PM1000 post number 80,000

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honkyjonk

Member
Joined
Apr 14, 2005
Messages
10
Hey everybody,

First post here, but I've been searching through the archives, and reading the very helpful info about people modifying their PM1000's

I'm in the middle of recapping mine right now, and I've been over to the krash jones site, and emailed tubejay a few times and they've been very helpful.

So after recapping a couple busses and a couple channels, I've pretty much decided to go w/ Panasonic FC and FM series caps. FM where I can because they're cheaper and are supposed to perform a little better (I don't know whether this is true or not but read somebody saying that on a Google Groups link) and FC caps w/ the smaller ones that aren't available in FM series.

Anyway, the things I'm wanting to do are probably the exact same as a lot of folks w/ PM 1000's.
1.recap the electrolytics + probably the tants
2.Change the eq.
3.add direct outs to about 8 channels
4.resistors?

I have a few questions that maybe you guys could iron out for me.

1. when replacing the tants, has anybody out there really found it to be worth it? I notice a small difference now that I've recapped a couple master modules but it's really not very big so far. Albeit, I havn't recapped the power supply yet.
I remember reading that tubejay was having some problems replacing one of the tants w/ a film cap simply because of the physical size.
Is there another solution besides a film cap? Have you guys reached any kind of consensus as far as good replacement values and types for the tantalums?

2. I've also heard about people wanting to replace resistors. This kind of bums me out just because it's one more thing, but I guess it really depends on whether it's gonna make a big difference. Why replace the resistors? I had thought resistors generally don't go bad.

3. In the eq, what I've read so far on the lab archives is tubejay modifying the eq, and dropping the 1K mid-range to 700Hz, and now I'll have to look again but I can't remember how much of the eq he actually ended up modifying.
But anyway, I'm wondering if it would be possible to drop it down into maybe the 400 Hz range, and to modify the other mid ranges too.
I guess there's probably a few different possibilities here, but I thought I'd bring it up again so I can really nail it down when I try to do it.
Is what Jay did probably the best way to go? Would trying to drop the 1K to 400HZ be possible? What would be cool is to do some channels one way, and a few another way.
I remember reading the values on the krashjones site that he'd suggested to get closer to 1073 or an API mid-range selections, but I'm not sure if he ever ended up actually doing it that way, so maybe you could chime in here Mr. krashjones. Is there an update to your web-page that maybe I havn't found yet?

Phew.

4. One of the buss modules that I recapped, I did with panasonic M series caps. The fader on this bus before recapped was kind of scratchy, and maybe I'm crazy, but it seems a little more scratchy afterwards. I'm wondering what the deal is here. I havn't yet ever sprayed any pot cleaner into any pots on the board, so I guess that might clear some things up, but I thought I might just ask if it might have been something I did wrong when recapping. I mean, either I'm hearing things, or it would have to be I guess, but I thought I'd ask. If cleaning the fader pot doesn't work, I really don't know what's going on. Sorry, this question is a total waste of time, it's just a try it and see thing.

5. Tubejay's recommendation was to try and increase the size of every electrolytic cap by at least 50% (correct me if I'm wrong here, Jay) so I've been doing that, but usually it's probably 2-5 times the Uf value. I'm actually paying the extra in caps to keep the Voltage value the same because I'm kind of scared to be sticking 50V caps in there where there's supposed to be a 35V. I know, probably not a big deal, but. . .
So my question is, does this sound alright? (2-5 times bigger, keep the voltage the same) Most sources I've read say it's okay w/ this mixer, but a few times I've asked people and they've been wary about suggesting bigger caps and tell me to just keep all the values exactly the same.
And, if we're replacing the tants w/ films, how much higher are we actually going to go, since theyr'e so big? Oops I guess I already asked that one.

6. How are those direct out mods going? Jay, did you end up using the version I've been reading about in the archives? C37>transformer>output jack. Can you use both the direct out and send the channel to the buss at the same time? This seems pretty easy, so if I can locate some output trannies, I think I'll give it a shot, if I can use both the direct out and the buss at the same time.

but okay,

sorry this is so long. I'm just trying to get my digikey order straightened out.

Thanks in advance.
Jon
 
I use Tantalums in digital designs as they work well
and last a long time.

I keep Tantalums at least one kilometer away from
my audio designs!
Do not ever pass an audio signal through a tantalum cap.
If you do you will go to jail.
Get every one of the tantalums out of there; every one!
Try one module 100% recapped then listen to it.
That will tell you if you want to replace all the other cards.
If you cannot hear a difference then come to peace with yourself
replace want you want and be happy.
 
Tants can be used for power supply bypassing unless you are imitating the sound of some vintage designs or something. i doubt that you would hear a diff in this use of them, but maybe they are used as audio coupling caps?

I dunno, just blabbering...

HTH!
 
There should be no problem using 50V caps to replace 35V caps, provided they'll fit -- and since caps have been getting smaller, they should.

Peace,
Paul
 
A good aluminum electrolytic can often replace a tantalum. if the application can stand a touch of leakage, though the new 'lytics are pretty good about this. Unbiased tantalums potentially sound like ass. Seeing as how very few manufacturers bother to bias their coupling caps, lose the tants, unless you think they are contributing a particular "sound" to the desk.
This
http://members.aol.com/sbench102/caps.html
and this
http://members.aol.com/sbench102/caps1.html
help to explain why.
Don't worry about a higher voltage rating on your 'lytics, thats the amount they can take before blowing up, not their contribution. The only detriment I can think of off the bat is an increase in leakage current, so you don't want to go tooo far.
Replacing any tantalum bypass caps is a good idea, because when tants fail, they fail short, which can be hell on the PSU.

I've modded balanced outs for various pieces by just using a nice op amp buffer and a line driver like an SSM2142. Quick, cheap, and easy. I usually put a trimmer between them, and set up the op amp for a gain of 2 or so, which lets me tweak the level. You might want a real level control. The rest of the board being discrete, you may want to forget about this option entirely.
 
Okay,

Awesome. Thanks for the info guys.
this brings up another question. I don't have any of the modules in front of me, but from memory, I don't remember there being anything significant telling me which side of a tantalum is negative. Are you saying they're polorized or not?

I guess I'll order some films and some electrolytics to substitute, and see which I'll like better.

Tubejay where are you?
 
Okay,

I've read the archives a bit more, and also a post on Gearslutz that Jim Williams contributed to.

Anyway, I definately want to replace all the tants.

So, reccomendations are a little varied here. Jim Williams recommended on one post replacing one of the .47 uf/35v's w/ a 3.3/35 Wilma polyester cap for a better low end.
He said it fit in perfectly, so I'm inclined to go with that,

but then I see a recommendation in the archives here for .5ufd/50V panasonic B green series as a replacement for the tants. And that was in regard to tubejay having trouble with the input coupling cap? (if I remember correctly) and it seemed like he was using something that was about the size that Jim Williams is recommending.

And of course aurt has recommended an electrolytic in this thread. Thanks Aurt!!!

Anyway, unless somebody gives me a real good reason to go one way or the other (especially out of experience w/ recapping this mixer) then I'll probably go variety shopping and try 'em out and see.

I'm still unsure whether tantalums are polarized or not, and if they are, how can you tell which side is negative?

Also, has anybody noticed the 3.3ufd 35V tantalum way off to the size on the channel strips. There's only one per strip.
I wonder if I should try and up the value w/ that one too.
 

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