Replacing Capacitors, I Don’t Wanna!

I've got my amp in 2003 and only replaced 2 small signal caps and one driving transistor.

Global recap of an amp is an extremely stupid idea.

This thread had my anxiety up a bit. Back in the day I had a threshold 400A which I loved. It was a customer trade in so I bought it from my boss at a good discount. Long story short, I took it home and it sounded awful, boss said get new main caps installed, problem solved the amp served me and sounded amazing for the years I had it, (also kept my little apartment warmer).

I bought a Cyrus two with a PSX power supply and it arrived last week. I’ll admit some trepidation firing it up. Seller was very honest, the amp that was built in the mid 80’s had never been serviced, never needed it. It sounds great pushing my TDL compacts in my mancave room. If I could source a pair of Mission 767's, a Cyrus CD player and an Ariston TT I will have my dream system from when I was 25. 

It just had me wondering if there are designs that are more prone to stress capacitors, and other designs that are kinder.. I’m not an electrical engineer so all I know is the set up will sound great until it doesn’t, then I’ll worry about the capacitors.

My amps are fine but when my A/C quit cooling on a 90+ degree day last week I was not a happy camper. Fortunately, I'm on a priority status with my HVAC vender so I received same day service. Good/bad news, competent tech who quickly found a swollen capacitor in my condenser motor controller and replaced it for a paltry (ouch) $354. So, good example of catastrophic capacitor failure even if not audio related.

@rauliruegas Yeah, I hope to get more than another ten years out of them!

Dear @goofyfoot  : The electrolytic caps in your unit are the top of the line Vishay ones that you can't improve it because the Vishay are the top of the tops capacitors and could gives you another 10 years with out problemas.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

If it was competently designed with with descent components don’t touch it. Not even close to being ready for a recap IMO. 

I've had 50-year-old gear that's been laying dormant for decades power right up and play beautiful music on our test bench.  I've also had pieces literally catch on fire (moments after I shot off an email to let the customer know their equipment was ready to be picked up).

Borderline, aging components are risky and not worth catching the entire neighorhood on fire.  But, it does sound to me in this case that the capacitor swap is a bit premature based on the published life expectancy of the caps.

If it ain’t broke…

don’t fix it…

send it back to the manufacturer.....you'll get it back perfect

I just picked up a Mark Levinson no 27 amplifier from a client I believe the amp is from 1989-1990 before Levinson was booted and company bought off...

After testing it one channel sounds lifeless, no bass, tinny... I took it to the repair shop and was quoted $2200 for a full recap...

Im good at soldering so and the amp was free so I decided to see if I could fix it myself..

So far I have replaced the big main 45000uF caps and the 2200uF caps, after that I tested and it sounds amazing BUT I started tapping these other 8 caps on the amp stage and it starts going in and out, so now I'm in the process of looking for replacements, so far the biggest challenge is finding the parts, they are difficult to acquire and most are not available so I'm trying for stuff that is close in rating and values and size but it's been challenging. Good news is I think some Mundorf audio grade caps will work to replace those 8 bad caps, but they are higher uF and shorter, but I think they will work 

So far I've spent $400 and it will probably be another $200-$300 but this amp was $3500 back in 1989 which is like $12k in today's money and it sounds great.

I'm using almost 50yo stuff that has never been touched but cleaning and adjustments. It still sounds wonderful! While some of the capacitors might have drifted, they still should all be in spec. The only way to know is to measure all of them. Doubt you would really even want that done unless something is wrong.

From what I have been told, it's usually the power caps that wear out first. Sadly they are also the most expensive and sometimes hard to find.

Just measured the caps on my crossovers with my 35yo speakers, they were all in spec but all over the place alone with the resistors. But sadly not the same from left to right. I'm going to recap my XO's soon. The reason was the L/R are not sounding the same, right was a little more defined, left was a bit brighter.

If the unit is functioning properly ( no hum, visual inspections indicates no damaged/overheated/discolored caps I would advise against r&ring the caps.  As an experienced electronics hobbyist I've learned that one must be judicious when applying heat to circuit boards.  You observe that there are 50 caps which translates to at least 100 solders connections.  To r&r all of those caps would require at least 200 applications of your soldering tool to various solder joints on the board(s).  If you have a quality precision soldering station with assorted interchangeable tips, patience and a steady hand you might attempt it but only if those caps truly need replacing.  If this were a medical decision then a second opinion would be advisable.  After reading the other posts in response to your query is looks like there is a multitude of second opinions advising, "if it ain't broke don't fix it.

Hey All, Thanks for the input. With twenty eight capacitors per side in the amp. There are an extra two capacitors, if not three, per side. So if two per side end up failing, I can still use the amplifier. I’m not saying I wouldn’t want them replaced but I just wanted to mention that.

Also, mention of possibly having to replace those capacitors in the battery or power supply's is a good point. I was wondering about that myself.

No I don’t want to try to upgrade the capacitors.

Love these discussions. What are good high end caps

Hey all,

New to the group so thanks for the add.  With your kind indulgence I thought I'd jump into the capacitor pool here and likewise seek the counsel of wiser elders on the subject. (I'm 64 but still... 😬)

I'm building a small system for my kitchen (near-field use, spkrs at far end of kitchen table, about 36" away from head and about 36" apart -- probably far from ideal but my only option here) and got the stubborn, romantic idea into my head to buy my first *vintage* M&K satellites (fabulous Arcam Solo sub provides bottom end).  I went all the way back to the company's start buying pairs of both S-2B and S-3B satellites.  The taller/multi driver S-1B's were my default choice but too tall for this application.  

