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UPGRADE: Tannoy Monitor Gold 15

   As a big fan of vintage speakers, Tannoy Monitor Golds 15" were on my wish list for a long  time. Couple of years ago I have become a lucky owner of these beautiful drivers. As with nearly all vintage speakers, performance of these Monitor Golds was limited by poor quality electronic components. For this reason I have decided to perform the upgrades described below. They provide significant improvements in the sound clarity, smoothness and dynamics. Not cheap but well worth doing.


What To Upgrade
   The starting point is the electrolytic capacitors. Resistors can be changed too. The inductors are not the best in the world, but it would be very difficult to find exact match for one of them, therefore, I did not bother changing them at all. Cables and plugs are relatively poor quality and I would recommend changing these. The crossovers are nicely made, nonetheless, they are made from components that were available in the 60s - just bear in mind that vintage British gear can be full of surprises, the components values dont always match schematics, so it is good to have a RCL meter on hand.


Upgrades
   All sockets and plugs were replaced with low resistance, 4pin gold plated XLR Neutrik connectors. Sockets were mounted on the drivers using circular plywood adaptors and existing screw holes. Driver internal wiring was replaced with silver plated, OFC copper cables. Soldering relatively large diameter cables can be a bit tricky in narrow spaces, so it is always important to protect the diaphragm's back with something, if soldering is happening near the driver. 

   Due to limited space in the original plastic crossovers enclosure, I have decided to build them from scratch using only original inductors and replacing all the other parts with new, better quality components. Crossovers were built on the 10mm MDF boards, using Jantzen Audio gold plated terminal strips and damping materials under each component. All original capacitors were replaced with matched pairs of Jantzen Audio Superior Z-Caps. All resistors were replaced with Mills MRA12. All wiring was replaced with QED Silver Anniversary XT (silver plated, OFC copper). The original potentiometers (treble energy and roll off) were left in place with an intention of using them to match the sound to my room, and then soldering them permanently in desired position.

   All vintage equipment is prone to aging and Monitor Golds are not an exception. I have seen many of these drivers with white sediment inside the metal horns, which I can only assume is caused by combination of over 40 years of British humid weather and untreated metal horn. Not many people actually look in the horns as they are difficult to see through the mesh dust cap. Because of my pedantic nature, I always look where 'mentally healthy' people don't... My Monitor Golds had very thin partial layer of this sediment too. As this speakers were bought with an intention of keeping them for the rest of my life, I have decided to clean the sediment and spray paint the horns gold to protect them for any more sediments settling down in the future. Magnets together with horns were were fairly easy to disassemble (please note - it is important to mark exact position of the magnet against speaker basket before removing it). Magnets were wrapped in thick black foil and all the gaps were tightly sealed using tape. The sediment in the horns was cleaned using mini sand blaster and aluminium oxide abrasive. Horns were then spray painted gold (phase plug holes were sealed using small wooden sticks, to prevent paint from plugging them). Magnets were then mounted back to the baskets in the very same position as they were taken from.

 

List of Components & Prices
   Table below shows list of the parts together with prices, necessary to do crossover and connectors upgrade described above.

Project Summary:
Total Time: 20h
Total Cost: 366.85

 

Capacitors: Original Value Replacement Value Quantity Price Per Unit Total Price

Jantzen Audio Superior Z-Cap

16uF 15uF
1uF
2 44.61
9.94
89.22
19.88
6.8uF 6.8uF 25.08 50.16
3.3uF 3.3uF 16.24 32.48
1.5uf 1.5uF 11.81 23.62

TOTAL

215.36

 

Resistors: Original Value Replacement Value Quantity Price Per Unit Total Price
Mills Resistors MRA12 50Ω 51Ω 2 4.80 9.60
20Ω 20Ω 4.80 9.60
10Ω 10Ω 4.80 9.60

TOTAL

28.80

 

Miscellaneous: Item Specific Unit Quantity Price Per Unit Total Price
PTFE 0.91mm2 Wire Silver Plated OFC 0.3m 2 3.78 7.56
Jantzen Audio Terminal Strip Gold Plated Piece 2 10.00 20.00
QED Silver Anniversary XT Silver Plated OFC 1m 10 7.00 70.00
Neutrik 4P XLR Plug NC4FXX-B Gold Plated Piece 2 6.73 13.46
Neutrik 4P XLR Sockets NC4MPB Gold Plated Piece 2 5.83 11.66

TOTAL

122.69

 

Copyright 2014 by Brast.