Absolutely. It's also useful for story-telling when what you're selling is mediocre performance from old and pedestrian circuits in a fancy and expensive package.
FWIW, my preamps and power amps are dead quiet despite only using electrolytics in the power supply. Perhaps because attention was focused on the engineering rather than voodoo?
Those who are concerned about the properties of electrolytics but want to achieve a good engineering solution will use them in the PSU and maybe use film caps as local decouplers downstream. The converse, which I think is what you are suggesting, is daft. Most people are happy to use electrolytics in both places.michaelsamra said:
Given the poor electronics knowledge of most amp buyers and journalists it is quite likely that CJ see a benefit, but it is a marketing benefit not an engineering benefit.
An electrolytic can outperform a film cap when a little loss is required, or where value for money is required. "Cleaned up" and "very sluggish" are too vague to comment on, but I can assure you that changing the reservoir cap for a similar value but different dielectric will not affect amplifier non-linear distortion, frequency response or peak power.
DA does no harm in a PSU cap (or a coupling cap or a decoupling cap). The only place you would need to avoid DA is in a filter (such as a passive crossover or RIAA network) - even there all it would do is modify the LF frequency response. Don't believe all you read about "lost energy" or 'time smearing'; these are just fairy stories invented to frighten children and newbies.
Manufacturers (in a capitalist system) are in business to make money. That means making what the customers want to buy, and getting customers to want to buy what the manufacturer happens to be good at making.
DA does no harm in a PSU cap (or a coupling cap or a decoupling cap). The only place you would need to avoid DA is in a filter (such as a passive crossover or RIAA network) - even there all it would do is modify the LF frequency response. Don't believe all you read about "lost energy" or 'time smearing'; these are just fairy stories invented to frighten children and newbies.
In a coupling cap I would agree because we are not concerned with with DA because in the case of a coupling cap we are blocking the DC and passing the AC signal..In that case DA might even have an advantage being we don't want the DC to pass to the grid of the stage it couples to.
In a coupling cap I would agree because we are not concerned with with DA because in the case of a coupling cap we are blocking the DC and passing the AC signal..In that case DA might even have an advantage being we don't want the DC to pass to the grid of the stage it couples to.
You guys have made some eloquent arguments for electrolytics but it goes further.
When I look a an amp or preamp,I see nothing but a DC power supply we modulate with an AC signal..The purest form of DC I know of is a battery but since it isn't possible to put batteries into practical application for a tube amp,we have to work with what we have.
Sy,you mentioned that you use electrolytics and have absolutely no hum and I don't dispute that.If the purpose of that capacitor was just to kill hum and nothing more,you would have an excellent argument. The missing part of the equation is the fact that the cap has to store energy and supply energy to the load..This is where the difference comes in because even tho I have a very nice test bench,I'm measuring mostly under static conditions and not dynamic conditions where the real advantage of the better cap will show. Now even when I measure at different power levels such as distortion,power levels and pureness of sq waves,You can see differences even tho they may appear to be smaller. A film cap has definite advantages and now that price has come down,a lot more companies are using them.
Now if we could measure everything under dynamic and peak conditions in the way an amplifier typically operates with multiple frequencies going thru it,you would definitely see a bigger advantage then what I see under the typical one frequency at a time measurement..
Nobody is saying not to use electrolytics but in some cases like in the Mac Mc30s and the Mac Mc60s,the sonic difference was very noticeable on the big ESLs. With the Sherwood,the only and first cap off the rectifier being a poly made the amp so much quicker in the bass and midrange and this is on the Newform Research 645 ribbons.
I was also a skeptic just as you guys are and I always thought that if ripple was low,that's all that mattered. This is when I condescendingly decided to humor the guy that wanted me to try the film caps and I did. At first I thought what is the big deal but then I started to put different music selections on that I was familiar with, I could hear right away the advantage of the film caps in the power supply.
Film caps can't be used in many applications because of size constraints however,when you have the room like in a Mac amp with tube rectification,it's a whole new experience.
