Capacitor help...

  • Thread starter Thread starter peritus
  • Start date Start date
peritus

peritus

The not fountain head
Be Advised: I'm a newb to the electronics world....

I've got this mini reel to reel... I want to replace some visually failed capacitors... They are polarized, axial and appear to be film capacitors...

They read 10v 1000uf...

Problem is, I want to buy them from this local store (partsexpress)... I can't seem to find one to match exactly.... Can you help me find a reasonable replacement? I'm lost!

Thanks a million!

partsexpress.com
 
if you absolutely must buy from that store, perhaps they can special order it for you? philips makes those caps, for instance.
 
peritus said:
Be Advised: I'm a newb to the electronics world....

I've got this mini reel to reel... I want to replace some visually failed capacitors... They are polarized, axial and appear to be film capacitors...

They read 10v 1000uf...

Problem is, I want to buy them from this local store (partsexpress)... I can't seem to find one to match exactly.... Can you help me find a reasonable replacement? I'm lost!

Thanks a million!

partsexpress.com
Click to expand...

Those aren't film caps, they are electros. A 1000uF film cap would be . . . really really really big. Try this:

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=020-1048
 
It's OK to use caps with a higher voltage rating, if you were wondering.
 
peritus said:
Cool.. Thanks people... I just wanna make sure I understand..

Are capacitors polarized, unless otherwise noted?
Click to expand...

No, they are not polarized, unless marked. Electros have a stripe indicating the drain, and the drain lead is shorter. Which doesn't help after they have been clipped :o Axial caps will have an arrow pointing towards the drain.

Tantalum caps are also polarized, but really weensy, so instead of a stripe, they have a +. Sometimes they are so small even that is hard to read. I avoid them anyway because they are supposed to sound like poo.

Ceramics and film caps are generally not polarized.
 
Long overdue.... but Thanks...

I keep hearing poly film...

For example, in Frederic's mic preamp schematic, should I just look for all of the capacitors in poly film (if I want numero uno quality)? Is it foolish to proceed this way? After looking at various boards, over the years, it looks to me like there is a mixture of many types.... I'm so confused... :confused:
 
poly caps = good stability

good stability = good sound, mabye, mabye not
 
Manufacturers use different types of capacitors for different reasons, cost effectiveness being one of the biggest. Funnily enough Boss effects seem to use a large amount of polys in most of their circuits. Electrolytics are the worst for stability etc but are still used for filters etc.
 
peritus said:
Long overdue.... but Thanks...

I keep hearing poly film...

For example, in Frederic's mic preamp schematic, should I just look for all of the capacitors in poly film (if I want numero uno quality)? Is it foolish to proceed this way? After looking at various boards, over the years, it looks to me like there is a mixture of many types.... I'm so confused... :confused:
Click to expand...

It largely depends on the size. Anything over 1uF is usually electrolytic, because polys start getting pretty big. For example a 47uF poly is about the size of a C battery. Metallized poly caps are a bit smaller, but still quite large compared with an electro.

Instead, a fastidious designer might bypass the electro with a small poly cap, say 0.1uF. In theory that improves the poorer high-end response of the electro.

Between .001uF and 1uF, I always use polys. Below that, ceramic. Ceramics tend to color a signal, and if used in an EQ circuit, could impart a desirable or undesirable sound, depending on your preferences . . .

There are also different grades of electro caps, generally low-ESR caps are preferred. I use Nichicon PW series, and the Panasonic FC series is also popular with the DIY set. Most people don't differentiate too much between grades of poly caps, although audiophiles certainly do. If you get into passive crossover design, that is one place you will see people use large (and expensive!) poly caps.

A final thing to consider is whether a cap is in the audio path or not. Off the top of my head, I recall frederic's compressor was opto-coupled, so some of the caps there would not be in the audio path. Also, opamps often spec small filter caps very close to their supply pins. In that case, since you will have a small poly cap there, there is no need to bypass a large electro in the power supply.
 
orson198305 said:
Why is my "Rep power" so shit in comparison to everyone else? I didn't have a high self esteem to start with. :eek:
Click to expand...


The Rep Point system is a complicated one that factors in intelligence, attractiveness, charisma, and penis size.
 
Different project this time around... By the way, I bought the cap you mentioned MS and it works great! Thanks....

