NeverSatisfied is getting a fresh d500
- Thread starter grapplesaw
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Spence,
This is familiar turf for me -- that is, watching the gurus do something intricate...sweating bullets on the inside, poker face on the outside, meanwhile thinking WTF have I gotten myself into...in public no less? :0)
****
But the silver lining in all this? Well, instead of taking something perfect apart & running the risk of never being able to put it back to it's original glory, to be perfectly candid I can't believe that the D500 sounded as good as it managed to despite the factory wiring harness job. (J!m, how did that go -- angry lobster in a pot of spaghetti? :0)
Not trying to hijack Glen's thread...actually, I think the photos of my 'as built' D500 will help you develop a genuine appreciation for what Glen is going to do for you.
GOOD NEWS first:
While waiting for my order of (88) MJ21195/6 output drivers, (& a bunch of other stuff from White Oak) I decided to give the "Dual 500" I've owned for the past 40+ years a real cleaning -- basically, just see what I've got to work with.
First I took the front panel off in order to be able to evenly polish every square inch:
Panel as found after ~20 years of cold storage.
Front all back together after cleaning. 2 thumbs up, especially in person - whew!
Now to pop the lid & see what's inside:
Yikes -- audio signal wires cable tied adjacent to the AC main transformer leads! (Because of where the relays are located.)
Wait a minute...there's some sort of cryptic message written on the transformer?
Hmmm... I bought this unit (Serno #1691) from the audio store as brand spankin' new? Did something happen at the factory requiring a transformer swap prior to shipment? Or did the original transformer fail to proceed during a dynamic demo at the audio emporium at some point prior to my purchase?
And why is it just about anything I purchase has hidden treasures like this hiding inside? I just don't know...
****
All I do know is that this amp gave me almost 20 years of pure pleasure, the last 8 of which were driving a pair of loudspeakers known to stress-test amplifiers. Now, after 20 years of cold storage, with the help of Gepetto, Grapplesaw, Lee, and everyone else in here we're going to bring this beast back to "better than new" condition. My goal is no less than to make it just as pretty on the inside as it is on the outside. (!)
Given what I am planning to do, I can not wait to put up the 'after' photos so that we can compare them to these sad 'before' images. :0)
That's all I've got to say about that.
db gump
This is familiar turf for me -- that is, watching the gurus do something intricate...sweating bullets on the inside, poker face on the outside, meanwhile thinking WTF have I gotten myself into...in public no less? :0)
****
But the silver lining in all this? Well, instead of taking something perfect apart & running the risk of never being able to put it back to it's original glory, to be perfectly candid I can't believe that the D500 sounded as good as it managed to despite the factory wiring harness job. (J!m, how did that go -- angry lobster in a pot of spaghetti? :0)
Not trying to hijack Glen's thread...actually, I think the photos of my 'as built' D500 will help you develop a genuine appreciation for what Glen is going to do for you.
GOOD NEWS first:
While waiting for my order of (88) MJ21195/6 output drivers, (& a bunch of other stuff from White Oak) I decided to give the "Dual 500" I've owned for the past 40+ years a real cleaning -- basically, just see what I've got to work with.
First I took the front panel off in order to be able to evenly polish every square inch:
Panel as found after ~20 years of cold storage.
Front all back together after cleaning. 2 thumbs up, especially in person - whew!
Now to pop the lid & see what's inside:
Yikes -- audio signal wires cable tied adjacent to the AC main transformer leads! (Because of where the relays are located.)
Wait a minute...there's some sort of cryptic message written on the transformer?
Hmmm... I bought this unit (Serno #1691) from the audio store as brand spankin' new? Did something happen at the factory requiring a transformer swap prior to shipment? Or did the original transformer fail to proceed during a dynamic demo at the audio emporium at some point prior to my purchase?
And why is it just about anything I purchase has hidden treasures like this hiding inside? I just don't know...
****
All I do know is that this amp gave me almost 20 years of pure pleasure, the last 8 of which were driving a pair of loudspeakers known to stress-test amplifiers. Now, after 20 years of cold storage, with the help of Gepetto, Grapplesaw, Lee, and everyone else in here we're going to bring this beast back to "better than new" condition. My goal is no less than to make it just as pretty on the inside as it is on the outside. (!)
Given what I am planning to do, I can not wait to put up the 'after' photos so that we can compare them to these sad 'before' images. :0)
That's all I've got to say about that.
db gump
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- Joined
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Re: The stock wiring harness --
To be perfectly honest, if you set the Way-Back machine to the '70s this kind of wiring harness was not unheard of in *consumer* electronics. And my guess why the amp sounded as hum-free as it did despite what you see in the photo is due to the original design's PSRR. (Power Supply Rejection Ratio -- see attached .pdf file for a no-nonsense 3-page white paper from Analog Devices on this subject.)
And here's an article about another guy who bought his D500 new, actually had a hum issue, (despite the circuit's PSRR) and what he did to correct it. (Originally found this years and years ago -- the original mods are in the beginning, but the whole thread is of interest.)
****
Of course, given that I'm upgrading my D500s using the Grapplesaw method (new Gepetto WOPL driver boards & fully-complementary output stages, I have no doubt that the amp(s) will be quieter than ever. As a matter of fact, I think that the biggest challenge ahead of *me* is that I want the signal integrity of the wiring harness to be the equal of the 21st-century circuit design by Gepetto.
It's a good problem to have. For now, I'm in the peanut gallery & Glen is the one on stage.
Go, Glen, Go!
:0)
To be perfectly honest, if you set the Way-Back machine to the '70s this kind of wiring harness was not unheard of in *consumer* electronics. And my guess why the amp sounded as hum-free as it did despite what you see in the photo is due to the original design's PSRR. (Power Supply Rejection Ratio -- see attached .pdf file for a no-nonsense 3-page white paper from Analog Devices on this subject.)
And here's an article about another guy who bought his D500 new, actually had a hum issue, (despite the circuit's PSRR) and what he did to correct it. (Originally found this years and years ago -- the original mods are in the beginning, but the whole thread is of interest.)
****
Of course, given that I'm upgrading my D500s using the Grapplesaw method (new Gepetto WOPL driver boards & fully-complementary output stages, I have no doubt that the amp(s) will be quieter than ever. As a matter of fact, I think that the biggest challenge ahead of *me* is that I want the signal integrity of the wiring harness to be the equal of the 21st-century circuit design by Gepetto.
It's a good problem to have. For now, I'm in the peanut gallery & Glen is the one on stage.
Go, Glen, Go!
:0)
Nothing left to be said Spence. I’m returning your deposit and this will sit here. Just kidding!
Noise is for both high and low rail. Naturally the low rail is a little quieter
how the f@467 do you post a iPhone video? It said wrong format. You cou;d have seen it playing you know.
Noise is for both high and low rail. Naturally the low rail is a little quieter
how the f@467 do you post a iPhone video? It said wrong format. You cou;d have seen it playing you know.
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