PL2000 Series 2

Gepetto

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#41
Thank you Joe. Incredibly simple circuit when you consider I don’t use the turntable section (yet), and the same for the tone controls.
Given the various options of brands and manufacturers, as well as capacitor types: electrolytics, mica, tantalum, film, aluminum, etc., what selection methodology would you use to select replacement caps when doing a rebuild? I went with just replacing electrolytic caps with same value and volts, and used what I believe is a top-tier brand. Mark, you mentioned film…would that have been a better option to use for these caps? Trying to understand how you guys approach a rebuild. Thanks!
Hi Al
My first recommendation for large size caps is (Wima or Panasonic) Polypropylene Film, for very small values it is always CDE Mica.
 
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#43
Here's a interesting article about selecting caps.https://www.google.com/url?sa=t&sou...Vaw0QvEgvBYrcna2BxEcbiI1L&cshid=1620206494844
It's the best article I've found. I especially like the section where they explain the phono stage and how it works.
Thanks George, I have not stumbled on this article yet…looks like good reading. I’m amazed at how much has been touted about capacitor selection on “Web Wisdom”. Hard to sort through fact and fantasy…but I hold the comments made by the gurus here in highest regard, so thank you guys. Sorry for hijacking your thread here, George.
 

mlucitt

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#44
The guys that wrote the article, Picking Capacitors, are Walt Jung, probably the most highly regarded OPAMP design engineer ever. Here is Walt's website, it has links to interesting articles, some are a bit dated. https://mirror.waltjung.org/

And, Dr. Marsh, he might as well be called "Dr. Capacitor". His short bio:
Richard Marsh is a veteran in the audio industry, and you may very well have some of his other efforts in your system already. Dr. Marsh is a world renowned expert on capacitors. Some of his designs have received critical acclaim (MIT Z Series and Monster Cable HTS power products), and his Multicap capacitors have gained widespread use by manufacturers worldwide. And, he builds amplifiers:
https://hometheaterhifi.com/volume_7_3/marsh-sound-design-a-400-amplifier-8-2000.html

Read the article, you will become educated.
 

George S.

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#45
Thanks George, I have not stumbled on this article yet…looks like good reading. I’m amazed at how much has been touted about capacitor selection on “Web Wisdom”. Hard to sort through fact and fantasy…but I hold the comments made by the gurus here in highest regard, so thank you guys. Sorry for hijacking your thread here, George.
Fire away, let's talk caps, selecting them confuses the hell out of me. Lots to learn and discuss like how to improve the stock phono stage, do caps "burn" in, etc.
Polypropylene Wima or Panasonic seem to be best for the signal circuitry. I use Nichicon FG(Fine Gold) or Muse for the power supply filter caps. That all seems straight forward.
But what about the phono stage and the RIAA equilization curve. How does one measure this to ensure it's correct after changing/upgrading caps?
I recapped my PL5100 S2 tuner 2 years ago with the best Nichicon caps, mostly all FG. I forget how many caps, 30 or so? I precisely replaced each original Elna with same spec Nichicon, all electrolytic. Every single electrolytic was replaced, every one. It sounded like crap for the first full day of use and gradually improved until it became a excellent sounding tuner. Why? It wasn't my ears. Thought burn in was a myth.
 
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#46
Fire away, let's talk caps, selecting them confuses the hell out of me. Lots to learn and discuss like how to improve the stock phono stage, do caps "burn" in, etc.
Polypropylene Wima or Panasonic seem to be best for the signal circuitry. I use Nichicon FG(Fine Gold) or Muse for the power supply filter caps. That all seems straight forward.
But what about the phono stage and the RIAA equilization curve. How does one measure this to ensure it's correct after changing/upgrading caps?
I recapped my PL5100 S2 tuner 2 years ago with the best Nichicon caps, mostly all FG. I forget how many caps, 30 or so? I precisely replaced each original Elna with same spec Nichicon, all electrolytic. Every single electrolytic was replaced, every one. It sounded like crap for the first full day of use and gradually improved until it became a excellent sounding tuner. Why? It wasn't my ears. Thought burn in was a myth.
ok…prepare for incoming salvos

