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Threshold amps optimization - Get the best from your Threshold SA/3.9e or SA/6e

How to get the best from your Threshold Amplifier.

This article only applies to the SA/3.9e and SA/6e (monoblocks) amplifiers: it may work with other Threshold amps but the tips have only be tested with these two amps. And as you know if you are familiar with our site, we talk only about what we have lessoned to...

Preliminary remark:

The Threshold SA/3.9e and SA/6e, although they are very different in terms of price and power/current capabilities (the SA/6e is a monaural amp, so there is one amp for the left channel and another one for the right channel), share the same box, use the same transformer (800 VA...) and have the same components implementation. As most of the tips described herebelow relate to vibrations isolation/damping, and AC power optimization, it is normal that the two amps react in the same manner to a given tip.


1-.The different ypes of optimizations.

There are mainly 3 types of optimizations that you have to know:

  • the optimization of the material on which the Threshold amp is put on
  • the optimization of the vibrations isolation/damping between the support of the amplifier and the amplifier itself
  • the optimization of the AC power cord/power source.


2-.The optimization of the material on which your Threshold amp is placed.

You *must* avoid to place them directly on the floor, particularly if there is a carpet: they do not like at all the soft surfaces, and I never managed to get a good musicality out of a Threshold amp it stays on a carpet at floor... this remark is particularly relevant for the SA/6e monoblocks, because the most common place for the monoblocks amps is down the floor...


These Threshold amps reach their highest musicality when they are placed on a heavy stone of granite (avoid wood as well as marble, which does not provide as good results as granite). I recommend a stone of granit weighting at least 15kg, which corresponds to a 3cm thick minimum, for the granite stone.

If you have a SA/4e, you should still use a 3cm granit stone, but the weight will simply be higher because the size of the amp is bigger (stereo vs mono).



3-.The optimization of the vibrations isolation/damping.

As soon as your Threshold SA/3.9e or SA/6e is placed on a granite stone, you immediatly notice a huge improvement of the musicality: it is more defined, more transparent, with more detail.

The next step to go further in the improvement is to work on the vibration isolation/damping between the granite stone and the Threshold amplifier itself.

There are different devices that can be used:

  • regular metal cones,
  • soft cones with a hard ball on the top, the brand name is VIBRAPOD
  • sophisticated cones having a particular shape and/or additional material (inside the cone) to enhance the efficiency,like the EUPHONIA cones.
  • different accessories using areceptacle with a hard ball (generally tungstene ball) on which the amp is placed

To date, we have deeply tested the 3 first ones.

The "winner" is EUPHONIA, then the regular hard metal cones, then the VIBRAPODs. It is important to note that these reults are valid only for these Threshold amps: I alos use the VIBRAPODs on other devices, and they are a better performer than the other ones.

The VIBRAPODs do provide an improvement on the musicality, but by a small margin. They usually perform better on lighter devices such as the DACs for example.

The regular hard metal cones perform far better, providing a big improvement in clarity, detail between the notes, clarity and overall presentation. Like for the EUPHONIA cones, the position of the cones under the amp is *very* important: the best position is given below. This is is the sign that the improvement is big.

The EUPHONIA cone is another animal... They have a particular shape and they are filled with a silicon matter, the combination of both being supposed to be the result of a more serious engineering study.


The EUPHONIA cone, with its specific shape and silicon internal matter.

The EUPHONIA cone has a razor sharp spike and is *very* efficient under the Threshold amps. It provide so more detail, that the position of the cones makes a *huge* difference in the final result.

The Euphonia cones should be placed spike up. You should use 3 of them. One should be placed exactly under the power transformer (but make your own placement tests). The  others should be placed approximately 1 cm before the back feet and just under the aluminium plates on which the power transistors are fixed. If you need more explanation on the exact position of the cones, contact me via the Forum on this site.

The EUPHONIA cones are delivered in a small suitcase:


The Euphonia suitcase.


into which a set of six cones resides:


The set of 6 Euphonia cones.

The price is approx 130€ which is my opinion is acceptable providing that they are more efficient than most of the other cones.

4-.AC power optimization.
The Threshold amps, as most of the high-end and very transparent amps, are sensitive to the quality of the AC.
This part will be completed soon...

Article written by Nounours.

Creation date : 14/03/2007 @ 15:18
Last update : 17/10/2009 @ 21:17
Category : Threshold amps optimization
Page read 794 times

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Reactions to this article

Reaction #2 

by Nounours18200 19/03/2007 @ 21:18

Hello Karawaci,

Je suis allé voir les produits en question: ils sont intéressants, mais correspondent à des amortisseurs de type "mou". Or en 15 ans d'essais, les meilleurs résultats que j'ai obtenus sur des amplis Threshold l'ont toujours été avec des accessoires "durs", de type cônes ou assimilés. Ces produits me semblent mieux adaptés pour isoler un appareil des vibrations extérieures (peut-être pour une platine ?).
Bref, tout ça pour dire que je suis toujours un peu sceptique quant aux supports non durs sous des Threshold, mais ils peuvent marcher sous d'autres types d'appareils... Il faudrait en effet tester, mais sans échantillon...
Merci pour ta venue et à bientôt,

Reaction #1 

by karawaci 18/03/2007 @ 08:14

Tu devrais faire des essais avec le matos proposé sur ce site :


Enfin trouver l’équivalent en France de ces produits.

Tu peux écrire aux établissements Grundey, fournir le poids du granite et de l’ampli.

Ensuite ils te calculeront le produit qui correspondra dans leurs gammes.



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