Accumulating 20 years experience in producing the tuning devices, the Japanese brand, Harmonix, is well established in our High End audio market and it has been the champion in the tuning devices category for the last 20 years. The tuning master, Mr. Kiuchi, has skillfully utilizing the physical characteristics of woods and metals, calculating for the best shape and right proportion, producing the various tuning devices for the best balanced sound.

TU-666M is a model under the “Million Maestro” series limited edition special tuning feet, being made to celebrate the 20th anniversary of Harmonix. It is also the top of the line of the Harmonix Tuning Feet. One set of 4 pcs., the list price is quite high at HK$12,000.-/set! Please do not be scared by its high price, after our test and experience, it’s proven to be very effective and that is why it’s so expensive. Moreover, we found that once you have tried it in your system, you can’t live without it!

Each piece of the TU-666M of which the diameter is 5cm with the thickness of 3.3cm and the net weight is 380g. It is a round metal tuning foot combined with an adjustable metal base. There is a piece of wood covered on the top of the metal foot and there is also a thin wood in lay on the metal base. The metal is well polished in the sparkling silver tone and it looks very sharp and elegance. The 4 pcs. TU-666M can hold up to 80kgs and it is advised to place under big and heavy preamplifiers, power amplifiers or speakers. As we only get one set of TU-666M, we can’t use it to place under the power amplifiers (as we are using the Goldmund monoblock). I first tried to place it under the Audio Note preamplifier and then tried to remove the original spikes (net weight of 55lbs) on the Wadia S7i CD Player and placed the TU-666M under instead. Obviously the TU-666M made the CD player sound a lot better than its original spikes. After several detailed AB comparison, if you are the Wadia S7i user, you should definitely buy a set of TU-666M for your CD Player.

During this listening test, I also discovered that the new Cardas flagship model Clear interconnect cable sounded excellent. I completely agreed with Megan who wrote the review for it on this same issue. The situation is that, before we used the TU-666M, the interconnect cable being used to connect the Wadia CD player is the Audio Note Sogon II Pure Silver Cable. This is the cable which I used to test the Wadia S7i CD player and I found it sound OK – the clarity and the tonal balance is good. When I removed its original spikes and placed the TU-666M under it (see the following pictures), we listened 3 different CDs. After using the TU-666M under the S7i CD player, we found the transient is definitely faster – you may feel that the hands of the violinist and the cello players moving faster, the music is more lively and dynamic. You can hear very clearly even when the music is played quietly. It gets you the extended high and ultra low frequencies. Moreover, the energy of the high frequency is not decreased but increased – when we listened to the percussion session of the second CD, it was so lively as if the metal China cymbal being played so hard causing sparkling. It was very lively and dynamic that I felt it’s a bit too noisy and it hurt my ears. The titanium dome tweeter of the Sasha is not tuned to be roll-off early, the curve of high frequency is extended to be flat. The TU-666M enhanced the clarity of the high frequency of the Wadia S7i CD player and it helps to reproduce the original recording of the extended high frequency. It should actually be a good thing. However, not all the high clarity and dynamic extended high frequency are pleasing to be listened. Therefore, I decided to remove the Audio Note Sogon II pure silver interconnect cable, and replaced it with the Cardas Clear pure copper interconnect cable. Bingo! It worked so well that the extended high frequency still sounded very lively and dynamic but it’s no longer to be unbearable even it was played in high volume level. To listen to the strings, vocals and Dire Straits’ electric music, Clear matching with the Wadia S7i tuned with the TU-666M offered you very pleasing, lovely and musical reproduction. Everything is perfect and well balanced. It reminds me of the Harmonix cables (interconnect and speaker cables) are made of pure copper, and it is similar to the Cardas Clear cable, not using pure silver conductors. I am sure that when Mr. Kiuchi developed the TU-666M, he must be using his own Harmonix cables for reference. That’s why it didn’t work well with the Audio Note pure silver cable but it worked perfectly well with the Cardas Clear pure copper cables.

The above case is a perfect example of the “mutual effect” of the tuning devices and I hope it’ll give tips to the readers to pay attention when using the TU-666M in their system. To make it short, the TU-666M definitely can help to improve the overall performance of the Wadia S7i CD Player – I can even say it in front of the boss of Wadia. The TU-666M does not sharpen or decrease the high frequency, it also does not “reduce” the low frequency but it actually “enhanced” the low frequency. It gets you the extended high frequency and the ultra low frequency – it means that it has wider the frequency response; the width of sound range increased, more dynamic, more lively and more passion. The drum of Dire Straits sounds more lively and dynamic, the low frequency is more solid and more punchy. The dynamic range and resolution is creased without distortion at high volume and the transient is faster. Furthermore, the weaker sound that was unnoticed before became clear that offered you high clarity and quiet musical background, excellent noise to signal ratio. Moreover, it helps to outline the images of the musicians in listening to every CDs – it just like the focus of your camera lens being tuned to be sharper to allow you to see the details of everything including those in the far side – it offered you the best musical soundstage and imaging.

After changing the interconnect cable, the soundstage is definitely wider and bigger, and it can played in high volume without distortion; the male Chinese opera vocal sounded angry enough to be scary which has proved the high clarity of the Wadia S7i CD player, to be very dynamic and lively. It really helps the CD player to fully reproduce the true sound.

Our listening test has confirmed that the TU-666M can really improve the overall sound performance and it is truly a successful design.

Listening System:

CD Player:
Interconnect Cable:
Interconnect Cable:
Power Amplifier:
Speaker Cable:
Wadia S7i
Analysis Plus Power Oval 2
Cardas Clear
Audio Note M6 Line MK3
Analysis Plus Power Oval 2
Goldmund Lineal
Goldmund Telos 250 x 2
Zonotone 6NSP6600S Meister
Wilson Audio Sasha W/P

Testing CDs:

1. Gala Stradivarius Concert (Start Records SCD 13)
2. The Chinese CD – please see the original copy for reference
3. Dire Straits: Brothers in arms (20th anniversary edition SACD)

Being published on Hi Fi Review August 2010 issue – written by Sam Ho