Updated 09/20/2009 0200 hrs. (Z)
The majority of tonearms came as stock "recommended use" by the builders of tables (40's-80's) such as Gray, Russco, QRK, ROK, Sparta, Spotmaster, Collins, Gates/Harris. Most--if not all--of these arms were "tested" or used in the radio/broadcast industry long before making their way onto the custom, do-it-yourself turntables/plinths of the public at-large.
Today, within the community of tonearm and table collectors there is a resurgence of "wanting the correct arm" to go with a specific turntable as recommended or "specified" by early designers/builders of "that" era of idler-drive units. That said, collecting and using of the stock idler units along with the early tonearms is difinately back! Actually, idlers never went away for idler drive owners from the 60'- late 70's, just a short holiday in time checking out all the offerings from afar!
Many of the early tonearms as well as the electronics directly associated with the arm (phono pre's) have now come full-circle, again coming back into "favor". Many are in collectors hands as "stock" units being used to bring back the sound as spec'd by the builders and engineers who first designed and produced them. Many other table/tonearm users/builders are in the custom arena being highly modified and tweaked by those who know what an idler-drive unit can sound like with the right cartridge, stylus, tonearm and phono preamp. RTC has been gathering original material (and original arms) to post under this heading to "spec-out" these arms in original verbiage as well as some interesting (if not "dated) photos.
As spoken of elsewhere on-site, there is a storehouse of information on the web; a vast easily accessible knowledge-base of information on the net concerning all the arms we will be describing and showing.
From Google to Yahoo and all the web-crawlers in between, that curser at your fingertips will ultimately lead you to some broad-based audio forums where resident guru's from newbe's to wizards (some audio folks have forgotten more than I will ever know) hold much knowledge and will help when asked. That said, our info is by no means the last word on any given arm nor is it complete by any means.
If you have any original documentation concerning these or other arms "of note" please consider contributing or sharing the info with RTC so we can post it here, (you will be given full credit for the information)
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Preface
Gray/Micro-Trak, Micropoise, Shure, Audio Technica, Technics, Grace, Russco, and many other tonearms from the 40's through the 80's and beyond...
Many tonearms were "recommended" by their respective turntable builders back when tonearm choices were few and far between. Most of the arms at that point were used, tried and tested in the analog realm of the station, recording studio and the "major" vinyl reproduction houses. Time moved on swiftly in the recording industry, the average consumer becoming impressed with what they could do at home, they listened and were drawn-in, finally the tonearms "of-choice" were made available, passing down to the "common" folks who fell in-like with music although selection was at best, sparse. Ultimately in the environment where reproduction was passed on to all through the "air waves" it was the sound engineer, station manager or one of the "staff" (what was a DJ?) using "their" equipment on-site who influenced the sound you heard. The person in charge having "found" their "preferred" tonearm (usually by way of a very good rep of station equipment) arranged to have "it" mated to the deck of choice which carried over into the studios and control rooms. When you realize many stations of that early era from the 40's-to the late-70's had their own vinyl lathes(sometimes combinations of cutting lathe/playback), thereby cutting, editing and producing their own tracks. A number of enterprising individuals took their equipment "on-site" cutting a master disk on the first "take", no go-backs, no, "let's try it again", "just one more time". Time and budgetary considerations were critical especially when cutting a 78, even more so when most vinyl was cut on one side and that cut was indeed 1 track, per side!
This was only one of the factors helping the station owner/engineer to make up his mind (no offense to the women of the day, but it was a man's world in broadcasting at that time) concerning the "what" to purchase equipment-wise hopefully of the same "ilk" so that their recorded tracks could be spun-up on one of the "recommend" turntables ALSO supplied by the lathe cutting machine company. In short, time moved quickly, improvements were made literally every week to playback and recording equipment. Many an engineer--not only in major markets but in the record industry itself--moonlighted in small side rooms cutting "daughter" disks from masters and playing the tracks on their machine of choice, can you say Presto, Gates, Rek-O-Kut and those were not the "first" big cutters! Once the basic patents on lathes and turntables ran out from the "big-boys", enterprising individuals with some experience on cutting lathes began taking the best designs of the day, combining their eclectic mix of early electric and electronic devices, eventually coming out with a turntable/tonearm/electronics combination THEY could live with, and market. Heck with the "big-boys", individual "audio" engineers and the apprentice help were coming up with some innovative equipment, now it was moving into the main-stream masses and becoming affordable to all.