I'm gonna re-cap my ARP omni, which will most likely take a number of years in labor....


Here's the cap breakdown, per the parts list posted around the web (I did the actual counts though, so I knew how many to buy)....

CAP, ELECT, 1000UF, 50V, +75-10% 2
CAP, ELECT, 250UF, 10V, +50-10% 1
CAP, ELECT, 250UF, 50V, +50-10% 1

CAP, PLASTIC,.1UF, 100V, 10% 17

CAP, TANT, 10UF, 35V, 20% 27
CAP, TANT, 1UF, 35V, 10% 20
CAP, TANT, 1UF, 35V, 20% 1
CAP, TANT, 22UF, 16V, 20% 2
CAP, TANT, 22UF, 25V, 20% 49
CAP, TANT, 3.3UF, 35V, 10% 2
CAP, TANT,.47UF, 35V, 10% 1


I may have already asked this at some point, but.. Upping the voltage rating in not a bad thing, correct? I've read that people have replaced the tants with elects, but I'm just not sure.. I'd really like to put it the way it should be....

How important do you suppose the tolerance rating is on these things? If I put 10's where 20's are called for, that's a good thing, right? If I put 20's where 10's are called for, that's bad?

What about polarization? Suppose I'll have to look at schematics closer to know about that question...

Ugh!... 123 caps to install...
 
peritus said:
I may have already asked this at some point, but.. Upping the voltage rating in not a bad thing, correct?
Click to expand...

A little is OK, but don't go crazy. You will just cost yourself money, and the higher rated caps are bigger and might not fit. Also I read something about a cap needing to see a significant % of its rating, like 30% or something, to prevent premature aging. Or something like that, I forget.

I've read that people have replaced the tants with elects, but I'm just not sure.. I'd really like to put it the way it should be....
Click to expand...

Should be OK as long as the electros fit. Smaller value tants might not be available in electros. It could change the character of the sound in the audio path. Be sure to note polarity.

How important do you suppose the tolerance rating is on these things? If I put 10's where 20's are called for, that's a good thing, right? If I put 20's where 10's are called for, that's bad?
Click to expand...

Most often tolerance is not too important. Just get 10% tolerance caps and don't worry about it.

What about polarization? Suppose I'll have to look at schematics closer to know about that question...
Click to expand...

A good PCB will have all the caps facing the same way. A good PCB . . .
 
For this line...
CAP, PLASTIC, .1UF, 100V, 10% Quantity 17

I was thinking about using these, since its a small cap value:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=62729&Row=193845&Site=US

MKT%20SERIES%206.5H,7.2L.jpg



Does that make sense?

P.S. Here's a link to the docs on it... The caps I'm talking about are on the far right of the Lower Voicing assembly....

http://people.umass.edu/brownp/arp/techinfo.html
 
Those are Fair quality Metal Fim caps....If they Fit use them...

I would recoment replaceing the Tantilum Caps with electro"s just because Tants are very sencitive to reverse Voltages and will literally explode if subjucted to reverse Voltages and Tants sound like Crap, even worse than Electro"s......

It might also be a good idea to bypass most Electro"s with a low Value Polly cap (0.1uF) as it will help with high frequency distortions that electro"s are known to produce.....


Cheers
 
Minion said:
Those are Fair quality Metal Fim caps....If they Fit use them...

I would recoment replaceing the Tantilum Caps with electro"s just because Tants are very sencitive to reverse Voltages and will literally explode if subjucted to reverse Voltages and Tants sound like Crap, even worse than Electro"s......

It might also be a good idea to bypass most Electro"s with a low Value Polly cap (0.1uF) as it will help with high frequency distortions that electro"s are known to produce.....


Cheers
Click to expand...


Cool.. Should I try to fit the metal films where the tants were ... and if the metal films don't fit, use elctro's?
 
You generally won"t be able to Put Metal Films were the Tants were as metal Films of the same Value would be quite large but if you can find Metal Film or Poly that will fit were tant is then go for it.....

I would use Low ESR Electro"s were the Tants are if they fit and Bypass them with a Poly if you can (Bypassing basicly means to put a Metal Film in Paralell with the Electro).....

Good Luck
 
You must log in or register to reply here.
Back
Top