If a capacitor has the same value and can handle the power driven through it do different types of capacitor have an effect on the sound quality or do they all sound exactly the same. I’d say they probably sound the same but open to being proven wrong.
Naim listen to just about every component during development, not just capacitors, the most expensive ones can often fail their listening tests.
If you take a look inside your Naim equipment you’ll probably see a load of small blue electrolytic capacitors and a load of light brown? Tantalum bead capacitors.
You chose the equipment you bought because you like the sound those capacitors produce.
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I know it’s not really the same thing but I think the analogy works.
Consider a lightbulb with a 40W rating and saying all 40W lightbulbs should provide the same light.
Yet it’s common knowledge amongst those who purchase and fit the lightbulbs in their homes that 40W lightbulbs come in a many shades of warmth and colour.
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Capacitors do sound subtly different. The difference in the various sounds is caused by the variables such as construction, materials (electrolytic, plastic film etc..) and the electrical properties within the capacitor itself.
Capacitors are not just simple capacitance; they also include small values of resistance and inductance.
Resistance “R(p)” parallel with the components capacitance.
Equivalent Series Resistance “ESR”
Equivalent Series Inductance “ESL”
Most of the quality capacitor brands will state ESR in a data sheet, but ESL is hardly ever shown.
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Having taken several vintage Adcom amplifiers (GFA-5500, et al) to ridiculous heights by upgrading their capacitors in a strategic manner (among other mods, like new discrete rectifiers, etc), it really depends on where the cap is in the circuit, in addition to the caps’ specs.
For caps in the feedback network or the main filter/reservoir caps in the Adcoms, they make an enormous difference. But most of the caps on their boards are not very critical and just need to meet electrical spec. E.g. they aren’t worth ‘upgrading’, only maintaining such that they meet spec.
Going to low-ESR Mundorf M-Lytic caps (smaller values) or TDK-EPCOS (main filter) caps in strategic places is an easy way to hot rod these older designs by a significant amount. I’ve communicated directly with Nelson Pass about these things, as he designed these amps with all the same parts of his early Pass Aleph amps. The GFA-5500, for example, is 2/3rds of an Aleph that also functions into A/B. Per Nelson. Same International Rectifier HEXFETs as the output devices (just fewer of them) and the same input devices, etc.
That said, Naim have been auditioning caps and controlling for their alteration/improvement to the signal path for decades and it would be a lot more difficult to truly improve (read: net-better in every area, both electrically and acoustically) on Naim equipment from the last 20+ years.
So, to put a point on it, all caps do not sound the same. The amount of same or non-same depends on their criticality in a given circuit.
Like in a loudspeaker crossover; a shunt cap matters far less than a main tweeter cap, for example.
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So do either Resistance, ESR and ESL vary as f(freq) depending on the type of capacitor?
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Naim designed the 332 with the large gold Promisic caps they’ve used in their preamps for decades. Then, right before production, swapped them for a tiny and extremely cheap cap with similar values. Their reason when questioned was claimed supply chain issues. The tiny cheap cap sounds just as good as the much more expensive Promisic cap they’ve used for decades, according to them. My point? Naim also contradicts themselves. Just because they choose one component, it doesn’t mean there aren’t other options that are better or just so good.
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I really don’t care what Naim or any manufacturer puts inside their product. If i like the sound i will have a home demo, and buy if i feel it ticks the right boxes for me.
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Yes, they (everything) varies depending on numbers of things, inc environmental conditions and operating parameters.
But this is deep dive stuff and a bit too much for a forum, but very quick one line answers
ESR decreases with frequency rises until it reaches the capacitor’s self-resonant frequency.
ESL effectively constant at low frequencies but can increase as it nears resonance.
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As well as capacitance (and its tolerance) and maximum voltage, capacitor characteristics include temperature rating, coefficient of capacitance rating with temperature, equivalent series resistance, equivalent series inductance, leakage current, susceptibility to microphonics, dielectric type, and maybe more. If these all are identical the capacitors might sound the same - and if not they might not, depending on what exactly they are doing in the signal path.
i am not an expert on capacitors, but my understanding is that the actual construction (both choice of materials and process) can affect many of these.
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The specs on the cap themselves also do not indicate things like charge rate and discharge curve, both of which can be measured with a function generator and an oscilloscope.
The other measurable but not part of the printed spec is the ripple leakage with some passing on more than others. Then there is microphonic susceptibility and also the degree to which they may also cause microphonics. Although for the latter, the past batches of Panasonic caps I bought both had data sheets describing the effect of microphonics on performance and the degree to which they may emit microphonics too.