As these pairs are both from the (probably *early* '80s), we're talking about 40-year-old speakers and assuming they've never been attended to, dried out or leaking caps were a distinct possibility and their replacement advisable/necessary.  In giving them each a listen, the bigger, hardier S-2B's sound just dreadful, as though a blanket's been thrown over them, and although most noticeable in the high end this affliction seems to be across the audio spectrum.  

With the S-3B's, performance is really pretty sublime with the one niggling exception of not being able to hear ride cymbals!  Crash cymbals come through much better.  (I should add that I'm a lifelong drummer and thus particularly attuned to such audible information.  I've also read in various forums that these satellites have small sweet spots but I've bobbed my head left right up down and that doesn't seem to be what's at play here) Other high note details from all(?) other instruments seem totally present.  Weirdly enough, on *certain* recordings (maybe 20%?), the ride cymbals ARE audible -- so this 80/20 split is rather baffling given my main theory of the case regarding caps gone bad.  I recognize that different recordings have varying quality levels but this as an explanation seems improbable though I suppose not impossible?

I haven't cracked open either speaker yet to visually investigate what's happening on the boards but before I proceed with anything I thought I'd elicit thinking from you wise folks about what I'm likely experiencing and what my best path forward is.  Many thanks!
 

As a retired electronics (mostly) vacuum tube technician, I can’t imagine any kind of electronics needing their capacitors replaced after just 13 years.  As someone else mentioned, it looks pretty over designed and I can’t imagine you even needing to think about replacing the Nichicon capacitors until the 20 to 30 year mark.  The only reason I’d say 20 years is if you started hearing hum issues or other sound quality issues like flabby bass, grainy, dirty sound quality, etc.  I think your technician is just trying to earn a buck.  Or maybe he’s thinking of upping the capacitance values of the capacitors which gives better filtering (not that it looks like it needs it) but also improves bass and makes the sound cleaner.  I’d just leave it alone unless you start having issues.  It looks like it was designed well and should serve you nicely. 

      The Emitter amps have an amazing number of electrolytics, between their power supplies and the capacitor banks in their amplifier chassis.

             The good news = Germans have a tendency to overbuild their gear.

       My guess would be: their engineers chose some of the best caps available, for that creation.

       Still: any electrolytics can dry out, start leaking, internally short, or explode, without any particular excuse/warning.   

                              The perfect electrolytic just doesn't exist.

        Given your system's initial price and what it would cost to repair it, if something catastrophic were to occur; a comprehensive testing of all those caps, by a competent Tech, would (no doubt) be a great preemptive/preventative measure.

         Kind of like: someone interested in their health, getting a physical now and then, by a good Physician.

         Electrolytics are one of those things that (especially when they dry out slowly) can have an effect like VERY slowly raising the temperature of the water around a frog, one degree at a time.    The critter's perfect at ease, until it croaks (about 40 degrees C).

          Likewise: slow changes in the presentation of sound systems and the adjustments our ears and brains can make.

                                             Happy listening!

The problem with replacing parts with “better” parts is determining what IS a better part.  It is not always the case that more expensive parts with a popular buzz is the right choice.  If a part change can change the sound it can do so for better or worse.  I’ve heard tube amps whose sound dramatically changed in bad ways by swapping capacitors, in one case, very expensive Blackgates for cheap caps, making the amp sound broken. 

The replacement or upgrade to better capacitors will improve the sound so just don't replace, upgrade them and a few resistors to Mills or Audio Note non-magnetic.

Happy Listening

My 40- year old Sumo Andromeda amp has been in daily use now for several years. Perfectly quiet - no problems. If your ASR amp is the same I wouldn't worry. The only caps that might become problematic would be the power supply caps. There are typically two or four in most amps.

@gs5556 Thanks, that's good for my mental health!

I looked at a picture under the hood and I see those blue caps are the Vishay BC 135 series capacitors. Their lifespan is 250,000 hours at a 40C ambient. That's over 28 years if you do the maths. If the temperature inside the case is lower, say 30C, then the lifespan is 630,000 hours. So hopefully by then your great-great-grandchildren will be handy with a soldering iron.

@larryi @kmtang ;  Everything is working as it should, obviously no need to concern myself with replacing capacitors at this stage. To be fair, I think my speaker tech has the tendency to overthink things. So what you’ve both shared is pragmatic and sound advice. 

That's real BS.  

Usually, the electrolytic capacitor in audio amplifiers would last many years. The new ones are very reliable.

I used the LCR meter to check the ESR, dissipation factor, and capacitance to confirm the condition of the Capacitors. Without testing them with instrument, I won't replace them without any reason.

Replacing the capacitors with different type/kind, it maybe cause distortion/problems.

If it ain't break, don't fix it.

Johnny

Is the amp beginning to hum, make any other noises, or otherwise sound like it is going bad?  Does your amp run hot all of the time?  If it is not acting up, and it is not an amp that subjects its internal parts to high heat levels, I would not worry that much about the state of the capacitors.  You could have someone just take a look under the cover for bulging/leaking caps, resistors that look a little burnt, etc.  If your tech looking under the hood can do in-circuit tests of capacitors (equivalent series resistance (ESR)), he might be able to spot one going bad without big hassles and high labor cost. 

A preventative replacement of all caps seems extreme to me.