Bubo

Once the audio signal hits the crossover, speaker drivers and cabinet, and all of the variables in free air, inc humidity........ Too uncontrolled for any repeatable measurement unless you have a controlled test chamber. Tea time

My thought is to send a tone through the cap and measure using an oscilloscope on the in and out and comparing Within frequency range, you may be able to characterize a cap the same way you would characterize an amplifier using test tones, I'm no xover guy....but the caps roll off at different freqs, combined with inductors becoming more resistant with frequency The faster they roll off the steeper the crossover point...... It should be possible to characterize a cap like an amplifier within it's range.

After I finish my slice of carrot cake and PG tips tea I may dive back in........ On my long list of things is setting up a test rig for caps just for fun Resistors is another one that easier to demonstrate noise and design. My thought is to send a tone through the cap and measure using an oscilloscope on the in and out and comparing Within frequency range, you may be able to characterize a cap the same way you would characterize an amplifier using test tones,

Capacitor Comparison using Bass guitar and test measurements Found no real differences in test or audible Instrument repair tech https://www.talkbass.com/threads/capacitors-and-tone.1442449/ The musician boards seem keen on which caps to use with instruments

At different frequencies electrolytic capacitors have different capacitance. Suppose it is 50 uF 16V capacitor (type K50-16), then the measurement results are (using russian E7-14 RCL tester): 1) At 100 Hz - 57,31 uF 2) At 1 KHz - 38,20 uF 3) At 10 KHz - 3,56 uF So my question is - which frequency the manufacturer had in mind? measurement capacitance share improve this questionfollow edited Mar 4 '17 at 11:59 Autistic 10.5k22 gold badges2222 silver badges4747 bronze badges asked Mar 4 '17 at 11:18 Ernestas Gruodis 17711 silver badge1010 bronze badges At a frequency where its ESR is negligible compared to its capacitive reactance. Look up its ESR in the datasheet and see if it explains the anomalous results at higher frequencies. – Brian Drummond Mar 4 '17 at 11:23 1 Special electrollytics should be used when high frequencies are applicable, such as with switch-mode circuits. – skvery Mar 4 '17 at 11:40 Hard to find info about K50-16 russian capacitors, but I have noticed, that for similar types like (K50-15) here it is clearly mentioned test condition: "Capacitance tolerance (25 °C, 50 Hz), %". So I suppose I should use 50 Hz test frequency (in my case only 100 Hz available, but it is closer to truth). – Ernestas Gruodis Mar 4 '17 at 12:37 Why measure an electrolytic? If it's new and bought from a reliable source just use it. If it's old then don't use it. How much do you value your time? – Andy aka Mar 4 '17 at 14:29 If its good, why to replace? But how do you know if its good? So this raises the question how to test it properly. – Ernestas Gruodis Mar 4 '17 at 14:42 You have your question backwards. Instead of asking what conditions you should reference, you should instead start from the conditions which you wish to deal with. If your cap is a filter on the output of a bridge capacitor with a 50 Hz line frequency, 100 Hz is the nominal condition of interest. If you are using the cap as a blocking cap in an audio amplifier, then your audio frequency range is what's important, If you don't know how your cap will be used, it is impossible to tell what test condition is appropriate. – WhatRoughBeast Mar 4 '17 at 15:28 Yes, I understand. Just want to test as it was tested at factory conditions - at specific test frequency, as they did. Its like testing radio tubes - at some written conditions in datasheet. – Ernestas Gruodis Mar 4 '17 at 17:00 The answer to a slightly different question, which is "what is the standard measurement parameters for electrolytic capacitor capacitance?" is as follows: Modern electrolytic capacitors use a standardized measurement method to determine their capacitance. This method is 20°C and 0.5VAC at either 100 or 120Hz (which is derived from the traditional common usage of electrolytic caps, which was to smooth the output of a bridge rectifier. That ripple is going to be 2*50Hz or 2*60Hz, depending on the country). The exception is photoflash capacitors, which typically have their DC capacitance measured. Virtually all electrolytic capacitors will cease being capacitive at all before 100kHz, and beyond that, will be inductive. This is universal to all electrolytic capacitors. Generally, an electrolytic capacitor will gain about 10% capacitance if the DC capacitance is measured. It will lose about 10% by 1kHz (or more in the case of your capacitors - but they say they are designed for DC and ripple applications, so they are probably not optimized for anything above 120Hz). But to actually answer your question, "at what test frequency should electrolytic capacitors be measured?" They should be measured at the frequency of interest for your application. That's the frequency they should be measured at. Why would you ever measure their capacitance at anything except the frequency of most interest to your planned use? Which makes me wonder - why are you even doing this? It sounds like you are trying to verify if a capacitor is within spec. There is no reason to do that however, and you are just wasting your time if you are. The failure mode of electrolytics does not involve a reduction in capacitance, so measuring it and comparing that value to what it was designed to have is not useful. Beyond that, virtually every electrolytic capacitor, including those russian ones, have pretty awful tolerance. They can vary from -20% to +80% the rated value. So even if loss of capacitance WAS a valid way to determine if an electrolytic had gone bad or not (which it isn't), then a capacitor that reads the right value might have began life at +80% that value, and has lost nearly half of its capacitance, but you'd never know. Not that this ever happens though. The failure mode of electolytic caps is that their electrolyte dries out. This does not have a meaningful impact on their measured capacitance. What it does do, however, is cause ever increasing ESR, until eventually the ESR is so high that they are no longer useful as capacitors. Even then, they will have the 'right' capacitance. So I can think of nothing useful being accomplished by verifying the actual capacitance value. Now, if you don't know the value of a capacitor, because the label has fallen off, the lettering rubbed off, or whatever, then that's when you can do something useful by measuring the capacitance. Or if you need to verify the capacitance at a specific frequency of interest. https://electronics.stackexchange.com/questions/290252/at-what-test-frequency-should-electrolytic-capacitors-be-measured

