Riaa passive filter calculator

Riaa passive filter calculator. So, if for example, a user enters a notch frequency of 4KHz, 4KHz is greatly attenuated by the circuit. wave, around 1V at all frequencies, to the inverse RIAA and the phono stage will see normal signal levels. The RIAA passive filter is between the 1st and 2nd triode sections. The low-pass filter will pass a signal with minimal distortion May 25, 2011 · The real challenge with passive eq tube circuits would be noise (I would think). Screenshots simulation images: Dec 8, 2023 · The remaining 318us (500Hz) and 75us (2122Hz) time constants can easily be dealt with by a simple passive filter. 19. 1% tolerance resistors and capacitors should be used for the filter components. In this article, we'll have a detailed look at high-pass filters Oct 2, 2009 · The RIAA filter is reasonably accurate, at least in simulation. com . ) Resistance Value. Frequency response is accurate to within +/-0. Using an arbitrary capacitance value of 1 µF, the Mar 22, 2017 · Here’s a spreadsheet I built for calculating RIAA values in two stage tube phono preamps. INTRODUCTION. Capacitance Value. Figure 1 - Active RIAA Amplifer using Lipshitz's 'network 1a'. 1+. The transfer functions of this crossover network are of the form. Its voltage transfer function is given by with zero and pole time constants determined by The lower RIAA zero-pole pair is at 3180 µs and 318 µs. Shure is typical at 200pF. ) BTW, the passive composite RIAA network you linked to, lacks Allen Wright's "50KHz pole". LCF = 1/2*pi*R2*C2 LCF = 1/2 ∗ pi ∗ R2 ∗ C 2. f_c = 1 / (2 * π * R * C) Welcome to the Low Pass Filter Calculator, your ticket to tranquility in the world of electronics. The following figure depicts the response of a RC lowpass filter. Fill two of the three fields to compute de desired value, the frequency, the resistance or the capacitance. My take of an MM phono using this approach is attached. Designing a robust filter circuit, made easy. May 3, 2009 · The circuit is from the RCA tube receiving manual and meant for use with the famous RCA 7025 twin triode. You need a lot of gain for aa good RIAA section. An inductor L L acts the opposite way a capacitor does: An inductor becomes a short-circuit for low-frequency signals and an open circuit for high frequencies. 7 times 40. Aug 27, 2022 · 1- reconfigure the gain ratio between the two stages. The gain values shown yield a 1-kHz gain that is the product of the U1-U2 gains (24. the 50Hz and 500Hz shelving frequencies; the second, the 75µs time constant, i. 3 kΩ resistor and a 47 nF capacitor (which are standard resistor and capacitor values). As such, it reacts faster to a signal frequency and has twice the frequency slope (also known as frequency roll-off) in the Bode plot compared to a passive filter like RC or RL. This is to be expected because the 2 days ago · You can build an RC low-pass filter with a cutoff frequency of 1 kHz using a 3. For first order filter the attenuation is +3dB or -3dB acording to high or low pass. 3 kΩ × 47 nF) = 1. Apr 22, 2013 · The first stage, consisting of Q1 and Q2, is a simple FET audio amplifier, where the FETs are connected in parallel to reduce noise. 11 and 19. The low-pass filter will pass a signal with minimal distortion Jun 22, 2001 · Figure 6 - Alternate Reverse RIAA (Quad Design) This has identical frequency response to the version shown in Figure 1, but the source impedance has to be very low. Its cutoff frequency is also very simple to calculate: f_c = \frac {R} {2\pi L} f c = 2πLR. highpass A passive filter (also known as a lumped element filter) is used to attenuate a signal above or below a determined frequency. 8. This crossover calculator can be employed for the calculation of passive filters (first, second, third, and fourth order) in two-way and three-way crossover networks. If you are human, leave this field blank. Apr 24, 2020 · So there are two EQ processes: 1. The net result is a flat frequency response, but with attenuation of high-frequency noise such as hiss and clicks that arise from the May 21, 2024 · An RL high-pass filter, built with a resistor and an inductor. You can still use normal RCA inputs with one end of the cartridge output grounded. The filter network is normally driven from an amplifier stage that has a certain output resistance and quite possibly an AC coupling (DC blocking) capacitor. C is the capacitance of the capacitor and R is the ohmic resistance. Both the two 318 μs/3,180 μs forming impedances Z2 (f) can be formed of type C ub or D ub feedback networks (Figs. If you want to estimate values for something like a CCS loaded Jan 1, 2021 · The iRIAA Filter is a two-channel passive inverse RIAA response filter for use in testing phono preamplifiers. 