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Back to:  TD-160 Dept.

The 'Chadwick Mods' revisited.

Above photo: 9/7/2015. Just after the latest restoration.

I've decided to undo some of the 'Chadwick mods' I had carried out on my TD160 several years earlier.  After making the listening observations I have, and in consideration of another individual (Charles Trayhorn ) recognized as an Audio Professional, I have decided to take a more conservative approach that employs the best of Trayhorn's ideas along with what I consider the most effective mod carried out by Steven Grant's company known as Chadwick Modifications.

What I'm keeping: 

The more substantial bottom plate.
The Dynamat I applied to the underside of the motorboard.  
The RCA jack plate installed to the back of the standard Thorens cabinetry.
I'm keeping the foam inserts 'out' of the suspension springs.

What I'm undoing:

The cork / silicone applied to both sides of the suspended subchassis 
Almost all of that Blu-Tack I had applied to the adjoining surfaces of motorboard and cabinet.
That ridiculous thing I did; covering the outer casing of the motor with blu-tack.
At one time I had stuffed the underside of the plastic armboard with blu-tack.  It came back out not long after.  Just noting.
I had put some Dynamat on the top of the motorboard that is obscured by the inner platter.  That came off.
That Dynamat I had applied to the underside of the inner platter (hub).  Out it came. The Dynamat residue cleaned off nicely with acetone.
I'm putting the transit locks back into the cabinetry.

What I'm doing:

Using a bituminous felt ( a rather stiff version of it I've been able to source) applied to the bottom side of the suspended subchassis.
Making a new bottom plate, this time with MDF.
maintenance on the TP16 tonearm.  disassembly, clean all parts, especially pivot brg cones and cups (with balls) with alcohol and/or acetone, reassemble and adjust pivot bearings.

Here are some photos of the TD160 C after the 'restoration / modification'.

The Subchassis

DSC_1522.jpg (237968 bytes)  DSC_1523.jpg (224149 bytes) hint: click on thumbnail to view the image full size.

Above two photos: The subchassis after the cork/silicone removal.  Back to standard....., briefly.

DSC_1530.jpg (306165 bytes) A photo showing the bared subchassis next to the binuminous felt about to be applied to it. This 'felt' is very stiff.  Very tough.  Cuts better with a saw than by blade.

DSC_1531.jpg (222906 bytes)  After the glue dried.  Now I've got a single layer of dampening material that also happens to stiffen the metal subchassis a tad.

DSC_1532.jpg (340810 bytes) Oh yes, the adhesive that was used.  Dry time takes 48 hours for a full cure. Pretty strong stuff.  Don't inhale!  It uses MEK.

DSC_1534.jpg (260831 bytes) Looking at the cleaned up TD160 cabinetry. (aka plinth). In this view we can appreciate that the veneer on the inside is Walnut while the veneer on the outside is Teak.  Standard for that period of production. Also in this view can be seen the RCA jacks as well as the ground stud mounted to the jack plate..

DSC_1535.jpg (257289 bytes) From the back side the RCA jack plate is seen.  I chose American Walnut for the plate material.  I could have used aluminum plate, but chose to stick with organic materials.

DSC_1536.jpg (344314 bytes) Close-up view of the jack plate and jacks.  Gold plate on brass connectors with white teflon insulator.

DSC_1537.jpg (276311 bytes)  Looking at the original bottom cover which I assembled to the cabinet for this photo.  The original bottom cover makes an excellent pattern for making the more substantial cover to be used.  Otherwise, it stays off.

DSC_1541.jpg (244736 bytes) The new bottom cover installed. Material: 1/2" MDF. I deliberately chose MDF for its audio friendly properties.  1/4-20 thread inserts were installed so that cone feet of choice can be used.  Additionally, the rubber feet at each corner is also an option, depending on what one might choose.

DSC_1540.jpg (236209 bytes) From above looking inside. Note that the transit lock screws have been installed.  I'm retaining the functionality of the transit locks for practical reasons.

DSC_1544.jpg (232781 bytes)  Looking at the cone foot.  It partially covers the counter-sunk screw that secures the bottom plate to the cabinet.  If one wants the four corner screws can hold rubber feet. The screw hole countersink is made deep enough so that the cone foot does not make contact with the fastener screw.

