What would you do with this vintage?

[pyonc]

Hi friends,

I've got a vintage preamp JBL SG 520 in super clean condition, which I bought in April.
According to the ebay seller, it was kept as collectable, not used for many years.
True to his words, it was very clean both inside and outside (cosmetically 9 out of 10), with no modifications at all.
Compared with my back-up SG520, however, this unit lacked clarity&brightness in mid/high and depth in bass.
When I asked the seller about this, he checked back with his tech, saying it would continue to improve sound with the capacitors "reforming about two months."
(The tech also mentioned no leakage from capacitors and other defects inside the unit)
Since then I've used this one more than 30 minutes almost daily, hoping the capacitors would "reform" enough to result in improved sound.
Well, the outcome is disappointing. Sound reproduction from speakers is just the same as when I first heard it,
and clearly the reformed capacitors didn't affect the sound at all.
Eight months of continued use is long enough to have any NOS capacitors like this unit reformed, right?
So, I strongly feel like disposing of it rather than keeping it much like a "collectable" at a museum.
Anyway I have another same unit working very well.
What would you do with this unit? Any feedback or advice would be much appreciated in advance.

[hjames]

Hi friends,

I've got a vintage preamp JBL SG 520 in super clean condition, which I bought in April.
According to the ebay seller, it was kept as collectable, not used for many years.
True to his words, it was very clean both inside and outside (cosmetically 9 out of 10), with no modifications at all.
Compared with my back-up SG520, however, this unit lacked clarity&brightness in mid/high and depth in bass.
When I asked the seller about this, he checked back with his tech, saying it would continue to improve sound with the capacitors "reforming about two months."
(The tech also mentioned no leakage from capacitors and other defects inside the unit)
Since then I've used this one more than 30 minutes almost daily, hoping the capacitors would "reform" enough to result in improved sound.
Well, the outcome is disappointing. Sound reproduction from speakers is just the same as when I first heard it,
and clearly the reformed capacitors didn't affect the sound at all.
Eight months of continued use is long enough to have any NOS capacitors like this unit reformed, right?
So, I strongly feel like disposing of it rather than keeping it much like a "collectable" at a museum.
Anyway I have another same unit working very well.
What would you do with this unit? Any feedback or advice would be much appreciated in advance.

If you have tried it over and over and it does not produce a sound that pleases you,
either pay someone to rework it for you so it DOES play the way you want it to, or sell it off to someone else.
It sounds to me like you value the SOUND over the LOOK of it being collectable.

Good luck however you decide ...

[JeffW]

Sell it to somebody with a museum, buy something made in this century.

[Mr. Widget]

Sell it to somebody with a museum, buy something made in this century.

I agree... I love vintage gear as much as the next guy, but for systems where I care about sound quality, high quality modern equipment can't be beat.


Widget

[pyonc]

If you have tried it over and over and it does not produce a sound that pleases you,
either pay someone to rework it for you so it DOES play the way you want it to, or sell it off to someone else.
It sounds to me like you value the SOUND over the LOOK of it being collectable.

Good luck however you decide ...

Thanks, hjames. Yea, I don't keep it as collectable.
The only thing that bothers me at the moment is I'm not sure if the sound from this minty SG520 is what you call "neutral" or not, compared with the other SG520 that's more pleasing to my ear...

[farleybob]

Has your backup unit been recapped? If so, maybe that's the difference. Otherwise -- if you like the preamp, it might be worth finding a good local tech and have him or her take a look at the unit that doesn't sound quite up to par. There are lots of folks who can give you better advice than me, but if you're hearing a problem in both channels, maybe there's a power supply issue. Lower than nominal voltage can make things sound dull. If, at the end of the day, you're not happy with it, I'd let it go.

[pyonc]

Has your backup unit been recapped? If so, maybe that's the difference. Otherwise -- if you like the preamp, it might be worth finding a good local tech and have him or her take a look at the unit that doesn't sound quite up to par. There are lots of folks who can give you better advice than me, but if you're hearing a problem in both channels, maybe there's a power supply issue. Lower than nominal voltage can make things sound dull. If, at the end of the day, you're not happy with it, I'd let it go.