0047OF capacitors. TCJ Push-Pull Calculator has but a single purpose: to evaluate tube-based output stages by simulating eight topologies' (five OTL and three transformer-coupled) actual performance with a specified tube, power supply and bias voltage, and load impedance. (11) and. Z. The formula for calculating an RC low pass filter is: V o u t V i n = 1 1 + ( ω C R) 2. The formula for calculating the center frequency of a bandpass filter is as follows: Feb 25, 2024 · Check Details What makes a good passive eq schematic ? Passive baxandall tone control (2 band equalizer) – electronic circuitEqualizer circuit bass circuits schematic opamp electroschematics mạch schematics amplifier 3-band graphic equalizer circuit – electronic circuit diagramCircuit bass electric active preamp wired passive eq equalizer band pre. Active/Passive RIAA – T2, T3 and T4 are implemented in the feedback network, while T5 (the 2122Hz pole) is implemented by means of a primary post filter. Welcome to Sonic Imagery Labs Jul 24, 2015 · From this, I used the calculator Kabusa RIAA, and from the resistor R1. Active RIAA Calculator. Bass filters are only a good thing when used with typical stand mount speakers. Feb 16, 2022 · E: Energy stored in C. Select a filter type to begin your design. Software version: 9. Our calculator allows you to create an active or a passive filter, depending on your needs. Capactive Reactance: XC = 12πf0C X C = 1 2 π f 0 C. C 1 requires the low cut-off frequency F L and the resistance of R 1. Enter two of the values below, in order to calculate the third. An "RIAA Filter" is the passive network used in many (not all) phono preamp designs. LC Band-Pass Filter Calculator LC Band-Pass Filter This passive filter calculator has you pick your composition (RC – Resistance/Capacitive, RL – Resistance/Inductance) and enter your values to calculate the cutoff/-3dB frequency. www. On the record itself, songs are engraved so that low frequencies are cut in volume while high frequencies are boosted. 0261 kHz. Calculators Capacitor charge Impedance Matching Calculator Inductance Conversion Op amp voltage & gain Passive Filter Calculator PCB trace width Pull up Pull down resistors Transformer Turns Calculator Twisted pair impedance Manufacturer Tools; Reference Designs Feb 8, 2010 · The transistor based difference amplifier will have a gain of around 43dB which will be followed by my RIAA filter. Jan 20, 2024 · A = Ao / (1 + B * Ao) Where A is the overall complex transfer function (RIAA preamp ), Ao is the OLG transfer function, B (Greek beta) is the transfer func of the feedback network. 022OF and . By far the most significant change in the circuit, which started out as the AudioKarma CNC, is the RIAA equalization filter. This passive filter calculator has you pick your composition (RC – Resistance/Capacitive, RL – Resistance/Inductance, or LC – Inductance/Capacitive) and enter your values to calculate the cutoff/-3dB frequency. You need 40dB of spare gain just to do the EQ, and more to provide the NFB, and another 30-40dB to get the level up to somewhere near line level. Oct 15, 2018 · Joined 2006. AIUI the 'original' passive RIAA network was simply R1 & R2, and C1 & C2, from your Case #1 (no DC blocking cap). This passive filter calculator has you pick your composition (RC – Resistance/Capacitive, RL – Resistance/Inductance) and enter your values to calculate the cutoff/-3dB frequency. The detailed derivation of these design equations is provided in the appendix. Then the band pass filter transfer function applies: V o u t V i n = 1 3 + j ( ω R C – 1 ω R C) ω is the angular frequency of 2 ⋅ π ⋅ f. #1. valves. In the 1960 issue of the RCA tube manual (RCA 20) there is a passive RIAA phono stage (fig 20-16,page 216) using two 12AX7 stages. Until the Recording Industry Association of America hit the headlines in recent years with its antipiracy campaign, the initials RIAA meant one thing to seasoned audiophiles: the vinyl-disc equalization characteristic introduced in the 1950s to standardize what had previously been an anarchy of different EQs. Normally two equal resistors and two equal capacitors are selected for one bandpass. Nov 26, 2016 · They are RJS VSPS 300, dual mono, active RIAA filter, 1% DALE resistors, Cornell Dubilier capacitors; Scrodahl Mufssy, passive RIAA filter based on AK hi end phono stage, 1% metal film resistors, Wima capacitors; Phono preamplifier by Rod Elliot, RIAA mixed filter; Solidphono of TNT, with passive RIAA filter, with first stage amplifier SSM2017 Isolated Passive Inverse-RIAA Filter Allows you to connect line level audio to the phono input of your ROWE/AMI Jukebox amplifier Works with any amplifier having magnetic phono inputs. Time Constants: τ τ: 