A stepped attenuator built with the use of fixed resistors is far more better than a potentio meter. I'm using stepped attenuators for years now and will not use any potentio meter even if it is branded Alps BlackBeauty, Noble or Penny&Giles.... But what if a company claims to make a stepped attenuator that is even better than the ones I make myself? Well, I have to say that caught my attention! This company is named Tribute and they were so kind to lend me the attenuator for reviewing purposes.
The main principle of this stepped attenuator is the same as mine, except for using induction in stead of fixed resistors. This was to expect: Tribute is a dedicated audiotransformer company.. More companies are using "magnetic" stepped attenuators, be it that they often use primary and secondary windings. The trick in doing this well, is to correctly dimension the secondaries to put out enough low-end response at lower listening levels (much attenuation). Tribute uses only a single primary thus providing a fixed inductive load to the source without having problems in reproducing low-end at low level listening. This is called an "autoformer". The source will see a very high ac-resistance whilst having an amazing low dc-resistance (especially when compared to conventional attenuators). This means that the source will almost "see" no load, so can work having less stress. Also is the grid resistor replaced by this autoformer, being able to perform even better, so Tribute says... Well I'm curious!! This attenuator has a dc-resistance of 35ohms at an induction of 180He (can be adjusted to customer specification).
Building in: These attenuators are huge! An Elma 24-step switch backed up with an amorphous toroid core with a diameter of 4cm. Due to the exporting of the taps on the autoformer, the height of the "tincan", in which the autoformer is housed, is about 4cm... An that for only one channel! I couldn't place this in my pre-amp and had to mount them outside. This turned out to work fine, without having any hum! Since I use a Sowter 8347 step-up transformer in my dac, I had to decrease the resistorvalue, which is placed across the primary, to 37ohms to stay beneath the desired 10Kohms. This is neccesary as the highest impedance for full bandwith is not to exceed 10Kohms (in this version that is). Don't take this into account when using an original output! Apart from my own dac I have also a Sony SCD940 connected to its original output to listen to.
The diference? Music comes out with even more ease, displaying
incredible fine details. These details are more refined without having any fatique.
Also the Sony, using the original output, renders from these attenuaors: SACD
is very good, but sounds even better now. The swich works fine: no "clicks"
are audible and all steps are well dimensioned.
I'm convinced of the tonal qualities of this attenuator! This is sonically a better attenuator than the stepped attenuators with fixed resistors!!
Tribute makes these attenuators on customer specification. That means that if a higher source impedance is available, the design can be adjusted to this. The price, for one attenuator without the Elma switch, will be approximately 100 Euro. If you can't/won't assemble it yourself, you'll have to pay extra for the Elma's... Please inform at Tribute.