We will go in-depth as much as possible where tonearm, cartridge/stylus and table combinations come into play where they concern idler-drive units. There are tens of thousands of pages out there on the web with many thousands more supporting posts within forums on the who, what and why of which tonearm to use on belt driven and direct-drive units. We are sticking to the "what" of "what" we know within the idler-drive turntables as in QRK, Russco and "other" branded units , information will be updated as received.
We will have other pages up soon concerning the older "factory branded and recommend" tonearms as in Micro-Trak/Gray, Micropoise and more. Most of these arms were originally used in the studio whether radio or mass-production houses, some passed-on into history yet others came to be used in the home audio systems, not exactly what you needed for quality audio reproduction but better than a gramophone tonearm with a sharpened stylus.
Pictures, Links, write-ups are now being added daily as they are approved as well as the "Go-to" companies we highly recommend.
IMPORTANT INFORMATION
Neither Russcoturntables.com nor QRKturntables.com make ANY profits from the companies we recommend to you, whether tubes, tonearms or parts from these companies. After speaking personally with the owners and reps we know them to be honest in their dealings with all and are well qualified to recommend, sell, and repair any type SME tonearm within their field. Just because we at RTC know Russco, QRK and some other idler units does NOT always qualify RTC to tell you what you want in, (or out) of your analog audio system, your ears have the vote, not your wallet, hmm, well sometimes your wallet sort of "helps" you!
The most expensive turntable is not necessarily the best, likewise the same with tonearms, we are not going to cover re-cover old ground nor delve into horns, woofers, tweeters, cabinets , crossovers, amps, pre-amps, placement or "speakers" in general
Check-out these 3 recommended companies if great sound is what you desire from your Russco-style deck at a reasonable price. Bring your idler-drive table kicking and screaming into the 21st century analog side, hear and feel audio from your 40-50 year-old unit you never thought possible.
You never knew you missed "full" sound reproduction until you once again hear.
Add an Idler-Drive, mix well, Ear Candy!
Idler-drive decks have never left the playback scene. Despite what some "purists" may espouse, idlers have been a well-kept secret awaiting a great tonearm. No need to "guess" what your deck could sound like when brought up to date. SME tonearms and the sound they bring when paired with a Russco style idler-drive table can be measured and heard, bringing listening pleasure to all take the time to listen. SME and Russco, where you want to be when older technology meets new, especially THIS Company!
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Partial update: 09/20/09 0200 hrs. (Z)
Here are some photos of the Russco RTA-12 Tonearm. This was a precision, hand-made piece of equipment, and--therefore--was one of the more expensive tonearms on the market at that time it was being made and sold. RTC's new owner, Skeeter Nash, took these photos to show the elegance, beauty and craftsmanship that went into the RTA-12. Yes, the photos show the Russco tonearm mounted on a QRK 12-C turntable...it was the only one available with a large enough hole to accomodate the tonearm's main support shaft! Special thanks to the tonearm's owner, Mark Moskowitz.
We are in the process of gathering more information on the Russco RTA-12, and when we have it, we will add it to this section of this page. In the meantime, enjoy a look at a genuine piece of American hand-craftsmanship, made in Clovis, CA, USA!
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Once again Mr. Ed Trombley has sent some goodies from his "stash" of info. A good friend with years of "hands-on" tech-time and in-depth knowledge of broadcast "know-how," Mr. Trombley has been instrumental in sharing many pages of info with RTC and allowing us to pass this on to you.
Check the PDF below for Audio-Technica ATP-16T Tonearm Mounting Instructions/Template
Full scale "printable" diagram coming soon (you can download the PDF).