63. We’ll sift through the chaos of frequencies and make sure The band pass filter capacitor calculator can be used to calculate the values of capacitors needed to create a filter with a specific cut-off frequencies F L and F H. It is characterized by a faster roll-off rate than a Butterworth filter but introduces ripple in the passband due to its design. Complexity: Intermediate. Then you can input a fixed level sine. Full software version nedeed : No. Passively Equalized RIAA Phono Preamp using Sonic Imagery Labs Discrete Operational Amplifiers. I used this sheet for El Matématico. Components number: <10. To use this calculator, all a user must do is enter any 2 values, and the calculator will compute the 3rd field. Brief for RC Filter circuit: Jun 10, 2011 · Passive Equalization Passive RIAA equalization means brute force equalization: the frequency response is tailored to fit that of the RIAA curve by varying the amount of attenuation at different frequencies through a complex RC network. There are two types of preamplifiers for magnetic phono cartridges. Lag-lead filter section. These are the main characteristics: Only 2 stages Only 2 vacuum tubes on the signal path No capacitor on the signal path (escluding RIAA network) No resistor on the signal path (escluding RIAA network) Less components of any other design Output impedance and Nov 13, 2019 · Borbely’s approach to a phono preamp in 1985 can be described as half-active and half-passive; a linear gain stage up front is followed by a passive low-pass filter for the RIAA 75µs rolloff and an active shelving equalizer for the 500Hz/50Hz low-frequency boost. The iRIAA Filter is a two-channel passive inverse RIAA response filter for use in testing phono preamplifiers. The passive balance and volume controls have a loss of 6 dB. I have taken the values of resistors up to 99. Jan 3, 2024 · 2024-01-03 10:57 pm. upper audio octave – see for example Denis Colin’s LP797 RIAA equalizer published in Audio Express here LP797. FIGURE 1: Inverse RIAA network; precise values for 1 micro dB accuracy and -40dB at 1kHz. 3- Add another Op Amp in the first stage and make a cascaded Voltage Amp (each of the two cascaded OPAs run at a lower gain setting to hopefully get more headroom) Step 2: The Inverse RIAA Curve. e. But it is a somewhat atypical design that uses two pentodes (one of which is triode connected) and two triodes per channel. Last edited: 2021-01-15 9:36 pm. Mar 16, 2022 · The idea of the RIAA before the phono stage is to provide a normal input signal to the phono stage, as provided by an LP, with boosted treble and reduced bass. 40% and 100% of the calculated value (values using serial and parallel). GlassWare Audio Design Software. Think about this transferfunction as a transfer function of one whole system, described by the given Laplace transform A - the inverse would then be A_inv=1/A. C 2 requires the high cut-off frequency F H and the High Pass Filter Calculator. It will also create a circuit diagram and provide the component values you require. It is easy to correct for output resistance when there is no AC coupling: take the Thévenin equivalent of the source and you see that its output resistance is in series with the input Feb 28, 2022 · However the shown schematic component values are correct when checked with an on-line "RIAA passive filter component calculator" so I can only imagine that the actual fitted components do not sum up correctly. It is feature rich, user-friendly and available for free from any desktop or mobile device. See the picture above—this is the playback curve when the bass is boosted back up 20dB and the high frequencies are rolled off. It's easy to show, though, that either R 2 or R 3B has to be made zero, otherwise you get an extra (finite) zero in the transfer. Figure 3. Design, optimize and simulate complete multistage active filter solutions within minutes. 2% of its final value. The low-pass filter will pass a signal with minimal distortion Passively Equalized RIAA Phono Preamp. engineeringvista. Although this plot is for a specific corner frequency, all RC lowpass filters will have this shape. 