Bob Pease on Capacitors

[WA4SWJ]

Hey guys - check this out:

http://www.electronicdesign.com/Article ... feed=Top20

Bob says polyprops rule and to stay away from oil caps.

What else is there to know?

Just thought this would be of interest.

Regards,

[WA4SWJ]

Here's the other link. Download Bob's handout and read it carefully. See his comment at the lower right of the handout.

http://www.edn.com/blog/1700000170/post ... 1116334704

Regards,

[TomMcNally]

hmmm ... so do you think these were a good deal at a few cents each ?




+125°C Metallized Polyester Wrap and Fill Axial Lead Capacitors

[TerrySmith]

I have tried almost every signal cap ie: orange drops, the yellow ones like pictured, PIO, the cheapest Xicons, and they all sound the same to me.

The yellow caps are great for restorations as you can stuff it in an original wax capacitor casing and make it look original.

[Shannon Parks]

Bob's video shows are pretty enjoyable. I must have mentioned him ten times to my boss yesterday as we were stymied on a comparator that keeps blowing up though we can't find a fault condition. I kept saying that even Bob Pease must not solve everything. He did have problems with his gutters once. Yellow_Light_Colorz_PDT_20

[EWBrown]

My own basic rule of thumb regarding coupling capacitors in the audio path:

Just say NO! to ceramic disk caps, as they will distort the waveform, as they have a small, but discernable, piezoelectric effect. Anything else is a simply matter of personal preference and just a smattering of the good old Placebo Effect ...

I like the orange drops, Xicons, WIMAs all about the same. I also like the Russian PIOs and teflons, simply because they are cheap money, and those who are gifted with better ears than mine state that they do indeed sound better. I wouldn't shell out $50-100 for a Mundorf teflon cap, but a couple of bucks for a Russian K75 teflon cap isn't too "extreme".

Those inexpensive yellow Illinois Caps as shown a few posts earlier, are pretty good, too. Bang for the buck, they're Number one!

The platinum plated stuff, lovingly hand-crafted by Tyrolean Gnomes and then Blessed by the Dalai Lama himself, are just expensive and ostentatious Snale Oil, IMNSHO Yellow_Light_Colorz_PDT_03

/ed B in NH

[Hi-Fi Low-Life]

I have a question regarding ceramic disc caps. I’m rebuilding an amp which has ceramic disc caps going to ground in several places in the circuit.

Can the type & quality of a cap that goes to ground affect the sound quality of the amp? Should I bother to replace these ceramic discs with something better? Thanks for any advice.

[TomMcNally]

The ceramic discs are usually not in the audio path, but in the filament circuits and across the power switch and things like that. Check out what they do on the schematic, but I'm gonna say they won't matter much.

I've tried the "boutique" type caps for coupling and can't hear them either, so I'll stick with the Orange Drops and Solens and these Illinois jobs ... the latest get*set*go has the silver Russian caps, and I did grab a pair of Auricaps that I'll use in something.

[EWBrown]

A lot of the old cheap consumer-grade "console" stuff used ceramic discs everywhere. Yellow_Light_Colorz_PDT_21
If they're bypassing DC, they're OK, or for the RF / AC ground for filament windings, a-la ST70. And for RF they're fine, in the tuner.

The ST35 and SCA35 boards have a few ceramic discs in the path, especially that nasty little 0.1 uF on the input, and the 18, 27 1nd 33 uuF caps may be ceramic on some boards, mica on others. Mica is good, ceramic is bad...

Just look at these nasty little scope traces here:

http://members.aol.com/sbench102/caps2.html

FWIW, electrolytics and tantalums are not suitable for signal path usage, either (especially in speaker crossovers) :

http://members.aol.com/sbench102/caps1.html

And some more generic capacitor application info:

http://www.zedaudio.com/Technical/Capacitors.htm


For more of this just google "the sound of capacitors"

Ceramic Discs are fine for the noise reduction across the power tranny secondary, for "spike recovery" (RRSF) between HV secondary ahd the SS rectifiers, and similar applications. The Pesky PECs in the PAS series preamps have ceramic inside, best to ditch them and use real resistors and caps, in the phono / tape equalization and the tone controls (or better yet, ditch the tone controls and "filters" altogether.

/de B in NH

[Hi-Fi Low-Life]

That's some SPECTACULAR information... Thanks guys! Yellow_Light_Colorz_PDT_06

[wiredbecker]

The yellow caps are great for restorations as you can stuff it in an original wax capacitor casing and make it look original.

Now that is a great idea. I'll definitely be trying to work that into my repairs. One question though: What to do with the guts of the old cap? And another: Are its contents toxic?

[erichayes]

Hi All,

Everything in electronics is toxic. Use common sense and live a few days longer.

The technique I "developed" (actually a work in progress) a couple of antique amps ago was to boil the caps (in a pan purchased especially for the process--no use pissing off the XYL unnecessarily) until the guts separated from the outer sleeve. This is the trickiest part, as the manufacturers had different techniques for assembly. Be patient. What you do next will become obvious.

In my case, I was lucky and the sleeve came off intact. I used one of those "third hand" gizmos with the alligator clips and ball joints to hold the replacement cap vertically by its upper lead. I took the sleeve and slid it up over the body of the new cap, took a 1" square of waxed paper and slid it up the lower lead of the cap. Used a second alligator clip on the lower lead to position the sleeve over the cap.

I melted one cake of regular canning paraffin along with about a half inch of yellow crayon--you might want to use a little brown, too--and used a Dollar Tree plastic measuring cup to pour the wax into the sleeve. Put the whole contraption into a pyrex cassarole to reclaim the spilled wax, and pour slowly or you'll get air bubbles.

[erichayes]

Hi All,

Regarding the "sound" of capacitors: When Bud Wyatt was here in '05 and we were terrorizing my prototypes with mods and tweaks, the last thing we did was change the coupling and grounding caps, because we knew the change would be very, very subtle.

We found a manufacturer in SoCal that had an overrun of 0.47µF 630WV polystyrene instrumentation grade caps that were about the size and weight of a D cell for (I think) around 15 bucks per.

Well, the change was subtle, and for the better. That prompted me to get some Auricaps, Magiccaps and Musicaps to see how they would compare.

Stick with the Xicons, Illinois, Orange Drops and Solens, fellas. As Herr Doktor Brown would expound: SNAKE OIL!

BTW, Ed, I'll be sending you a PM later today.