Improving the Coupling Capacitors for Better Tone Sounding

[GrannyGremlin]

Hi!

If the caps you want to replace are old and if they are without pedigree then an improvement will be had with either Sprague "Orange Drop" capacitors or WMF (I think they are CDE brand, aka Cornell Dublier). You will find these on ebay. I think both can be found new. WMF are expensive. Orange Drop can be polyprolpylene or polyester...I have used both....don't hear much difference. Guitar players like them. WMF has a great tone overall, big and warm...probably the best sounding cap ever. They tend to be expensive. Just say no to paper in oil (or anything from former USSR) or any paper , that's old tech that is often decaying like salmon that has spawned.

Don't buy electronic components on ebay (unless you know and trust the seller) - tonnes of fakes and QC rejects. That goes double for ICs.

CDE (yes Cornell Dubliner) orange drops are available new from reputable sources (in North America Digikey and Mouser as examples, who will also have Sprague electrolytics; both probably ship to SA as well). Sprague orange drops are available from most tube amp (hifi or guitar) parts suppliers.

I never heard about the NPO/CGO ceramics capacitors at least with those names!; do you have more info about the Scott Gurcer study or investigation? Where I can find this investigation paper or notes?

Thanks a lot,
opacheco

NP0/CG0 (those are zeros) is the dialectric used in some MLCCs (MultilLayer Ceramic Capacitors) - only use MLCCs of this type (if it doesn't say don't buy them). Old school ceramic discs (and other types of MLCCs) are bad - wide tollerance and drift significantly in value with changes in temperature (so like in a hot tube amp) so performance (trem rate as mentionned above, filters etc) will be inconsistant. They also get worse over time. NP0/CG0 MLCCs are not cheap (they won't break the bank but compared to other dielectric types and basic ceramic discs they cost significantly more).

Def replace ceramic discs with NP0/CG0 MLCCs for a performance improvement (or at least more consistent performance). Only buy them from reputable stores. (again Digikey/Mouser and the like). I use them in my guitar pedal builds. One good brand is Murata.

Polystyrene are also good for the pF range, but they tend to cost even more (use them if you need higher V handling - then they may be comparatively cheaper than NP0/CG0). They may be better in tube amps because they are axial vs radial like MLCCs.

 

[musipol]

I could have sworn that the old cap factory I used to work at 40 years ago made NP0 ceramic discs. Those were quite stable as I recall. Or this could be early onset dementia?

 

[JohnRoberts]

I could have sworn that the old cap factory I used to work at 40 years ago made NP0 ceramic discs. Those were quite stable as I recall. Or this could be early onset dementia?

Npo or cog (?) have been around for long time but mainly only tiny values for use stabilizing clock timing crystals and applications like that.

Their recent popularity for use in audio has encouraged manufacturers to offer larger values (not sure which came first, larger values or wider use?).

This makes me happy (at least a little).

JR