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Update 07/31/2009 0825 hrs. Z
All notes below from original Micro-Trak Corporation "how-to" pamphlets that came with the 303 and 306 tone arms. The pamphlet we are using to take information from is from a stock Micro-Track 306 still boxed, not yet assembled in our collection. If you need a "true copy" we are having them reprinted for those who wish to have an exact replica for information purposes with their arm whether 303 or 306 at a minimal cost of print only. The original 303-306 Tone Arms were branded under the "Gray" logo before being bought out by Micro-Trak Corporation, 620 race St., Holyoke, Massachusetts, 01040 USA.
RTC does not yet have a copy of the original manual from Gray, it may be different. If you have an original or a good copy please let us know, RTC would like to add it to it's free information online.
Template's and photos will be added below information shortly.
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| MICRO-TRAK Corp. 303 & 306 Information 01-09-1977 |
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Gray/Micro-Trak
Instruction Manual
Model 303 Professional Tone Arm
Model 306 Professional Tone Arm
General
The following steps should be followed in order for best results:
1. Unpacking 4. Cartridge Installation
2. Mounting And assembly 5. Final Check
3. Wiring
Unpacking
Carefully remove the parts of the arm from the carton. There should be five separate pieces:
1.Tone Arm Assembly 4. Small Parts Bag
2. Tone Arm Base 5. Template
3. Pivot Assembly
Check the contents of the small parts bag against the list at the back of this manual. Do not
discard any packing material until all parts are accounted for.
Mounting and Assembly
For convenient operation the tone arm should be mounted on the right side of the turntable.
The front of the arm should be located as far as possible from the motor to minimize hum.
The pivot point (center of rear base) should be located as follows.
Model 303 Tone Arm: 8 5/16 inches (211 mm) from the spindle.
Model 306 Tone Arm: 10 5/8 inches (269 mm) from the spindle.
For general installation
The template provided may be used to mark the turntable for drilling.
When the turntable has been marked, drill three (3)- 3/16 inch (4.74 mm) diameter holes for
the base mounting screws, and one (1) - 1 inch (25.4 mm) diameter hole for the pivot and
lead wire. Drill a 7/32 inch (5.55 mm) diameter hole for the arm rest. Mount the base such
that the wire slot is toward the left rear; and mount the arm rest such as the sides are
parallel with the edge of the turntable housing. Note the overhanging portion of the arm
rest. This patented feature of your tone arm is designed to protect your stylus from damage.
If the front rest is located such that the platter, when removed, just clears the end of the rest
overhand, the rest when adjusted to the proper level will not allow the stylus to hit on the
edge of the platter; a major cause of stylus failure. The rear base is mounted with three (3)
1 7/8 inch (47.62 mm) long machine screws, nuts, and washers provided with the hardware.
For SP10 MKII installation
For mounting on our SP10-II Turntable, your model 303 arm is equipped with a new type
mounting base to allow proper mounting for the Technics SP10 Mark II Turntable. The tone
arm is mounted off turntable itself directly to the table surface of the turntable cabinet. You
will note the base is triangular in shape. In the normal installation the tonearm is snug
against the side of the base located per the template. Except for location, the mounting is
the same as above.
Install the pivot assembly in the base leaving the fill hole accessible. remove the cap from
the tube of Anti-Skate fluid and insert the entire contents of the tube into the hole in the
pivot assembly. Take your time during this operation as it may take a few minutes to get all
of the fluid into the housing. Rotate the pivot shaft as you fill.
The arm may now be removed from it's plastic bag. Position the flat on the pivot shaft on the
same side of the arm as the lock screw in the bottom of the arm. Place the arm on the pivot
and tighten the lock screw. feed the wire through the hole in the base, dressing the wire in a
flat loop counter-clockwise around the pivot then into the wire slot. Allow enough wire in
the loop such that the arm swings freely to the center of the platter.
