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Discussion in 'Amp Central Station' started by Haloskater24, Sep 17, 2020 at 1:37 AM.
Is it safe to use NOS caps in a new build/Clone? I’m talking about the Cornell Dubilier greenies
No such thing as 'NOS caps.' They degrade whether they're in an amp or on a shelf for 30 years. You would be better off using these for tone caps in a guitar.
Even if they test within spec ?
Well... Testing them within specs - I mean the value - is indeed good but not enough. You would need to test the ESR (Equivalent Serie Resistance) and the behavior (leaks, distortions) under AC (signal) + DC (plate) voltages to be complete. But OK...
IMHO : you can install them in your amp and see if they work safely (if you have the skills and tools to do it). If htere's a problem around them, they would be likely the culprit then.
That said, I'll rather follow the advice of member @Haloskater24, if you don't want to hassle. I used some in DIY FX pedals too, which can be another alternative for you.
In the stompbox below, I used a "Big-Vintage-NOS-Full-Of-Mojo-Tar-Glass-Paper-Oil CAPA 0.1MF" :
Oh, and indeed, you trust me without any doubt at all if I categorically and unfailingly attest that this capacitor changed completely the tone of the pedal, from absolutely dull to incredibly wonderful, right ?
Electrolytic capacitors are the ones you really have to worry about going bad over time.
Probably the only NOS caps I'd mess with would be one of the "famous" coupling caps, like the blue ones used in blackfaces or mustard used in old Marshalls. Maybe the yellow Astrons used in tweeds, but those are known to leak DC. Greenies not so much, seems I've replaced a few in old Ampegs. And I can't think of a vintage amp where replacing them is detrimental to the resale.
Not all caps will degrade.
I have a small stock of glass caps. They will probably never degrade (well, not for a very long time).
They're designed to be very stable and handle extreme environments.
I've found some of the big blue caps leaky also.
NOS PIO and film/foils can be wonderful. Use them. After installation, just check for D.C. leakage, if none you're good. ESR is more of an issue with electrolytics. Don't use old Electrolytics! Try not to use new ones either, if you have the room for metalized films.
You could probably get away with older caps for a while. But I would get an ESR meter and check them. Uncle Doug on youtube has a good video on that. Personally for me I really like the Mojotone Vitamin T paper in oil caps in lieu of older vintage caps.
Paper in oil caps have a shorter lifespan than do ceramic or film caps. I do not even question whether they should stay in an old amp...they come out during a replacement of electrolytics. Electrolytics as mentioned definitely have a limited lifespan.
Wally, while that is true and I agree with you, for some reason my rebuilds using them seem to come off smoother sounding. I know it can be subjective, but I find that when I demo my amps for different players, unknowingly to them about what's inside, customers always seem to pick the rebuilds with the Vitamin T caps sound more harmonic. This is usually a demo with the amp by itself and not in a band situation.
I wouldn't use NOS oil, spark plugs, or brakes in my classic car.
Well, the Vitamin T are new. That is different from NOS, which was the gist of your OP. The NOS C.D. Sealed film caps might be good, bit some PIO caps from the same era would not be an option for me. Ommv.
As for sonics of caps, until one is comparing caps of exactly the same measured value, there is an ongoing....read interminable...debate over sonics vis-a-vis the type of capacitor. I do have my own thoughts on silver mica versus ceramics for treble caps based on what I hear...just as you have a preference for PIO caps.
The next debate, which is again interminable because it is subjective, is whether a softer tonality is preferable over a more articulate result.
Depending on the application, I would be concerned about the 400 VDC
Please, we all know the NOS mojo is in that germanium transistor not the cap.
I guess I am in more of the mindset that believes "circuit design" eclipses component quality to a greater extent.
Don't get me wrong, I certainly believe that component quality is important, but when it comes to this "NOS is better" argument, I can't say that I've ever experienced this to be true across the board.
I have a modern amp project I've been working on for the last couple of years, a Fender Champion 600 Reissue based on their AA764 circuit. In it's original form the C600 Reissue was less than impressive, but then I decided to make some relatively minor modifications to see if it could be improved. It became an experiment to see if this basic design could be made to convincingly sound like its vintage predecessor.
The mods I made did not involve any of the original capacitors.
I added some components to reduce noise. I also added tone controls and modified the tone stack to shift the frequencies a bit better to my liking. Here's the last thread I posted describing some of these changes:
Anyway, the point is that I am now literally quite thrilled with the way this amp sounds - even without a single NOS component in it!
So, to me, all this "NOS" and "PCB vs Point to Point" stuff is a bit of a farce... sorry, but my Mesa Boogie TA-15 and TA-30 amps sound excellent as well - without nary an NOS component in either of them.
The proof is in the pudding I suppose, but "old" does not guarantee "good" in my book.
Anyway - unless I need more power - these days I easily play my little modified Fender Champion 600 Reissue 90% of the time - and you know damn well that they used the cheapest components in it as possible! (probably not unlike how Fender built them 70 years ago).
My 2 cents worth...
Ah, OK - So you discovered Hot Water... Never too late !
Why not? If they are NOS those items are good to go...except maybe the oil. NOS oil has a value to it.....there are people who buy UOS oil cans. If the cans have never been open and therefore are NOS, the discussion changes. Spark plugs and brakes...good to go. Gap the plugs, take the edges off of the shoes so they don’t squeak and squeal...get it done!
Now, I certainly would not use UOS oil, plugs and brakes.
Because new stuff is generally cheaper than old stuff. Not many deals on vintage parts up my way. Plus I don't mind the longer life on platinum plugs and synthetic oil and don't like eating asbestos.
Same with oil/paper caps. They look nice, but If I am replacing caps in an amp, I don't much care how cool they look. I just want something I can rely on - especially if I were building a new amp as the OP is doing. Although I do like the look of orange drops...
Spend your time and money how you would like. That is just my opinion.