J!m
Veteran and General Yakker
Check out the Rean (Neutrik) brand ones at Mouser. Good quality and about $2 each.
No more 60 Hz hum in a PL2000 preamp.
- Thread starter George S.
- Start date
e30m3mon
Chief Journeyman
NeverSatisfied
Chief Journeyman
That is going to pair nicely with your new D500 after you get it built.
e30m3mon
Chief Journeyman
At the moment I have the C1 in the rack, but going to tear into that shortly - needs a refreshing, so the 2000 will fill that void. Making some space for the D500 at the (very) bottom of the rack. The back of the 2000 looks awesome with the gold Neutrik RCA jacks.
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MusicSteve
Journeyman
George
What is your pros and cons for the ceramic caps versus Silver Mica Capacitor
I found a some that are cheap. sounds like they worked for you?
I think you said you replaced all the ceramic caps w Silver Mica Capacitor?
Thanks
Steve
Well, ceramics are usually not real accurately made and have a wide tolerance. Given where a manufacturer used them, generally not a issue, but some of the ones I've pulled out of the PL1000 S2 I'm currently working on are far off spec, probably because of age and cheapness.
I use silver mica to replace them because they're generally thought to be very stable, long lived in that epoxy coating, and very accurate in value. Some "audiophiles" say they can tell the difference in sound between silver mica or film. But that's not me, I'm not one of them. My philosophy is build it once with the best parts and price that makes sense.
Lastly, Joe has said ceramics are terrible in audio and PL cut costs by using them and electrolytics where they could. From the help the forum gave me on my journey to learning how to on the preamps, I can condense it to this. No ceramics allowed, use silver mica for the lower values but watch cost, use film where silver mica is too expensive or won't fit due to size for replacing a electrolytic. Use electrolytics where nothing else will work. That's my philosophy. Would be great to hear other options please! I'm wanting and willing to learn.
I use silver mica to replace them because they're generally thought to be very stable, long lived in that epoxy coating, and very accurate in value. Some "audiophiles" say they can tell the difference in sound between silver mica or film. But that's not me, I'm not one of them. My philosophy is build it once with the best parts and price that makes sense.
Lastly, Joe has said ceramics are terrible in audio and PL cut costs by using them and electrolytics where they could. From the help the forum gave me on my journey to learning how to on the preamps, I can condense it to this. No ceramics allowed, use silver mica for the lower values but watch cost, use film where silver mica is too expensive or won't fit due to size for replacing a electrolytic. Use electrolytics where nothing else will work. That's my philosophy. Would be great to hear other options please! I'm wanting and willing to learn.
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gene french
Veteran and General Yakker
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good morning george!!
And if you must use an electrolytic in an audio path (not power supply filtering purposes, electrolytics shine for that purpose) make sure you bypass it with a film cap.
MusicSteve
Journeyman
Thanks
I will have to buy some, Their on sale and cheap so why not for the old PL 400II and 700II boards, I bought some ceramic caps class 1 (recommended by another forum ) but they were tiny and when I touch them I heard noise lol
I bought silver mica from Mouser and Digikey when I did the preamps. Very expensive and 300 V with thick leads that required drilling the through holes slightly larger. On the PL1000 S2, I shopped eBay for brand name 100 V versions. Lower prices and thinner leads that haven't required drilling. I'm sure there's a better source of 100 V silver mica out there. Just haven't found it.
For films I'd prefer WIMA, but almost impossible to fit those little square and rectangular boxes on old boards. So, after a lot of reading, I use Panasonic ECW polypropylene with crimped leads when available. The crimped leads make for a little easier fit because the lead spacing is often close but never exactly matching the board. Good reviews from audio sites on the ECW series for recaps.
For films I'd prefer WIMA, but almost impossible to fit those little square and rectangular boxes on old boards. So, after a lot of reading, I use Panasonic ECW polypropylene with crimped leads when available. The crimped leads make for a little easier fit because the lead spacing is often close but never exactly matching the board. Good reviews from audio sites on the ECW series for recaps.
Oh, and TDK films are also supposed to be very good. I used them for snubbers on the preamps and Mark L. said he's using 40 something uF TDK films on the outputs of his PL2000 preamp. They must be huge! Mark L., please post a photo of them if you read this and and are able.j
MusicSteve
Journeyman
I also been using the WIMA for .47uf or less
Here another source for Silver Mica Capacitor from Parts Express, I Been buying the Miflex KPCU 0.10uF 600VDC Copper foil Poly/Paper in Oil for my Speaker crossover Bypass. I been buying them when on sale (they just double in prices now I glad I stocked up) so I think these are good? , I will find out what do think?
