CEC Capacitors

[rhomanski]

Re: CEC Capacitors

Most of the old ones came with good caps but they are getting old. It improves the sond a great deal to use good quality modern caps like Panasonics and Nichicons. Mostly I use Nichicon KL series low noise for the audio path and PW series for everywhere else. In a lot of the older gear they used big power caps to help with big bass pulls.

Peevey was always the cheaper garage band brand. Marschall was what the big guys used. I remember Ted Nugent had a ramp behind his stacks. At the beginning of a concert he would run up the ramp and jump in front of the amps and speakers. You couldn't see him until he was airborne and he would land playing.

[Spork Schivago]

Re: CEC Capacitors

Most of the old ones came with good caps but they are getting old. It improves the sond a great deal to use good quality modern caps like Panasonics and Nichicons. Mostly I use Nichicon KL series low noise for the audio path and PW series for everywhere else. In a lot of the older gear they used big power caps to help with big bass pulls.

Peevey was always the cheaper garage band brand. Marschall was what the big guys used. I remember Ted Nugent had a ramp behind his stacks. At the beginning of a concert he would run up the ramp and jump in front of the amps and speakers. You couldn't see him until he was airborne and he would land playing.

Rhomanski,

Because I still struggle with understanding the purpose of capacitors and how / why to use them in circuits, could you please explain how capacitors affect sound in these systems? And how replacing them with new ones improve the sound?

[rhomanski]

Re: CEC Capacitors

I'm not an engineer Spork but I can still hear. It seems they become more selective with frequencies as they age. Attenuating the highs and lows more than the middle frequencies. I have wondered if the time constant of the charge and discharge changes as well because the midrange sounds muddied not clear and crisp as a new one does. Perhaps it's not charging as fast and it slows the charge until it should start discharging causing the peaks to smear as it were.

I have two pairs of speakers from 1976. I decided to replace the capacitors in the crossover. It was the first part of the system I recapped. After doing the first pair I sat down in front of it and listened. It sounded pretty good. I got up and sat down in front of the ones that were still original. They sounded much worse. The violins were barely recognizable while I could almost pick out individual ones on the new cap ones. I got up and shut off the stereo and started in replacing the caps in the other pair. As I built my system I recapped each component. I did my Brothers system first though and I'm glad I did. After finishing his I started on mine and before I could finish mine he passed away. Wish he could have heard it after I finished. Best system I've ever heard. Maybe some would say it's not as good as McIntosh or whatever, but I still think it's great. Never heard anything to beat it.

[keeney123]

Re: CEC Capacitors

Rhomanski,

Because I still struggle with understanding the purpose of capacitors and how / why to use them in circuits, could you please explain how capacitors affect sound in these systems? And how replacing them with new ones improve the sound?

Do you have a particular circuit diagram you are talking about? I would say the affect of capacitors in a sound system would be dependent on where they are located. Some capacitors are used to block DC from affecting a circuit. Some are for regulating the power supplies ripple. Some are used for filtering frequencies. Such as low pass, high pass and bell shaped filters. Some are used to create oscillators.

[rhomanski]

Re: CEC Capacitors

All that's true Per, I don't know how much of an effect a marginal cap would have in those positions. I was speaking more about ones in the audio path. I've recapped 5 Sansui AU-717's for my surround sound system and the new caps have made them stable as a rock and clear as a bell.

Spork here is a schematic that shows the audio path as a heavy black line to help you see what one looks like. Just join up for free and you can download any schematic they have for audio equipment. https://www.hifiengine.com/manual_li...h/mc2100.shtml .

[Spork Schivago]

Re: CEC Capacitors

I'm not an engineer Spork but I can still hear. It seems they become more selective with frequencies as they age. Attenuating the highs and lows more than the middle frequencies. I have wondered if the time constant of the charge and discharge changes as well because the midrange sounds muddied not clear and crisp as a new one does. Perhaps it's not charging as fast and it slows the charge until it should start discharging causing the peaks to smear as it were.

I have two pairs of speakers from 1976. I decided to replace the capacitors in the crossover. It was the first part of the system I recapped. After doing the first pair I sat down in front of it and listened. It sounded pretty good. I got up and sat down in front of the ones that were still original. They sounded much worse. The violins were barely recognizable while I could almost pick out individual ones on the new cap ones. I got up and shut off the stereo and started in replacing the caps in the other pair. As I built my system I recapped each component. I did my Brothers system first though and I'm glad I did. After finishing his I started on mine and before I could finish mine he passed away. Wish he could have heard it after I finished. Best system I've ever heard. Maybe some would say it's not as good as McIntosh or whatever, but I still think it's great. Never heard anything to beat it.

