90usec, don't recall the specs for all tape types. There is also a 3180 usec or 1590 usec boost in the low end. So the overall frequency response is the sum of all three EQ's. It is tedious way to do it but the curves are standardized EQ's for NAB. Google for Flux Loop. Or look around on the Ampex Mailing list. You might find the curves. When all is said and done, you still have the issue of tape to head contact, and azimuth at high frequencies, and fringing at low frequencies. A flux loop doesn't help out with that part of the alignment. And it won't help you set the correct playback operating level.Dolby chips need to be hit with the correct operating level otherwise the dolby processing will screw with the EQ too. It might be fun to do, but in the long run, a flux loop will not align a tape deck.

I used to buy BASF alignment tapes at about $100 a shot. They were the only ones that were consistant for cassette. And they didn't last long. I beleive you can still find tapes from MRL (magnetic reference laboratories) or check with JRF, John French. Any tape that is worth using will cost alot. The sony and teac tapes were mass produced garbage.

bg

Good point. Once the playback EQ has been set, it doesn't need adjustment. In fact, most tape decks //don't// have adjustable playback EQ! The curve is standardized.

So the OP doesn't really have a problem. Even if there //is// a pot in the playback EQ, there should be no reason to touch it.

Dolby B dynamically adjusts the curve slightly. Are you trying to calibrate with a compander running at the same time? When all else fails use your ears, after listening to your favorite source material on the same speakers. At 1+7/8 ips it's a miracle they work at all.

Let's back up. Dolby B does not modify playback EQ. This is fixed.

The OP wanted to trim the playback EQ. But on most decks, this is impossible.

• So that brings the discussion to its logical conclusion.

If you're simply /measuring/ the playback response, then of course the noise reduction should be shut off.

• When I bought an Otari MX 5050 many years ago, I noticed that the playback response, using an MRL tape, was off. Looking at the schematic, I discovered that the playback EQ had the wrong resistor value. I changed it to the theoretically correct value -- and the response flattened out to what it should have been. Naturally, the people at Otari told me I didn't know what the hell I was talking about.

I replaced all our Ampex 300s, 350s and Crowns with MX?5050B2s (One 1/2 inch 4 track I think). NTIA grant. Public radio.

Did you ever check playback response with a standard tape? If so, what did you find?

They are all high quality machines and work very well, but I know (particul arly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

nd/or what claims to be NOS, and Chinese new, but none of these are anythin g that I'd be willing to put any faith in. When I last looked there was a c ompany which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anythin g about either of these sources.

use. These alignment tapes used to be available from manufacturers like Son y and Nakamichi, and they were relatively inexpensive but unfortunately tho se have not been manufactured for many years.

to to properly align a machine.

They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a ca ssette unit I think. The adapter had a tape "head" of sorts and it had a ca ble coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of a n IPOD or whatever and the adapter's head would induce a signal onto the ca ssette players head. I guess this unit must have employed the NAB character istic curve because the ones I've heard always sounded pretty good to me.

generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for ali gnment purposes? That would totally eliminate the concerns with used tape o f stretching and high frequency roll off.

trying to use one of these run of the mill adapters, or any other high qual ity version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

s group for as long as I have already know that. And although I can no long er hear much above 8KHZ anymore, if you can appreciate it I just want to kn ow that it's there. I just like to transfer my music to cassette and be abl e to listen to it wherever. Thanks Lenny

During the early 70's I worked on professional multi track Ampex and Scully machines. They were loaded with adjustment pots in both the record and pla yback amplifiers. The adjustments are there to compensate for differences i n heads and to address the problem of component aging. I don't want to assu me that frequency response is OK. I want to see it.

recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.

to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.

way to to properly align a machine.

idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.

my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.

in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny

I must agree. I see many ways to design the precision out of the adapter.

?-)

Nothing terribly unusual. A lot depends on the tape used. We tried to use 406 (stolen from NPR) or 456 exclusively. We were pretty careful with tape as we had more pancakes than flanged reels, and occasionally had to dub a priceless master. After Crowns and Ampex 350 series, I noticed nothing terribly weird about the decks.

By "a standard tape", I meant a reference calibration tape, such as one from MRL.

What standard? We frequently exceeded 250 nW/m or whatever. For a while MRL had no alignment tape for higher saturation operation. If the compensation was off as delivered we wouldn't have dwelled on it, we would have fixed it. My problems were more of mechanical in nature. You can get those things for nothing nowadays.

I'm talking about playback frequency response, which as what the OP was actually interested in.

It doesn't matter what the reference fluxivity is. You can set playback /level/ wherever you want it.

First of all, I tried to post a couple of times and for some reason it woul dn't go through. It's not Google either becasue I already eliminated them a s a problem. I must live in one of "those" areas". Figures.

Anyway, before I was not aware of exactly what you were after, I assumed it was azimuth like most people. Now I see what you are trying to do. In fact upon further examination I take it you also want to record ? Wow.

The problem is getting a reference, you ain't gonna. Even if you get ahold of an old reference tape it is likely to be out, stretched, oxide falliong off or something. As such, thre closest refernce must be determined.

Hopefully you have something that'll generate a 1Khz square wave. I would r ecord that and see how it comes out. In fact I wouild lower the frequency s ome until it comes out pretty much square. Try it at about -3Db, because un less the deck has Dolby HX it is going to roll off more highs at higher lev els.

Then you play it back.

I am going to be right back and reply to myuself becaus all this typind for noting is for the birds.