It is currently Mon Mar 16, 2020 7:45 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 8 posts ] 
Author Message
Post subject: O.T. Opinions of/experience with certain capacitors
Posted: Sat Jul 28, 2018 4:03 pm
Offline
Aspiring Musician
Aspiring Musician

Joined: Thu Dec 12, 2013 2:54 pm
Posts: 618
Given the recent topic of capacitors, I was wondering if anyone had opinions of, or experience with Ruby Gold capacitors. I can't find any data sheets, but given their temp ratings of 105°C, I wonder if their longevity is any better than F&T caps. or if this a moot point, because of other factors, like ripple current, or ESR.
Thanks in advance,
Bill

_________________
"Where confusion abounds, there's money to be made."


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Sat Jul 28, 2018 10:45 pm
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1022
The longevity of a capacitor in a tube amp is not so much original cost, but the heat environment it is subject to.
The ripple current rating caps in SS amps are more critical than tube amps because of ligher current demands
If no spec sheets are available, ripple capacity can be deduced by thickness of the leads coming out of the cap. Compare wire diameters with similar caps.

Now the first cap sees a lot of 60 cycle ripple from the ac line. The rest of the caps have to filter the signal frequency and keep the stages isolated, or "decoupled " from each other.
So large caps are ok for the first stage, but small capacitors are better at filtering in the later stages.
The latest thing I've seen in high end audiophile amps is using banks of two or three smaller caps to come up to the desired total uf. This allows the caps to filter to a much higher frequency for better stage decoupling.
Then, adding a non-polar .1uf to the bank extends decoupling to a much higher frequency. This results in higher separation between stages and clearer sound.


Top
Profile
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Tue Jul 31, 2018 7:20 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
100% thumbs-up, with Tim. That's why I like the way Fender has been placing the main filter caps, in a separate area --- away from the rest of the resistors, transformers, and tubes. Under its own cover. Convenient to work on, too! :)


Top
Profile
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Tue Jul 31, 2018 8:07 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1022
The Fender doghouse is an iconic feature of the old Fenders.
Its obsolete however. The purpose of the doghouse is to prevent fires from exploding filter caps. Up until the mid 1960s, caps used paper insulation that would catch fire.
If you wanted to get your amp into a public venue and onstage past the union roadies, it had to be UL approved. All filter caps had to be in a flameproof enclosure. The multi cap can and doghouses were for fire prevention.
Since the 1960s, filter caps have been constructed with plastic fireproof insulation. Now you can mount the caps safely in the chassis and connect them closer to the circuit. The long wires to the doghouse reduce the effectiveness of the filter circuit.
So I replace multi cans with individual caps and locate them close to their circuits, leaving the old can for appearance. The doghouse usually has a couple resistors as well, so it takes a little more engineering to relocate the PS caps. But you can remove more than a foot of wire between the caps and the plate resistors for better stage decoupling. I zip tie them together or to chassis hardware for vibration control.


Top
Profile
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Tue Jul 31, 2018 5:25 pm
Offline
Aspiring Musician
Aspiring Musician

Joined: Thu Dec 12, 2013 2:54 pm
Posts: 618
Thanks everyone for your replies. I will call the distributor tomorrow, as emails have proved inconclusive.
TimsAudio wrote:
The longevity of a capacitor in a tube amp is not so much original cost, but the heat environment it is subject to.
Pretty much the point of the question. Given the temperature rating, is a 105° C necessarily a better cap than an 85°C one?
F&T's data sheets list a 5000 hour life for their 85°C caps versus a 3000 hour life for their 105°C rated caps, at their rated temperature given the same ripple current. Those same data sheets list exactly the same ESR, ripple currents, and dimensions for the same 22°μF 450V capacitor, regardless if it is rated at 85°C or 105°C. The only difference is the (unimplied) leakage current.
I simply asked if anyone had opinions of, or used, Ruby Gold capacitors.
Thanks again.
Bill


Top
Profile
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Tue Jul 31, 2018 6:41 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
No experience with Ruby Gold caps. I believe they are re-labeled Chinese made stock. I wouldn't trust the 105C rating, versus ratings by F&T or Sprague.

On the other hand... Rubycon (Japan made) are excellent caps. As good as Panasonic or Nichicon, in my experience. Esp in solid-state amps.

:mrgreen:


Top
Profile
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Tue Jul 31, 2018 7:53 pm
Offline
Aspiring Musician
Aspiring Musician

Joined: Thu Dec 12, 2013 2:54 pm
Posts: 618
BMW2002Ti wrote:
No experience with Ruby Gold caps. I believe they are re-labeled Chinese made stock. I wouldn't trust the 105C rating, versus ratings by F&T or Sprague.

On the other hand... Rubycon (Japan made) are excellent caps. As good as Panasonic or Nichicon, in my experience. Esp in solid-state amps.

:mrgreen:
Their data sheets suggest that anything in excess of 15 years is wrong. I'm not talking about about solid state amps, I'm talking about tube rectified, tube amps.


Top
Profile
Post subject: Re: O.T. Opinions of/experience with certain capacitors
Posted: Wed Aug 01, 2018 8:48 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1022
The difference of 85C and 105C is simply the melting point of the insulating plastic inside the cap.
However, the bulb temp of a 6L6 can reach 250C. So even 105C caps aren't up to snuff in many cases. The doghouse does shield Fenders somewhat from the heat.

The double crimp of the Ruby caps is distinctive and suggests it is not a rebrand. That type of construction, without the lead spotwelded to an aluminum can, suggests a manufacturing process that also produces non-polar caps. Ruby also sells a lot of crossover caps with this type of construction. So I expect them to be from their own factory in China.

In sourcing caps, use reliable vendors. Fakes are out there with small caps inserted into a larger can with a well known label.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: