Capacitor Myths

[Pete B]

1 hour ago, Carlspeak said:

I agree with Kent and feel the use of multiple caps of the same value was driven more by economics - the 10 uF caps being available and very cheap and film instead of lytic for those who have a bias against lytics. 

I mentioned Peter Snell before. You should see his bundles of 4 uF lytics in the Model A! I guess he bought thousands of them and paralleled as many as he needed to get the total he wanted. In the case of the Model A he also added a flat profile drop shaped cap for gluing the bundle to the crossover board.

Below is a picture of a Model A bundle. It's been lifted away from the small film drop shaped cap peeking out from below the glob of glue.

 

Or, more likely, Peter Snell had a good reason just as I just stated.

[Pete B]

2 hours ago, DavidR said:

On the issue of bypassing and cascading: I know North Creek was known for this (they just closed up shop about a  month ago). They always chose a bypass that had higher voltage rating than the base cap and when cascading each successive bypass was of a higher rating. I don't know the purpose of this.

I've also read on Tony Gee's site for cap evaluations (ughhh) that he recommends a Vishay 1837 0.01uF (10nF) cap for a bypass to 'smooth out' and 'improve' the SQ of the base cap. This cap is (I think) rated for 100VAC and 160VDC. I'm not sure of this but wouldn't that make the base cap a 100VAC cap as well? In other words if the base cap was a 400VDC cap by putting that small cap on as a bypass make the base cap the lower of the two ratings?

 

There is no science behind any need or improvement by using different working voltages,

smaller values tend to have higher voltages or the person doing it thought there was some 

magic to it.

[Stimpy]

Brian Cheney of VMPS often paralleled groups of capacitors to build values.  Plus, I believe Brain like to exactly match cap values between pairs of his speakers.  So, he often added tiny values to achieve this.  In fact, one speaker bundle might have 3 caps, and the corresponding bundle, in the 2nd speaker might have 4 caps.  But, when measured, the values would be the same.

One other thing, MCM Electronics just started carrying a new line of metallized poly caps. The brand, JB Capacitors, has a decent range of values, up to 200uF ($36).  There's also an 120uF for $14.  Three of those would add to 360uF, and only cost $42!  Still within about 3% of nominal, and much cheaper than the Solen option, for the 90s.  Now, I wonder how they sound...?

JB Capacitors

[AR surround]

On 1/9/2017 at 6:56 PM, Stimpy said:

...One other thing, MCM Electronics just started carrying a new line of metallized poly caps. The brand, JB Capacitors, has a decent range of values, up to 200uF ($36).  There's also an 120uF for $14.  Three of those would add to 360uF, and only cost $42!  Still within about 3% of nominal, and much cheaper than the Solen option, for the 90s.  Now, I wonder how they sound...?

JB Capacitors

Thanks Stimpy.   Regarding that 120uF JB Capacitor, I checked the dimensions and confirmed them with MCM Electronics.   Unfortunately, those beasts are 4.25" in diameter and almost 2" long.   It would seem that trying to install three of them in an AR90 would be a challenge.   I'd like to hear if anyone tries and how they make out.  (New Myth:  Shoehorning banks of giant capacitors into an AR90 is fun. LOL)

[DavidR]

7 hours ago, AR surround said:

Thanks Stimpy.   Regarding that 120uF JB Capacitor, I checked the dimensions and confirmed them with MCM Electronics.   Unfortunately, those beasts are 4.25" in diameter and almost 2" long.   It would seem that trying to install three of them in an AR90 would be a challenge.   I'd like to hear if anyone tries and how they make out.  (New Myth:  Shoehorning banks of giant capacitors into an AR90 is fun. LOL)

 They should fit if you stack one on top in the middle of the bottom 2.

Also, there should be no "sound" associated with using the JBs as it is a shunt cap (in parallel)  and all it does is shunt any high frequencies to ground that made it past the coil. Its the caps wired in series that are associated with any particular sound.

