Which Capacitors for Audio?

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English seems fine. I know the maths there thanks. But isn't impedance matching what output transformers are for ? I'm not a "valve person" but am aware of a trend to use lowish power valve amps to drive high efficiency speakers with UK hi fi circles at least
Impedance matching with pentodes would result in very low output power.
It is important to decorrelate the impedance of an active electronic circuit and it's power delivery capability.
A 6L6, whatever the mode can switch about 400V at 140mA. It is what determines the order of magnitude of the load. Other considerations, such as distortion and reliability will guide the final choice.
Specs say:
Triode Rp=1 700 ohms, load 5 000 ohms
Pentode Rp=22 500 Load=5 000
 
The tin plating turned black, the copper surface underneath was black too. The cable wax in principle of good quality, OEM factory for some big brands.

And the measured degradation was an increase in general noise floor on the AP2 FFT as well as increased levels of individual harmonics doing loopback.vs selecting genmon as input.
I would rather suspect a degradation of the insulating material resulting in increased dielectric losses.
 
Impedance matching with pentodes would result in very low output power.
It is important to decorrelate the impedance of an active electronic circuit and it's power delivery capability.
A 6L6, whatever the mode can switch about 400V at 140mA. It is what determines the order of magnitude of the load. Other considerations, such as distortion and reliability will guide the final choice.
Specs say:
Triode Rp=1 700 ohms, load 5 000 ohms
Pentode Rp=22 500 Load=5 000

Poor choice of language by me in this context. I didn't intend to imply equal source/load impedances. Rather the transformation of level and impedance to suit the amplifier / speaker interface.
 
I don't know of any major companies who design by ear... Human hearing is too unreliable for important work.

Audio phoolery is closer to religion than hard science .

JR
To everyone in this conversation - some very good points. I still use MIT Multicaps made by Rel-cap. Each type sounds different.

HOWEVER : Stop trash talking audiophiles. Those that do have no idea what they are talking about.

The initial post of this whole thread is about making something that sounds the best it can.

This response is addressed to those who poo poo hi end audio, call the art form fraud, audiofoolery. What irks me is attitude of the engineers that claim cables, connetors and caps, etc. don't make an audible difference and they think they know better because it doesn't fit into their limited model of thinking - base band audio is too simple or ESR in caps is no longer important, or they can't measure it. etc. Wire is wire, a cap a cap etc.

I'm bugged at all the arguments I see about cables, caps, amps from so many who never worked in high end audio. If you've never been to a hi-end stereo trade show then you're opining about something you know little about.

Did you spend hours trying different caps and cables? Did you tune your amps for a sound that draws you into the music? Did you have electrostatic speakers to listen through? What is your source material? Did you audition music from master tapes, CDs, uncompressed? E-stat headphones? Go to the trade shows and get opinions about your product? Have reviews? Do the attendees want to stay in your room or get up and leave fast?

What's is wrong with doing something better than average if it pleases you? That's what all the mic people are doing here.

The hi end boutique corner of the world - Yes, there's some claims that don't stand up but there is also spectacular sound in many different flavors that is much better than what industry standard control rooms have. I did it for 40 years - design, manufacturing, trade shows, modifications updates. And I'm respected in that world. I'm a musician besides being an engineer so I rely on my ear for the final evaluation. WTF else is MORE important? NOTHING BUT YOUR EAR.

The hi end audio is about art, pleasing the senses, the meters just help you get there. If you can borrow a design idea from the art world and have it make your idea or product better without sacrificing anything significant then why wouldn't you??
 
English seems fine. I know the maths there thanks. But isn't impedance matching what output transformers are for ? I'm not a "valve person" but am aware of a trend to use lowish power valve amps to drive high efficiency speakers with UK hi fi circles at least
Yes, the OPT matches speakers and amps impedances. It's one of the greatest benefits, to work with low powered amps in combination with high eff. speakers. It's hard work to design a good sounding amp which delivers huge power, but it's relative easy to do so with a small powered design. Many amps on audio fairs I wouldn't like to listen at home, all those big bricks standing in between speaker pairs, because they are too massive for putting them into the rack. My amp has 8W, and even this seems huge for a matching horn speaker.
 