03dB of the direct preamp measurement. Mar 20, 2024 · Bandpass Filter Formula. Crossover Calculator. In the second case you get to use tubes with better reputations for good sound but less gain (say The Bandpass Filter Calculator is a tool used to design and analyze electronic circuits known as bandpass filters. Plug the phono cable onto the 4-pin connector on the inverse-RIAA filter. The following equation is used to solve for the values. Using passive network synthesis techniques, it's possible to obtain the component values exactly, without resorting to any approximations other than the ideal op-amp assumption. Separate output levels of –40dB and –60dB (referenced to 1kHz) accommodate moving magnet and RIAA Utilising TA7325 Option 2 Baxandall Bass and Tone Project Baxandall Circuit Design Baxandall Calculator Tone Control Circuit Practical Circuit Example Bass and Tone Calculator RIAA Preamp Project DIY - Magnetic Cartridges Part 1: RIAA Preamp Circuit Design Part 2: Baxandall Bass and Treble Control Part 3: Split Rail Power Supply Part 4 Considering the value of the resistor and capacitor, calculate the cut-off frequency of a series RC passive filter. Working on a split RIAA networks eq, I used this old spreadsheet of mine. This will be interfaced to a audio transformer for I/V conversion. Whether you have trouble with RC high-pass filter calculations or filter circuit configurations, you've come Dec 21, 2023 · For what it's worth, my DIY valve phono preamplifier follows the RIAA curve within +0 dB/-0. Calculate LC filters circuit values with low-pass, high-pass, band-pass, or band-stop response. The ω is the angular frequency, ie the product of 2 ⋅ π ⋅ f (frequency). This passive RL low pass filter calculator calculates the cutoff frequency point of the low pass filter, based on the values of the resistor, R, and inductor, L, of the circuit, according to the formula fc= R/ (2πL) . The total midrange gain is 30 dB (stage1) - 20 dB (passive RIAA) + 30 dB (stage2) = 40 dB. The gain of both op amps is constant over the audio bandwidth. I would like to add (per Allen Wright) a third filter stage for a 75uS (20KHz) roll off after the second tube Jan 31, 2021 · A high-pass filter (HPF) “passes” the high-frequencies above their cutoff frequency while progressively attenuating frequencies below the cut-off frequency. Thanks for looking. Nov 5, 2022 · With our high-pass filter calculator, you can design a filter that only lets high-frequency signals through while cutting off low-frequency ones. Calculation of each capacitor value requires two inputs. Such a circuit will deliver an exact cutoff frequency of. In the record player’s Dec 8, 2008 · A single gain stage of 6DJ8 drives a passive RC network which accomplished the necessary equalization for records. 3 days ago · An LC filter is a second-order filter circuit because it has both an inductor and a capacitor, whose impedance depends on the signal's frequency. (For perfect RIAA equalisation, the output will be the same level for each frequency between 20 and 20KHz, using a reverse RIAA board. 1OF . Formula: Cutoff frequency: f0 = 1 2πRC f 0 = 1 2 π R C. passive filters have this supposed disadvantage of high damping so that the signal needs to be re-amplified many people report that they prefer passive equalization because of the better sound quality. Disconnect the 4-pin phono cable from your record mechanism. Unlike traditional networks, the iRIAA Filter includes a correctly placed upper 3. [/fstyle] “Filtering Out the Noise, Because Life’s Already Loud Enough!”. g. audio. FIGURE 2: Inverse RIAA network; selected values in actual circuit, ±0. When the record is being cut - there is bass cut and treble boost applied to the signal before the master is cut. 2- Add an extra gain stage and split the RIAA time constants between the three gain blocks. Pay attention on the correction factor of 1/10, this should be a shift up to 20dB at 0Hz, so the correcting factor here is 10. 5% and 99. Figure 1. The twin T notch filter calculator calculates the values of the resistors and capacitors needed to obtain a notch frequency as entered in by the user. Metal film resistors and capacitors are polypropylene. The LM833 is especially well-suited for active filter applications because of its high gain-bandwidth product. Feb 15, 2016 · A subsonic filter is full audio band, all the way or almost all the way down to 20hz, which is inaudible, but shakes everything in the room, including your speakers and turntable. 12V RMS. When comparing results to other published designs using the same filter network, everything looks correct (within a few percent due to estimation of Rp). The first part of this circuit comprised of resistor R1 and capacitor C1 compose the high-pass filter. Its called passive equalization because the frequency shaping is all done by attenuation using resistors and capacitors. 03dB accuracy. The fully symmetrical nature of the circuit means that distortion is low and common mode input noise is rejected very well. lowpass. In other words, high-pass filters remove low-frequency content from an audio signal below a defined cut-off point. For a two gain stage circuit that means high gain tubes pushed relatively hard or three medium stages used less hard. Depending on the configuration of the components you can construct a low pass or high pass filter. Where LCF is the lower cutoff frequency (hz) HCG is the high cutoff frequency (hz) R1 and R2 are the resitances in a passive Brief for RC Filter Calculator: Compute the first order RC filter using the given formula. With a (more-or-less) typical source impedance of 100Ω, the response is down by about 0. The RC high pass filter transfer function is calculated according to: V o u t V i n = 1 1 + 1 ( 2 π f R C) 2. 