[Stimpy]

7 hours ago, AR surround said:

Thanks Stimpy.   Regarding that 120uF JB Capacitor, I checked the dimensions and confirmed them with MCM Electronics.   Unfortunately, those beasts are 4.25" in diameter and almost 2" long.   It would seem that trying to install three of them in an AR90 would be a challenge.   I'd like to hear if anyone tries and how they make out.  (New Myth:  Shoehorning banks of giant capacitors into an AR90 is fun. LOL)

Members over at the Polk Audio Forum, often mount large poly caps, offsite of the crossover board and mount them inside the cabinet, and then extend wiring to the new location.  No reason that you can't do the same the 90's.  Now, as DavidR pointed out, the 350UF cap is a shunt capacitor, and in theory doesn't impact the sound of the speaker.  So, NPE's are probably sufficient and much cheaper.  Though, personally, I'd still add a low value poly or film and foil bypass cap, to help the discharge rate of the 350uF cap.  Can't hurt, and cheap to try too.

[Pete B]

On 7/23/2007 at 11:59 PM, Pete B said:

Found the link with Ken's post on break-in:

http://www.classicspeakerpages.net/dc/dcbo...28&mesg_id=2658

The above link to Ken Kantor's comments is dead but I found this one:

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/749-speaker-break-in-myth-or-fact/&tab=comments#comment-52320

Here is the text repeated in case that link goes dead also:

Ken Kantor wrote:

I don't want to sound like a curmudgeon, but one could make a career out of logically countering the spurious claims of audio manufacturers. From low end to high end, the bullshit factor is enormous. There just isn't enough time! I know this leaves the customer very bewildered, since everyone claims to be an expert and a golden ear. All I can say is that I have no reason NOT to suggest speaker break-in. In fact, many people have a "buyer's remorse" let-down when they first hook up their new speakers at home. So, it is very convenient for speaker companies to suggest a day or two of break-in. No harm, no cost, fewer returned speakers. But the perceived changes are generally psychological.

If you have a fast connection, the following link may be amusing:

http://www.aural.org/resume_01_files/articles/fetish/

One of these months, I will make PDF's of these old publications. Meanwhile, here's something I posted a few years ago:

"Speakers are mechanical devices, and do have some degree of

"memory". We play each one before it leaves the factory, but

then who knows how long it sits unused, and at what temperature?

Generally, a woofer will be in top shape after a minute or two of

reasonable level play; a tweeter much sooner. But I have seen

rare extreme cases, for example, a ferrofluid tweeter had been

subjected to sub-zero temperatures and needed an hour of pretty

hard drive to get in gear. 99% of the time, I believe your ears

do much more adjusting than your speakers do after the first

minute or two of play."

A Google Groups search for "loudspeaker break-in" should also find some excellent comments by the late John Dunlavy.

[Transmaster]

It is funny how things have changed for me on this subject over the years. The first set of crossovers I rebuilt Polk Monitor 10B’s I spent a lot of money on Sonicaps. A crapola Onkyo amp blew all of that up. Now I have all of the instruments to measure everything. I rebuilt the 10B’s with Mundorf M-Cap’s less money better sound.  Next I rebuilt my Wharfedales with Mundorf E-Cap NPE’s great sound even less money.  The M-Cap’s did seem to have a burn it time, the E-Cap’s zero time good from the get go. I spent just over $100 bucks on the capacitors for the 10B’s.  Less the $20 dollars for the E-Cap’s for the W-35’s, and W-45’s. It was a real pleasure not trying to fit something the size of a doorknob were a Vienna Sausage sized cap was.  Now I wonder what my 10B’s would sound like with $14  Dollars worth of E-Cap’s. But I know the Anchromatic Wharfedales do best with NPE’s. 

[Transmaster]

It is funny how things have changed for me on this subject over the years. The first set of crossovers I rebuilt Polk Monitor 10B’s I spent a lot of money on Sonicaps. A crapola Onkyo amp blew all of that up. Now I have all of the instruments to measure everything. I rebuilt the 10B’s with Mundorf M-Cap’s less money better sound.  Next I rebuilt my Wharfedales with Mundorf E-Cap NPE’s great sound even less money.  The M-Cap’s did seem to have a burn it time, the E-Cap’s zero time good from the get go. I spent just over $100 bucks on the capacitors for the 10B’s.  Less the $20 dollars for the E-Cap’s for the W-35’s, and W-45’s. It was a real pleasure not trying to fit something the size of a doorknob were a Vienna Sausage sized cap was.  Now I wonder what my 10B’s would sound like with $14  Dollars