When I look a an amp or preamp,I see nothing but a DC power supply we modulate with an AC signal..The purest form of DC I know of is a battery but since it isn't possible to put batteries into practical application for a tube amp,we have to work with what we have.
Sy,you mentioned that you use electrolytics and have absolutely no hum and I don't dispute that.If the purpose of that capacitor was just to kill hum and nothing more,you would have an excellent argument. The missing part of the equation is the fact that the cap has to store energy and supply energy to the load..This is where the difference comes in because even tho I have a very nice test bench,I'm measuring mostly under static conditions and not dynamic conditions where the real advantage of the better cap will show. Now even when I measure at different power levels such as distortion,power levels and pureness of sq waves,You can see differences even tho they may appear to be smaller. A film cap has definite advantages and now that price has come down,a lot more companies are using them.
Now if we could measure everything under dynamic and peak conditions in the way an amplifier typically operates with multiple frequencies going thru it,you would definitely see a bigger advantage then what I see under the typical one frequency at a time measurement..
Nobody is saying not to use electrolytics but in some cases like in the Mac Mc30s and the Mac Mc60s,the sonic difference was very noticeable on the big ESLs. With the Sherwood,the only and first cap off the rectifier being a poly made the amp so much quicker in the bass and midrange and this is on the Newform Research 645 ribbons.
I was also a skeptic just as you guys are and I always thought that if ripple was low,that's all that mattered. This is when I condescendingly decided to humor the guy that wanted me to try the film caps and I did. At first I thought what is the big deal but then I started to put different music selections on that I was familiar with, I could hear right away the advantage of the film caps in the power supply.
Film caps can't be used in many applications because of size constraints however,when you have the room like in a Mac amp with tube rectification,it's a whole new experience.
To be clear, I used the word "noise" not hum. Ripple has a lot of higher frequency components, as does induced noise from the line and other parts of the circuit. That's exactly what the purpose of the first cap is.
Downstream caps further reduce ripple/noise and decouple the attached stages. For class AB stages, they also provide a degree of regulation. Electrolytics work fine for that- local bypasses for HF can be small film caps but are unrelated to the energy storage and release function of the supply.
In the case at point here (a preamp), the circuit is run in class A, so the average draw is constant. In this case, the function of downstream caps is purely ripple/noise reduction and decoupling, and that's a matter of design, not dielectric.
In a couple of my preamps such as the SP3a and the Airtight
I measure almost ripple even at the lowest scale..They do use SS regulators and being many are gain type regulators,they can also act as capacitance multipliers.
I see Curcio did this with his power supply boards because I would be puzzled at the fact that I would see very low value lytics like in the 10uf range and yet it would filter just beautifully.
That brings me back to the preamps because if you have a regulator with a gain of 100,putting a 50uf on the base and measuring at the collector should have an effective capacitance of 500uf should it not? I'm not saying these are the values but being I can't measure the ripple content to be as low in a non regulated circuit,it makes me think the capacitance multiplier must be taking affect.
I measure almost ripple even at the lowest scale..They do use SS regulators and being many are gain type regulators,they can also act as capacitance multipliers.
I see Curcio did this with his power supply boards because I would be puzzled at the fact that I would see very low value lytics like in the 10uf range and yet it would filter just beautifully.
That brings me back to the preamps because if you have a regulator with a gain of 100,putting a 50uf on the base and measuring at the collector should have an effective capacitance of 500uf should it not? I'm not saying these are the values but being I can't measure the ripple content to be as low in a non regulated circuit,it makes me think the capacitance multiplier must be taking affect.
Yes, for low current draw, you don't need huge amounts of capacitance, and if you do the wise thing and actively regulate, you can make the noise and source impedance very low. That was a big motivator for Joe since his preamps had dreadful power supply rejection. Ditto Allen Wright's designs.
A simple cap multiplier seems silly these days since active regulation is cheap and easy compared to what it was in the past.
