Detailed Information

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, 20K, 25K, 50K, 100K, etc.)

2. Choose the value of the stepped attenuator (or other type of volume control) to match the input impedance (of what it will be controlling).This applies to both preamplifiers and power amplifiers when the control is to be installed at the input. If necessary, check your owner's manual to find the the rated input impedance of your unit, or contact the manufacturer directly. This also applies to choosing the stepped attenuator value for an in-line level control or "passive preamp".

3. You can usually use a level control value which is LESS than the rated input impedance of the gear it will be controlling - and some people prefer to do this. So, if your amplifier has a rated input impedance of 100K, instead of using a 100K level control, you could use a 50K, 25K, or even a 10K level control. (But you can also get away with using a stepped attenuator value which is HIGHER than the input impedance - don't worry about this very much. It doesn't really hurt anything to use a level control value which is higher. About all that would happen is front panel -dB calibration markings, if shown, could end up being a little bit less accurate - but the sound quality will not be affected).

4. Vacuum tube equipment usually uses 100K, 50K, or 25K level controls, due to the high input impedance of tubes. Solid-state gear usually has 50K, 25K, or even 10K level controls. (note: We shoot for controlling both vacuum tube and solid-state gear with our Goldpoint Passive Preamps by installing the "more versatile" 25K value in them.)

5. You typically begin to have "high frequency roll off" beginning to appear with attenuator values above 100K. If you don't have an engineer handy, or just can't decide, 25K is usually a good choice for both vacuum tube and solid-state equipment, especially for passive line controls.

-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. I highly recommend our new Mini-V attenuators with their low noise, laser trimmed precision resistors already installed. (0.1% tolerance, 25ppm, thin film, SMD (Surface Mount Device)

Our new 0.1% resistors are SO good, that we no longer hear any advantage to producing Ladder or Shunt type stepped attenuators. These resistors are SO "quiet" you can string dozens of them together and that will still sound like a single individual resistor! You are welcomed to try this for yourself...

Alternatively, you can use our Mini-V Custom stepped attenuator (blank) switches to make stepped attenuators of any custom value or custom step taper. 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 result in various (usually slight) sonic differences. (Goldpoint Historical and Attenuator Type Comparisons)

Yes, it is true; hand wired gear can actually sound better than gear with printed circuit boards, although PC boards themselves are not typically a major cause of sound degradation. PC boards need to be designed properly for audio applications, especially how the individual components on them are connected to the circuit ground. And Goldpoint Stepped attenuators really do sound better than pots. To get sound improvement in your PC board based gear, you can usually simply run short wires, of practically any type or size, from the stepped attenuator IN, OUT, and GND to where the potiometer(s) used to connect to on the PC board.

-How Do I Wire The Stepped Attenuator?

Normal Wiring: Wiring is easy for both our standard Mini-V and Mini-V 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). The chart below shows the size of the steps we use. Our modified audio taper has larger steps for the first six positions, and then -2dB per step up to full ON.

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 are easy to remedy, 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: 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 on the page titled: How To Get More Usable Steps For Your Stepped Attenuator

-Which Stepped Attenuator Values Are Stocked?

Mini-V stocked values include: 5K, 10K, 20K, 25K, 50K, 100K, and 250K.
These are all available in mono, stereo, quad (4 channel or balanced stereo), and 6 channel.

Note: Normal Stereo "single-ended" attenuators are used as monaural attenuators for Balanced Input applications. Single-Ended quad attenuators are used as stereo attenuators for Balanced Input applications.

We also offer a special precision volume control replacement for the McIntosh C20:

-Can I put a Loudness Control Tap on a Mini-V Stepped Attenuator?

You can choose from the many places which are available along the perimeter of the stepped attenuator.

Use an ohm meter to test your old, worn out potentiometer to find where the tap was made. Then you use your ohm meter to choose the closest matching tap point on the Mini-V.

If you have the standard Mini-V which has surface mounted resistors, take care to not overheat the small pad (which is one side of the SMT resistor) when attaching your tap wire.

-What Kind of Switches Are Used
----and What Are their Dimensions?

Goldpoint stepped attenuators employ ELMA, 24 position, precision switch components. They have smooth turning torque, great for audio applications.

All current models employ thick, hard-gold plated switch contacts on PC boards designed (with high precision) by Arn Roatcap. They are fabricated in the San Francisco Bay Area by a leading PC board fabrication facility.

Click here or on image for dimensions

-Which Attenuators Come In Kit Form, and Can I Get a Custom Value?

Currently, there are no kits being offered, but we do offer blank switches (MVC type) which accept any 1/4 watt or 1/2 watt through-hole resistors of your choice. If you want any special taper, attenuator value, or special type of resistor, the Mini-V Custom switches are for you. These attenuator switches come fully built but without resistors. You can use our resistor lists if you wish, or make up your own.

If you want an attenuator value which we do not stock, or one with a special taper, contact us to work out your custom resistor list - we will get onto your project typically within a couple of days.

Sometimes we have the time to install your resistors for you, but we do charge extra for that.

-How About Some Knobs?

The shafts on all Goldpoint attenuators are 6mm (.237"). This size is close enough to 1/4" (.250") to allow you to use knobs designed for 1/4" shafts. However, if you are using knobs designed for 1/4" shafts, we recommend wrapping a few layers of tape, such as Kapton or common Scotch tape onto the attenuator shaft to create a better fit.

We sell custom machined aluminum knobs designed specifically for 6mm shafts. All of our knobs are shown (half-way down) on the Prices page, click here or on photo >>

-How Do I Mount The Stepped Attenuator? How Thick Can The Front Panel Be?

If you use the two hex nut method, one hex nut on the front of the panel (with a flat washer), and one hex nut on the inside of the panel, your panel thickness can be about .1" (2.5mm). If you do this, make sure that the hex nut on the inside of the panel does not touch the sharp, protruding key.

If you make the required .4" (10mm) hole, put the .10" key way slot there (see below), and use only one hex nut with flat washer on the front of the panel, your panel thickness can be up to about .25" (6.3mm).

Likewise, if you file off the protruding (pointed) key on the stepped attenuator and use only one hex nut and washer, your maximum panel thickness can be about .25" (6.3mm).

-Recommended Stepped Attenuator Panel Mounting Hole Pattern:

The 0.1" notch is for the protruding key at the front of the rotary switch. This keeps the rotary switch from turning when the knob is turned, even if the front panel nut is not tight.

A notch may need to be filed into the front panel or else
the stepped attenuator could become warped when the hex nut is tightened.

Alternatives:
1) You can skip filing a notch into your front panel IF the panel is thin enough for you to mount the rotary switch with two hex nuts - one on the inside of your panel, and one on the outside (front) of the panel along with the flat washer.
note: If you mount it this way, do not allow the protruding key
to touch the hex nut on the inside of your panel.

2) The protruding key on the switch itself could be filed off.
(But it is usually better to mount the rotary switch with two hex nuts).

-How to Determine if Your System Will Sound Good With a Passive Preamp:

In-Line Volume Control (only one channel is shown)

Use a stereo audio taper potentiometer for building an In-Line Volume Control. Split some audio cables in half and wire them to the pot as shown above. An audio cable is required for each of the stereo potentiometer sections, (one for the Left channel, and one for the Right channel).

The inexpensive stereo pots and audio cables from Radio Shack work well for making this "Passive Preamp Tester".

If using this In-Line Volume Control still yields you enough "headroom" (meaning you can still turn the system up louder than you need), then you can get even better performance by using a Goldpoint Level Control box (passive preamp).