Silk Transformer Attenuator
 
SACThailand is celebrating. Have yourself listen to +1,100 Henry Attenuator.
 

" S I L K " Supermalloy Transformer Attenuator (STA-522A)
 Featuring SILK winding technology
 
We are exciting to announce the available of the new SILK Transformer Volume Attenuator STA-522A model 2009. This new attenuator extends the sound performance of its very successful predecessor by adopting the newest development of Supermalloy core (PCC-02) for even higher permability and lower loss. Winding mechanism and implementation are also improved to increase linearlity of frequency response and boost the working level up to +8Vrms.

The former STA-522 has already established the highest quality Supermalloy transformer with 22 carefully selected steps in secondary winding to function as stepped attenuator with very high inductance (in excess of 450 Henry or equivalent to 50Kohm) with very low loss winding technique (called Nano winding technology). The primary coils are made such that it can be connected to generate +0dB or +6dB which acts like a step up transformer in a system where load input sensitivity is low. The new STA-522A retains all features and further boost the total primary inductance up to +1,100 henry!!! Without a doubt, new SILK STA-522A continues to offer highest value, sound and joy for the most serious audiophiles.

The benefit of replacing plastic type volume control to stepped attenuator is obvious! However, the accuracy of tracking and the quality of selector switch plus low noise resistors can reduce the signal loss to some degrees. Moreover the regular stepped attenuator featuring resistor type fails to offer impedance matching over plastic volume control. That's why at high attenuation level (low signal out, low listening level) the bandwidth of such volume control is very poor and the bandwidth is not constant over any switch position

  

It can be clearly seen in this actual plot of the Frequency Response Characteristic of the new 2009 STA-522A. We have eliminated the nasty peak/dip usually associated with regular transformer based attenuator. From 10Hz to 35,000Hz the frequency response is only -1dB deviation from 1KHz reference point. Source impedance is 12K ohm, load impedance is 10K ohm. Series primary connection.

The improve winding scheme of the new 2009 STA-522A brings very smooth phase response plot thus superior phase behavior is ensured throughout audio spectrum. Out of phase will not happen near or close to audio spectrum.
This figure shows both frequency response and phase response of the new 2009 model SILK STA-522A.
This figure shows both frequency response and phase response of the new 2009 model SILK STA-522A.
After extensive experiment, we finally found new ways to create super inductor (in excess of 1,100 Henry) with perfect waveform. The actual screen shot of 10KHz square wave response at high voltage level (11.3V peak to peak) Series primary connection (1:1), 12K ohm source impedance, 10K load.
10KHz square wave response at high voltage level (19.6V peak to peak) Paralleled primary connection (1:2) 3K ohm source impedance, 10K ohm load impedance.
 
 

Transformer is still the ideal signal transfer device since it offers much lower signal loss and much lower output impedance (10 times lower than regular stepped attenuator) thus it will process very wide frequency response at any attenuation setting. Listener will hear this evidence at first time when compare our Supermalloy Transformer Attenuator to any other types, guaranteed.

Not only our Supermalloy Transformer Attenuator can be used in replacement of any existing volume control device in pre-amp or integrated amp, but it can also be great used as stand alone Passive Pre-amplifier. Since it has very low output impedance, it can drive long cable better than regular Passive Pre-amplifier; moreover, its ability to make +6dB signal makes it very versatile in environment where source level is low or load input sensitivity is low.

Although several manufacturers are now introducing transformer volume control but non match (or even come closer) the accuracy of winding, number of attenuations, highest inductance with lowest insertion loss of our new 2009 model SILK STA-522A. We build this transformer to under 0.5% precision with highest quality parts and craftsmanship available anywhere. The best thing is that everyone can afford it. At $395USD/pair (for standard wire version), or $425USD/pair (for Silver Plated/Teflon wire version) it is the best value and performance. Guaranteed!

 
 

STA-522 has attenuation level as follow:

  
Step
0 dB attenuation
+6 dB attenuation
1
Common
Common
2
-48
-42
3
-44
-38
4
-40
-34
5
-38
-32
6
-36
-30
7
-34
-28
8
-32
-26
9
-30
-24
10
-28
-22
11
-26
-20
12
-24
-18
13
-22
-16
14
-20
-14
15
-18
-12
16
-16
-10
17
-14
-8
18
-12
-6
19
-10
-4
20
-8
-2
21
-6
0
22
-3
+3
23
0
+6
  The new model STA-522A has been carefully design to provide smoothest transaction between each step to let user feel like a conventional smooth type volume control. We guarantee each unit will have less than 0.5% error in tracking to outperform even those 0.5% metal film resistor type stepped attenuator.


  
 

Silk Transformer Volume Attenuator STA-522A PASSIVE PREAMPLIFIER Available now!!! (info Click)