Assembling the Motorboard:

DSC_1547.jpg (306408 bytes)  The motor board with subchassis, ready to go in.

DSC_1548.jpg (348217 bytes) It goes in from this side (top).

DSC_1549.jpg (275375 bytes) Now it just needs the four fastener screws and we don't forget the four decorative screw caps.

DSC_1551.jpg (284649 bytes) DSC_1552.jpg (311111 bytes) DSC_1553.jpg (268608 bytes) DSC_1554.jpg (276274 bytes)  The flexy black plastic cap 'snaps' over the screw.

DSC_1556.jpg (323437 bytes) Looking in with the turntable inverted.  Hook up the speed change shaft.  Install the power cord retainer. Tonearm has yet to be installed.

DSC_1557.jpg (300258 bytes) Next; install the tonearm.  The TP16 (mk1) will be retained.  But not after a full disassembly, clean, reassemble and pivot brg adjust.

DSC_1558.jpg (255897 bytes) Nice and clean. 

DSC_1560.jpg (225689 bytes) The three mounting screws (2 visible) installed and secure.

DSC_1561.jpg (354188 bytes) Turntable is inverted again.  This time with extra care to protect the exposed tonearm underneath.  The cue is operated by a spring loaded flexible steel cable.  The knob in front operates the cable which needs to be connected to the knob cams.

DSC_1562.jpg (358114 bytes) In this shot the cue cable has been installed to the cams underneath the control knob.

DSC_1565.jpg (284581 bytes) Close-up detail showing the cue mechanicals at the tonearm end.

DSC_1566.jpg (344927 bytes)  Tonearm signal wires are soldered to the RCA jacks.  The tonearm body ground wire solders to the ground stud on the jack plate. The chassis/bearing ground from the ,motorboard tab solders also to the ground stud at the jack plate.  Original Thorens signal wires are retained.  These are extremely fine gage cable and of a low enough capacitance to be used on even the fussiest of cartridges.

External views:

DSC_1568.jpg (307713 bytes) DSC_1569.jpg (306950 bytes)

DSC_1570.jpg (291825 bytes)  DSC_1585.jpg (250456 bytes)

DSC_1584.jpg (185808 bytes) trying out Simone Luchetti's precision machined aluminum clutch pulley (more info on this pulley: link)

DSC_1573.jpg (133612 bytes) DSC_1574.jpg (157927 bytes)The cartridge is a Realistic R1000ED. (re-labeled Shure M75 ED) 

DSC_1578.jpg (204602 bytes) In this pic the dustcover is installed.  This turntable I pampered all its life.  Dustcover is free of any scratches.  That's rare for a turntable bought new in 1975.  (making me the original and current owner)


UK. Charles Trayhorn at Metrosound. Early development of what was to become the Thorens TD160 Super.

Trayhorn mods: circa mid 1970's

remove foam from suspension springs
motorboard and subchassis damped on underside with bituminous felt
replaced plastic tonearm board with a high density version left blank to be cut to customer's choice of tonearms
standard cabinetry replaced with a larger more solid version
dustcover hinges replaced with metal ones

Thorens TD160 Super

Thorens essentially used the above list of 'Trayhorn mods' and based them on its TD160 mkII in AB configuration. (Came without a tonearm)

Chadwick Modifications: 

"Chadwick Modifications" was the name of the company. Steven C. Grant operated it in Cambridge, Massachusetts.. And...his middle name was Chadwick, hence the company name.

The Chadwick 'mods' carried out on a Thorens turntable were different from those employed by Trayhorn and Thorens.  He used the standard Thorens cabinetry, but replaced the thin flexy masonite bottom cover with a far more solid bottom plate made from 1/2" thick  baltic birch plywood.  He used silicone damping materials on the undersides of the motor-board and sub-chassis.  He used silicone also to damp the inside of the inner platter (hub).  See below for a list of mods carried out on a TD125 that was featured in a review by Steven Stone in TAS vol 14, issue 58, march/april 1989 (pgs 102,105).  Readjustment of tonearm pivot bearings and selectively dampened the arm tube.

