View Full Version : Tannoy Monitor Gold External Crossover Development by Tannoyista

The Black Adder
09-01-2012, 19:50

Hi all.

Here are some pics of the development of my Monitor Gold external crossovers by Tannoyista for those interested.

All images contained in this thread are copyright of Tannoyista 2018


This was my first version. These were originally for my 12" MG fitted in Lancaster cabinets. All of the components including the coils were from Falcon electronics.


After a while I had these taken out of the cabinets. I must say that moving the crossovers out of the Lancaster cabinets is a big plus. The of the 12" MG in the lancasters is always bettered with the front port open. Closing the port makes the sound chesty and the swing of the low frequencies are much to be desired.

So if you are running 12" MG's in Lancasters and you have the port sealed up, I recommend you unblock it.

If however you are running 15" MG's in Lancasters the idea of the port being sealed makes total sense... Let's just say that the white coats at Tannoy back in the day knew what they were doing.


Made my Nick Gorham.

Nick made a new version which included much better sounding components such as Clarity Cap ESA capacitors. The little plug board you can see is to change the roll-off settings as per the original design.

The cases were nice too. This version of the crossover was as the design of the Tannoy G Schematic which was floating around on the net at the time. But unfortunately it had been doctored with inaccurate values. Although they still sounded great, electrically wise it wasn't correct.

Original Tannoy crossovers were (at the best of times) inconsistently built. Reportedly components such as capacitors, resistors and sometimes coils swayed massively in value. Some down to age but a large part of the components were actually wrong to start with.

Time constraints and overbooked order sheets causing shortages of certain components were probably to blame.



Component wise these were pretty much spot on but the board was a little to small but this design took things to the next level.

V3 was still using the same coils as V2 but with the addition of a Sowter Autoformer which I must say was a huge step up in sound quality. It was a bit of overkill as I only needed the level setting. But the quality of the winding made it worth while.

These had wired outputs to the speaker which also stepped things up once more.


Using Clarity Cap MR a and Jensen caps I found the sonics were instantly wider, deeper and with much more flesh. I also used Duelund Cast resistors in these to which I must say are totally excellent.

The R&D of these had me go through a number of types of caps and resistors before settling on this combination. Over 100hrs was put in getting to this stage, each change was noted and each note was meticulously cross referenced back.

Every change of component was noted and given listing time, only one change was made at any one time.

At this point I was now using both 12" and 15" MG's to give a good comparison between the two drivers. Some people diss the 12" over the 15" but truth be told the 12" MG has a beautiful speed and vibrancy. It's slightly quicker sounding than the 15" and therefore it should never be said that it's way more inferior to it's larger sister. The 15" MG does have everything you need and more but to get the 'everything' out of either sized driver you need to match them with a well designed cabinet.

The cabinet is very important and if you get that right the use of either size driver will bring a magnificent grin to your boat. (Boat / Boat race = face).

The MG's need internal space to give you their best. Unfortunately the Lancaster cabinet is way to small for this. Although you get some of the Tannoy magic using the Lancaster (or equivalent) it's only until you use something like the Lockwood Universals or better still the Lockwood Major type cabinets where you hear what all the fuss about with these drivers.

The next stage for the final V4 (below) was to keep the design of the V3 but to experiment on the coils even more. Read on.



Handmade using some of the finest components like Mundorf, Duelund, Jensen and ClarityCap the V4 was the version which made it to a small production of over 10 pieces world wide before production stopped.



The V4 has a bespoke acrylic laser cut base board and has been made to accommodate Mundorf coils with a fixed value HF coil. Ditching the Sowter was a bit of a scary thing to do but it made no sense having a muti-tap unit when level was all that was needed.

The coils are spaced accordingly to avoid interference and this time the board was double sided.

The schematic for this version was in some respects more pure to the original design from Tannoy but the values of the coils and some of the caps were changed to become electrically correct. It was not influenced on the incorrect values given to the doctored schematic which everyone seemed to take as gospel.

Image of circuit designed in 3D.





The V4 is the ULTIMATE crossover for the Monitor Gold. There were 3 versions available with different combinations of specially chosen components. The base board was designed and made with precision with adaptable slots for each configuration. No extra cutting or drilling was needed. Caps and resistors could be changed to any of the 3 major manufactures chosen by Tannoyista (Clarity Cap, Mundorf and Duelund) without disassembly or cutting a new base board. The design enabled people to adapt and change this version to suit.

A truly bespoke crossover designed with passion and care.

All of the binding posts are Cardas Solid copper which IME are unsurpassed.

The beautiful casework is dovetailed and lacquered solid oak.

The underside of the unit (the base) also came with an option of choosing your own note personal too. I chose a lyric from Pink Floyd for my reference crossovers.

I hope you found this article interesting, if you have any questions please get in touch.