It's often an argument between pro audio and HiFi. If a recording mixer was made using the same methods and principles that pertain to HiFi, it would cost several $M.
When they listen to their million $ stereo, they should realize the signal probably went through dozens of electrolytics caps, TL07x and Blackmer VCA's.
I thought most of this was settled last century. It was always amusing to hear about audiophools, complaining that they could hear the degradations from running audio through a single switch contact. They would be depressed to learn how many switch contacts audio must negotiate to get through a typical recording console.

The big analog desk market has been in free fall for a couple decades. The small handful of people I know who built their own consoles, only did it once after the learned the total effort involved. Modern digital mixers (like Behringer) deliver remarkable bang for the buck and decent performance.

To everyone in this conversation - some very good points. I still use MIT Multicaps made by Rel-cap. Each type sounds different.

HOWEVER : Stop trash talking audiophiles. Those that do have no idea what they are talking about.
I will trash audiophools all day long... I don't consider all audiophiles "phools". At my last major day job I had a resident golden ear that I used when appropriate. (He happened to be a degreed engineers and did some good engineering in Peavey's transducer engineering dept).
The initial post of this whole thread is about making something that sounds the best it can.
The unarticulated dispute here is designing using object science (bench test measurements), versus a general disdain for
This response is addressed to those who poo poo hi end audio, call the art form fraud, audiofoolery. What irks me is attitude of the engineers that claim cables, connetors and caps, etc. don't make an audible difference and they think they know better because it doesn't fit into their limited model of thinking - base band audio is too simple or ESR in caps is no longer important, or they can't measure it. etc. Wire is wire, a cap a cap etc.
Show me the data... I wrote about several of those topics back in the 80s in my "Audio Mythology" column.
I'm bugged at all the arguments I see about cables, caps, amps from so many who never worked in high end audio. If you've never been to a hi-end stereo trade show then you're opining about something you know little about.
I haven't been to one this century, but recall seeing my share of high end rooms at old AES shows in NYC when I used to regularly attend (I probably saw you there).

Here is a personal anecdote that shaped my distaste for the esoteric audio market sector. Back last century I was manufacturing a modest priced phono preamp ($150) that was extremely linear and very RIAA accurate. That preamp received two magazine reviews that couldn't have been more different. One reviewer said violins through my preamp sounded like "sawing on wires". :rolleyes: Coincidentally without my knowledge my preamp was shared with a highly regarded reviewer, who compared my preamp favorably to a $5K high end favorite. That surprise good review (in TAS) came a little too late for me. I had already decided to walk away from that business. My estimate for how the same preamp (it was literally the exact same unit) could receive such different reviews. My judgement was that both reviewers were accurately hearing the performance of their personal phono carts, speaker systems, and rooms. The better reviewer likely had a better room and better playback system.

The thing I preferred about working in professional sound reinforcement is that you can't BS hundreds/thousands of people in a large auditorium, like you can in a small listening room.
Did you spend hours trying different caps and cables? Did you tune your amps for a sound that draws you into the music? Did you have electrostatic speakers to listen through? What is your source material? Did you audition music from master tapes, CDs, uncompressed? E-stat headphones? Go to the trade shows and get opinions about your product? Have reviews? Do the attendees want to stay in your room or get up and leave fast?
No
What's is wrong with doing something better than average if it pleases you? That's what all the mic people are doing here.
I used to operate a kit business and there is a certain amount of satisfaction gained from DIY audio (hey I built that)..
The hi end boutique corner of the world - Yes, there's some claims that don't stand up but there is also spectacular sound in many different flavors that is much better than what industry standard control rooms have. I did it for 40 years - design, manufacturing, trade shows, modifications updates. And I'm respected in that world. I'm a musician besides being an engineer so I rely on my ear for the final evaluation. WTF else is MORE important? NOTHING BUT YOUR EAR.
I have some old studio monitors in my living room but rarely listen to recordings. I used to throw huge beer parties with live bands jamming in my living room. Compared to the live bands my hifi system sounded a little puny. 🤔
The hi end audio is about art, pleasing the senses, the meters just help you get there. If you can borrow a design idea from the art world and have it make your idea or product better without sacrificing anything significant then why wouldn't you??
I recall back last century in a discussion about meter readers vs golden ears, I opined that we (product designers) also need to understand ergonomics and human factors engineering to deliver the best customer perception of the products. To that end I put gold plated RCA jacks on my last phono preamp, not to be better electrically but to improve customer perception. Likewise in console design gain law curves, and EQ voicing can have an impact on customer perception.

