A Source with Gold Signature sold on eBay

 I saw this deck and Odyssey Gold Signature for sale on eBay via Westlake Audio in Newton Abbot in Devon.

The deck is a standard Source with the 3D power supply, but the arm is Gold Signature number 015, with an amethyst as decoration on the head block. Both look like they are in excellent condition.

Serial Numbers

 I found a list of some Source serial numbers among some old papers, but only from early December 1986  to late March1987. They show number, customer, plinth and top plate finish, type of power supply, arm board cut-out, and shipping date.

 I have no other information on later decks.

Turntable Wiring Diagram Revised

The early MRM Sources had an LED on the front to indicate 33 and 45 rpm. Due to the strange way it was done the platter would occasionally start cogging when ostensibly switched off with the switch in the centre position. Mike's solution was to either ignore it or switch off at the plug (or the power supply if you had a 3D, which of course he had).

On the later Source-Odyssey models I redesigned the circuit and omitted the LED so that the switch actually disconnected the psu. A number of owners have revised their early decks to eliminated the LED. Using the existing components it is not possible to have both the LED and the disconnected psu without changing the switch to one with an extra gang such as a rotary switch. An alternative is to wire in a second switch to switch the feed from the power supply.

To get an idea of the options and what is involved in changing the wiring, here is a description of the wiring layout in the early Source. Photos of his deck, courtesy of Rob Cole. 

The early MRM  decks had a bicolour LED at the front. These AC PSU decks had a full wave bridge rectifier  (the little black box on the motor board) near where the wires from the power socket at the bottom of the photo, enter at pins 4 and 5. They could also run on DC from the bigger supplies such as the 3D. The wires near the round capacitor are pins 6 and 7. The group of three and the group of two grey wires are heading to the switch. The three are for the speed change and are actually coming from the far edge of the board, pins 1,2,3, passing under the motor.

The LED was fed from a little circuit mounted on the switch which was powered from pins 6 and 7. See photos and circuit schematic Fig 1.

  

 

The LED had three wires one for each colour and a common. 

There was no switching on the supply side, so the deck was prone to cogging when the switch was in the middle position (the notional "off") as this also switched off the speed setting, leaving the motor without a reference.

The cogging can be avoided by switching off at the power supply or mains socket.

The later decks had no LED, and a DC PSU connected to pin 6 (via the switch) and to pin7.  One gang of the switch switched the motor board speed connections, and the other gang broke the supply to the motor when in the centre position, like the Fig 2.

 

If you are rewiring the deck to eliminate the LED, take care with the motor board solder points, as they are fragile and the pcb tracks can lift and break. It is best to leave them and use the existing wires which are already soldered to the board. Doing it this way has the added advantage of not needing to remove the motor, which can be a pain. See schematic Fig 2.

 

The safest procedure is to first unsolder the LED wiring from the switch, leaving untouched the group of three grey wires connected to the speed change pins 1, 2, and 3 on the motor board (top three in the photo below).

 

Remove/ de-solder the components (resistors and transistor), leaving only the group of two grey wires. Solder one of these, together with a short insulated link, to an outside tag on the switch (where the purple wire is in the photo above,) and the other to the centre tag of the switch )where the white wire is. Solder the other end of the link  to the other outer tag of the switch. Don't forget to solder this link across the switch.

Then at the input socket unsolder the wire on the round pin of the two pin DIN (the power supply wire which goes to pin 5), leaving it still attached to the motor board.

As close to the motor board as you can, snip off the group of two wires which supplied power to the LED. Then take one of the two grey wires returning from the switch, strip the end and solder it to the DIN. Solder the other end to the wire going to the motor board, insulating with heatshrink sleeving.

Unless you use a different 3 position switch with an extra gang, eg a rotary switch, it is not possible to have the two colour LED. 

 

You could have a single colour to indicate on/off if it is wired in parallel with the switched supply i.e across pins 6 and 7. See schematic Fig 3. In this case you would desolder the wire at the round pin of the DIN, and leave the group of two grey wires from the LED uncut at the motor board as is.

The components and LED would be left in situ and the wires to the switch disconnected (white with green stripe, purple, green) at the switch. Then connect the old centre wire (white with green stripe to whichever of the LED wires you have just disconnected from the outer tags (purple or green) to get the colour you prefer. 

You would then have to run two new wires, to replace the two grey ones in the non-LED circuit (Fig 2). One  from the centre tag on the switch,  to join the wire to pin 5 that was previously disconnected  from the DIN and one from an outer tag at the switch to the DIN. At the switch, a link would be soldered to
between both outer tags.

 If you wish to add an extra switch to isolate the input from the power supply,  insert it so that it breaks the circuit from the psu input socket to the motor board - which are the two wires, grey and grey/black on the left of the picture.

Any questions, drop me an email.

 

Note that wiring colours may be different in decks of different ages.  

Below is my original sketch. The top sketch is the later dc version with either DIN or XLR sockets. Ignore the rest...

A review of upgrades for The Source

I received the following interesting information from Richard Langthorp concerning his various mods to his deck. Thank you, Richard.

MRM  Source upgrades

Lid

The ‘retro-style’ smoked lid supplied can be replaced with a custom made lid if needed to suit the height of arm in use.  My external dimensions were 470w x375dx 83h – holes pre-drilled to suit the existing lid hinges which can be transferred.  Supplier used - Plastics-on-line in Hull.

Platter mats

The following mats auditioned on my Source (VTA adjusted to suit the changes in mat thickness) with the following findings;

Felt Mat (1.5mm) - softer and warmer with a fuller bass but provides a vinyl friendly surface to use on spinning platter.