I am so sorry to hear about your brother. That makes me really sad. Our cat Mocha had cancer. I was working on a toolchain for the playstation 3. I spent a lot of time on it. She sat next to me the whole time I worked on it. She knew it was important to me. The docs realized they misdiagnosed me and took me off all my medications. This put me in some sort of manic episode where I was sleeping maybe 2 or 3 hours a night for weeks at a time. I finished it but didn't work out all the bugs. I couldn't get a test program to display the menu on the PS3. At that time though, we discovered she had cancer and I stopped working on it. After she died, I went back to it and figured out what was wrong and thought how much she would have loved to see me get it finished. We had to put her down. She had a tumor in her plural cavity, so every time she breathed out, she couldn't breath in as much, because the plural cavity filled with more blood. It was the hardest thing we ever did and I miss her so much. She was family. We tried getting it removed but they said she was too old and wouldn't survive the surgery. They said the cancer had spread and was affecting her brain and that's why she'd twitch. I remember when we drove her up to Cornell one night (they were the only ones open at night). Her breathing got too bad and we knew she was suffering. She knew something was wrong, we was crying so bad, my wife and me. We stayed with her the whole time, even when they put her down. We told her to look at us. She was scared. I hate cancer. An extremely large number of inside cats die of cancer. Outside cats never make it that long. I'm talking like 96% of them or something insane like that. If we spent the time and money to figure out why, maybe we could use that to stop it in humans too.

Did you ever think about trying to use those polymer capacitors in one of those amps?

[Spork Schivago]

Re: CEC Capacitors

Do you have a particular circuit diagram you are talking about? I would say the affect of capacitors in a sound system would be dependent on where they are located. Some capacitors are used to block DC from affecting a circuit. Some are for regulating the power supplies ripple. Some are used for filtering frequencies. Such as low pass, high pass and bell shaped filters. Some are used to create oscillators.

I'm talking about all circuits, but tomorrow, I will send you a zip file with a schematic and board layout if you want that has capacitors on it. Do you think you could help me understand how the caps work in this circuit and how the transistors work? It's a fairly simple schematic. I have tried soooo many times to learn about both but everytime I start reading, I get so confused. With transistors, they start talking about weird things like holes and p's and n's and stuff like that. Can you read schematics in Eagle format or do you want me to send it in a PDF?

I'll add some more to the post. You say some are used to create oscillators. When you say oscillators, you mean a clock pulse, right? On, off, on, off, on, off. I tried using one to do just that. I took my breadboard. I took an LED and hooked a capacitor to it. Added some resistors so the LED wasn't getting overloaded. I heard and read that capacitors "fire". I hooked a battery to my circuit. What I expected was the LED to blink on and off. What actually happened was no light at all, until I actually removed the positive terminal from the battery! So I've read they're kinda like batteries but don't hold much of a charge. I can figure out what voltage a capacitor needs to be rated for. Just figure out how much voltage is on the line, right? Get a cap rated for at least that much voltage. But the farad rating.....no idea.

[rhomanski]

Re: CEC Capacitors

The way to think about hole flow, is it's just like chinese checkers. The marble is an electron, when you jump over another marble, you fill a hole and leave a hole behind you. That's hole flow. When you move across the board you leave a little positive charge behind you which sucks in another electron.

P and N are the materials the board is made out of. You have three layers PNP or NPN. By controlling the middle layer with a small voltage you can increase or decrease the total currant flow. the total currant flow will always be bigger than the applied voltage on the middle layer. Almost exactly like a triode tube. Electrons come from the bottom go through the middle grid as to how it's biased and flows out the top. If you put an audio signal on the middle layer of a transistor or the grid of a triode, it will control the currant flow exactly as the audio signal comes in and amplifies it that way.

And the amps already have tons of polymers in them for the smaller values. When they were made polymers couldn't be made large so electrolytics were used and electrolytics couldn't be made small enough so polymers and ceramics were used.

[Spork Schivago]

Re: CEC Capacitors

Thank you for the explanation for the transistors. Why is the total current flow always going to be bigger than the applied voltage on the middle layer? When the electron moves from one hole to another, does it always jump over an electron? Or are there just a bunch of empty holes and it moves from to another, and every hole it moves to, when it leaves, it always leaves a little positive charge, that pulls in the next electron?