There is actually a lot of science studying human perception, ranging from audition to the man-machine interface.

JR
 
To everyone in this conversation - some very good points. I still use MIT Multicaps made by Rel-cap. Each type sounds different.

HOWEVER : Stop trash talking audiophiles. Those that do have no idea what they are talking about.

The initial post of this whole thread is about making something that sounds the best it can.

This response is addressed to those who poo poo hi end audio, call the art form fraud, audiofoolery. What irks me is attitude of the engineers that claim cables, connetors and caps, etc. don't make an audible difference and they think they know better because it doesn't fit into their limited model of thinking - base band audio is too simple or ESR in caps is no longer important, or they can't measure it. etc. Wire is wire, a cap a cap etc.

I'm bugged at all the arguments I see about cables, caps, amps from so many who never worked in high end audio. If you've never been to a hi-end stereo trade show then you're opining about something you know little about.

Did you spend hours trying different caps and cables? Did you tune your amps for a sound that draws you into the music? Did you have electrostatic speakers to listen through? What is your source material? Did you audition music from master tapes, CDs, uncompressed? E-stat headphones? Go to the trade shows and get opinions about your product? Have reviews? Do the attendees want to stay in your room or get up and leave fast?

What's is wrong with doing something better than average if it pleases you? That's what all the mic people are doing here.

The hi end boutique corner of the world - Yes, there's some claims that don't stand up but there is also spectacular sound in many different flavors that is much better than what industry standard control rooms have. I did it for 40 years - design, manufacturing, trade shows, modifications updates. And I'm respected in that world. I'm a musician besides being an engineer so I rely on my ear for the final evaluation. WTF else is MORE important? NOTHING BUT YOUR EAR.

The hi end audio is about art, pleasing the senses, the meters just help you get there. If you can borrow a design idea from the art world and have it make your idea or product better without sacrificing anything significant then why wouldn't you??
In fact, when designing my audio system, I only used those parts that sounded the best to me. And everything do make a contribution to the sound, thats kown to me since three decades and it's no believe system, it's a practival approach, learning the sound of parts.

That doesn't mean one has to go to extremes, I never do. But with every single active and passive parts, even with the rack of your audio system, one can tune the sound. Good to know but it doesn't make things easier in life. If everything contributes to a fraction of the whole sound, every tiny detail becomes important. I can understand when people still don't believe this fact or don't hear differences. Nobody should behave arrogant about others, we all strive for a sound we love and that can mean individual ways and solutions.

Often people who can't design own gear tend to go into cabling orgies or prefer other tuning things for achieving, personally I think that mostly the gear itself contributes by far to differences, so it should be designed and matched to other parts of the system to work perfect.
That matching is often a problem and people don't understand the technical terms, so they continually swap gear to achieve their goals. Every swap means new experiences and that's a way of learning, too.
 
There are pro audio people with wacky ideas. Given enough rope the wacky ideas tend to hang themselves. I don’t have patience for cable swappers but people who put in the design time and show their work are interesting to me, even if it’s wacky.
 
I'm not talking about teh capacitors used in filters, I'm talking about the caps that are necessary to prevent DC in the pots.

