Originally posted by paulraff
I had a go at it last night and.... it's done. The first one was a bit tricky as I was probably being a bit too gentle with it, but by the second one I was a true "foam-modder" 
It opens up the sound a bit more. Since I'm still running 'em in I'll need to wait a while to see just how good they get.
Thanks for pointing out this mod.
Good to hear you got that sorted Paul, it has been said that the foamies do result in quite a good increase in the clarity and cleanliness of the sound. The headphones will probably take about 200 hours to run in if my CD3000's were anything to go by.
Right again Mr. B.!! I tried the Sony's on my NAD C350 and they are silent when they ought to be. I had been using my OBH21-SE on my main CD-listening set-up, where I was getting some background hiss. Even there I was able to effectively eliminate this by switching to the second output on the OBH. (In fairness to Creek they point out that the impedance varies between the two outputs and that you should try both for the best sound.) I've read your reviews of the Perreaux and that may be in my future...
Now, my theory as to why the hiss vanishes when you use the NAD and the alternative output on the Creek is because on the Creek you are likely using the output with the higher impedance, and on the NAD, it will have a much higher impedance anyway. Increasing the output impedance of the jack increases the effective electrical resistance of the headphones and therefore, eliminating the hiss. You'd actually find the same would happen if you used higher impedance and/or lower sensitivity headphones. I can tell you now, that if there is a hiss evident in the chain somewhere (unless its actually coming from the amp itself) then the Perreaux will make it EVEN MORE evident, since this amp is equally clean in its output as the Sony's and has a virtually 0-ohm output impedance (which I might add, is desirable for the best quality, but also more unforgiving of "problems" in the chain).
Now, you could try different interconnects, or maybe something needs grounding, but I have not actually had this problem myself, so I can only suggest trying those.
BTW, I have to agree with yourself and others that the CD1700s are great value for money, at £74. They have a very dynamic presentation, with plenty of slam. Vocalists really come to the fore as well. I've spent quite a bit of time in the past few days comparing 'em to my Grado 325s and 80s. On balance I like the 325s a bit more, as they give more air around acoustic recordings (probably the open design?), but I'd be hard-pushed to say the difference was worth the additional £201 they cost me! (Including £25 for an extension lead for the Grados that you don't need with the Sonys, thanks to their "real-world" 3.5m lead - kudos for that!) Also, the Sony's screw-on adapter is a simple but sensible way of ensuring a good connection, one that doesn't come apart when you pull out the lead!
The Sony's are VERY amp dependent (they like an amp with 0-ohm output impedance, which neither your NAD or Creek will be able to provide). The "veiled" effect you speak of is IMO, definitely caused by an increased output impedance at the jack. When I listened to my CD3000 side by side with the foam modded CD1700 on my Perreaux, I found that while the CD1700 is slightly less clean and clear than the CD3000, that may have something to do with the fact the CD3000 are more than double the price!! The CD3000 are definitely the cleanest sounding headphones I've heard, and CD1700 were close second.
The Grado's on the other hand, in particular your model, are obviously open so will do the airy thing a little better, but are also said to be more forgiving of amps. Also, the 325's are known to be VERY bright, and increasing the output impedance of a jack will have the effect of taming treble. I'd be willing to bet if you got a good clean amp with 0-ohm output impedance in the chain, you *may* find that things might even sway in favour of the Sony's!! Thats not to put the Grado's down, but I personally think the Sony's are SERIOUSLY underrated for that price.
There are only two things I can say against the Sonys right now. Firstly, they have a slightly veiled sound compared to the Grados and, secondly, I happened to look into a mirror when I was wearing them last night... Bl**dy h*ll, they look huge. The sort of sight that gives headphone wearers a bad name. I'd be as well off strapping my SA1550s to my head. I'll have to stay away from windows in case I frighten the neighbours' kids!!! "Mommy I've just seen the Elephant Man" 
Like I said with the veiled effect, whenever I have used both the CD1700 and CD3000 with increased output impedance, they have both sounded veiled. Give it a 0 ohm impedance at the jack, and that veil will vanish, completely, I promise you that. The Creek simply CANNOT deliver this fundamental requirement for driving headphones well, and I dont mean to put it down, but I found it very suspicious when Creek would not tell me what the output impedance of the jacks were when I specifically asked them. They simply replied "use which one sounds best". When measured by someone on headfi, the output impedance was something like 80 ohm for one jack and 120 ohm for the other (IIRC). They should provide a 0-ohm jack, and no arguments. The 120 ohm jack can only possibly benefit headphones specifically designed for this impedance (like the Beyerdynamic DT931), and also very high impedance phones that suffer from excessive brightness (not that many of those AFAICT).
And by the way, if you think you look daft with the CD1700's on, then think of me - the CD3000's, no exagerration, are considerably BIGGER than the CD1700's
Anyway, enjoy your headphones, I promise when you sort out your problems, you will be amazed at what they can do.
. The foam mod, is I think, reversible (simply stick them back on). Most, if not all people who have done it said they would never go back to having the foamies on once they've performed the mod, but that is certainly up to you. Certainly, my mates foam modded CD1700's were usefully close to my CD3000's given the cost through my rig. Certainly, they are my second favourite phones that I have heard, only trailing behind the CD3000, and beat out the Senn HD580, HD650, Beyer DT531, DT880, DT990, DT931 and the lower models Stax to my ears.
And I reckon it would be hard to rely on the guarantee when they ask me what happened.. "Well I'd heard about the foam mod..." :shame:
