This Goldpoint SA4 Precision Stereo Passive Preamp is a high-quality product from a reputable brand, with four L/R RCA inputs and two channels for optimal sound. It has been well-maintained and functions perfectly, providing a fantastic audio experience for your home entertainment system.
Detailed Information



Our Most Frequently
Asked Questions
-How To Choose the Correct Stepped Attenuator Value. General Rules and Considerations:
1)-When upgrading from a potentiometer, use the same value stepped attenuator. (5K, 10K, 25K, 50K, 100K, etc.)
If you need to find the potentiometer value by measuring it:
1) Unplug the equipment from any AC source.
2) Unsolder two of the three wires going to one channel of your potentiometer. (It does not matter which two wires.)
2)-Matching the volume control value to the amplifier/pre-amplifier input impedance is not as important as some people think, so you typically don't really have to worry about this. For a 100K input impedance, use a 100K, 50K, 25K, or even a 10K level control. This applies to passive preamps, active preamplifiers, and power amplifiers when the control is to be installed at the Input. Check your owner's manual to find the the rated Input Impedance of your unit, or contact the manufacturer directly. Our 25K stepped attenuator usually value replaces replaces 20K potentiometers.
3)-Regarding the choice of stepped attenuator values in Goldpoint SA1, SA2, SA4 (25K) and SA1X, SA2X (10K), much observation and thought has gone into this over many years. We concluded that the values which we are using for our standard off-the-shelf passive preamps and precision level controls should not be changed (unless really necessary or preferred for some other reason). Lower stepped attenuator values make them more compatible with a wider range of power amplifier Input impedances - which they might encounter over time.

Notes:
One common opinion states that with the higher value level controls, such as 50K and 100K, you can hear higher amounts of (desirable) high frequency harmonics, or even that "it sounds more open and airy". A similar opinion states that the lower values, such as 10K and 25K sound slightly "richer" or "more full bodied". The actual truth may depend on the equipment being listened to and/or which set or ears is doing the listening. I have found that the stepped attenuator (volume control) value is usually not so critical - and that it does not make as much difference as some people claim - but that other aspects of the equipment or system can make bigger, more noticeable sonic differences.
There is a common misconception that higher value volume controls such as 50K or 100K will result in LOUDER sound compared to using 10K or 25K volume controls. This is not true. 10K controls usually yield exactly the same loudness as 100K units. (Technically, there are other reasons why different value controls are used in different places or applications.)
Vacuum tube equipment often uses 25K, 50K, or 100K level controls, due to the high input impedance of tubes. Solid-state gear usually has 10K, 25K, or 50K level controls.
You can begin to have "high frequency roll off" beginning to appear with volume control values above 100K. If you don't have an engineer handy, or just can't decide, 25K is a good choice for both vacuum tube and solid-state equipment, especially for passive level controls.
We use the 25K stepped attenuator value in our home audio (RCA connector) SA1, SA2, and SA4 passive preamps. Our balanced (XLR connector) SA1X and SA2X precision level controls use 10K stepped attenuators - as this level control value is common in the Pro Audio environment.
Actually, you can also use a stepped attenuator value which is HIGHER than the rated input impedance - this doesn't really hurt anything - they are essentially just voltage dividers! So don't worry about it if that's what you end up with. The sound quality will typically not be noticeably affected.

Goldpoint Standard stepped attenuators of any value will always sound better than potentiometers -
due to the transparent sonic quality of the Thin Film Nichrome resistors we use on them.
-Which Type of Goldpoint Stepped Attenuator Sounds Best?
All Goldpoint stepped attenuators improve sound quality and provide much better channel-to-channel signal level matching compared to potentiometers. You just cannot beat them. Highly recommended, ourV24 stepped attenuators have low noise, precision resistors already installed. (0.5% tolerance, 25ppm, Thin Film, 0805 SMD type).
Our resistors are SO transparent sounding that we no longer hear any advantage to producing Ladder or Shunt type stepped attenuators. You can string dozens of them together and that will still sound like a single individual resistor!
(see Goldpoint Historical and Attenuator Type Comparisons)
Alternatively, you can use our V24 or V47 Custom stepped attenuator (blank) switches to make stepped attenuators of any custom value or taper, even linear controls. With these custom stepped attenuator switches you must, however, install your own chosen brand of through-hole resistors. Different brands or different kinds of through-hole resistors typically do result in various (usually slight) sonic differences. (see Goldpoint Stepped Attenuator Resistor Values)

