Re: Rode NT1-A requires 3 minutes warm-up time
|
On Sun, Oct 27, 2024 at 07:15 AM, Richards wrote:
While I am NOT an expert, it just sorta kinda almost seems it might perhaps possibly be a capacitor or two on the circuit board taking a long time to charge up - sorta like an old camera flash unit taking longer than normal to charge its thyrister so it can flash a full blast. That's what I thought when I came across a pair of speakers from the 1970th that nobody wanted anymore and that were thrown at me because everyone knew that I like listening to sound and analogue equipment.
When I opened the speakers and saw the old crossovers, my first thought was, "Omg, how am I going to replace those ones?! They must have almost certainly dried out after occupying storage space for decades."
?
?
The only thing I knew was that the speakers were from a Pioneer S-77M Turntable Stereo. I looked for technical information but couldn't find anything useful. So I tried to find information about these old metal caps and came across an interesting article that might also be of interest to some of you. The article was published in Italian by Emilio Ciardiello on the German site radiomuseum.org with the title “Replacing Old Capacitors” and contains, in my humble opinion, a lot of useful information about (old) capacitors in general and error analysis tips. This may not be relevant to micbuilders and would probably be difficult to understand for someone unfamiliar with the subject matter, like me :-). Anyway, I dropped the English translation of the article to the files section.
?
The following takeaways were relevant to me at that time:
?
1.? Capacitance meter and insulation meter are usually required to trace faulty capacitors.? To this day I do not own either of these.
?
2. The substitution of properly working parts with more or less similar components is useless, may impair the operation of the equipment and may also result in additional failures. Original components, when still good, are stable and not subjected to infant mortality.
?
3.? When first handling any old equipment it is advisable to perform some preliminary operations before replacing components. After a good cleaning, a visual inspection returns a first list of damaged parts, as hardened rubber cables or cracked capacitors that must be replaced before power-up. As a general rule, if the equipment was stored for a long while, six months or more, regardless of its previous operative conditions, a soft wake-up procedure should be run to allow reforming of electrolytic capacitors and of selenium rectifiers, if any. It is advisable to run equipment at about half voltage for half an hour, monitoring B+ voltage and watching for fluid losses from electrolytic capacitors, for overheat of components, hum and other alarming conditions.
?
So I removed and checked the speaker drivers for any defects (there were none...). (I replaced the aged and smelling needle felt inside the speaker housing...).
?
?
Checked and replaced any faulty or loose connections (there were some...).? And connected the speakers in series to the amplifier, ?as a soft wake-up procedure to allow the reforming of the capacitors,? when switching it on and using it for the first time.
?
That was three years ago and the effort was worth it. To this day, I really appreciate the lovely sound of these aged speakers. Of course, I will never know whether the gentle wake-up procedure made a difference, but to my understanding this approach made sense. After so many years, the old crossovers in the speakers still work perfectly.
?
Many thanks!
?
Heinz
?
@Richards
You are absolutely right. Repairing the NT1-a could quickly become expensive, especially since I do not have the original purchase receipt.
?
?
|