Origin Live (1mm) – soft, flexible and vinyl friendly.  Noticeably more forward vocals and mid-band than felt mat and provided an increase in surface noise with a lighter balances but more punchy and ‘peaky’ in nature.

Origin Live on top of felt mat - this largely combined the best of the two, though surface noise remained a little higher than the felt alone.

Funkfirm Achromat (3mm) – positive first impressions, with seemingly a more open but forward mid-band, though there was a slight mid bass boom/bloom not encountered with any of the other mats.  Possibly imaged better and more punchy but longer term listening did leave the impression of introducing some mid-range colouration masquerading as greater openness?   Had concerns over dropping vinyl on to a relatively hard spinning surface.

Funkfirm Achromat (5mm) – whilst sharing some of the characteristics of the 3mm it sounded quite splashy and detached, strident and aggressive. 

Oyaide BR12 (5mm) – rather dulled and lacking sparkle and nothing really to commend it against the others with bass a little 'dead' and lacking colour/texture, detail and a bit lifeless, though the soft and patterned rubber should be kind to vinyl.

Blue Horizon (1.5mm) – very different visually comprising light coloured, soft (vinyl friendly) composite cork, rubber, leather combo.  Using only the single layer of the two supplied this provided a well-balanced presentation, solid, well defined bass, good imaging and provided vocals with a sweetness not present with any of the new mats and appeared to build on the best features of the felt mat and was well balanced and focused presentation.

The Blue Horizon appeared to show up the OL and Achromat as being coloured in bass, mid, vocal areas and a little 'confused' in the mid-range emphasizing sibilance/splashiness; which the Blue Horizon separated and left far more enjoyable and relaxing; all the other mats would have left an unsatisfactory compromise.

Power Supply

My Source came with a plastic cased 19V supply and having considered having a 2D or 3D supply made I decided to buy a bespoke but commercially available supply from MCRU. 

The new supply revealed more solid, punchy focused tuneful low frequencies, better rhythmically with greater texture and detail.  The mid-upper range showed vocals better separated on multi-mixes with greater space and improved fine detail and more natural throughout.  Soundstage was a lot wider with greater 3D effect in all directions with more space - an improved and more engaging experience.  On switch back to the basic supplied unit, the soundstage collapsed in on itself width quite dramatically, bass was a little slower and less interesting the whole sound being in relative terms a little flat and less natural. The only perceived changed in balance was that this now appeared a little 'thinner' and the mid/upper bass and the mid-range it appeared that there was now a 'bloom'/ or a layer of  unwanted background mush which had been eradicated in the new unit.

Mains lead

The standard mains lead was thinner, smaller, more forward sounding with an increase is surface noise; vocals a little veiled/pinched/raw compared with a Clearer Audio Copperline.  A further quite significant benefit was noted when using a Clearer Audio pure Silver Optimus Reference mains lead which produced tighter, more controlled and more punchy and dynamic low frequencies; mid and higher up the range the sound was more delicate, and open with more air around the vocals with a greater sense of fine detail, ultimately more natural, enjoyable and tuneful.

Source sold

Deck now sold.

Source Sold

This Source was for sale on ebay from HiFi Hangar:

I have no opinion on the condition or otherwise of any deck. Just letting you know.
It is an MRM or early Source-Odyssey deck, with the LED on the front and the big 3D PSU.

Cleaning the bearing

The Source bearing consisted of a chunky brass housing with a screw thread which had a hardened steel thrust plate at the bottom of the bore, lined with two ptfe sleeves to take radial forces.  The housing was attached to the sub-chassis with a large nut and lock washer.

The spindle was steel, hardened and ground, with a countersink machined in the end, which rested on a chrome steel 8mm ball.

If the platter is tight and not free running, then there are some simple things to try.

The sub platter should lift out. If it is stuck and doesn't move at all, then the oil in the bearing will have dried out and it would be best to initially try a solvent such as Zippo lighter fuel to try and loosen it, by tilting the deck and letting run down the bearing. Use plenty paper kitchen towel to stop the fluid getting on the deck surface. Give it 5 minutes, then see if there is any movement.

If not, then an alternative is a product such as Liquid Wrench, or other penetrating oil, which can be directed to the bearing via the little tube they provide. Leave it to work overnight, then repeat if necessary.

Once the sub platter is out, clean up the shaft with solvent and 0000 grade steel wool. Rinse it well with lighter fluid to ensure no wool or residue remain on the surface. then wipe with oil. Clean off any belt rubber residue on the rim. (While you are at it, do the same for the motor pulley, using lighter fluid, and put a tiny drop of oil on the shaft of the motor so that it runs down into the bearing.)

Remove the ball bearing from the housing by using a magnetic screwdriver or suchlike. If it is pitted, buy a replacement ball. The ball is chrome steel, 8mm.

Pour lighter fluid/ penetrating fluid, into the bearing housing and use cotton buds to clean it out and remove residue from the sleeves and thrust plate. rinse with lighter fluid and dry it out.

The bearing housing only needs enough oil to cover the ball halfway. Don't over-oil as the sub platter spindle will displace it as it enters the housing. Wipe the spindle with oil prior to inserting it. Remember to put the ball in before replacing the sub platter.

Use specific turntable oil or compressor oil to relube.

The sub platter will take some time to sit properly in the housing, because the air has to escape as the platter drops. Don't force it down, let it settle by itself.

While you're at it,  replace the belt. A Thorens TD150/160 belt will do.

Note: Only use polish on the outer platter. Don't use it anywhere near the sub platter and bearing, or the motor pulley.

For reference, if the motor and PSU seem ok, then there are a few other things to go wrong, other than in the bearing. The motor pulley might be slipping on the shaft, or, as mentioned above, the belt is stretched and too slack, or there is rubber residue on the motor pulley and sub platter, causing rough running.