| Author |
Topic: '65 Band Master caps |
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 28 Mar 2018 11:33 am |
|
Should I assume that these paper Mallorys should be replaced? And if so, with what? TIA!
 |
|
|
 |
Tony Prior
From:
Charlotte NC
|
Posted 29 Mar 2018 1:13 am
|
|
well those are dual can 25 u, they are in the tone stack, for now leave them alone.
what you do want to change are those under the doghouse, ( reverse side) of the chassis. There should be 2 @ 60u and 3 @ 20 u, probably all in the 500 vdc range. These are your critical Power Supply caps. Also, again on the circuit side, the 25 u at the bias adjust pot. Many will argue don't replace them , they look good. Well a clean shining car with no motor looks good too ! E Caps have a life expectancy of +/- 15 years,it's your call to replace them, I would and have.
Brands ?
Interesting, Fender now has what they call Fender yellow, other common brands Blue Sprague, Black F+T and the Grey Illinois which is found in many new Fender amps these days.
Is one better than another ? I guess many will argue yes but typically it's about longevity. I have used all except the Fender yellow, no issues. I use what is available from a single distributor. Brands don't much natter to me. F+T or Illinois have been fine.
regarding the ones in the photo, the tone stack, thats a toss up. They are aged and supposedly the Fender Yellows are said to be good replacement . Who can say. I've used Orange Drop, F+T, Sprague and Illinois in the tone stack, , couldn't tell the difference. Others may have varied opinions and experience.
regardless, pull those E caps under the Doghouse and tackle those first.
SAFETY !!! remember you are dealing with caps that can be charged to over 400 VDC. This is dangerous.
_________________
Emmons L-II , Fender Telecasters, B-Benders , Eastman Mandolin ,
Pro Tools 12 on WIN 7 !
jobless- but not homeless- now retired 9 years
CURRENT MUSIC TRACKS AT > https://tprior2241.wixsite.com/website |
|
|
|
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 29 Mar 2018 1:25 am
|
|
| Thanks Tony! The ones in the dog house were done as soon as I got it! Amp works fine and sounds good, so I'm fine with leaving them for now. Thanks again for the info! |
|
|
|
Michael Brebes
From:
Northridge CA
|
Posted 29 Mar 2018 8:54 am
|
|
The dual 25MFD capacitors share a ground so when you want to replace them us two 25MFD caps with plus at the two locations and the negatives both share the same hole that goes to ground.
_________________
Michael Brebes
Instrument/amp/ pickup repair
MSA D10 Classic/Rickenbacher B6/
Dickerson MOTS/Dobro D32 Hawaiian/
Goldtone Paul Beard Reso
Mesa Boogie Studio Pre/Hafler 3000
RP1/MPX100 |
|
|
|
Tim Heidner
From:
Groves, TX
|
Posted 29 Mar 2018 9:48 am
|
|
| You never replace the blue Mallorys unless they go bad. At least that's what I've read, they have all the mojo in them. |
|
|
|
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 29 Mar 2018 12:44 pm
|
|
| Thanks to all for the info! I had it open to check the bias, saw the paper ones, and was curious, as I've read about replacing the the 'paper ones' as a safety measure. Paper ones in the doghouse makes sense, but I wasn't sure about the others. Thanks again! |
|
|
|
Brad Sarno
From:
St. Louis, MO USA
|
Posted 29 Mar 2018 8:18 pm
|
|
Those blue molded signal caps are great, always leave those in. They are an excellent sounding mylar film & aluminum foil capacitor with a smooth, rich tone. The modern equivalent to the blue-molded is the 225p series Orange Drop, but I think the old blues are a tiny bit warmer/darker.
Personally, I'd replace the brown paper electrolytics in the preamp. They're not about hum or noise or safety, but they do absolutely affect the performance of the preamp gain stages. Those are cathode bypass cap's and they're a very busy and significant cap in those stages. I find that old electrolytics in that cathode bypass position can sound dull and sluggish, almost too "warm" or soft. Sometimes the preamp stage can snap back to life with more gain and clarity and punch when those are refreshed.