Capacitor Self-resonant Frequency and Signal Integrity https://resources.pcb.cadence.com/blog/2019-capacitor-self-resonant-frequency-and-signal-integrity Frequency dependent capacitor for AC sweep analysis in LTspice https://electronics.stackexchange.com/questions/410388/frequency-dependent-capacitor-for-ac-sweep-analysis-in-ltspice Capacitor AC Response The frequency dependent impedance of a capacitor is called capacitive reactance. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/accap.html

I have to believe that the Cap mfgs must run frequency and DC leakage tests for their products to characterize them. And that the equipment mfgs must bring in the top 10 meet or exceed spec caps to test and listen to in the design. Thanks to Deang for his measurements This is the spec sheet from Nichicon's premium "audio" capacitor Muse Measurement made at 120HZ Not sure I understand Tangent of loss spec, loss across cap uniformity at tested frequencies ? http://www.nichiconcapacitors.com/pdf/e-ukz.pdf https://www.nichiconcapacitors.com/product/nichicon-kz-muse-1000uf-25v/

The 75 W amp looks like a more robust design on one metric The second amp may have problems with peaks You also have to look at SN, THD etc.... YMMV

This is a review of a headphone amp, not hard to extrapolate to an amp Charts with the measurements Review and Measurements of Massdrop THX AAA 789 Amp https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-massdrop-thx-aaa-789-amp.5001/