18us (50kHz) corner in its transfer function. The phono preamp uses a passive RIAA equalization filter. Formula – band pass filter calculation. 4dB at 20kHz, and is down by 0. 1% resistors are used. If this isn’t close enough, you either have an exceptionally accurate preamp or should seek Apr 2, 2009 · Cut and Thrust: RIAA LP Equalization. 3 Passive RIAA(f) 1-step-solution type (A ub) Fig. 12 ). 4 Passive RIAA(f) 1-step-solution type (B ub) app. Jan 14, 2021 · Active RIAA isn't practical for tubes unless you use several stages. The Filter Type tab in the tool (Figure 1) gives you the option to select low-pass, high-pass, band-pass, band-stop (notch) or all-pass filters. 12dB at lower frequencies. So subsonic filters, when properly implemented, are always a good thing. The advantages: no voltage overload, no feed-back, no instability problems. Input the DC resistance, the inductance, the load resistance and capacitance at the preamp end, and the nominal output voltage, and voila, you know what you’d get with a perfect, noiseless Jul 31, 2015 · The RIAA equalization (de-emphasis) for flat playback can be generated actively (frequent-dependent voltage alteration via a negative feedback loop in the preamplifier) or passively (with a filter network in the preamplifier). the 2122Hz low-pass filter. Designing an active RIAA preamp circuit is extremely simple with this calculator, and this example is for a filter design that professionals use in commercial products. The following applies to the impedance Z: Z = R 2 + X C 2. It is still passive, it still sits between the two gain stages, but the values have been changed and it has shed one component. Bandpass filters are used to allow a specific range of frequencies to pass through while attenuating frequencies outside that range. I figured the other component values. A recording is made with the low frequencies reduced and the high frequencies boosted, and on playback, the opposite occurs. 8 RIAA Networks 229 Fig. Instructions: Choose your crossover type (two-way or three-way), input Low pass filter online calculator for step input response and sinusoidal noise signal This calculator helps engineers and electronics enthusiasts design high pass filters with specific cutoff frequencies and gain characteristics. The passive RIAA Phono Equalizer is an appealing circuit from an audiophile perspective for 2 main reasons. A filter such as this in the feedback loop of an operational amplifier usually provides the best RIAA response characteristics. The theoretical output at 20kHz is over 9. (12) Period is TC = 1/fC. The basic formula for calculating an RC high pass is: V o u t V i n = R Z. Formula – RC high pass filter calculation. The formula used to calculate the components of a high pass filter depends on the filter’s specifications, such as the cutoff frequency and filter order. Calculators Capacitor charge Impedance Matching Calculator Inductance Conversion Op amp voltage & gain Passive Filter Calculator PCB trace width Pull up Pull down resistors Transformer Turns Calculator Twisted pair impedance Manufacturer Tools; Reference Designs Jan 2, 2012 · Here’s a handy-dandy little spreadsheet riaa calculator which allows you to calculate the maximum signal to noise attainable for a phono cartridge. 1 user. After the groove is "read" by the needle - in the phono preamp stage, the reverse EQ is applied, which boosts the bass and cuts high frequencies. 9% of the calculated and capacitors to 99. 2018-10-15 7:54 pm. Schematic: 7025 / ECC803S / 12AX7A Tube Phono Preamplifier with RIAA Equalization Jan 24, 2014 · The RIAA curve, developed by the Recording Industry Association of America. Some cartridges require no C at all: others up to 500pF. Output level is switchable between -40dB and -60dB. τ τ: within 0. 2. Resistance Scale. (Remember to set the Unit Scale for the values you enter. SPICE software: PSpice. The notch frequency is the frequency that is most greatly attenuated by the circuit. When Ao is very high it'll tend to cancel in the above expression, so we get the simplified formula A = 1/B. Launch the tool now. To find the amplitude and phase at a particular frequency, use the highpass and lowpass amplitude and phase calculators. Full size image. Thi op amp bandpass filter produces a noninverting signal at the output. Project Type: For-Credits. That’s why these passive solutions are the ideal choice for high voltage gain stages like e. HCF = 1/2*pi*R1*C1 H CF = 1/2 ∗ pi ∗ R1 ∗ C 1. The input impedance is equal to R/2, or 12 kΩ in the circuit of Figure 9. Cutt-off Frequency. 