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Tweaks for Rega Planet, the long, unabridged version

Lately, I have seen several questions on tweaks to the original Rega Planet.

I performed the following tweaks to a friend's player, it now sounds WAY better than a Rega Jupiter. The CDP will sound less digital, smoother and maintain its original qualities of excellent
instrumental timbre and soundstaging.

My mods consist of :
damping
adding mass
shielding
upgrading passive parts
upgrading the digital power supply
upgrading the power cord
modifying a low-lass filter in the output section.

Additionally, you can purchase from Guido Tent in Holland a very
affordable super clock of his own manufacture that comes with a
dedicated power supply regulator. I believe it costs Euro 128. This is a worthwhile upgrade and very easy to perform, because the Rega has the clock installed in the middle of the board, in a non-crowded area.
I think I spent less than $300 doing the mods, not including a new clock.

Shopping list:

four 11DQ10 schottky diodes from Digikey

one LM1086-NT-5 5v fixed regulator, latest generation, from Digikey

very thin and flexible teflon/silver wire (AWG 24-26 is fine, stranded
is OK) for the grounding/shielding connections

pure OFC AWG 22 copper wire for the analog output connections (avoid CAT5 wire,
it sounds bright).

Four automotive sound-deadening sheets from partsexpress.com or from
auto supply stores, at least 1/8" thick, the thicker the better.

One Audio Additive aluminum damping sheet from musicdirect.com

Two RCA female connectors of your choice ( I highly recommend Vampire
OFC with direct gold plating from Welbornelabs.com, IMO they sound much better than Cardas or other gold/over silver or gold/over nickel RCAs)

One Belden 83802 power cord from Subaruguru's power products, minus the
IEC plug (you won't need that). ernest_meunier@msn.com.NO.SPAM

One roll of 3M shielding copper tape from digikey.com.
I bought the 3/8" wide tape. This is expensive, $25, but worth every
cent. This tape is used by embassies, the CIA and FBI to seal their
communications rooms against electronic espionage.

Panasonic THSA, Elna or Sanyo Oscon replacements for EVERY electrolytic cap on the main board. Welborne Labs has few values but excellent prices. Elna are discontinued, avoid them or buy lots of spares. Look for the rest on Google.

One small rubber grommet

Elmer's glue

Blu-tack (Poster glue)

You will have to open up the Rega (four Allen screws on the bottom) to
find out the capacitor values, I did not keep an inventory.


Here's the Rega layout (pretend it is clock dial):

12 o'clock: toroidal trafo
1: digital output section
2: DAC and analog outputs (on a semi-isolated board)
3, 4, 5: digital logic
6: display and display PS
8-10: transport


Mods:

1-Open up player. Watch out the 3 wires connecting the transport cover
switch to the
digital board. If possible, cut them and fit a small 3-4 pin gold plated
connector pair to facilitate disassembly/reassembly.

2-Remove ribbon cable from transport to digital board. Mark which side
goes up. Wrap ribbon cable with 3M tape (like a bandage), taking care
not to short the end connections. Stick a piece of thin silver plated
wire under the last turn of 3M tape. Wrap tape around one more turn and make sure that the wire is secure. Leave 10" of wire to enable
connection to the central ground point.

3-Remove short ribbon cable between digital and analog sections, wrap with 3M copper tape and ground it (as above).

4-Remove 5 Phillips head screws and lift circuit board WITH back panel and display attached.

5-Cut a piece of aluminum damping sheet and stick it on top of every IC (same size as IC), excluding the DAC and including 2 ICs hidden under the circuit board. Do the same the ICs under the transport. Remove blue protective plastic from the aluminum pieces.

6-Cut a 10" piece of thin insulated wire, strip 1/2", place it on top of every aluminum damper and hold in place with the 3M tape. Press firmly with your nails, make the 3M tape hold the wire firmly in place and watch for shorts against the IC pins.

7- Trim the length of the wires, strip the other end and solder all the ground wires to the central ground point (close to screw and pressure
washer at 1 o'clock).
In my friend's player, I found out that grounding the transport ICs
increased read errors and track skipping, so I left those out.
Shielding the DAC seemed to increase its temperature too much, I left it out.

8-Re-tighten transport screws to the same torque as the tightest one. The transport on a Rega should NOT be free to float.

9-Replace the 2 pairs of parallel diodes closest to the transformer with Schottkys. Watch polarity, the cathode side is silk screened on the board.