If using Fet Op-Amp's, many such capacitors can be dropped.

People don't want to hear ugly scratches when they select frequency or change gain.

That is not an excuse to go "let's just dump a bunch of rlcaps in there. If only because they have poor long term stability. Unsuited to professional tools.

Not a reasonable choice when you want 4 parametric sections in a mixer channel. Each section having 4 or 5 opamps.

I am familiar with that. Personally I did variable Q simple parametrics, these tend to actually work better than fully parametric ones, for music.

It cuts down the number of Op-Amp's to one per band. The capacitors to block DC are also the actual filter response determining ones, so we get DC blocking for free.

Yet SSL, Neve et al didn't do it; not even Studer or Focusrite.

Yes, I noticed. Mind you, most of these also did not fit 5 way fully parametric EQ's per channel.

You're totally neglecting the industrial aspects, where cost optimization is a vital factor.
I'd be curious to see the BOM for an analog music recording mixer designed after your principles.

Funnily enough, it would likely be lower than one done your way, especially in the 80's when active components actually were expensive.

You would have found discretes for the Mic Pre (with the traditional input transformer), discretes for the main EQ Amp and special audio focused op-amps (with an open collector out from the VAS) for the gyrators that replaced tapped inductors and reduced the real estate and cost while offering more bands.

Mix Amps - discrete.

EQ's on subgroups same as inputs. Of course, it would be modular.with "cassettes" and could be used in mixer frames from the 1960's.

These were designed to meet the formal requirements of the East German Standards, but perversely perhaps were additionally judged by listening panels of experienced sound engineers. So they had to both "sound right" and "measure well".

Not mentioning real-estate and the nuclear plant to power it.

Not needed.

It's often an argument between pro audio and HiFi. If a recording mixer was made using the same methods and principles that pertain to HiFi, it would cost several $M.

A serious desk cost a lot anyway.

Optimising it for sound quality doesn't need to make it a lot more expensive, if any.

When they listen to their million $ stereo, they should realize the signal probably went through dozens of electrolytics caps, TL07x and Blackmer VCA's.

I know what was used to record KOB and non of that was involved. I also know it was for 80's pop. Not that I listen to either, habitually at least.





One recording represents Artisanal music production with high production values and is still a landmark.

The other represent an industrial production line approach to making next week's number one this week, next week we do Kylie instead. It's really only good for Rickrolling and yes, if you clicked on the second video....

Thor
 
I don't see how a piece of Al can result in strong damping. Maybe I lack vision...

Well, I know some Pro audio cone midrange drivers with a single piece Alu former. They have a Qm of around 0.2 and a Qt of closer to 0.1. We was much higher than Qm.

What happens is called eddy current braking. If you want to be fiendish, you use a split former and bring out both sides of the split using classic tinsel connections. Add a variable resistor and you can adjust Qm fairly freely.

There is a commercial example of a loudspeaker using small speakers with extreme mechanical damping. It takes 1.7kW on the bass section to provide decent spl.

There is no "extreme damping" in that. It's the Sunfire subwoofer.

I find the way devialet does sub's on the "Phantom" much more interesting, to get low bass (at very low efficiency) in a small box.

Motional FB is just another way of applying electrical damping.

Absolutely not. You are (hopefully) not using the voice coil back emf, but dedicated sensing that senses (preferably) the actual sound pressure.

Like this:
Meyer Sound X10

Thor
 
If using Fet Op-Amp's, many such capacitors can be dropped.

What about something with a low level and low source impedance like an MC Phono stage?
That is not an excuse to go "let's just dump a bunch of rlcaps in there. If only because they have poor long term stability. Unsuited to professional tools.

If you turn a knob in the middle of a take and it makes noise the take has just been ruined for the sake of sound quality.
I am familiar with that. Personally I did variable Q simple parametrics, these tend to actually work better than fully parametric ones, for music.

Sounds better and works better from a user perspective aren't always the same thing. I'll take works better any day of the week.
 
