Hello,

I have to go along with another poster here...think higher up the food
chain. (see note at end why some grammar constructs).

I have BCC'd this to someone I know at another archive at your
institution who may have a machine to help you out, but I'd like to use
your question to provide some general, overall philosophical approaches
to this.

First, I've been known to say, "Oh, you want me to restore this tape for
you, well, first I need to restore the machine to play it on."

That is usually said tongue-in-cheek.

Seriously, my goal after over a decade of full-time professional audio
tape restoration is to minimize the platforms that I need to maintain.

To that end, I have apparently cornered the market on Sony APR-5000
machines. If you can get a good-condition, late-model Sony APR-5000 and
a few less wonderful machines (mainly for their head assemblies) this is
perhaps the best machine ever made for transferring a wide variety of
tapes. John French can make you specialized head assemblies from his
broad collection of heads.

It will remember settings for up to 12 different head assemblies, and
each head assembly can be programmed via its DIP switch to have the
machine run at 3.75/7.5/15 in/s OR 7.5/15/30 in/s. You can reserve two
memory locations for the same head assembly, changing the DIP switch as
you remount it to run 3.75 in/s to 30 in/s with the same assembly, with
7.5 and 15 in/s available in either setting.

But wait, there is more, you're wondering what this has to do about 1.88
in/s. Well, the machines (if they are working properly) have a +/- 50 %
variable speed control, so by running the machine at 3.75 in/s and
dialing in -50 % varispeed--presto a machine running at 1.88 in/s. A
solid, professional, three-motor, three-head machine with top notch specs.

In fact, I am in the process of getting out of A810s completely, though
they are lovely machines, they duplicate all the functionality I have on
the Sony APRs plus my other transport of choice for serious music, the
Studer A80.

Now, you may be wondering about equalization. That is easily
accomplished by purchasing a 1.88 in/s calibration tape from MRL and
running it on the APR-5003V with the 50 % varispeed engaged. There are
three presets for each speed for each of the 12 head assemblies -- a
total of 108 presets can be stored in each machine (though you need to
separately calibrate each machine/head combination, you can't just
transfer the numbers). I prefer to call them bank A/B/C, so on machines
I do 1.88 in/s transfers, I set up bank C at the slow speed to be
correct for 1.88 in/s.

Another option is to use a better transport at 3.75 in/s and ingest at a
96 kHz sampling frequency and then halve the sampling frequency and
adjust the EQ if necessary. There are several ways to adjust the EQ. (1)
Use the 1.88 in/s calibration tape and play it at double speed and
adjust that to be flat
(2) Use the normal 3.75 in/s EQ and find the required offsets using the
tools described here
http://home.comcast.net/~mrltapes/standard-tape-flux-vs-freq.html
(3) Use the 1.88 in/s calibration tape and the normal 3.75 in/s playback
EQ as in (2) but make a filter based on the tape playback rather than
using the calculated offsets.

The upper frequency limit of this transfer is seriously limited. I
recall looking at Tandberg specs for 1.88 in/s and my recollection was
the record-play response was lucky to make it to 8 kHz. With standard
heads, that is about all you can expect. If you invest in narrow-gap
repro heads (Susan's Logging Revox has such heads) you can reproduce a
bit higher--I would guess 12 to maybe 15 kHz, but I doubt anything was
put on the tape that high at 1.88 in/s. This is the reason why ending up
with a 48 kHz file is just fine for this speed.

The coating thickness makes good high-frequency response difficult at
1.88 in/s with standard audio tapes. Cassettes made it out to 22 kHz
with everything tweaked correctly on a few Nakamichi machines, but that
tape has a thinner coating. Some cassette tapes would lose the extreme
highs just sitting around doing nothing. We don't know why. No one was
ever interested in investigating it.

As to azimuth, I am a firm believer that the only correct azimuth is the
one that matches the azimuth of the record head for the tape currently
being transferred. To me, there is no such thing as a "good azimuth
setting" out of context of the azimuth needed to play the tape.

I do recall receiving several tapes from a studio where my friend Roger
Ginsley had worked and I called him up and asked him if he had worked
there during those years. I told him the tapes had his signature on
them. They were the closest I had ever seen to calibration tape azimuth
in, at that point, six or seven years of work. He had worked there when
the tapes were made.

Rather than belabor the azimuth point, I have an article on my blog
about this and I may turn this into a blog post as well.
http://richardhess.com/notes/2006/09/27/azimuth-hows-and-whys/

One other optional transport that I would consider for this--and this is
a long discussion--is the Racal Store 4DS instrumentation recorder. It
requires more EQ tricks in the computer as it has instrumentation
equalization, not audio equalization. Here are a few blog posts on that
machine which also mention the Sony APR.
http://richardhess.com/notes/category/audio/reels/racal-store-4ds/

One other thing to consider with the Sony APRs. I have turned a pair of
them into a "Frankensony" 4-track playback machine. One machine pulls
the tape, but the head channels 2 & 4 are jumpered across to the
adjacent machine via a modified head assembly and use that machine's
electronics to play back those channels. In that way, I can deal with up
to four-channel tapes on a pair of APR-5000s.

Did I mention the APR-5000 can also be fairly easily converted to
1/2-inch operation as long as you get one with the large rollers that
have inverted cups on them rather than one-piece assemblies?

I am removing your name and identifying information and taking the
liberty of cross-posting this to ARSC list as some there might benefit
as well.

Cheers,

Richard



On 2014-11-04 9:28 AM, someone wrote:
> Hello all-
>
> Before I get started on a new, large project, I thought I might ask which decks some of you might be using for digital transfer of 1 7/8 ips tapes. I have several small decks at my disposal (Sony TC-800B, Uher 4000 Report-5, etc).
>
> I have great signal strength and the azimuth is set nicely on the Sony and the tapes are in good shape, so I think I'm fine, but I wanted to throw this out to a larger pool of brains and expertise.
>
> Any thoughts are welcome.
>
> Thanks!
>
--
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada 647 479 2800
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.