Various tape formulas & Record BIAS/EQ Switches

[Charlie]

For many years, I was pretty loyal to Maxell UD tapes. Just once, I used an XL2 EE to record the Goodbye Yellow Brick Road album at 3 3/4 on my X700R. I never bought another EE tape after that. Not that I was unsatisfied with the recording... I just figured I would have been just as happy using a UD tape on 7.5. During that time, I was also using an A-2060, and it just didn't sound right on that machine.

Since then, I've obtained a few other machines. Here's what I have nowadays....

X-700R
A-2050
A-2060
A-3340S
A-4010S
A-4010GSL
A-4070
TC-377

Three of the above models have seperate BIAS & EQ switches, and the Sony has a "Normal/Special" tape switch. In the past couple of years, I've obtained a selection of various tape formulas. The owner's manuals of the machines give a small chart of tape models showing how to set the switches, but they're mainly older tapes that we rarely see anymore. Years ago, this really wasn't a concern for me being I only had two machines and stuck to one type of tape. But now.... soooo many choices! How should the BIAS & EQ switches set for the following tapes....

Maxell XL1
Sony ULH
TDK Audua LB
Scotch Dynarange

Also, are there any other tape formulas that require the higher settings on the recorder?

Out of the different tapes I've used, I've only been disappointed with the Ampex/Quantegy 456/457 tapes as they developed that sticky tape syndrome once they got a few years on them. Ampex really dropped the ball on that one! Those made really nice recordings 15 years ago, but today they won't even pass thru the machine without squealing and coming to a halt.

 

[goldear]

Trial and error is the best that I can recommend. When you make your recordings try ti both ways and settle on the seeting which makes the tape sound as much like the source as possible.

The problem is that even if you have an up-to-date chart for each machine, unless your machine has been calibrated recently (very unlikely, unless you have done it yourself), these machines will all be far enough out of calibration that the settings probably wont be a reliable match anymore anyways.

If you have a spectrum analyser, you can record some pink-noise through the machine and simply set your setting to the place where you get the flattest reponse.

Lastly: I've never heard of sticky-shed infecting Quantegy tape. To the best of my knowledge, that was purely an Ampex problem which when away when Quantegy took over production of these tape forumlations.

 

[Charlie]

I know for a fact that the 3340 hasn't been touched on the calibration. As for the others, I'm just going to assume they haven't been. I did try switching back and forth between the settings and I can notice a very slight difference, but it's only because I'm doing the switching. I suppose I'll just leave them on the normal settings as that's what I've always done in the past.

Yes, I have a couple of Quantegy 407's that will barely play through any of my machines. Fast forwarding and rewinding is certainly out of the question. Perhaps they were simply old stock Ampex in a Quantegy box. I've read how you can bake them in the oven, but sounds like only a temporary fix and I'm not going to bother with that.

 

[goldear]

You misunderstand me: All equipment naturally drifts out of calebration over time with no effort on anybodys part. Father time does this all on his own. Carbon resistor drift in value over time, and Electrolytic capacitors become progressively less capacitive, and more resistive over time, paper capacitors become leaky, mica capacitors become leaky, trimpots get dirty, heads get worn, etc.

My point was that unless you are going to the effort to re-calebrate all of your machines, the old bias tables will not be that accurate for a given machine anymore. Do a little experimentation on your own, and see which way your ears like it best.

 

[Charlie]

Sorry, I worded that poorly. I meant that these machines haven't been touched up on their calibrations since leaving the factory years ago.