Me too, but when they have a tool missing from their toolbox it's not so great.
Dear Lord! You really have no idea what horrible people you are, do you? How lucky I am that my tenure in this hellhole of lazy, dogmatic, close-minded, out-of-date egotists lasted only a week or so. As I said when deleting my account, it was like finding yourself enrolled at a rather unpleasant school.

This reply is shining example of the revolting and poisonous culture you have nurtured here.
 
Dear Lord! You really have no idea what horrible people you are, do you? How lucky I am that my tenure in this hellhole of lazy, dogmatic, close-minded, out-of-date egotists lasted only a week or so. As I said when deleting my account, it was like finding yourself enrolled at a rather unpleasant school.

This reply is shining example of the revolting and poisonous culture you have nurtured here.
Good luck...

JR
 
What about something with a low level and low source impedance like an MC Phono stage?

Direct couple. Use a correct circuit that. cancels base currents to keep them out of the cartridge coil. Trivial.

If you turn a knob in the middle of a take and it makes noise the take has just been ruined for the sake of sound quality.

Why? I didn't suggest to just remove capacitors.

But rather to design circuits so that the debated electrochemical capacitors OUTSIDE OF FEEDBACK LOOPS are eliminated.

Sounds better and works better from a user perspective aren't always the same thing. I'll take works better any day of the week.

I suggest that sound quality is the Raison d'être for sound equipment. It is not optional.

Works better is actually optional!

However IME there is rarely a need to compromise this, though some re-learning may occasionally be required from the operator.

Thor
 
Dear Lord! You really have no idea what horrible people you are, do you? How lucky I am that my tenure in this hellhole of lazy, dogmatic, close-minded, out-of-date egotists lasted only a week or so. As I said when deleting my account, it was like finding yourself enrolled at a rather unpleasant school.

This reply is shining example of the revolting and poisonous culture you have nurtured here.
Probably the same guy who exited with a similar diatribe a couple months ago.
 
I know what was used to record KOB and non of that was involved. I also know it was for 80's pop. Not that I listen to either, habitually at least.

One recording represents Artisanal music production with high production values and is still a landmark.

The other represent an industrial production line approach to making next week's number one this week, next week we do Kylie instead. It's really only good for Rickrolling and yes, if you clicked on the second video....

Thor
I think they used what was available in the studios at that time, and this was old tube recording gear. One can see the VOTT being used, too.
It was the american tube amp gear with lots of electrolytics, audio signal transformers and golden tube age technology.



My own record collection contains many of those oldtimer mono records and they sound different to modern ones, but not that they do sound bad, just different. Pop music of the 80's with it's homogenized sound is often enhanced and was engineered to let it sound good on ghetto blaster audio systems.
But I own mono records which only used limiters, and they don't do much harm to the recording it seems. Some of the old dinosaurs are excellent in all aspects and highly sought after today.
 
IPop music of the 80's with it's homogenized sound is often enhanced and was engineered to let it sound good on ghetto blaster audio systems.

Fun fact, the greatest likelihood of 80's pop is on the ghetto blaster by the side of my pool, when all of us old geezers with our young girlfriends have a poolside BBQ and pool party. Usually after more than the first Chang Beer too.



Thor
 
Why? I didn't suggest to just remove capacitors.

But rather to design circuits so that the debated electrochemical capacitors OUTSIDE OF FEEDBACK LOOPS are eliminated.

Abbey said this was not possible in many cases. I am not a designer but you are suggesting most of the circuit designs I've seen in pro audio are no good. That's a big claim. I see capacitors used for this purpose all the time.
I suggest that sound quality is the Raison d'être for sound equipment. It is not optional.

I have heard many things described as good sound quality that I would strongly disagree with. One man's trash is another man's treasure. I suggest that capturing and reproducing audio of interest is the goal. Compelling audio is my not optional goal.
Works better is actually optional!

Tell that to the record label spending $20K per hour.
 

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