Thinking that a capacitor is just voltage and capacitance is “good enough” for some very simple applications but constitutes nowhere near all the electrical properties on their full datasheet. That coupled with a few properties that are measurable but may not be on the datasheet and you soon realise that very few, if any, two capacitors with the same capacitance and voltage values are truly the same spec.
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I recall back in my early days when I was Naim’s customer service manager, being contacted by a customer who had recently bought a Naim CD player but was writing in to complain that ever since they had “upgraded” all the capacitors with much more expensive items (black gates etc.) it now sounded awful. The message followed with a long diatribe about how they felt they had been mislead by the hifi magazines and online hifi chat groups, the long and the short of it being that they wanted it fixed by Naim.
The lesson of course being that the components Naim use are there for a good reason having been auditioned and assessed very carefully to take into account performance and production viability. I have spent many hours sitting in with Roy, Gary, Steve et al.. while listening to a particular component, often something like a capacitor, and listening for the subtle way one example might influence the overall performance. It’s painstaking stuff, but all part of product development.
And it doesn’t stop when a product is discontinued. Caps are often a service item, particularly the large reservoir caps in power supplies and power amps, so when a favoured capacitor stops production then R&D have to undertake tests on the available alternatives to determine which sounds best. It’s how Naim ended up using the large Felsic capacitors - one of the most expensive options, unfortunately, but much the best, and with excellent supply, so that’s what they went with.
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Not a Naim person but an electrical engineer told me, “it’s important to read and understand data sheets, particularly with power supply parts in amplifiers, ESR and ripple current matter.” But of course listening to the result is what really matters which Naim definitely do as well.
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I’ve always thought it was odd that the XPS doesn’t use the large format Felsic caps while every other power supply does besides the Flatcap. Even the HiCap does which is less than half the price of the XPS. They all serve the same purpose with varying numbers of regulators. Any idea why?
I don’t exactly, and not being a Naim engineer I can’t say I’m any kind of expert on the subject, but I do recall during my early days of asking a thousand questions over lunch, being told once (by Roy or Gary perhaps??) that there are sometimes certain advantages that become apparent during listening to using a number of smaller caps over one large one, but in every case Naim would use the most performance appropriate caps in type, size and make, for the item in question.
IIRC I was questioning the change from the large caps in the power amp power supplies to a greater number of smaller types in the NAP250.2/300 etc..
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In my pre-retirement work – and nothing to do with Naim or SQ, but I suspect some of this was/is in Naim’s thinking – we always used a bank of smaller capacitors in parallel in place of a single large capacitor.
We found they gave better performance with improved electrical characteristics, increased reliability and it optimises available space.
In some applications we also added a small “fast” low ESR capacitor
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Resitance doesn’t vary with with frequency.
Impedance is a combination of resistance and reactance and so varies with frequency… albeit the resistance is constant in terms of frequency but can change with temperature and age. Reactance is the complex resistance through a capacitor or inductor. Inductive reactance increases with frequency, capacitive reactance decreases with frequency.
So how such components are are used and whether they are in parallel or serial will affect how they affect an alternating current / voltage - ie an audio signal.
ESR is equivalent serial resistance of a component - ie the DC resistance plus reactive losses (ie its actually an impedance) . capacitors used with audio frequencies typically have very low ESR compared to reservoir type capacitors used in power supplies etc so as to minimise small signal losses.
ESL is the parasitic inductance of a capacitor and therefore is a reactance and will vary with frequency.
Capacitor constructs absolutely affect audio signals .. because the construction and materials cause different side effects, and their differences will affect circuits.
Film type capacitors are often ideal and usually used for audio signal path as they are low loss and low side effects such as parasitic inductance.
- Polypropylene is typically considered high performance because of low loss and side effects but higher cost.
- Polystyrene are often considered the best of the best but harder to source in volume and higher cost. Also sensitive to heat so challenges with surface mount.
- Polyphenylene Sulfphide is less ideal but more suited for miniature SMT type capacitors
- Polyester is lower cost general purpose signal path - but has higher losses.
Others in the thread have discussed reservoir and low frequency/high capacitance capacitors such as Electrolytic Aluminium and Tantalum typically used in power supplies and regulation.
RF ground coupling are often Polyester.
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I seem to recall that this reduces ESR, but memory could be failing.