He sold a 'corktone' platter mat and included that in his list of mods. He offered to replace the standard signal cables with a Sumiko PIP rca output box and then the customer could use any interconnect preferred.

End of updates.


Below: Old notes circa 2001 - 2003.  I maintain these to this page just for reference.  Many mods done then are now considered by me to be obsolete and I won't go there again.


This page documents modifications done to my TD-160 and reports how well they worked.

8/19/2003: Some time has passed since I first wrote this page. Back then I was looking for a project and so thought it might be fun to make improvements to a turntable.  As it turned out, it is quite fun and nearly two years later, I'm still at it. What follows is the revised and continuing story of my test mule, a TD160 mk1 that sounds much better than any standard Thorens has a right to.  Initially, I just wanted to see whether it was easy or hard to improve on one of these models.  Now I can say that much of this work really is simple and, as a bonus, cheap to carry out.  

You can't really start a project without a plan.  Initially, I looked for a plan, a list of procedures to carry out.  What I came up with was the list below.  The Chadwick mods.  These became my plan. Back in the latter days of the LP era, Chadwick used to advertise in the classified sections of audio magazines.  He offered an upgrade service for Thorens turntables.  I remember sending for and receiving his catalog.  I never did send in my Thorens and, ultimately, lost track of the catalog.  Then came CD's and years of idleness for the Thorens.....sigh. 

 Chadwick ad_sphile_89edits.jpg (438850 bytes) hint: click on thumbnail to view image full size.

Above scan taken from an audio magazine classifieds circa 1989

I didn't completely forget the Chadwick mods and when renewed interest in vinyl came over me, (circa 1990's) I began looking for information on Chadwick Modifications and exactly what it was that the company did for its customer's tables.  The links below offer the best detail I could find.  Steven C. Grant died in 1999 and, as far as I know,  took the knowledge of his method with him.  Otherwise I'd have called him up.

Link: http://www.audioasylum.com/audio/vinyl/messages/15633.html

The Thorens is a much discussed turntable on the internet at the audio-asylum, (vinyl-asylum) which can be found at the link below:


Within the archives there I was able to dig up the following scraps of a recipe  of Chadwick mods on a TD-125.  Here  is the link to the full post which refers to a magazine article in the Absolute Sound and an A/B comparison between the modified Thorens and a much pricier VPI table: http://www.audioasylum.com/audio/vinyl/messages/95257.html


9 mods were done:

  1. baltic birch plywood 1/2 inch replacing the existing bottom plate with three spikes or cones underneath

  2. isolation of the 3 suspension springs of the suspension using new gaskets and silicone

  3. dampening the top of the motor plate and the underside of the top plate with 2 kinds of silicon damping material

  4. readjustment of the bearings and selective damping of the arm tube

  5. dampening of the platter hub with silicon and rebalancing

  6. lining the underside of the arm board with cork for further isolation

  7. replacing the rubber mat with a Chadwick "Corktone" mat

  8. replacing the standard interconnect with a Sumiko PIP box and the interconnects of your choice

  9. installing and aligning of the arm and cartridge of your choice


I have experimented with the above list and have the following thoughts about it.

  1. The birch ply bottom plate really does work wonders for a TD160, but mdf should work fine too. 

  2. I do not use silicone on the rubber grommets at the susp. springs of a TD160...!  Follow the Tim Bailey method instead.

  3. Yes, damp the motor plate

  4. Yes, adjust tonearm bearings, they probably need it especially if the arm is a TP16.

  5. Yes damp the hub platter.  The attached spindle shaft spins in bushings and noses down against a vertical thrust plate. Bearing vibes happen there. It helps to keep plenty of oil in the bearing housing, by the way.

  6. Sure, damp the arm board.  Why not.  Just don't add a bunch of weight.

  7. Yes, the standard platter mat can be improved.  Cork works.

  8. Nice idea.  The Thorens phono outputs can be improved on.

  9. Yes, naturally.  A better arm and cart will work miracles.

Below are links to pages that detail the various work to be done.