Are these holes physical holes on the P and N materials that the board are made out of?

I don't know what a triode tube is, but if it's a type of vacuum type, I don't know anything about them. When I was growing up, I think they stopped using vacuum tubes. Only time I ever seen one in real life was with Jason's really old pig nose amp.

What do you mean by how it's biased? With the audio signal, increasing it's current amplifies the signal to make it louder?

[Behemot]

Re: CEC Capacitors

Lamps are still used in hi-fi stuff, it's actually coming back. Firms are starting to make them again.

The actual reality is still unknown, details go to quantum physics. But for basic understanding, you can indeed imagine the planetar model of atoms. Electrons can "jump" over couple atoms easily even in semiconductors. In later studies it seems hole conductivity is greater than electron conductivity.

In conductors we imagine "electron gas" as they are shared between all atoms, and from statistical models of quantum physics it is really more like a "gas" or "fog" of location probability. That is also why conductors conduct so well, the electrons are largely free.

In standard, bipolar transistor you controll the flow via current, in unipolar, FET, by voltage. FETs are more efficient as there are only very little currents on the gate. while bipolar transistor base can draw couple amps.

In any case, you just induce little conductive path which can than conduct much larger current, that is the amplification ratio of a transistor. By controlling the "width" of the path (or, how much it is opened), you can than controll how much power goes through. Like a valve in water tube.

[rhomanski]

Re: CEC Capacitors

Here's a couple pictures. The triode was the tube equivalent of the transistor. Now it's all chips for the most part. In the triode you have a cathode which puts out the electron fog Behemot spoke of. It approaches the grid. If the grid is biased highly negative the electrons are repulsed and no currant flows. If the grid is not biased at all, sitting at 0 volts, a little currant will flow. If the grid is biased with a positive voltage, maximum currant flow will result. The grid will suck in electrons and then the positive plate will pull in the rest.

Solid state works very similarily. The N gives electrons, the P determines if they go on at all, a little, or like gangbusters. The second N sucks up all that comes through from the other N layer.

In the diagram, they use the heater filament as a cathode which is usually not the same in later tubes. The cathode is actually a separate plate.

[Spork Schivago]

Re: CEC Capacitors

Here's a couple pictures. The triode was the tube equivalent of the transistor. Now it's all chips for the most part. In the triode you have a cathode which puts out the electron fog Behemot spoke of. It approaches the grid. If the grid is biased highly negative the electrons are repulsed and no currant flows. If the grid is not biased at all, sitting at 0 volts, a little currant will flow. If the grid is biased with a positive voltage, maximum currant flow will result. The grid will suck in electrons and then the positive plate will pull in the rest.

Solid state works very similarily. The N gives electrons, the P determines if they go on at all, a little, or like gangbusters. The second N sucks up all that comes through from the other N layer.

In the diagram, they use the heater filament as a cathode which is usually not the same in later tubes. The cathode is actually a separate plate.

Okay, I'm almost understanding now. But I still don't understand something. Let's take the NPN transistor. So, we have

123
NPN
  ^
  |
  |
 gives electrons

NPN
 ^
 |
 |
Controls if the electrons flow, and how much, to the first N

NPN
^
|
|
Sucks up all the electrons from the first N, depending on P

Is that right? I still don't understand though how that "sucks up all the electrons from the first N, depending on P" can generate more electrons than it receives. That'd be amplification, right? Generating more electrons than what it's receiving?

[Behemot]

Re: CEC Capacitors

Mainly that would be against the law of conserving energy (matter). I think there is enough electrons coming from outside the transistor, isn't it...?

[rhomanski]

Re: CEC Capacitors

What your missing spork is there is a large amount of electrons sitting on the bottom N. They have to go through the P section. The P section is biased to either repel them and no currant flows, (to speak of), or it's neutral so that some electrons flow through, or it's positive and all electrons flow through. A small voltage on the P varying up and down will control a large flow from N to N and that makes it an amplifier. Using a square wave on the P can make it a switch. On off on off.

"Controls if the electrons flow, and how much, (from)to the first N" to correct your example.

And I was being less than accurate when I said "sucks up" the electrons are rather pushed into the other layer of N. The layer is already slightly negative so the electrons have to be forced into it. It's called the collector because it takes most of the electron flow. The one that forces is the emitter because it emits all the electrons, and the controlling layer is called the base.

