What To Upgrade
Tannoy Monitor Gold are really special drivers, but similarly to other vintage speakers, performance of these is limited by the quality electronic components used in the crossover. Upgrades described below provide improvements in the sound clarity and smoothness. They are not exactly cheap, but one could perform these using less expensive capacitors and achieve similar level of improvements. Tannoy Monitor Gold crossover’s weakest point is the electrolytic capacitors and replacing these will provide the most significant difference in sound. Replacing resistors in not essential, but doing this using a good quality non inductive resistors is not going to do any harm. 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 too. 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 don’t always match schematics, so it is good to have a LCR meter on hand.
Upgrade Process – Tannoy Monitor Gold Crossover
Due to limited space in the original Tannoy Monitor Gold crossover enclosures, I 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 non-inductive 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 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 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.
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 a 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 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 Tannoy Monitor Gold crossover and connectors upgrade described above. The prices were correct at the time of publishing this article.
|Capacitors||Original Value||Rep. Value||Quantity||Price Per Unit||Total Price|
|Jantzen Audio Superior Z-Cap||16μF||15μF
|Jantzen Audio Superior Z-Cap||6.8μF||6.8μF||2||£25.08||£50.16|
|Jantzen Audio Superior Z-Cap||3.3μF||3.3μF||2||£16.24||£32.48|
|Jantzen Audio Superior Z-Cap||1.5μF||1.5uF||2||£11.81||£23.62|
|Resistors||Original Value||Rep. Value||Quantity||Price Per Unit||Total Price|
|Mills Resistors MRA12||50Ω||51Ω||2||£4.80||£9.60|
|Mills Resistors MRA12||20Ω||20Ω||2||£4.80||£9.60|
|Mills Resistors MRA12p||10Ω||10Ω||2||£4.80||£9.60|
|Miscellaneous||Item Details||Unit||Quantity||Price Per Unit||Total Price|
|PTFE ø0.91mm2 Wire||SP OFC||0.3m||2||£3.78||£7.56|
|Jantzen Audio Terminal Strip||Gold Plated||Piece||2||£10.00||£20.00|
|QED Silver Anniversary XT||SP 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|