Reforming capacitors?

[pyonc]

Hi guys,

I need your urgent help!!!
This is related to my recent thread on the comparisons of two SG520 preamps,
one in near mint condition (A), and the other in good used condtion (B).
My puzzle was I hear brighter and clearer sound from the mid and high drivers, and tighter bass from the woofers from B than A.
And now I got the answer from the ebay seller who quoted his technician:

"The technician said the newer one (A) has not been played in a while prior to check up, but kept as a collectable. He said it takes about 2 months for the capacitors to reform and the unit will continue to improve in sound during this period."

What do you think? Is it worth for me to "reform" this capacitor? Can you reform by just playing this unit for a couple of months?
If not, is it just a hopefuless job and wise for me to just return this item to the seller? Thanks much for your advice in advance.

[audiomagnate]

Hi guys,

This is related to my recent thread on the comparisons of two SG520 preamps,
one in near mint condition (A), and the other in good used condtion (B).
My puzzle was I hear brighter and clearer sound from the mid and high drivers, and tighter bass from the woofers from B than A.

The technician said the newer one has not been played in a while prior to check up, but kept as a collectable. He said it takes about 2 months for the capacitors to reform and the unit will continue to improve in sound during this period.

What do you think? Is it worth for me to "reform" this capacitor or is it better for me to return this item to the seller?
Do you think I can really get improvement in sound over the two months period with this so-called "reforming"?

If the difference is clearly audible, then one of the amps is out of spec and needs to be serviced. The real question is, which one? Full Disclosure: I'm not "believer" in the whole break-in thing or all of the other nonsense that many audiophiles swear are real. I do believe in slowly bringing up old tube stuff with a variac to prevent cap failure, but that's about as far as I'll go.

[pyonc]

If the difference is clearly audible, then one of the amps is out of spec and needs to be serviced. The real question is, which one? Full Disclosure: I'm not "believer" in the whole break-in thing or all of the other nonsense that many audiophiles swear are real. I do believe in slowly bringing up old tube stuff with a variac to prevent cap failure, but that's about as far as I'll go.

Yea, I hear an audible difference between SG520 in near mint condition (A) and the other one in good unused one (B).
The tech said he has serviced this near-mint A, "with no issue and no repair". As it turns out, however, he now says the capacitors, which sat idle as a collectable for very long, now need reform to get improvement in sound, compared to the other one in good used condition.
The thing is can you expect improvement in sound by just playing this unti for a couple of months or "reform" capacitors naturally by just playing it?
To "reform" capacitors like this, I need to bring this unit to a service tech, right?

[Allanvh5150]

Hi,

If you have been running the amps already, there is no point in "reforming"

Reforming is usually done if a piece of gear has been sitting and not being used for a number of years.

Reforming is used to bring the capacitors up slowly. The usual method is to power the device on and
not apply a load to it for, rule of thumb, one hour per year out of service. This is for capacitors that
have been out of service for up to 2 years.

The other method is to supply the equipment with a "current limited" voltage source, with no load for
the same 1 hour/year time. This is used when the device has been out of action for more than 2 years.

As far as I am aware, this is only to prevent damage when the capacitors are charged for the first time
and generally will only relate to electrolytic capacitors used for filtering the power supply.

Obviously you have run the amps without any issues apart from they sound different. Just play it and see
if things improve.

Allan.

[pyonc]

Hi,

If you have been running the amps already, there is no point in "reforming"

Reforming is usually done if a piece of gear has been sitting and not being used for a number of years.

Reforming is used to bring the capacitors up slowly. The usual method is to power the device on and
not apply a load to it for, rule of thumb, one hour per year out of service. This is for capacitors that
have been out of service for up to 2 years.

The other method is to supply the equipment with a "current limited" voltage source, with no load for
the same 1 hour/year time. This is used when the device has been out of action for more than 2 years.

As far as I am aware, this is only to prevent damage when the capacitors are charged for the first time
and generally will only relate to electrolytic capacitors used for filtering the power supply.

Obviously you have run the amps without any issues apart from they sound different. Just play it and see
if things improve.

Allan.

Well, in my case I've run this preamp several times for the the past two weeks, playing CDs and records.
So, there's no point in reforming at this point?
When you said that, do you mean I just should have powered up this preamp alone for a hour?
The tech mentioned "natural reforming" by playing the unit for a couple of months. Looks like this one sat idle as a collectable for more than two years.

[Allanvh5150]

To be honest, I have never worried about doing this. Reforming is a term from power electronics. Wind turbines and backup generators. Where they are dealing with hundreds of kilowatts and more. The last thing you want when you have to use your backup in an emergency, is that the capacitors explode. In general, reforming is done every year.

Allan.

[hjames]

The problem with me is I got this unit ($2700) from an ebay seller who gives me two weeks of return, and tomorrow is the last day.
I've got to decide whether to return or take the risk of keeping it and continuing to play it for the next couple of months to confirm reform process.
What if I don't hear any sound improvement despite this "natural reforming"? Look at the inside pic of this unit.
And now according to the seller, "all new or products that have not been used in a while go through a break in period. During that period the caps naturally reform. It's a normal process when an item is being used. Audio people tend think that after this break in period that things sound better.