[Spork Schivago]

Re: CEC Capacitors

What your missing spork is there is a large amount of electrons sitting on the bottom N. They have to go through the P section. The P section is biased to either repel them and no currant flows, (to speak of), or it's neutral so that some electrons flow through, or it's positive and all electrons flow through. A small voltage on the P varying up and down will control a large flow from N to N and that makes it an amplifier. Using a square wave on the P can make it a switch. On off on off.

"Controls if the electrons flow, and how much, (from)to the first N" to correct your example.

And I was being less than accurate when I said "sucks up" the electrons are rather pushed into the other layer of N. The layer is already slightly negative so the electrons have to be forced into it. It's called the collector because it takes most of the electron flow. The one that forces is the emitter because it emits all the electrons, and the controlling layer is called the base.

Okay, so a transistor cannot actually create more current than what's already at the collector? I know with a series circuit, the current is the same throughout the entire circuit. With a parallel circuit, the current for each parallel branch equals the total current. So, with parallel circuits, the current is kinda divided equally for each branch.

With transistors, if no current is flowing through it because the base is negatively biased, those electrons don't move, but they won't build up a giant supply at the collector, until it's turned on, right? I remember current flows from the positive terminal to the negative terminal. Electrons flow from the negative terminal to the positive terminal. I've been looking at electrons as current, maybe that's where I'm getting hung up. Because with current, just because there's no load, the current isn't going to build up to create more current...

I can see now how a transistor can be used to limit the amount of current flowing through the transistor. If you have 2 amps of current, it now makes sense to me how we can use a transistor to allow less than 2-amps of current to go through that transistor. But to me, I wouldn't call that an amplifier. It's more like a current potentiometer, or a current variable resistor...if a transistor cannot amplify the current at the collector, than why do people say they can amplify? Do they just mean the signal at the base can be amplified by as much current that's at the collector?

[Spork Schivago]

Re: CEC Capacitors

...A small voltage on the P varying up and down will control a large flow from N to N and that makes it an amplifier. Using a square wave on the P can make it a switch. On off on off.

This is where I'm still struggling. What is it actually amplifying? I thought the current that comes into the collector....but now I think I might have been wrong there...

[Behemot]

Re: CEC Capacitors

The ratio of collector current vs. base current.

You put small current (like signal) on base, lot of available DC power on collector, and get the same signal with much more power on emitter, which you can directly send to for example speaker. Voila, you just made sound amplifier.

[Spork Schivago]

Re: CEC Capacitors

The ratio of collector current vs. base current.

You put small current (like signal) on base, lot of available DC power on collector, and get the same signal with much more power on emitter, which you can directly send to for example speaker. Voila, you just made sound amplifier.

Okay, hold on now. So, the emitter always outputs the signal that's on the base? But if the base controls the amount of current that goes through the collector to the emitter, if you were to put an audio signal on the base, wouldn't that not provide a steady amplification, because the audio signal isn't a straight pulse? Wouldn't it be equivalent to just turning the volume knob up and down really quick like? I've looked at audio signals in editors before, they're all squiggly lines.

[rhomanski]

Re: CEC Capacitors

The transistor amplifies the signal. A volume control can only attenuate a signal.

The transistor amplifies loud and quiet passages the same. When the source to the base goes negative the transistor passes very little currant. Then when it goes positive again you get a large currant flow. So it mimics the input to the base but with much higher currant flow out of the collector.

Think of it as a large water pipe with a spring loaded valve in it. The valve is connected to a smaller pipe. The water pressure controls the valve. As the pressure goes up on the small pipe, the valve opens more. As you vary the pressure on the small pipe the water output from the large pipe will vary in the same way. You really haven't amplified anything in a sense because the water is always in the big pipe. But you have amplified the varying pressure signal on the small pipe. The big pipe will mimic the pressures on the little pipe.

[Spork Schivago]

Re: CEC Capacitors

The more voltage you apply to the base, the more current that's allowed through the collector, right?

The audio signal would be seen as voltage, wouldn't it? If you applied to it to the base, I understand how it'd get amplified, but wouldn't it constantly be adjusting the amount of current that goes through the collector to the emitter?

Just for example, if we applied something like 50 millivolts to the base, a little current might come out the emitter, but if we applied something like 200 millivolts, more current would come out the emitter, right? Wouldn't the audio signal produce a varying degree of voltage to the base, depending on the frequency of the person talking, which changes with what they say, right?