Macoms fixed attenuator chips are fabricated using our state of the art thin film metallization and advanced photolithography technology. Design and construction of a quality stepped attenuator. This product is featured in edns hot 100 products of 2014. There has a lot of talk recently about the improvements that can be made to the sound quality or rather in this the case the transparency of a pre amp by using a stepped attenuator like the one pictured above that makes use of the vishay dale military grade rn60 metal film resistors which are highly regarded in audiophile circles for their lack of sound. Click here for a shunt attenuator calculator potential divider resistors rx and ry as shown. Indeed, using smd resistors on a stepped attenuator can be beneficial by reducing the length of the signal path. Stepped attenuators join our community subscribe to pauls posts. A5 stereo stepped attenuator amazing, just amazing. Calculates the resistor values, attenuation, impedance, reflection coefficient, vswr and return loss of a t attenuator. There is also a selection of suitable connectors available. The attenuator resistor values in the table are given for a 50 ohm system as this is the most likely impedance system required. If my understanding is right, this attenuator will present itself as a 10k load to the dac and an output impedance of 1k to the amp. Quantization errors in resistor values are inherent to javascript.
Improved consistancy between separate audio channels stereo or multichannel less sensitive to dust and wear. That is quite a difference, as such a 41step volume control is bound to let you come closer to the desired replay levels, whereas a control with a limited number of positions may most of. Alternatively, generate r1 and r2 for a wanted attenuation. The circuit diagram is displayed as following diagram. This calculator is designed to help calculate the value of the resistors r1 and r2 to be used in tpad attenuator. The layout of the pc boards and the choice of smd resistors have reduced the signal path to a minimum length typical five times shorter than conventional stepped attenuator designs with leaded resistors.
Highquality stepped attenuators for less highquality stepped attenuators for less is a sequel to a previously published article of mine on load impedance and stepped attenuators audioxpress 0605. However it is recognised that other impedance systems may also be used. This cleverly designed stepped attenuator exploits both the series attenuator and the shunt attenuator configurations to yield the best compromise between flexibility, performance, and cost. Beequiet stepped attenuator upgrade for beepre bottlehead. An elma stepped attenuator populated with kiwame resistors. L pad calculator impedance attenuation damping db decibel loudspeaker speaker voltage divider eberhard sengpiel sengpielaudio. Neville roberts following the recent successful upgrades to various resistors and capacitors in my wad k5881 mk ii power amp and wad series ii modular preamp, i decided to turn my attention to the volume control. Therefore, there are totally 46 resistors for two channels. Grayhill rotary switch as stepped attenuator jimmys junkyard. Highquality stepped attenuators for less is a sequel to a previously published article of mine on load impedance and stepped attenuators audioxpress 0605.
An rf step attenuator when you can find a good, commercially made rf attenuator, expect to pay the price. Shunt type stepped attenuators in a shunt type stepped attenuator, a voltage divider is formed with one constant value inputtooutput resistor, and one other resistor selected by the rotary switch position. At current stage, i go with takman rey metal film resistor. The manual provides a table with an alternative set of resistor values for the attenuator to configure a 10kohm input resistance. If unequal termination resistances are used and an attenuation value is selected that is lower than what is physically possible a negative resistor value is displayed, then a message will appear in the box over the schematics. Here is a shot of the interior of the unit prior to base installation.
Using a 9k1k resistor network i can achieve the desired 20db attenuation. Shunt type stepped attenuators in a shunt type stepped attenuator, a voltage divider is formed with one constant value inputtooutput resistor, and one. An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. Although a shunt design presents a variable input impedance.
Controlling the volume level in your stereo system is an obvious and important function. L pad calculator attenuation db damping impedance decibel. Although there is a quality alps blue supplied with the. By denton bramwell, k7owj 39 royalton hts rd st joseph, mi 49085. Support was added for a 16x2 character oled display, as alternative for the standard 2digit 7segment display. Calculate stepped attenuator 24 steps hifi loudspeaker design. Similar to the acoustic dimension it is a series attenuator, and it uses smd resistors. Improved quality of the electrical contact, in comparison with the slider. We tried all sorts of schemes inexpensive carbon potentiometers, our old standby sweetest whispers attenuator, high end stepped attenuators from other manufacturers, transformer. Stepped attenuator resistor string calculator neville. Pa1b power attenuator calculator including download. Other values can be chosen with the help of the online calculator. This calculator provides configuration data for logarithmic stepped attenuators or logarithmic ladder networks.
If we want to split hairs, these thin film resistors are attached with solder to a pcb with signal traces, so the signal would have to travel in series through all these solder joints and signal traces probably on the average about. Resistor switch networks can offer advantages over the potentiometer such as. Instead of using advanced javascript functions that would make the script incompatible with older browsers, i. But the dact has 24 steps, where the ad boasts a 41 position control. Stepped attenuator resistor string calculator neville roberts. What resistor values would be required for both the. Grayhill rotary switch as stepped attenuator jimmys. Click here for a resistor string attenuator calculator potential divider resistors rx and ry as shown. But at 15x price tag compared to takman rey, definitely i need to win some lottery first. T attenuator calculator enter values for r1 and r2 to calculate attenuator loss and impedance. There are at least three types of stepped attenuator based on the resistor arrangement. In a ladder type stepped attenuator, the rotary switch is used to select an inputtooutput resistor and an outputtoground resistor, forming a set voltage divider for each switch position.
