Hi, Dave,

You have received some good advice already, spanning the gamut from 
Otari to a Studer A820.

The criteria you are looking for is a DC-servo-motor based machine which 
eliminates all dependence on power line frequency.
That suggests that the Studer A80  would not be my first choice as it 
needs different capacitors in the motor circuits for 50/60 Hz.

In the Studer line, the A807, A810, A812, and A820 would work for you. 
The A10 has AC servo motors, but I checked and you don't have to change 
the motor capacitors when the frequency changes. All of these were 
available with the three speeds you request, but they also were 
available in other speeds. For the A810, if you don't want to do 30 in/s 
you're better off with a machine with a four-pole motor. A810s that did 
30 in/s were usually equipped with two-pole motors.
A807/A810 [100/110/120/200/220/240V +/- 10% 50...60 Hz]
A812/A820 [100 to 14 V or 200 to 240 V +/- 10 % 50 or 60 Hz]

The Sony APR-5002 or 5003 or 5003V would be a good choice as well, 
although maintenance is more difficult to find.
[AC100/110/120/200/220/240V at 48Hz to 64Hz]

You need to change the voltage setting on all these machines AND change 
the fuse to ~ 1/2 the value at 240 V as at 120 V. None of these work 
like modern computers that can take 100-240 V without switching.

Unfortunately, most Tascam BR-20 machines sold in the USA, Canada, UK, 
Australia, or Europe, according to the service manual, did NOT have 
adjustable voltage!

As to heads, when you say half track either NAB or DIN, please realize 
that for optimum transfers you need both. Customizing a head assembly 
(or two) with two play heads (one can be covered with teflon tape when 
it is not being used to preserve it) can be made by John French.

All of the above will handle at least 10.5" reels. The Sony and some of 
the Studer machines will handle 12.5" reels.

The Sony and Studer machines are switchable NAB/CCIR EQ.

There is some cobbling involved in dealing with AEG/DIN hubs. Revox made 
a nice DIN plate, the A820 has wonderful DIN hubs.

I think Otari also made DIN plates. Long ago, a company I think called 
"DarkLab" in Germany made EIA to DIN adapters out of plastic.

At this point, if the collection is mostly NAB and EIA reels, I'd wind 
all the DIN mounted tapes onto NAB reels UNLESS they are B-wind, in 
which case you best bet is a B-wind Studer A816...or convert the tapes 
to A-wind. (A-wind is oxide in, the most common in North America, B-wind 
is oxide out.)

Good luck!



On 2021-11-19 3:21 p.m., Walker, Dave M. wrote:
> Hello,
> The Smithsonian Center for Folklife and Cultural Heritage has an upcoming archival audio preservation project in the country Georgia (Sakartvelo) and is seeking recommendations for 1/4” open reel tape machines natively operable on 220V/50Hz AC. In addition, we are seeking sources for a refurbished machine suitable for preservation work meeting the following specifications:
>    *   Capable of handling fragile acetate-backed 1/4” open reel audio tape
>    *   Has a minimum of three playback speeds: 3.75 ips, 7.5 ips, 15 ips  (38.1 cm/s, 19.05 cm/s, 9.525 cm/s)
>    *   Has quarter-track stereo and half-track stereo (NAB or DIN) heads
>    *   Operates on 220V/50Hz power without the use of step-up transformers; switchable is okay
>    *   Capable of handling reel sizes up to 10.5” (NAB or AEG DIN)
>    *   Optional: switchable NAB/CCIR (IEC) EQ
> If you have any information, questions, or potential sources for professional machines meeting these requirements, feel free to direct responses to me off-list at [log in to unmask] Thank you for your time!
> Regards,
> Dave
> -------------
> Dave Walker
> Audiovisual Archivist​
> Smithsonian Institution
> Center for Folklife and Cultural Heritage
> Ralph Rinzler Folklife Archives and Collections
> office: (202) 633-0663

Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada                             647 479 2800
Track Format - Speed - Equalization - Azimuth - Noise Reduction
Quality tape transfers -- even from hard-to-play tapes.