A simple cap multiplier seems silly these days since active regulation is cheap and easy compared to what it was in the past.
I am puzzled. How does DA improve the blocking of DC by a coupling capacitor?michaelsamra said:
No, not missing. Some people talk about 'energy storage' as though this is something extra and esoteric that a cap does, which ordinary engineers don't know about. A cap works by storing charge; this inevitably involves storing energy so energy storage is intrinsic to the operation of a capacitor.
I suspect this is another aspect of Fourier denial; people think that by doing a time-based cap measurement (e.g. DA) they are finding something fundamentally different from frequency-based measurements (e.g. impedance). They are not. DA will show up in very low frequency impedance measurements, as a drop in impedance or rise in capacitance - this is useful, as it works in the right direction!
How does DA improve the blocking of DC by a coupling capacitor?
If you read what I posted I didn't say exactly that it did..When it was mentioned that DA would not be a problem in coupling caps, DC voltage getting absorbed into the dialectric so maybe it can't pass as DC to grid would be a good thing.. I was simply agreeing that DA in a coupling cap isn't an issue.
You said:michaelsamra said:
and
So DA may be an advantage and a good thing in not passing DC, yet this is not what you mean?
No, you said it was an advantage. You now accept that DA in a coupling cap is not an advantage but merely irrelevant?
The usual audiophile mix of true, partially true, true but irrelevant, and downright wrong.
Once you hit something like this, you know you're in voodoo land.
OK, so we are back to saying that DA may be a good thing for a coupling cap because "the dc gets aborbed into the dielectric to where it can't pass to the grid of the next stage" - whatever that means! Do you actually understand how capacitors work?michaelsamra said:
I will refrain, if you don't mind. If it says things like
then I am not missing much by not reading it.
DA is caused by the dielectric polarisation being 'sticky' so it takes time to respond to changes. The net effect is a boost in capacitor value for very low frequencies, although complicated by a resistive element too. DA can be modelled by using a ladder network of C and R.
I would say there is unexplained phenomena going with caps in audio
that even the most well versed engineers on the subject of capacitors can't explain their on effect on the audio signal. There are those that say that different types of capacitors have no affect on the sound and that just isn't true. http://diyaudioprojects.com/mirror/members.aol.com/sbench102/caps.html
that even the most well versed engineers on the subject of capacitors can't explain their on effect on the audio signal. There are those that say that different types of capacitors have no affect on the sound and that just isn't true. http://diyaudioprojects.com/mirror/members.aol.com/sbench102/caps.html
Last edited:
OK. It makes you feel better if you believe nobody understands capacitors.
Different capacitors can of course affect sound, especially if they are used wrongly e.g. wrong value, wrong dielectric.
You can believe popular myths, or you can learn to design electronics.
Different capacitors can of course affect sound, especially if they are used wrongly e.g. wrong value, wrong dielectric.
You can believe popular myths, or you can learn to design electronics.
Note the word "can" versus "will." Dave is very deliberate in his phraseology.
It's all predictable by standard and well-understood basic engineering. Of course, if engineering is well understood, one won't draw in inappropriate demonstrations like Steffie Bench's and believe it to be applicable to the matter at hand here.
It's all predictable by standard and well-understood basic engineering. Of course, if engineering is well understood, one won't draw in inappropriate demonstrations like Steffie Bench's and believe it to be applicable to the matter at hand here.
Keep in mind we can't measure everything we can hear due to the complexity of the human composition. For instance I love the sound of paper in oil capacitors by the very nature of the way they present the music and in circuits where their have higher dc voltages like 100vdc or above,they definitely present a sonic advantage at least to my ears and on circuits where little or no DC is present,they take much longer to break in even tho some will argue there is no break-in but that isn't true IMHO...Maybe we acclimate to it over time and that may be whats at play..
I think reality is the opposite: we can measure lots of things we can't hear - our hearing is weak and easily fooled.michaelsamra said:
Finally you said something I agree with.michaelsamra said:
- Status
- Not open for further replies.