Hificollective are proud to bring you the ultimate stepped attenuator. The total series resistance of each two resistor set is equal, so the signal source always sees the same impedance. Resistor string value calculator for constructing stepped attenuators. A free excelbased resistor calculator tool is downloadable from the elma website. Instead of using advanced javascript functions that would make the script incompatible with older browsers, i elected to leave the quantization errors. While an amplifier provides gain, an attenuator provides loss, or gain less than 1. Attenuator resistor values table electronics notes. Build your attenuators with carbon resistors or metal film resistors. Note that rx and ry are made up by the string of resistors in the chain. Download attenuator calculator a handy application designed to compute the resistor values inside an attenuator in order to accomplish a userdefined attenuation. Ct2 uses a resistor network built on noninductive smd resistors. The advantage of this network over other topologies is its simple construction. The element used to turn the level up and down is important as well.
Install a 12inchsquare brass shield between each 10db section to ensure that signals dont couple around. A comparison of ladder, series, and shunt type stepped. If you look inside a preamplifier youd discover its one of the simpler devices in your chain. This can be built into a flexibox and a transmission line pcb is available which easily adapts for this circuit. Pi attenuator calculator useful to add to the input of a high gain amplifier, that needs to be driven by a high power radio. Page 5 the total length of a mono attenuator is 60mm instead of 70mm for a stereo one. An attenuator is a passive network, designed to weaken the power being supplied from a. This cleverly designed stepped attenuator exploits both the seriesattenuator and the shuntattenuator configurations to yield the best compromise between flexibility, performance, and cost. Resistor value calculator for constructing shunt attenuators with up to 50 steps. The pi attenuator is one of the more common passive attenuators used in rf applications. If you want to attenuate 10w to 1w, 10db you will need to build the attenuator with resistors capable of dissipating 10w. Both dac attenuator and attenuator amp will have a nice 100x impedance ratio. Both dacattenuator and attenuatoramp will have a nice 100x impedance ratio. It uses high quality miniature latching relays and precision discrete resistors to achieve a level of performance unattainable with conventional potentiometers or mechanical switchbased rotary stepped attenuators.
Passive attenuator impedance question audiogon discussion forum. Aug 10, 20 at current stage, i go with takman rey metal film resistor. The pi attenuator consists of one series resistor and two parallel shunt resistors to ground at the input and the output. Hificollective shunt attenuators series resistor comparison. When we were developing the beepre 300b preamp kit we built the prototype preamp circuit itself on a pair of chassis, and we built several outboard chassis platforms that allowed us to try various attenuator schemes.
Audio note stepped attenuator shunt, mono version the audio note 23 step mono stepped attenuator is available as 50k, 100k or 250k. An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform an attenuator is effectively the opposite of an amplifier, though the two work by different methods. A shunt stepped attenuator is a simple design where the signal is fed through a fixed series resistor rx in figure 1 and the shunt resistor, ry, is selected from a range of values ranging from zero to infinity by means of a selector switch. The pa1b power attenuator calculator enables you to take good available resistors with a modest power, from the e12series. Resistorswitch attenuator networks for audio volume control. Good audio attenuator rotary switches are made for instance by dact. Pi attenuator pad is the simple layout pad with provision to solder three rf chip resistors. This can be built into a flexibox and a transmission line 50 ohm track pcb is available which easily adapts for this circuit with one simple trimming. Their series resistor networks consist of 23 noninductive, low noise, smd metal film resistors. All devices are available in chip form with a metallized ground connection on the back.
Download the free dact attenuation curve calculator acc here 187kb. Danish audio connect manufactures a range of highend stepped audio attenuators for hifi, av and proaudio, used by diy audiophiles and audio equipment manufacturers throughout the world. It is easier to etch out a pi network on a thin film circuit compared to etching a balanced or bridgedtee attenuator circuit. My future plan is to use custom texas components tx2575 resistor.
Id rather go stepped in this case as i control all 4 phase sections in one attenuator. The user only needs to enter the attenuation in decibels db and the given characteristic impedance of the transmission lines to be matched. Calculates the resistor values, attenuation, minimum attenuation, impedance, reflection coefficient, vswr and return loss of a matching pi attenuator. Heres where doing it yourself can provide you with what you need inexpensively. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. Highquality stepped attenuators for less was originally published in the 2006 october issue of audioxpress. The tee attenuator tpad is a specific type of attenuator circuit which resembles the shape of the letter t. Fixed pi and t attenuator calculator enter values for rin, rout, and attenuation, then click calculate.
Such relayplus resistor networks are used for volume control in audio electronic devices, as a replacement for traditional analog potentiometers. This stereo attenuator offers 36 volume settings, but only holds two 6position rotary switches. If you must leave a resistor ground lead longer than you like, use a generous blob of solder to make the lead less inductive. Audio step attenuator with 47 positions offers precise volume. Our stepped attenuator is made with thin film resistors 0. To convert the values in the table to another value of impedance, they should be multiplied by the factor z 50, where z is the characteristic. The pa1b power attenuator calculator will calculate the resistors effortlessly. Mar 02, 2011 indeed, using smd resistors on a stepped attenuator can be beneficial by reducing the length of the signal path. The laddertype resistor network consists of resistors rin and rg in serially. The number of resistors in the chain, as well as the number of switch steps, will. Audio note stepped attenuator shunt, stereo version the audio note 23 step stereo stepped.
912 478 688 823 1293 222 1090 1409 1631 285 1431 278 887 529 1551 758 62 344 871 1055 678 1396 368 199 751 868 1430 913 954 1288 1172 1538 1607 934 701 955 1298 297 960 52 195