-Does the quality of the sound change at all as the volume is increased?
The factors involved:
1)-Higher volume output levels go through less resistance than lower volume levels. This applies to potentiometers as well as stepped attenuators. Higher signal levels yeild higher signal-to-noise ratios.
2)-Using resistor voltage dividers and other methods of signal attenuation (such as transformers, solid-state volume controls, or using active amplifiers/preamplifiers) generally change the original signal sound a bit. Sometimes, the original signal can take on the sound "coloration" of the resistor type or brand. At worst, there can be moderate coloration or even some high frequency signal amplitude loss. But with the best sounding resistors (Nickel Chromium or Tantalum) there can be very good transparency (no sound quality alteration).
3)-At Goldpoint we studied resistor sound qualities for two decades. In 2012 we discovered that the Nickel Chromium type of metal film is why the brands that use it sound better. By far most other resistor brands use Ruthenium metal film to make thick film resistors - which just does not sound as good! The Nichrome resistors we now use (exclusively) have excellent, transparent sound, better even compared to the "exotic" Vishay Bulk Foil type, Caddock (non-inductive), or Tantalum resistors such as the Audio Note resistors, etc. Our conclusion: Use good quality Nickel-Chromium resistors wherever possible in audio circuits.
-How Do I Wire The Stepped Attenuator?




Normal Wiring: Wiring is easy for both our standard V24 and V24C Custom stepped attenuators: The pads are labeled IN, OUT, and GND. They are oriented the same way as on a potentiometer - as shown in the rear view sketch at right:
-How Much Attenuation is Right for Your System?
The word "attenuation" means the opposite of amplification or gain. It is "reduction in the amplitude of an audio signal" or "how much the volume level is turned DOWN".
On all stock Goldpoint stepped attenuators, turning the knob fully counter-clockwise is OFF, (= infinite attenuation). Turning the knob fully clockwise is zero attenuation, (= full ON). 
For the V24s, the Goldpoint audio taper has larger steps for the first six positions, and then -2dB per step up to full ON. The chart below shows the V24 step sizes. 


Unlike the chart above, the V47s, have 1.5dB for each and every step (which it stll a logarithmic taper - because we're talking decibels, not resistance, here.)
The real world loudness levels are the same for any chosen knob position for all the stepped attenuator values, (5K, 10K, 20K, 25K, 50K, 100K, and 250K.) In other words, position 8 on a 24-position 10K stepped attenuator will yield the same loudness as position 8 on a 24-position 100K stepped attenuator. Position 16 on a 47-position 25K unit will be the same loudness as position 16 on a 47-position 250K unit. This is because loudness is determined not only by how much total resistance, but by resistance ratios (the ratio of the total series resistance before the rotary switch wiper compared to the total resistance after the wiper.) 
The stepped attenuators are actually stepped voltage dividers. Choosing an overall stepped attenuator value is usually not as critical as some people might think. The different stepped attenuator values are offered for input impedance matching purposes. Different values usually work equally well in many circuits or systems. 
Our off-the-shelf stepped attenuators supply the correct amount of attenuation for most audio systems. But with some systems which have relatively low overall gain, you might have to turn the knob up past the 12 o'clock position to achieve normal listening levels. And some systems with relatively high gain cause the volume level to be too loud after turning the knob up to only the 4th or 5th position. These conditions can often be remedied, however, as explained below. The graph shows standard and modified stepped attenuator tapers. The blue line is the standard Goldpoint taper.

-"It gets loud too soon".
This could mean that your system has relatively high gain (or too much gain). The volume level is too loud after turning the knob up only a few steps - and there are lots of unusable positions higher in the knob rotation because they are all too loud. This is easy to fix by adding a pre-attenuation circuit (two resistors per channel), as shown at left. The red line in the chart (above) shows the results of adding this pre-attenuation circuit. In the example, we gave the stepped attenuator -20dB more attenuation (at every knob position). See more: Sample resistor values are shown on the page titled:
Pre-Attenuation - How To Get More Usable Steps For Your Stepped Attenuator




-"It does not get loud enough soon enough".
This could mean that your system has relatively low gain available. There would be a large number of silent knob positions before you could hear anything. One fix for this is to add a resistor as shown (at left). The green line in the chart (above) shows the results of adding a resistor to the ground terminal of the stepped attenuator. In this example, we made the stepped attenuator start at -42dB, instead of OFF, so the volume level will be "louder sooner". See more: Sample resistor values are shown lower on the page titled:
Pre-Attenuation - How To Get More Usable Steps For Your Stepped Attenuator


-Which Stepped Attenuator Values Are Stocked?
V24 stocked values include: 5K, 10K, 25K, 50K, 100K, and 250K.
V47 stocked values include: 10K, 25K, 50K, 100K, and 250K.
They are all available in Mono, Stereo, Quad (4-Channel or Balanced Line Stereo), and 6-Channel.