01% of its final value. The simplest way to realize an passive RIAA filter is to use The generic filter section shown in Figure 3 is a simple lag-lead type with a zero and pole in the right places. This calculator is for an active noninverting op amp bandpass filter. 20dB higher signal level at 20kHz than at 1kHz. RIAA equalization is a form of pre-emphasis on recording and de-emphasis on playback. Nov 12, 2011 · The thread started with a commercial design having both R2 and R3B. This is followed by a passive RIAA network consisting of 240kO and 15kO resistors and the associated 0. The output is fed to a second 6DJ8 gain stage for a total gain of 32 dB. Select Chebyshev, Elliptic, Butterworth or Bessel filter type, with filter The best and, possibly, only way to implement this idea is to use passive RIAA equalization and break the curves into two sections, the first encompassing the 3180µs and 318µs time constants, i. LC Filter Design Tool is a web-based application for lumped LC filter synthesis. This project born to be a no compromise phono preamplifier without budget limit. 75V RMS, but this never happens because at 20kHz all recordings will be 15-20dB below the level at 1kHz (being very conservative). It provides the inverse transfer function of the RIAA response and level shifting so that a line level signal is converted into exactly what a phonostage input expects. Jan 1, 2011 · Type C b or D b RIAA network (active 318 μs/3,180 μs + passive 75 μs): change from an un-balanced to a balanced configuration with in-amp topology type 2. 2) times that of the interstage network. Professional Audio Products Application Note AN-13. Overall result (A) is inverse of FB NW (B). Phono End preamplifier Feb 7 st, 2009 . The accuracy of the simulation depends on the accuracy of Jun 9, 2015 · RIAA Equalization. It should be mentioned that an LCR-RIAA module belongs to the passive filters. The results are nothing less than spectacular. I couldn't find on the net (not even here) any formula which keeps into account the effect of the input impedance of the stage following a network. Dec 9, 2019 · The RIAA curve is an equalization filter applied to vinyl records and then corrected in record player amplifiers in such a way that the listener is never aware that any change has occurred. 5dB from Mar 5, 2019 · ejp said: You need to make C4 selectable. This means that the output signal is exactly in phase with the input signal. A Chebyshev bandpass filter is a type of filter that allows a specific range of frequencies, called the passband, to pass through while attenuating frequencies outside this range. Capacitance Scale. Calculate. f c = 1 / (2π × 3. Here, V i n stands for the input voltage and V o u t for the output voltage. The reduction in bass helps us get the twenty plus minutes per side, and the exaggerated treble works as a very effective noise reduction. 12AX7A and ECC803S twin triodes can also be used with this circuit. The following formula is used to calculate the cutoff frequencies of a bandpass filter. The feedback to the input will also be routed via the transformer center-tap for a balanced to SE conversion. It should also be in practice since 1% caps and . I've include a secondary LP filter to address the non-inverting amp's roll-off at unity gain, a 20 Hz rumble filter and a simple flat gain stage with potential gain adjustments The inverse RIAA Filter is an accurate reference for testing modern phonostages. You may need to disconnect Apr 11, 2006 · Then you can see what your phono stage is actually doing. This calculator does. This is very important for correct response in the top octave, and is about loading the cartridge correctly, not about RIAA. Jul 26, 2015 · The result was within ±0. # Low Pass Filter Formula. - The high frequency reproduction of the curve is extremely accurate - The two amplifiers operate with a constant feedback gain. The gain is ( 1 + R6 / R5 ), with the values listed its 30 dB. Sep 23, 2023 · September 23, 2023 by GEGCalculators. how to implement a passive filter to equalize the RIAA (Recording Institute Association of America) curve. The 10pF represents the cable from the turntable to the amplifier. The basic equations to calculate the values for the components An input signal to stage 2 at 17mV (5mV phono cartridge output) would then give a normal output at 1kHz (before the passive filter) of 1. 3 dB from 20 Hz to 20 kHz (measured, with respect to 1 kHz). Frequency Scale. om cs ao td fc rm ov tc ak tr