Perhaps the question is: Is a more Robust Amplifier more desirable ? A. Yes It can handle a greater number of variances off of the ideal load. Greater power reserves and the ability to deliver without distortion The same goes for performance at higher and lower frequencies When the Engineers design an Amp, they should and most likely Characterize it in the lab with a variety of load conditions, inputs and faults. To see how the Amp handles them, compared to the design. "High Current" to me is more of a Marketing Slogan I stumbled across the THX Lab tests they use to characterize Amps once, I wish I had saved it. Might have been over 200 measurements under varying conditions to characterize the amp and determine if it was in tolerance to meet THX defined loads The THX Controller Metrics Tested on THX Controllers: Reference Output Voltage Voltage Gain Input Impedance Gain Control Range Gain Tracking of the Master Gain Control Overload Source Voltage D.C. Bias Current at the Input Maximum Output Voltage of Low-Level Outputs Output Source Impedance Polarity D.C. Offset at the Output Frequency Response Deviation Signal Time Delay Noise Output Voltage Input Level Indicator (Clipping Indicator) Video Path Switching Video Level Sync Level Bar Tilt Pulse/Bar Ration K-Factor (K-2T) Frequency Response Amplitude (0.5 to 4.2 MHz) Group delay (0.5 to 4.2 MHz) Chroma Gain Chroma Delay Differential Gain Differential Phase Noise Video Conversion Harmonic Distortion and Noise Difference-Frequency Distortion Dynamic Range Digital Data Sampling Rate Support Input Mode Control and User Interface Design Input Mode Switching Automatic Detection of Data Types Output Modes and Post Processing Equalization and Tone Controls Signal Headroom Bass Management Filter Characteristics LFE Channel Level Scaling Loudspeaker Position Time Synchronization Auto Calibration Auto Setup Output Levels Dialogue Normalization Another key element that THX requires for receivers and SSPs is the reference setting for volume control. When a system is calibrated according to the manufacturer’s instructions, “0.0 dB” on the volume control corresponds to reference level playback. In turning the volume down, the volume level is expressed in -dB, or how many dB below reference level you are. Metrics Tested on THX Amplifiers: Reference Output Voltage Voltage Gain Output Current Output Source Impedance Overload Restoring Time Stability with Capacitive Load Harmonic Distortion and Noise Modulation Distortion Difference-Frequency Distortion Noise Output Voltage Phase Response D.C. Offset at the Output Hum Crosstalk Acoustic Noise Level Mechanical Noise Input Sensitivity Input Impedance Output Impedance Load Impedance Range Voltage Output Capability Current Output Capability Transient Output Capability Transient Overload Recovery Time Asymmetrical Clipping Frequency Response Phase Response Phase Margin Time Total Harmonic Distortion Intermodulation Distortions SMPTE IM Distortion IHF IM Distortion DIM 30 Distortion Noise Hum Radiated Interference Conducted Interference Crosstalk Make no mistake: THX Ultra power amplifiers tend to be very powerful. We’ve never seen one with less than 100 watts/channel continuous RMS, full band, all channels driven, BUT because of the “practical sum” THX has defined for themselves, even seemingly modest receivers under $1,000 can get THX Select2 certification and provide a satisfying experience for a lot of people who can’t afford a stack of THX Ultra power amps (we’ll talk about Select- vs. Ultra-Certification a little later). Metrics Tested on THX Speakers: Axial Frequency Response Analysis Directional Characteristics Sensitivity Impedance Harmonic Distortion Low Frequency Cut Off Phase Angle Stray Magnetic Flux Maximum Output Level Acoustic Noise Level Polarity https://www.thx.com/aaa/

If I win the lottery..... A barn Conversion So I can pack it full of gear that is wired so I can listen to all of it. Pair of Jubes Would probably need a larger TV in the middle. I once saw listed a pair of Altec Bass horns, exponential?, standing about 8 ft tall and 2ft wide, guess about 8 ft deep, 1 or 2 driver. I want a pair of those for watching The War of the Worlds 1953 Jeff Wayne - The Eve of the War (Official Audio) ft. Richard Burton, Justin Hayward 208,407 views •Jan 30, 2020 https://www.youtube.com/watch?v=Poii8JAbtng

I was looking at a Marantz 8000 surround receiver the other day 15 years old ask was $200 Superb built in DAC and performance measurements, 100Wpc I like to use the older surrounds as Stereos with built in DAC etc Some of these have superb tuners You would have to have a phono pre amp https://www.cnet.com/products/marantz-sr8000/

The reasons young people are flocking to vinyl is: No quantization error if analog source No loudness wars, won't fit on vinyl No psycho acoustics added to trick the ear for low bit rate and $2 ear buds. Guttenberg interviewed a friend who masters music, asked which mastering is the best, answer, the version for vinyl.

Excellent and to the point. Last time I stopped by a Magnolia Center, I had them play one track with Poe using their totl Marantz and switching between speakers, most expensive to least expensive (monkey coffins) Her voice was unintelligible on most, difficult on a few and clear on the Klipsch R series book shelf Sales mgr was upset and stopped the test. Put on something was mostly rock instrumentals turned up. My understanding is that Magnolia isn't allowing people to bring their own music as of 1-2 years ago.

