The Ultimate Attenuators

 

The Ultimate Attenuators are super premium volume controls that mount directly on the amplifier input jacks giving the audiophile the purest and most transparent sound possible. By mounting the attenuators directly on the amps an interconnect is eliminated and its associated capacitance driving problems.

The Ultimate Attenuators feature the world's most transparent volume control (developed by us and copied by Reference Line, BAT and others). This attenuator has only a fixed resistor (Vishay brand) in series with the signal, soldered directly from the OFC input jack to the OFC output jack (the world's shortest, purest signal path). Attenuation is accomplished by using a premium rotary switch to switch different resistors to ground. All parts, wire and solder are world class. Some of the parts used are Sound Connections OFC male and female RCA jacks, Wonder Ultraclear solder, Swiss made Elma rotary switches, and of course, the world's best resistor (nude Vishay) for the series element.

The latest version of the ultimate attenuator is the Nude 24 position Ultimate Attenuators. These attenuators have no chassis and are therefore more transparent and less expensive that their predecessors. The nude unbalanced attenuators will not fit properly on any component that has the input jacks closer together than .75 inch center to center. The area above the input jacks must be totally open and clear.
 

The price (per pair) is $350.00 for the standard model 24 position Nude unbalanced Ultimate Attenuators plus shipping. 30 days unconditional money back guarantee on standard model, no money back on custom models.

The standard attenuation range is 2 db steps of attenuation from wide open to about -30 db and then progressively 3, 4, and then 5 db steps at the bottom of the range.
 
If you want a Nude balanced version or a customized nude unbalanced attenuator with different values then normal, we can do this but the attenuators are sold on a no money back policy and must be paid in advance with a Money Order. Custom unbalanced attenuators cost from $400 to $450 depending on how much work it is for us to source the different resistors, etc. A balanced attenuator is $600 (per pair) and again must paid in advance with a money order and also has a no money back policy. Picture of balanced attenuator located below.
 
Attenuators are available in a low impedance version (1K) and a high impedance version (10K). The low impedance version usually works best with solid state amps and sources and the high impedance version with tubes and tube sources. You must call us for info on compatibility with your amp and system before ordering.
 
 
Finally have some pictures of these gems. Knobs are smaller and cuter.
 
Some info on passive attenuation follows the next two pictures.
 
 
 
 
Picture of balanced nude Ultimate Attenuator showing the nude Vishay (T2408-IK) and black damping material.
 
Customer comments:
 
Email received from Chaucer in Hong Kong 9-25-03
Hello Ric,
I can't be happier to have the Ultimate Attenuators installed!  It simply outperforms sonically my 
other passive pre-amps in the 1st minute of playing. It is better than the others in all aspects IMHO.
Most noticeable are more musical details, bass extension and control, vocal voice fullness. More life
in short.

Ultimate Attenuators allow the music to flow much more precisely than before!
Thanks Ric!   
Questions and answers about attenuators:
1. How do I know if I am passive compatible?

Passive preamps (attenuator/volume control) do not work in every system.  Here is a 
very general rule:  If you have a 2 volt CD source (player or DAC), an amp with at 
least 26 db of gain (20 times), speakers at least 88db sensitive and don't listen screamingly
load and don't have a huge room, then you are probably passive compatible. Any one 
perimeter not met and it may not work. 

Here is how to test for compatibility.  You must be careful when doing this test or 
speaker damage could result!!!  Turn off the amp, plug the source directly into the 
amp, and turn the amp back on.  Put the lowest level/softest sounding music CD in 
your player and hit the play button (with finger over the stop button, in case it is 
too loud).  This is essentially full gain when using a passive preamp.  If the volume
on this test is as loud or louder than you ever listen, then you are passive compatible.
If you change any one link in your chain to be less sensitive or you move to a bigger     
listening room then the compatibility may no longer be there.  



2. Why do you have two different impedance models and how do I know which one I need?

The low impedance version works best with solid state amps and can be used for tube 
amps as well. It has a 1K input impedance at low volumes and has a somewhat higher 
input impedance at higher volume settings. The output impedance is always below 1K 
and usually in the 100 ohm range in normal use.

If you have a tube amp with at least 100K input impedance than the 10K attenuator 
would be the best choice.  Its input and output impedance are 10 times higher than 
the low impedance version at the same volume settings. Because it has at least a 
10K input impedance it is easier for the source (CD player, phone stage,etc.) to 
drive and the low input capacitance of a tube amp insure that there is no high 
frequency rolloff.  

Neither the low or high impedance attenuators can be driven by tube electronics 
unless they have a low output impedance follower (at least 500 ohms or less).

If you are not sure what you need then buy the low impedance one as it will work
with both solid state and tube electronics.


3.. What is a shunt attenuator and how is it different from a Ladder or series 
attenuator?

A shunt attenuator uses a fixed value resistor is series with the signal (nothing else)
and varies the resistance to ground following it.  We us a 24 position switch to switch 
different resistors to ground.  The shunt attenuator has only one element in series with 
the signal, so tends to sound the most transparent. The shunt attenuator has a variable 
input and output impedance.  For instance, our 1K attenuator has at least 1K input 
impedance but rises in impedance towards full volume.  Some people think that you need
to load the source with a constant input impedance.  In our experience of over 
14 years with the shunt attenuator we have not found this to be necessary.  As long
as the source can drive the input impedance of the attenuator then it works fine.
If you were using a shunt attenuator in a preamp between a phono stage and a line stage,
then there might be some difference of loading on the phono stage, if the phone stage
uses RIAA feedback rather than passive EQ.  When using a shunt attenuator the series
element (resistor) can be soldered directly to the circuit with no extra wires in the 
signal path. 
  
The Ladder attenuator uses a two pole switch per channel and switches a series resistor 
and a resistor to ground at the same time.  This type of attenuator costs more to make 
than the series type but sounds better.  The Ladder type of attenuator has two pieces
of wire, one resistor and two switch contacts in series with the signal. The Ladder type 
of attenuator has a fixed input impedance and a varying output impedance.

The series attenuator has a series of resistors that the switch taps off of.  So if you 
are using a series attenuator half way up, you have half the resistors and older joints
in series with the signal and the other resistors and solder joints to ground. You also 
need wires from the switch to the source and load.  The series attenuator tends to be the most 
veiled but fairly easy to make. It has a constant input impedance and a varying output
impedance.

4. How can I build my own and where do I get the parts?

See Attenuator design info
  

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