You'll find many reviews on the Timbre and Timbre Ultimate around. Paraphrased, many say "I can solder really well, but this is hell". Lesson one, believe them. They tell no lie.
I bought the Timbre Ultimate more out of curiosity figuring that if it didn't work out I'd at least have a silent jack, (which is a great thing). Pairing it with Sommer Spirit LLX cable at 7,2 mm was either brave or foolish & was out of the spec which gives 7mm as the max. cable diameter for the Timbre.
Some assembly tips and notes. Prepare the cable according to the Neutrik instructions. This will almost certainly help with smaller diameter cables around 6mm. For the LLX prepare to be up for a challenge and get creative. Firstly put the connector together as it should go but without putting in any cable. Notice how it should all fit, notice that the cable chuck has 2 cut-outs so get the orientation right for correct assembly, otherwise you will need to rotate by 180 degrees. Soldering isn't the problem¬ use a good holder for the connector, a hot iron, and take care. Nothing fancy there. The problem is mechanical. It's routing the centre conductor and ground shield connections either side of the central mounting screw and its post to get the two connector halves together. In doing this you'll also need to stow and route the red wire from the top half of the connector and which provides the connection from the jack tip to the capacitor switch. You may need to reapply your solder joints to do this and there will surely be a lot of fritzing about. Eventually you'll get it and screw the 2 connector halves snugly together nice and flush. This screw is important as it also provides the ground connection to the capacitors in the switch. At this point you might breathe a sight of relief. But not so soon! You've got to fix your cable in the chuck and insert it and clamp it down using the screw threads on the rear of the connector. You've done this before with Neutrik connectors right? Don't forget here though how little space is available inside the connector given that now you have that cable in there and that central screw and its post too. Good luck.
Now there are companies out there that will provide you finished cables confectioned with Neutrik Timbre plugs attached. And I say "kudos" to them: there has to be easier ways to earn your money.
Anyway dear reader: I did it and succeeded. Finally finished the assembly & all well mounted, tight and working. So let's review this thing.
What the Timbre does with it's 4 position switch is, either nothing or adds 1, 2.2 or 3.2nF capacitors in parallel across the cable. This is akin to adding virtual cable length to your setup. This rolls off the high end and at the max capacitance emulates Hendrix-era coily cables that actually tamed the ferocious highs of dimed Marshall amps at the time.
Does it work? Yes it does.
Isn't it just like your standard tone control? Actually nope it isn't. The reason is to do with the resonance peak coming from the RLC circuit of which your pickups, volume controls, tone cap(s), cable capacitance and amp input impedance are all part. The cable capacitance affects the Q, and its position in frequency in a subtly different but significant way than the fixed guitar tone capacitor that is fed into the circuit via a variable resistor (pot). This then affects the high-frequency roll off in a different manner. It is also not akin to the bright switch on your amp (which is more like a "treble-bleed" circuit) or to the tone stack in your amp either (which is post-buffer).
In my main squeeze, a strat copy, I have 16-way Stellartone ToneStylers installed as tone controls for the neck and bridge pickups. Each adds 15 different capacitors across the guitar output (cable) and provides very nuanced tone controls without ever adding "mud". It's superficially similar to the Gibson Varitone circuit and there are other commercially available products out there. The Timbre does the same albeit in only 3 capacitance steps, at a lower cost by putting it on the end of your cable rather than requiring a guitar mod. My mid pickup alone doesn't have a tone control and using the Timbre gives me a greater degree of tonal flexibility. Very quick to adjust on the fly and very intuitive. Since I added a 280k volume pot to this guitar I've been getting more highs, and on-demand I can tame them with the Timbre, (with the ToneStylers too ofcourse). All very clearly noticeable in a home or studio situation but live I don't know how many folks would notice or care. In my opinion though the Timbre can get you into rounded jazzy tones and Carlos Santana tonal territory. Not to forget SRV and Hendrix who clearly didn't like too many highs in their signal. I haven't tried it but imagine using a preferred Timbre setting and adding additional high roll-off with a mild, non-muddy tone control setting would be beneficial and versatile.
And a gentle observation - it's amazing how many folks are actively chasing vintage guitar tone right down to the absolute last incredible material science detail. Many times they are listening to their vintage tones through modern, low-capacitance cables with superb conductors. In short, they are not hearing vintage correct tones without taking into account the types of instrument cables that were available at the time.
Famously the first wireless guitar systems were considered by many to be too harsh, allowing too much top-end through. Guitarists complained and the companies listened adding a parallel input capacitor to their inputs to emulate a longer rather than shorter connecting cable. I'm not running wireless but I am sure a Timbre plus short connecting cable to the transmitter would do the same thing for such a system but with a greater degree of control.
So I started this as an experiment really, but colour me impressed. Although the design in some ways isn't great. I don't see how Neutrik could have done it better really. Unless having a quarter inch jack socket as an output rather a cable connector would have been an option, (at the same size & in order to be able to connect different cables). That would have been great. But I cannot fault the function of the unit: tactile & grippy, intuitive & providing real EQ differences without mud; like a tone control does & should do.
Do you need one? No probably not. And particularly if you regard all of this as cork sniffing.
Do you have the inclination and perseverance to assemble one in the face of adversity? Probably not and especially given the price.
Would I recommend it? Actually yes. If you have the money to spend. Well done to Neutrik for having the balls to produce such a fiddly, niche product that only few will need and use but will in-fact be appreciated by those that have them. When I finished it I told myself that I would never be able to install one on my Evidence Audio Lyric HG cable. And now I'm starting to wonder..... if I might be up for another challenge.....