I do believe some caps and probably other components need time to “age” to their full potential; some mfrs will burn-in systems for a period of hours to accomplish that need, which also ensures the system is properly working well.
I found this on the today…
“My standard replacement policy is as follows:
1. In the Power supply section – Panasonic EB and Nichicon PW.
2. The main power-supply decoupling caps are usually Panasonic TSHA or Nichicon GU
snap-ins.
3. In the Audio Path, Nichicon KT, Panasonic FM and sometimes FC, and all electrolytics of
6.8uF and smaller are replaced by Wima MKS2 non-polar film caps.
4. Elsewhere, Panasonic FC and Nichicon HE and PW.
5. For Axial Capacitors, especially in European equipment, I choose Vishay (formerly Philips)
138AML capacitors. Some are blue, and some are light-grey”
 

George S.

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#47
ok…prepare for incoming salvos

I do believe some caps and probably other components need time to “age” to their full potential; some mfrs will burn-in systems for a period of hours to accomplish that need, which also ensures the system is properly working well.
I found this on the today…
“My standard replacement policy is as follows:
1. In the Power supply section – Panasonic EB and Nichicon PW.
2. The main power-supply decoupling caps are usually Panasonic TSHA or Nichicon GU
snap-ins.
3. In the Audio Path, Nichicon KT, Panasonic FM and sometimes FC, and all electrolytics of
6.8uF and smaller are replaced by Wima MKS2 non-polar film caps.
4. Elsewhere, Panasonic FC and Nichicon HE and PW.
5. For Axial Capacitors, especially in European equipment, I choose Vishay (formerly Philips)
138AML capacitors. Some are blue, and some are light-grey”
From what I've learned here, best not to use electrolytics in the audio path of a amp or preamp. That article by Jung and Marsh describe upgrading a old Dynaco preamp to polypropylene caps with a readily noticable improvement.
Not sure the manufacturer of the cap is the greatest importance. Thinking type of of cap is primary, then the quality which is related to the manufacturer. Caps are relatively inexpensive. Seen lots of arguments on other sites about saving a few cents here and there on this Nichicon series versus another series. Is there really a lot of difference? I don't know, I just select Muse, or FG, or etc in that order. Now don't start talking about low ESR caps for computer motherboards, that really confuses me.
 

George S.

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#48
Lots of snake oil on the web. Used to use Rubycon for radio work decades ago. Once I started getting back into stereo I went with Nichicon and Panasonic based on recommendations by Badcaps Forum many years ago. WOA uses Nichicon and Wima, so there you go.
 

Gepetto

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#49
Lots of snake oil on the web. Used to use Rubycon for radio work decades ago. Once I started getting back into stereo I went with Nichicon and Panasonic based on recommendations by Badcaps Forum many years ago. WOA uses Nichicon and Wima, so there you go.
And CDE for Mica
 

George S.

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#51
Joe, where are mica caps best used in a preamp? Only place I've seen them used is in mobile linear amplifiers for 10 and 11 meter radio transceivers.
Now pretty obvious they're also in the WOPls. Never noticed when stuffing boards, will check out the BOM next time I have a amp open and find them.
 

Gepetto

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#53
Joe, where are mica caps best used in a preamp? Only place I've seen them used is in mobile linear amplifiers for 10 and 11 meter radio transceivers.
Now pretty obvious they're also in the WOPls. Never noticed when stuffing boards, will check out the BOM next time I have a amp open and find them.
Small value caps in phono stage or other stages where the cap value is <300 pF generally speaking. Ceramic caps may be there now.
 