No, the back-up unit has never been recapped. Neither has the newer unit. In terms of sound, however, back-up unit emits more sonorous, brighter mid/high and deeper bass at the same or even a bit higher volume. Again, the vintage tech looked into the newer unit and found no issue.

[farleybob]

If I understand your original post, it was the ebay seller's tech who looked at it. Considering how much that unit costs, it might be worth it to spend a few bucks to have your own guy verify that. Or sell it and find one local that you can listen to before you buy.

No, the back-up unit has never been recapped. Neither has the newer unit. In terms of sound, however, back-up unit emits more sonorous, brighter mid/high and deeper bass at the same or even a bit higher volume. Again, the vintage tech looked into the newer unit and found no issue.

[hjames]

I agree with Farleybob - with the kind of gear you are passionate about,
you need an INDEPENDENT tech whose opinion you can trust -
one who is NOT connected to the ebay seller you bought it from.

[grumpy]

Warm up period, perhaps (30 min), but reforming caps on low voltage solid state gear?
this is somewhat applicable to higher voltage tube gear (electrolytic capacitors),
but I would not expect the lesser sounding unit to get better on its own.

2 mo sounds more like an (unfortunately oft used) ploy to have you get used to a component's
"character" rather than realizing any actual improvement (vs living with something that sounds different
than what you're used to and finding you eventually like it better, which at least has some validity).

Having a 2nd unit to compare, puts you in a unique position to evaluate by ear, but a good shop should
be able to run a check on all voltages, run a frequency response, and perhaps distortion at nominal levels
and load. If you can readily identify differences between identical design preamps without hesitation,
then I would suspect one is grossly misbehaving (could be simple or difficult to identify the source and fix).
I'm assuming you've used some method to match levels when comparing (?)

I'm afraid I side with the move-on camp unless you're determined and willing to have someone attempt
a full restoration to spec.

It would sure be fun to run one I trusted in a vintage setup

[pyonc]

Warm up period, perhaps (30 min), but reforming caps on low voltage solid state gear?
this is somewhat applicable to higher voltage tube gear (electrolytic capacitors),
but I would not expect the lesser sounding unit to get better on its own.

2 mo sounds more like an (unfortunately oft used) ploy to have you get used to a component's
"character" rather than realizing any actual improvement (vs living with something that sounds different
than what you're used to and finding you eventually like it better, which at least has some validity).

Having a 2nd unit to compare, puts you in a unique position to evaluate by ear, but a good shop should
be able to run a check on all voltages, run a frequency response, and perhaps distortion at nominal levels
and load. If you can readily identify differences between identical design preamps without hesitation,
then I would suspect one is grossly misbehaving (could be simple or difficult to identify the source and fix).
I'm assuming you've used some method to match levels when comparing (?)

I'm afraid I side with the move-on camp unless you're determined and willing to have someone attempt
a full restoration to spec.

It would sure be fun to run one I trusted in a vintage setup

Thanks a lot for your insight and helpful comments, as always.
I think I have to stick with the oft used SG520, which is clearly more pleasing to my ear...

[pyonc]

I agree with Farleybob - with the kind of gear you are passionate about,
you need an INDEPENDENT tech whose opinion you can trust -
one who is NOT connected to the ebay seller you bought it from.

Yea, you're right. Thanks!

[pyonc]

By the way, guys,
I've stayed away from tech's check-up on these SG520s of mine because they've worked very well up until now.
I am not sure if they're up to the specs, of course, but all the functions, such as bass, treble, volume, phono, etc just work fine.
But now I'm going to bring them to the tech shop, as you suggested, for a thorough check-up, given their vintage status.
Is it really necessary for the tech to run a check on these vintages, even if they work well?

[JeffW]

Depends on the tech. Would you trust them to Billy Bob's Backyard BBQ and Electronics Repair? Finding a guy who knows his stuff and won't screw them up would be a priority. I would probably just continue to use the one that sounds good and use the other as a guinea pig (that is if I didn't just sell the one I didn't like and buy something that didn't need work). That way, if the tech screws up, at least you still have a working unit in the mean time.

[SEAWOLF97]

Is it really necessary for the tech to run a check on these vintages, even if they work well?

As we used to say at Intel "if it ain't broke ... fix it ..'till it is"