Altec produced a lot of great products The 19 was considered their best home speaker by many The cabinet with 2 connected chambers is a different design philosophy than the LaScala 19 = 2 drivers, better driver alignment LaScala 3 drivers, fully horn loaded. 19 is 2-way so one less crossover point to manage LS probably better for vocals with crossover at 400hz vs 1200Hz 19 goes to 30Hz, LS bottoms out at 50Hz If I had room I would own a pair of 19s in addition to all my other gear. I have always loved the LS for female vocals.....

The no brainer improvement on the Fortes would be the addition of a protective metal cage over the rear radiator, black. Would the tweeter be better if sweeter sounding but rolled off after 17khz ? take one of the horns from the better reference and use it as the tweeter ? Would the Forte 4 be better with no tweeter, just two drivers ? A larger, fuller range mid horn ???? If the Tweeter is eliminated, a larger horn becomes possible, and or dual woofers. The Forte is a compact combination of frequency range 30-20Khz, and woofer mid driver alignment. would be better of tweeter aligned too. Alignment is something Altec and JBL seemed to focus on. What would be the benefit of more height ? I am suspect of MDF, prefer Birch Cabinets. Cross bracing and damping are cheap and easy real estate to add, no brainers. What effect would porting have on sound quality if any, would it defeat the radiator ? Each of the Heritage speaker lines was a different design philosophy, Forte being radiators. Heresy has better Horn Woofer driver alignment, tweeter too short LaScala fully horn loaded, woofer horn 1 ft longer than mid horn etc etc.

When I look at any work product to evaluate it The question I ask myself is: What would I add to the Product to improve it ? What would I take away from the product to improve it ? Ranking the changes can be done by category Mandatory to have a sellable product World Class cut above the competition Nice to have features that have some value So yes, the question is what would you add or take away from the Forte 3 that should be incorporated into the Forte 4 ?

Caps have a shelf life, 30 years it's time New gaskets for the screw on compression driver, they dryrot Crites and others have the parts. Leave the woofer alone, rotate makes sense Wires can be replaced with standard 12GA speaker cable If you don't want to solder a new wire, you can strip, splice a section of new wire soldered and shrink-wrapped. If you are uncomfortable, ask your friends, one of them knows how to solder. If the cabinets are oil finish, watco natural oil them.

Question With the current Forte 3, what would you add, what would take away ? The list from 2 to 3 was easy....

Here it is You may discover you don't like a favorite band, or hear the added noise for psycho-acoustics

Take the lid off and blow it out with a can of compressed air, unplugged Think of it as a first kiss and jump in....... Good solder joints look like shiny Hershey's kisses, broken ones look broken, dull ones are cold joints. Bulged and leaking capacitors look bulged and you can see if it took a dump on the board. You can't damage anything by looking, and learning. Best

Better than expected, not sure what the message of the film was. I was expecting the usual "everything is hopeless" and didn't get it thankfully. Would be good on the big screen, wide panoramic shots, and might have had the feel of a real WW1 bayonet charge in the theater.

Either will work fine. I have a small room 5Mx4M approx. and use the surround S style in the rear corners angled in, sitting on shelves. They likely have greater dispersion than the R41s. You can try both and if S style, use the other pair for a bedroom system. If you have a bigger room in the future, you can use the S for the mid wall speakers Mine are Klipsch10 years earlier speaker line, but same configs. YMMV

The best way to make 2 speaker sound like 4 speakers, is to add 2 more speakers.... May be fast and cheap to add two low cost rear speakers and experiment with synthetic surround and various delay aka Concert Hall options. Can KGs be had cheap ? High quality 15 year old Surround Receivers are literally a dime a dozen, I usually pay less than $20 if in good working order. Who cares how much they paid, the market does not want them without the latest chip sets .......

What we listen too is .5 watt or less 2 Watts is screaming How an amp sounds at 100W is irrelevant for the high efficiency speakers The SS amp may have tighter engineering tolerances and less drift, tubes do age as they are consumed.