mlucitt

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#54
My .02 worth.
Capacitors are interesting passive creatures. They can block direct current (DC) and allow alternating current (AC) to pass, but we also use them in our DC power supplies to filter out (block) the AC and let the DC pass. They even store DC electricity like a battery! Weird, huh?
The two main categories are electrolytic and everything else, the difference is the construction but the construction has come to determine the use.
The electrolytic caps (most often polarized) in our amplifiers are used for two purposes. 1) Power conditioning, used to shunt away power line hum before it gets into the signal circuitry. The capacitors act as a local reserve for the DC power source, and bypass AC currents from the power supply. 2) Coupling and suppression. In coupling, capacitors pass AC but block DC signals (when charged up to the applied DC voltage), they separate the AC and DC components of a signal. This is AC coupling or "capacitive coupling". A high capacitance is used but the value is not critical, but the reactance is small at the frequencies used. In uncoupling, a capacitor used to protect one part of a circuit from the effect of another, for instance to suppress noise or transients. Noise is shunted through the capacitor. Uncoupling capacitors are used between the power supply and ground. These are also called bypass capacitors, used to bypass the power supply or other high impedance component of a circuit, like the power pins of an OPAMP. In suppression, look for electrolytic caps in industrial environments.
Other electrolytic capacitors are tantalum and niobium capacitors. The tantalum capacitor consists of a pellet of porous tantalum metal as an anode, covered by an insulating oxide layer that forms the dielectric, surrounded by liquid or solid electrolyte as a cathode. Tantalum electrolytic capacitors have two electrical functions. For timers or similar applications, tantalum capacitors are used as a storage component to store electrical energy. But for smoothing, bypassing, or decoupling applications, the capacitors work as AC resistors to filter undesired AC components from voltage circuits. Niobium capacitors are similar, a polarized capacitor whose anode (+) is made of passivated niobium metal or niobium monoxide on which an insulating niobium pentoxide layer acts as the dielectric of the niobium capacitor. A solid electrolyte on the surface of the oxide layer serves as the cathode (-) of the capacitor and a price rise for tantalum in 2000/2001 encouraged the development of niobium electrolytic capacitors.

The everything else category refers to film, mica, ceramic and everything except the electrolytic. These capacitors are not polarized and are plentiful in audio circuits as low voltage or low capacitance value bypass, filtering, and signal conditioning. These smaller value capacitors can be combined with resistors and inductors to form RC and LC networks. One use is the Zobel Network (.1 uF Cap and dual 5 Ohm 2W Resistors) on the speaker binding posts of our Phase Linear amplifiers. This network bypasses low frequency voltage coming back into the amplifier, generated from the coil of the woofer speaker.
These types of caps have their own ideal use.
Film caps can be film/foil or metalized film, they used to have an oiled paper dielectric but today the dielectric is polycarbonate, polypropylene, polyester (Mylar), polystyrene, or Teflon. They are wound with the edges of the two metallic windings in contact with the electrodes on both ends of the windings. This contact keeps all current paths to the entire electrode very short. The setup behaves like a large number of individual capacitors connected in parallel, thus reducing the internal losses (ESR) and the parasitic inductance (ESL).
Mica caps are made with thin (.025mm) sheets of muscovite mica coated with metal on both sides. They are used in high frequency applications due to low resistive and inductive losses. They are also extremely electrically and mechanically stable and can tolerate high heat.
Ceramic caps are the most common capacitors made (1000 Billion per year) due to their surface mounting (SMD) capability. These are the Multi-Layer Chip Capacitor (MLCC) and also the common disc capacitors. They are not polarized, which means that they may be safely connected to an AC source. Ceramic capacitors have a great frequency response due to low parasitic effects such as resistance or inductance.
The remaining group in the everything else category includes the miscellaneous category known by their dielectric: air, vacuum, glass, and silicone. They are uncommon in audio circuits.
I will not mention supercapacitors, because they are just to far out.

Some graphics to assist in the understanding...
Votage vs Capacitance 2.png

Types of Capacitors.png

Adapted from Wikipedia, with numerous edits for clarity.
 
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George S.

