Hello everyone. I have lurked here for a few years and have a few questions.
I am a longtime (~7-8 years) and very happy owner of Sennheiser HD 580s. I bought them at a time when they appeared to be phased out in favor of HD 600s and paid about $200 for them.
Long story short, I opened them up for cleaning 3 years ago and destroyed the left diaphragm. I contacted Sennheiser and purchased a new "replacement" driver, along with the metal HD 600 grilles and the HD 650 cable (due to a prior cable failure).
I assumed for these past few years that this was a true drop-in replacement driver. I now question this assumption. Here is an article that illustrates the visual difference I see;
The original drivers look exactly like the one on the far left of this image. The "replacement" driver I ordered looks like one of the images to the right, and also has the grey grille cloth instead of black. Most telling, my newest driver has imprinted upon its right side:
The old driver has no such markings, and its coil is darker and more copper-like - just like the image to the far-left in the link I posted.
At least 1 internet link suggests this is really a HD 650 driver. http://www.amazon.com/review/R1K159SVA2QGXB The prior visual comparison also supports this possibility.
I personally cannot tell a difference in sound quality or character between the old driver and the new driver. It still sounds excellent to me, even having recently heard the ATH-M50S, which my HD 580/650 beats easily in my opinion. I have tried the new driver in both the left and right earpiece, and the sound appears the same regardless.
This experience leads to these questions;
1. Is this HD 580 replacement driver actually a HD 650 driver? (My research indicates the HD 580 and HD 600 drivers are identical, but have different housing materials. The HD 650 driver is supposedly slightly different in construction and sound signature, with a heavier bass presence.)
2. Is there any audible difference between the HD 580/600 and HD 650 driver? I have seen posts stating that the differences are significant, and other posts suggesting that they are inaudible.
3. If indeed Sennheiser sells an HD 650 driver as a replacement for the HD 580, then what is the advantage of purchasing a late-model Sennheiser headphone from this series?
4. Is a carbon-fiber earpiece construction worth a few hundred bucks of sound quality improvement?
Sorry if this is a long post, but I wanted a true replacement driver for my beloved headphones of 7+ years. Based on what I hear there is either no difference between the new and old drivers in audible terms, or my sources are totally incorrect in their evaluation. Sennheiser should replace drivers with real equivalents, not close-enough drivers. I consider myself to be highly resistant to placebo effects.
All thoughts and experiences are appreciated.