"Does he make sense?

Seems like $2700 would buy you some nice new gear and not have to suffer through issues with mismatched vintage gear.
Also, more buyer protection with new. I'm getting less and less amused with the ebay Casino
(you pays your money and you takes your chances ...) ...

[pyonc]

Looks like my issue is related directly to the "break-in" period of capacitors, as you know.
While I've been playing the existing SG520 regularly,
the other one in near mint has been sitting idle for many years.
The tech confirms there is no leakage or dry-out of its capacitors,
only wanting 'reform' by playing two months (1-2 hours a day).
I'm really getting more and more curious:
Have you experienced any change in sound as a result of this break-in?

[Allanvh5150]

As these capacitors are not in the signal path I would not expect any changes at all.

Allan.

[pyonc]

[Q UOTE=Allanvh5150;360964]As these capacitors are not in the signal path I would not expect any changes at all.

Allan.[/QUOTE]

Hummmmmm......I get confused here.
What do you mean by "these capacitors are not in the signal path"? SG520 is a preamp.
Could you explain some more?

[Allanvh5150]

Reforming, as far as I am aware, is only done on electrolytic capacitors used in power circuits. In audio gear these capacitors are the filter capacitors in the power supply. These capacitors are not in the signal path so they will have very little effect, if any, on the "sound" of the unit. If you are already running the equipment, you are already "reforming" them. There are a bunch of other small electro caps in these pre amps which are probably mostly out of spec now. I wouldn't hurt to replace them.

Here is the service manual which has useful info. Hope it is the same as your models.

Allan.

http://www.jblproservice.com/pdf/Vin.../JBL-SG520.pdf

[pyonc]

Reforming, as far as I am aware, is only done on electrolytic capacitors used in power circuits. In audio gear these capacitors are the filter capacitors in the power supply. These capacitors are not in the signal path so they will have very little effect, if any, on the "sound" of the unit. If you are already running the equipment, you are already "reforming" them. There are a bunch of other small electro caps in these pre amps which are probably mostly out of spec now. I wouldn't hurt to replace them.

Here is the service manual which has useful info. Hope it is the same as your models.

Allan.

http://www.jblproservice.com/pdf/Vin.../JBL-SG520.pdf

Thanks much. Yes, it's the same one. And this specific one has been kept as a collectable, just sitting idle for many years. It's very clean inside (Refer to pic). And the tech has fully checked it and found no issue, all up to the spec. And he said with reforming of capacitors for two months, the sound will continue to improve. Now you are skeptic about this capacitor break-in.
On googling, I see many opting for capacitor break-in for the sound improvement. Here is one such comment by an audio specialist:

"All electronics require break in, especially the better stuff. Nothing will sound right brand new, even cables, and many times they might sound sort of awful. The engineers who designed them base their performance on what they'll sound like broken in, not new. The rub here is how one goes about it. Many people leave the gear on all day, for weeks even. I am very much against this. What do we mean when we say a part like a capacitor must "break in"? It's just wound metal impregnated with some kind of oil usually, what "breaks" in. Obviously the metal. From having some blacksmith knowledge, I know metal breaks in by tempering, but it can be tempered 2 ways. If it is hot all the time and then suddenly cold it makes it hard and brittle. If you get it hot then cold then hot then cold etc... repeatedly (in other words a middle range) it tempers it softer. If you play it no stop all you have is heat, and then suddenly it gets cold. I have heard too many people who do this complain that their systems sound strident and never "broke in" properly and I believe this is why. What's more it seems to lengthen the time required to break it in once they start cycling it properly. All gear is different but most electronics seem to take about 300 to 400 hours to fully break in. One advantage of buying used gear is that this is all or mostly done by the time you own it."

[audiomagnate]

If you found it on the internet it must be true. I stand corrected.

[Allanvh5150]

yes, I have read all the comments by various people saying that every component requires a break in period. I can fully understand a mechanical component like a speaker, but when it comes to comments about cables requiring a break in period, well.......

Most of these people that use the term "break in" are only trying to justify the insane amounts of money they spent.

Just plug it in and play it.

Allan

[rusty jefferson]

Hi guys,


......"The technician said the newer one (A) has not been played in a while prior to check up, but kept as a collectable. He said it takes about 2 months for the capacitors to reform and the unit will continue to improve in sound during this period."

What do you think? Is it worth for me to "reform" this capacitor? Can you reform by just playing this unit for a couple of months?
If not, is it just a hopefuless job and wise for me to just return this item to the seller? Thanks much for your advice in advance.

Capacitors do (imo) "change" their sound with use when installed in a new piece of equipment. You are dealing with something different. Regardless, there are 2 dozen models of new(er) preamplifiers that will sound better than this one for the same amount of money, or less. I appreciate the novelty of vintage gear, but if you don't have the ability to troubleshoot, repair, and upgrade gear yourself, it's a tough row to hoe. It is not uncommon for a part(s) failure to take out driver(s) in speakers.

Do you want to listen to it, or look at it?