Arm Rest Extension
Your model 303-306 Tone Arm is equipped with an adapter to extend the arm rest higher
than normal for use with turntables where the platter height above the rest mounting
surface makes it necessary. (ie technics SP-10). To use the adapter mount the arm rest in
the normal manner at the location specified on the template. Loosen the set screw holding
the Top Rest and remove it from the base. Find the adapter, 1/4 inch diameter with a male
thread at one end, and screw it into the bottom of the Top Rest post. be sure to tighten
completely. If available, a drop of thread locking cement will insure that it will stay tight.
Reinstall the assembled long Top rest into the base and adjust to final height. Tighten the
set screw. Your arm rest will now allow for approximately 1/2 inch higher adjustment.
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Partial Update 07/31/2009 1105 hrs. Z
If RTC adds any "notations" as per these assembly instructions they will be "noted" within brackets and in italics
Wiring the 303-306 Micro-Trak
The following color code is standard on all Micro-Trak tone arms.
Left Channel .............. Green
Left Channel Ground ... White
Right Channel ............. Red
Right Channel Ground .. Black
By convention, the left channel is used for monaural installations. The shield is wired not to
carry any signals, and serves only as an electrostatic shield (see a). Connect the wires as shown in
figure 1. (Diagram coming soon) To obtain best results with lighter tracking cartridges, check the cable dress and be
and be sure that it is set up as described in the mounting paragraph. With a well dressed cable
tracking pressures as low as 1 gm. may be obtained. (addendum: as per this Tone Arm)
_____________________________________________________________________________
(a) electrostatic shield
An electrostatic shield is principally a means to prevent the electric field from a static charged object from
penetrating. The shield itself can be charged, but inside, no electric field will exist. A component inside an electrostatic
shielding container is safe from the electrical fields associated with static. It is not necessarily shielded from
EMI however. It has been shown that an effective electrostatic shield must have a surface resistivity of less
than 10 4 ohms/sq.
______________________________________________________________________________
Cartridge Installation
Remove the head from the arm by pulling it firmly, straight forward from the body with
the right hand. (see b & c) The left hand should hold the arm body such that undue pressures will not
be applied to the arm support structure.
To obtain the desired tracking pressure, first mount the cartridge (use care in tightening
screws so as not to strip the threads) with no modular weights installed in the head. Replace
the head on the arm and lay weights on the top of the head until the arm achieves neutral
balance. (the stylus should be even with the top of the platter at this time) Add weights, one
at a time until the desired pressure is reached. Each brass weight provides 1 gm. of tracking
pressure. If weights of less than 1 gm. are required, they may be made from the 1 gm. weight
and scissors using the following chart.
3/4 gm. (750 mg.) = 1 inch (25.4 mm)
1/2 gm. (500 mg.) = 3/4 inch (18.7 mm)
1/4 gm. (250 mg.) = 7/16 inch (10.9 mm)
After balancing is completed, slide the wire terminals over the pins on the cartridge per the
appropriate color code as discussed in the wiring paragraph.
This method of balancing in the heads is called "Memory balancing" and using this method;
spare heads may be set up with different cartridges or stylus configurations and may be
used interchangeably without any balance adjustment to the arm, once each head is
balanced.
!! Important !! The position of the rear weight should never be moved. It has been positioned
at the factory to allow use of all standard cartridges currently available and any
repositioning may result in the in inability to attain proper balance.
(b) Be very careful, the Tone Arms are made up of LAMINATED Wood, head shells are Aluminum. The Wood has a female
"type" slot/guide cut almost half-way through the "meat" of the wood where the male
Aluminum "guide" aligns the shell with the Tone Arm. Any off-set or "twisting" of the wrist when "mating-
aligning" will cause irreparable damage to the Tone Arm. Unless you have an equipped machine
shop you will have a very expensive tooth-pick!
(c) Do NOT try and use a 303 head shell on a 306 Tone Arm or vice-versa, they "look" alike yet
the male "guide/slot" on the two arms as well as head-shells are NOT in alignment, NOT "slotted"
in the same place. If forced by mistake, the wood of the tone Arm will split-off!
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Click on a JPEG below to start slide show )
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