10-Replace the caps after those diodes with at least double the
capacitance, high-grade caps.

Do not replace diodes on the display supply, which is marked as -30V and is located close to the front panel.

11- Replace 7805 digital regulator with LM-1085 5V fixed regulator. Warning: the 1085 pin out is different. Print the data sheets of both regulators to figure out how to connect.
I mount the LM 1085 facing the opposite side of the player (because
the input leg is on the opposite side of 7805), insulate and cross the
Ground and Adjust legs.

12-Reassemble player, look for the 7V test point, adjust the on-board
trimpot for precisely 7.00 V (3 digit DMM). This must be done with a
plastic screwdriver and the transport connected... quite tricky!!

13-Substitute all the remaining capacitors in the digital and analog sections with same value/same voltage or higher voltage, except for two caps that feed + and - 12V to the DAC chip. They are located at the back of the player, close to the right hand corner. I found out that increasing their size to 470 uF 25 V improved the bass.

DO not increase the value of the digital board caps. They are small to keep ESL and ESR low and effectively shunt noise to ground.

BTW I do not like bypass caps, they always sound like a step-response to my ears.

14-Stretch the rubber grommet and fit it tightly over the crystal (small canteen shaped metal can). Fill the cavity on top with Elmer's glue. Let dry overnight. Put a LARGE blob of blue tack on top of the crystal and two ceramic caps that are mounted close to it. Cover everything with at least a 3/4" high blob. Press firmly towards the circuit board.

OR

Get a XO2 16.9344 Mhz clock from Guido Tent (Euro 128 last time I bought it):evaguido@iael.net.NO_SPAM

15-Cut out with pliers the steel links to the crummy plastic/nickel output jacks, remove back screw, remove the RCAs, replace with Vampire OFC, isolated from chassis with nylon washers. Wire with AWG 22 OFC wire (silver wire is no good on this player, the Rega lacks the last bit of bass punch, silver will make matters worse).

16-There's a shield in the back panel made of aluminum sheet. If the shield is torn, repair with the 3 M tape (the adhesive is conductive).

17-Solder in place a new, shielded, high current power cord. Remember to wrap the last 10 inches of cord to the ferrite ring. You will need to drill larger holes in the circuit board to accommodate the thicker wire. Do not connect the power cord shield to the player, only to the AC outlet side of the cord.
I strongly recommend SubaruGuru's (Ernest Meunier) or Chris Ven Haus
shielded power cords (http://venhaus1.com/VH_Audio_Test.html).
I believe it will cost less than $40 for 5 feet of cord plus a hospital grade AC plug.

18- Cut out to size and stick the automotive sound-deadening sheets to every surface close to the transport, including the cabinet bottom. The more the merrier.
Take care that the damping material does not interfere with the carriage movement.

19- Cut out two 1/2" by 1 1/2" (guesstimate) strips of automotive
sound-deadening sheet and wrap around the spindle motor and carriage
motor. Take care not to interfere with the white gears and transport
mechanism. Cover at least 50 % of the motors, that's OK for damping
vibration. If possible hold in place with a full circle of duct tape
(that's very tricky).

20- Last but not least, locate two 5Kohms resistors in series and a ceramic cap to ground (per channel) between the DAC output and the RCA OUTs.
Replace 5K resistors with 200 ohms Kiwame, Mills or Riken. Replace cap with 1.2 nanofarads polystirene cap (1n2).
The two Rs in series and the cap to ground form a low pass filter
centered at 660,000 hZ, it removes a slight edge from the treble (yes, I have read that human beings hear only to 20 Khz...go figure).
The Rega owner noticed the removal of the filter in about 15 minutes. I put it back, with smaller Rs and larger C, achieving the same filter response as the original parts, but with much lower output impedance.

21-Use AWG 22 wire to connect the second 200 ohm resistors to the new RCA sockets. Remove two ferrite beads per channel from the circuit board and feed the AWG 22 output wire thru the beads. Glue them in place with Elmer's glue to avoid shorts. You have eliminated at least 4 solder joints from the output section.

Happy tweaking and enjoy the music!
If in doubt, I can be contacted thru the Asylum.
BTW I do not perform these mods commercially nor have any business affiliations with the recommended suppliers.
Good luck!





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Topic - Tweaks for Rega Planet, the long, unabridged version - Carlos 22:41:37 05/24/03 (5)


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