No more 60 Hz hum in a PL2000 preamp.

[e30m3mon]

] Did you ever get around to creating that PDF or a final shopping list of parts you came up with during the 2000-II project? I noticed my right channel has dropped a few DBs and when I turn the balance control full right, there is an unusual buzzing sound coming from the left channel. Going to order some parts before pulling out the Weller "scalpel". Will replace the back row of RCAs with through-hole type whie I have it apart this time.
Thanks again
Al

Unfortunately, no. Never got to it, but hope to get to it in the future. Need some more testing equipment and earned expertise and experience first. On those PL2000 jacks, notice they are all self grounding. They have 3 solder legs. One hot and two grounds. The inputs use that second ground, but the outputs don't. That second ground on the outputs is a isolated solder pad. I replaced all of mine with NOS jacks and have a thread with the link to supplier.
Here is a link to the best PL2000 service manual scan I've found on the web. It comes from Don Watts Abundant and is hosted on the AudioKarma site.
http://akdatabase.com/AKview/displayimage.php?album=94&pos=1[/QUOTE]

Time indeed has no friend, but I wish I could buy more of it!

George - If I'm not mistaken, it was back a couple pages in this thread, referring to these jacks:

https://www.allelectronics.com/item/rcj-65/rca-jack-w/nc-switch/1.html

But there was some back and forth regarding quality of these parts and serviceability with using through-hole jacks (and insulators), so I wasn't sure how that that ended. No worries - I'll sort it out. Just figured I'd check
Thanks Al

 

[George S.]

Yup, the plastic jacks are crap. If you use through hole mounted ones, use stranded wire with a little extra for strain relief. Those old traces are very delicate. I'm going to find a better solution eventually. Lee has posted a few photos here.
https://forums.phxaudiotape.com/threads/dchristies-pl-2000.9402/

 

[mlucitt]

These are the Switchcraft jacks, I would have bought 18 of them to do the whole cabinet, but they cost $9.00 each.

 

[Gepetto]

These are the Switchcraft jacks, I would have bought 18 of them to do the whole cabinet, but they cost $9.00 each.
View attachment 60404
View attachment 60405

Yes they are pricey little buggers.

 

[J!m]

Check out the Rean (Neutrik) brand ones at Mouser. Good quality and about $2 each.

 

[e30m3mon]

Check out the Rean (Neutrik) brand ones at Mouser. Good quality and about $2 each.

That's the route I ended up going, Jim ....

 

[NeverSatisfied]

That's the route I ended up going, Jim .... View attachment 65358

That is going to pair nicely with your new D500 after you get it built.

 

[e30m3mon]

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.

 

[MusicSteve]

The pin vise is pointing to a CDE silver mica capacitor. Joe said to use these for the smaller values. He didn't say why, so I researched why. They are very expensive! The higher the value the higher the cost.
So, have to use electrolytic where a film would just be too large to fit, silver mica where it makes economic sense, and film everywhere else. No ceramic capacitors allowed on the board.

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

 

[George S.]

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.

 

[gene french]

good morning george!!

 

[Gepetto]

Well, ceramics are usually not real accurately made with 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.

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]

Well, ceramics are usually not real accurately made with 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.

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

 

[George S.]

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.

 

[George S.]

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]

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

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)

 

[George S.]

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)

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]

Mark L. said he's using 40 something uF TDK films

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.

 

[George S.]

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.
View attachment 68549

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]

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.