Blue_tack.jpg (159925 bytes)Chassis Damping

Sg_apart.jpg (41988 bytes)Suspension Tuning tutorial by Tim Bailey

rot_sprng.jpg (202357 bytes) More suspension tuning notes.....with lots of pictures....and movies

overhang_web.jpg (97898 bytes) Tonearm/cartridge alignment definition of terms use info here to align your tonearm.

BPS3d_styl.jpg (22192 bytes) Cartridge / Arm matching

RKbelt_1.jpg (81306 bytes) Finding a proper replacement belt Testing replacement belts from various belt vendors.

arm_assy.jpg (71996 bytes) TP16 MK I Tonearm, maintaining the cue mechanism Restoring the cue drop time.

plus Installing RCA jacks for the interconnect of your choice.

P6280002web.jpg (94603 bytes) Rewiring a TP16mkII with silver wire. Wei Zhu sent in these photos of his experience.


Mounting a different Tonearm, SME 3009 Improved

Parking it on a wall shelf  Suspended tables like it on the wall.




The result of all this work is well worth the time invested.  The transformation is like having a completely different table.  Background noise is way down. Signal to noise is way up.  A sense of "in-the-room" presence is apparent.  Soundstage, imaging.  Notes hanging in air that didn't used to hang.  Cymbals having more shimmer. Now it's making some music that draws you in.


Most Effective (Important) Tweaks:

1) Correct settings of suspension, tonearm and cartridge.  If it were a car, you'd call it tune-up, lube and maintenance.

2) Damping  

Make the heavy bottom plate  

Damp the motor plate  

Damp the inner platter  (bearing hub)

3) Wall shelf.  This eliminated the problem of structural born vibration disturbance that plagued this table when it was placed on a floor standing audio rack .  The wall shelf allows the suspension to become stable and then it can react as it was designed to against the forces happening between stylus and groove.  Also, life with the player is much better this way by allowing me the freedom to walk by without having to tip toe.   

4) Drive belt, renew it with an original equipment replacement. Worn out belts lose grip during the more dynamic moments on a record and in the lower frequency notes.  The result is lifeless music.  A new belt brings back your dynamics and bass response.

5) Tonearm / arm board upgrade (replacement with SME 3009)  The tonearm is important, but so is the arm board it mounts to.  Different materials result in different sounds.

6) Phono Cartridge, get one that matches well to your tonearm. (Effective mass versus compliance of cantilever)  Basic rule: More money in the cartridge = better sound.  The question becomes "where do you draw the line...?"  Consider the value of the table, quality of the tonearm.  More info to come on cartridge/arm matching.

7) Platter mat. For a long time, I was not a believer in platter mat tweaks.  That changed when I tested Malcolm Coulsen's Spotmat.  This led to some experimentation of my own and, ultimately, mat #10.  This mat allows a more solid lower frequency and a more alive and natural sounding midrange. More musical detail reaches my ears.  Yes, mats can make a difference.  Have some fun, make your own.



What is my reference.....?  Teres 145, Thorens TD124

 The SME 3009 S2 Improved is a lower mass version of their previous arm.  It is also lighter and smaller and fits under the dustcover of the TD160 without interference.  However.....

It might be best, when considering a tonearm swap to first choose the cartridge you wish to use.  Following that, select a tonearm that will match well.  Then, of course, you have the problem of determining if that arm will match well to your turntable.  One thing leads to another, then another....etc.  With the assortment of cartridges and arms available to choose from, your perfect match is entirely possible.  More info about using this tonearm on a TD160.


Materials list:

Bottom Plate

1/2 inch birch plywood, Grade A.  One piece at 12-15/16 x 16-1/2 (note, I had to buy an entire 4ft. x 8ft. sheet.)

4 - rubber feet, hole in center for wood screw mounting. (hardware store item)

4 - #8 x 1 inch brass wood screws


1 - 4 sq.ft. piece Dynamat (can be found at Car Stereo stores)

2 - 36 x 12 inch pieces of 1/8 inch automotive cork gasket material

1 - tube Blue RTV Silicone

1 - package of Blu-Tak (Bostik) available at audiophile vendors

4- packages of Elmer's Tac 'N Stik (Blu-Tak substitute, much cheaper commonly available)

Suspension Tuning

1 - can of talc (available at billiard supply shops)


Link to page for the tonearm details




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