Silver Mica Film Capacitors (partsconnexion.com)
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The price is right. I'd just be concerned about lead diameter for through holes. Easy enough to enlarge them with proper sized bit and pin vise, just go slow from the foil side and don't allow a burr to develop that causes the solder pad to twist free of the board. The PL2000 preamp boards had many non standard undersized holes that needed enlarged. Using 100 V silver mica caps on the PL1000 S2 because they have small diameter leads. No drilling needed so far. Same goes film caps.
mlucitt
Veteran and General Yakker
I tried the 47uF caps and they were just too big. I settled for these TDK 22uF 63VDC film caps and they fit perfectly.
Here is the Mouser P/N: 871-B32523R226M. They are $4.39 each, which is not too bad for what you get.
And the sound - beautiful.
Mark, is that a .01 uF cap on the RC4739 Browndogs? Did you also bypass the RC4136? That's slick how you mounted the bypass cap. Thanks for the photo. Can't remember the value I'm running at the outputs, probably about 4-5 uF and I remember Joe saying it would be beneficial to increase it.
Eventually I'll sit down and find a on board solution for the turn on thump. Just have other priorities for the foreseeable future.
Thanks for the photo Mark!
mlucitt
Veteran and General Yakker
George,
Funny how we learn from each other. Yes, that is a Wima .01 uF film cap across the supply legs of the OPAMP. Joe said that if you cannot bypass the positive supply pin to ground and the negative supply pin to ground, you can bypass them together. The RC4136 got replaced by the Browndog
#1016J which has (2) SMT OPA2134 OPAMPs installed, and it is bypassed the same way. Too bad Phase Linear did not include bypass capacitors for the OPAMPs supply voltage.
The turn on thump can be reduced or eliminated by wiring a 4.7M 1/4W resistor across each of your DC-blocking output capacitors to bleed them when power is removed. Mouser P/N 660-RK1/4DC404F.
Funny how we learn from each other. Yes, that is a Wima .01 uF film cap across the supply legs of the OPAMP. Joe said that if you cannot bypass the positive supply pin to ground and the negative supply pin to ground, you can bypass them together. The RC4136 got replaced by the Browndog
#1016J which has (2) SMT OPA2134 OPAMPs installed, and it is bypassed the same way. Too bad Phase Linear did not include bypass capacitors for the OPAMPs supply voltage.
The turn on thump can be reduced or eliminated by wiring a 4.7M 1/4W resistor across each of your DC-blocking output capacitors to bleed them when power is removed. Mouser P/N 660-RK1/4DC404F.
Thanks Mark! Going from the phone to the desktop and going to print that out and pin it above the bench. I think the PL2000 preamps sound fantastic after upgrades. I want to continue to improve them and your ideas are another step in the right direction. Thank you!
Got the 22 uF TDK output films installed in place of the 4.75 uF Panasonic's. And 4.75 m ohm resistors installed across the leads in a attempt to tame the turn on thump. No joy.
Turn on thump is as bad as ever. It'll peg the meters on the 400 S1 WOPL. So, I pulled those resistors out. Pretty sure I did this correctly, across the cap leads, right? Thought about going to the ground rail, but unsure.
Anyhow, it's not a issue if I turn the entire system on at the power strip. I'll do some more reading about turn on thump.
I hooked a analog multimeter up to the preamps outputs in a attempt to see exactly what the thump is, AC or DC. I get no movement of the meter on any setting. Same with a DMM. Tempted to look at it with the scope, but need to do some reading first.
Turn on thump is as bad as ever. It'll peg the meters on the 400 S1 WOPL. So, I pulled those resistors out. Pretty sure I did this correctly, across the cap leads, right? Thought about going to the ground rail, but unsure.
Anyhow, it's not a issue if I turn the entire system on at the power strip. I'll do some more reading about turn on thump.
I hooked a analog multimeter up to the preamps outputs in a attempt to see exactly what the thump is, AC or DC. I get no movement of the meter on any setting. Same with a DMM. Tempted to look at it with the scope, but need to do some reading first.
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mlucitt
Veteran and General Yakker
George, my brain knew what I was saying, but it did not come out correctly.
Just as in the PL700 amps, the input 220K resistor that bleeds the DC-blocking capacitors goes to Ground on the input jacks.
For PL2000, the 4.7M resistor has to bleed the caps to Ground. The Ground trace on the back of the circuit board is a handy place. I don't think it matters which side of the cap is bled off, I would choose the upstream or, circuit-facing lead because that would likely be the source of any DC voltage that is blocked by the capacitor.
Did the turn on thump get louder with the larger 22uF caps? Those caps can store plenty of volts, but the current is very small.