Daly Multi-Section 50/50uf 500v @ 40 years plus!

[TomCarlos]

Gents....

While I still have the Marshall 2000 head (and it will soon be returned to the owner), I am making up my recommendation list of items to address. And at the top of the list are the eight Daly Multi-Section, 50uf/50uf 500v caps. There are eight cans in this amp. The caps are original, as noted by the date code of "81" (for 1981).

Now then, I think we would all agree that 40 year old caps should be replaced? My recommendation would be the F&T or JJ Caps. It seems like the CE might be a bit too pricey- almost 4x the cost.

F&T - https://www.tubesandmore.com/product...n-electrolytic

JJ - https://www.tubesandmore.com/product...f-electrolytic

CE - https://www.tubesandmore.com/product...fg-500v-5050-f

Maybe this is a Jon Snell question as I vaguely recall he might have worked at Daly, but would any of your go with the F&T or JJ caps? I believe these caps should fit in the retainer and be right sized for the chassis hole.

As it stands, the amp does not have an audible hum and seems to produce plenty of volume. BUT... it is the cap age issue I am concerned with. I did test two of the caps and they seem to be within spec.

Thanks!!

[Chuck H]

FWIW I was all about replacing old electrolytics as a preventative measure. That said I've been convinced by many posts here that the best time to replace power supply filters is when they fail We've seen caps made by Mallory at over fifty years old still doing their duty with NO signs of failure. I've replaced some VERY high end power supply caps in a Kustom amp that were still performing just because of their age. There were no filtering problems at all but the customer had never had the amp serviced in decades. So I wanted the amp to have decades of service after I worked on it. I replaced those caps for the same reasons you propose. I don't think the caps I put in were any better than the caps I replaced at all. In fact I think the original caps were of a higher original quality than anything I could have replaced them with. Alas, electrolytic caps DO age. But WRT the vintage gear I think exhibition of failure is the time for replacement rather than as a preventative measure. But this is a new ideology for me.

[The Dude]

I was going to say the same thing, but did not for fear of starting "The Arguement". I will say, I don't get the whole "recap" ideology, but that's just one man's opinion. OF COURSE, test them. If they check good (low ESR and correct capacitance), I don't see any reason to change them. If they've started to dry out and lose function, your cap tester will tell you that. These days, the caps you replace them with could be worse than what you have in the amp...... Let the flogging begin.

[Jon Snell]

Talk of the devil and ....

Daly caps are fine if the ESR reads less than 7 Ohms and they don't electrically leak; (reads higher than 5M on an AVO 8). From memory, brand new they are rated at 5 Ohms or less. The capacity will reduce over time but the specification was;
Capacitance +20% - 15%. ESR 5 Ohms or less, at 100HZ.

My 1968 Simms Watt still has the original Daly caps in it and is checked yearly with no signs of issues.

When testing capacitors for mains smoothing, it is important to use the specific test frequency as many capacitance 'testers' use 1kHZ (ish), making them very inaccurate, unless used as coupling capacitors of course.

I can count on both hands, how many Daly Caps within these old amplifiers that were actually faulty but some were starting to vent from the valve between the connectors and were replaced after many years of hard work in a hot amplifier.
Luckilly, Marshall amplifiers tend to run with a cool bias, unlike Fender, the life of the capacitors reflect that.

People like to think that they are 'improving' their amplifier by replacing all electrolytics. Nine times out of ten, it is peer pressure or missinformation that is the cause. Many are perfectly serviceable, for many years to come.

Maybe, J04 means September 1984. 8121 may be the batch number. Check the transformers for date codes, that can verrify it.
Sorry, can't remember for sure.

[Chuck H]

I will concede this. If one cap exhibits signs of failure physically or in performance I will replace them all. This is because a caps life in the power supply is partly dictated by how they've been treated through time. So if one cap is bad there's a probability that others aren't far behind. This is still more aggressive than many repair techs that will replace only the failing capacitor. Maybe I'll come around to this notion too eventually but for now I still carry some "Do it while you're already in there" attitude.

EDIT: And... If I ever get an amp on my bench more than ten years old and it has IC caps in it I WILL replace them as a preventative measure because IC caps SUCK.

[TomCarlos]

Thanks guys!!

Great input and that matches other opinions I found on the net last night.

And Jon Snell .... thanks for finding this thread. I now have some guidelines for testing that will be followed for "its still good."

If you have been following my other thread on the Marshall 2000, this amp was in storage for many years as the owner knew it had an issue but it was hard to find someone who wanted to get into the guts and figure out what was wrong with it. The Dude and G1 gave me the big hints regarding the very odd Mix Input Jack. So now that I have that problem solved and mixing is working correctly (with the rewired footswitch), I am trying to triage some final issues before sending this amp home for a trial period before taking on stage for gigging.

Oh, one other note, I watched a series of videos done by Lyle at the "Psionic Audio" channel on YouTube focusing on the older Marshal amps "Ground Schemes" and eliminating "noise." He talks about connections between the can caps and chassis and references Merlin Blinko's writeup on the "Valve Wizard" site. One area to check is the cap ground connections going to the lugs on the chassis. So if there is something I can do that is not intrusive or forcing a rewire scheme, I'll see if I can do that.

Ground Schemes | Part 1 : The Ideal vs Good Enough vs Vintage Marshalls

'80 Marshall 2204 | Part 2 : New Ground Scheme Gets Rid of Nasty Noise

Again, my appreciation.

Tom

[g1]

In my experience, I seem to run into bad electrolytic failures more often with newish caps than old. By 'bad', I mean failures that can cause other damage, like shorting or leaking electrolyte onto traces.
With the real old caps, it seems more common to find high ESR, or just drying out and losing their capacitance value. Those kind of failures I don't worry about so much as far as collateral damage. It's been rare for me to find serious damage in a vintage amp that was caused by vintage cap failure, usually it's just hum.
Others experience may differ.

[Chuck H]

FWIW and IIRC the Metroamps site sells re-formed NOS Daly's. This is NOT a company that subscribes to any lore or mojo about vintage parts in their own builds so I actually believe they are doing this because they think the re-formed caps are valid. So why can't we get new caps that perform like the old ones WRT age? I don't know. Maybe something to do with regulations and electrolyte formula. Combined with current case properties reflecting expectant age? Companies like Nichicon sell caps rated for twenty thousand hours! Does that mean with continuous use under ideal conditions? Sure it does. I honestly don't think those caps would last like old ones if left in an unused amp for a couple of years. Continuous use for the charge/reform process seems to be critical for newly manufactured caps. The older Daly, Mallory, etc. didn't seem to be as sensitive to shelf age. Anyone else recognize this?

JM2C

[The Dude]

In my experience, I seem to run into bad electrolytic failures more often with newish caps than old. By 'bad', I mean failures that can cause other damage, like shorting or leaking electrolyte onto traces.
With the real old caps, it seems more common to find high ESR, or just drying out and losing their capacitance value. Those kind of failures I don't worry about so much as far as collateral damage. It's been rare for me to find serious damage in a vintage amp that was caused by vintage cap failure, usually it's just hum.
Others experience may differ.

Agree. And, those are some of the reasons I don't replace caps just for the sake of replacing caps. Usually, when I see a thread about "recapping", I steer away because I do not agree at all with most web nonsense regarding the subject and don't want to get into an argument. Some are proud of it saying things like, "I recapped the entire amp". Yeah? So what? I don't care. It just means you did a lot of work and spent a lot of time and money for nothing, IMO. The only reason I posted in this thread was to reinforce Chuck's post.