For cathode bypass cap's the Sprague Atom is the most popular for amp builders and restorers. But I like the tone of the nicer, audio-grade electrolytics better, especially for pedal steel. The Elna RFS - Silmic II is a great audio electrolytic. It uses a silk & hemp dielectric paper and just performs extremely well with audio signals. That's been a go-to of mine for 20 years. Another favorite is the Nichicon MUSE, a true audio-grade electrolytic that works great in that spot and really shines with pedal steel dynamics and overtones.
I say pull the brown paper cap's and drop in the good stuff. 22uF/16v or 25v is ideal.
I think Mouser carries both of the electrolytics I mentioned.
B |
|
|
|
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 29 Mar 2018 11:07 pm
|
|
Brad, looking at the Mouser site at the Elna's, they list a 55Ma and a 70Ma in the 16V, and 55Ma, 60Ma and 70Ma in the 25V. Advice? I'm over my head..  Would you prefer one over the other for the 2 brands you mentioned? Thanks! |
|
|
|
Carl Mesrobian
From:
Salem, Massachusetts, USA
|
Posted 31 Mar 2018 1:20 pm
|
|
My Vibrolux Reverb had a cathode bypass cap go bad and the tone lost any "stones" it had. It sounded dry and empty. They are definitely important ones.
Don't replace the blue caps, as they rarely, if ever, fail.
My Pro Reverb had a bad bias filter cap that injected a loud hum into the 6L6's . Easy fix.
For less money than Sprague prices, I trust Nichicon, F&T.
_________________
--carl
"The better it gets, the fewer of us know it." Ray Brown |
|
|
|
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 31 Mar 2018 2:01 pm
|
|
| Thanks Carl! Appreciate the info and your time! Still haven't heard back on the Ma values for those caps (above post)..any thoughts on that? |
|
|
|
Carl Mesrobian
From:
Salem, Massachusetts, USA
|
Posted 31 Mar 2018 4:52 pm
|
|
Not being an electrical engineer, I can't say, other than I opt for higher ripple current rating, and higher voltage - the packages aren't that different. I don't think the cost differences will kill you for the number you are replacing.
Personally I prefer axial leaded vs radial leaded caps, but I don't think the grades that Brad mentioned are available in axial lead package.
Buy a bunch that you will use within a reasonable time and try them out - they are cheap enough, probably less than shipping 
_________________
--carl
"The better it gets, the fewer of us know it." Ray Brown |
|
|
|
Mark Fowler
From:
Minnesota, USA
|
Posted 1 Apr 2018 6:14 am
|
|
Instead of Mouser try Antigue Electronic Supply (AES) or Mojotone, many others.
Spraque 25uf/25v e-cap
Nichicon 25uf/25v e-cap
Mark |
|
|
|
Brad Sarno
From:
St. Louis, MO USA
|
|
|
|
Jack Stoner
From:
Kansas City, MO
|
Posted 2 Apr 2018 2:16 am
|
|
Those old dual caps leak and short. I've replaced them on our lead guitar players 65 (AA165 chassis) Pro Reverb. One just fell apart when I unsoldered it.
FWIW I just replaced the power supply caps in his second 65 Pro Reverb. It still had the originals and was "humming".
3 20uf 600VDC caps and 2 70uf 450VDC. |
|
|
|
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 2 Apr 2018 8:50 am
|
|
| Thanks again to all. . Much appreciated! |
|
|
|
Jim Newberry
From:
Seattle, Upper Left America
|
Posted 2 Apr 2018 11:44 am
|
|
Anybody tried these dual axial puppies? http://www.partsconnexion.com/FTCAP-76352.html
They're too expensive, I know...
_________________
"The Masher of Touch and Tone"
-1950 Fender Dual Pro 8
-1950's Fender Dual Pro 6
-Clinesmith D8
-Clinesmith 8-string Frypan
-Clinesmith Joaquin
-~1940 National New Yorker
-~1936 Rickenbacher B6
-Homebuilt Amps |
|
|
|
Carl Mesrobian
From:
Salem, Massachusetts, USA
|
Posted 2 Apr 2018 1:04 pm
|
|
Read the dimensions and make sure it will fit on a Fender board. You might have to do some creative installation. IMO it's easier to use smaller caps (for less money) and splice the negative leads together. EDIT - If F&T made ones that fit easily in Fenders, they'd probably fly off the shelves.
_________________
--carl
"The better it gets, the fewer of us know it." Ray Brown |
|
|
|
Bill A. Moore
From:
Silver City, New Mexico, USA
|
|
|
|