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#55
My .02 worth.
Capacitors are interesting passive creatures. They can block direct current (DC) and allow alternating current (AC) to pass, but we also use them in our DC power supplies to filter out (block) the AC and let the DC pass. They even store DC electricity like a battery! Weird, huh?
The two main categories are electrolytic and everything else, the difference is the construction but the construction has come to determine the use.
The electrolytic caps (most often polarized) in our amplifiers are used for two purposes. 1) Power conditioning, used to shunt away power line hum before it gets into the signal circuitry. The capacitors act as a local reserve for the DC power source, and bypass AC currents from the power supply. 2) Coupling and suppression. In coupling, capacitors pass AC but block DC signals (when charged up to the applied DC voltage), they separate the AC and DC components of a signal. This is AC coupling or "capacitive coupling". A high capacitance is used but the value is not critical, but the reactance is small at the frequencies used. In uncoupling, a capacitor used to protect one part of a circuit from the effect of another, for instance to suppress noise or transients. Noise is shunted through the capacitor. Uncoupling capacitors are used between the power supply and ground. These are also called bypass capacitors, used to bypass the power supply or other high impedance component of a circuit. In suppression, look for electrolytic caps in industrial environments.
Other electrolytic capacitors are tantalum and niobium capacitors. The tantalum capacitor consists of a pellet of porous tantalum metal as an anode, covered by an insulating oxide layer that forms the dielectric, surrounded by liquid or solid electrolyte as a cathode. Tantalum electrolytic capacitors have two electrical functions. For timers or similar applications, tantalum capacitors are used as a storage component to store electrical energy. But for smoothing, bypassing, or decoupling applications, the capacitors work as AC resistors to filter undesired AC components from voltage circuits. Niobium capacitors are similar, a polarized capacitor whose anode (+) is made of passivated niobium metal or niobium monoxide on which an insulating niobium pentoxide layer acts as the dielectric of the niobium capacitor. A solid electrolyte on the surface of the oxide layer serves as the cathode (-) of the capacitor and a price rise for tantalum in 2000/2001 encouraged the development of niobium electrolytic capacitors.

The everything else category refers to film, mica, ceramic and everything except the electrolytic. These capacitors are not polarized and are plentiful in audio circuits as low voltage or low capacitance value bypass, filtering, and signal conditioning. These smaller value capacitors can be combined with resistors and inductors to form RC and LC networks. One use is the Zobel Network (.1 uF Cap and dual 5 Ohm 2W Resistors) on the speaker binding posts of our Phase Linear amplifiers. This network bypasses low frequency voltage coming back into the amplifier, generated from the coil of the woofer speaker.
These types of caps have their own ideal use.
Film caps can be film/foil or metalized film, they used to have an oiled paper dielectric but today the dielectric is polycarbonate, polypropylene, polyester (Mylar), polystyrene, or Teflon . They are wound with the edges of the two metallic windings in contact with the electrodes on both ends of the windings. This contact keeps all current paths to the entire electrode very short. The setup behaves like a large number of individual capacitors connected in parallel, thus reducing the internal losses (ESR) and the parasitic inductance (ESL).
Mica caps are made with thin (.025mm) sheets of muscovite mica coated with metal on both sides. They are used in high frequency applications due to low resistive and inductive losses. They are also extremely electrically and mechanically stable and can tolerate high heat.
Ceramic caps are the most common capacitors made (1000 Billion per year) due to their surface mounting (SMD) capability. These are the Multi-Layer Chip Capacitor (MLCC) and also the common disc capacitors. They are not polarized, which means that they may be safely connected to an AC source. Ceramic capacitors have a great frequency response due to low parasitic effects such as resistance or inductance.
The remaining group in the everything else category includes the miscellaneous category known by their dielectric: air, vacuum, glass, and silicone. They are uncommon in audio circuits.
I will not mention supercapacitors, because they are just to far out.

Some graphics to assist in the understanding...

View attachment 50536

Adapted from Wikipedia, with numerous edits for clarity.
Exactly(why I find choosing caps so confusing). Is it safe to say for a old PL preamp to:
Use electrolytics only for the power rail filter caps because a film cap of proper value would be too large to fit.
Use no ceramic disc caps.
Use film caps(polypropylene) in the audio stages.
Use mica for very small values less than 300 pF.
 
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#56
From what I've learned here, best not to use electrolytics in the audio path of a amp or preamp.
Now that is something I was never aware of - until just now. I thought Mark was making a snarky comment about electrolytics in the audio path. Never a loss for learning something new in this forum.
 

Gepetto

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#58
Now that is something I was never aware of - until just now. I thought Mark was making a snarky comment about electrolytics in the audio path. Never a loss for learning something new in this forum.
If you MUST use an electrolytic in an audio path because you need very large capacitance, make sure it has a companion non polar film type in parallel with it. The electrolytic will take care of the low frequency task and the film will take over from there. Like a speaker crossover.
 
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