"Mad Dog" by MrSpeakers, modified Fostex T50RP review
Feb 26, 2013 at 7:39 PM Post #3,736 of 6,388
ps Sorry if this sounded like a loaded question...it's not. Just a naive one. Can't wait to have my own pair soon though, as I've just purchased a Colorfly C4 and think the base and warmth of the C4 will suit the detailed neutral presentation of the Mad Dogs :)
 
Feb 26, 2013 at 8:53 PM Post #3,737 of 6,388
Just ordered a pair with alpha pads!!!!
smily_headphones1.gif
 This is going to be an agonizing wait...........
 
It'll be worth it though
 
Anyone know if there is a portable case that will fit these? (preferably hard case)
 
Feb 26, 2013 at 9:41 PM Post #3,740 of 6,388
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Quote:
Just ordered a pair
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Hey!  Awesome!  I know you've heard them, enjoy 'em, and let your dad take a listen.

I got him a pair of Beyerdynamic DT660(didn't buy it, but suggested it) because he loves classical and doesn't want to use an amp. But I'll make him jealous of them.
 
Feb 26, 2013 at 11:36 PM Post #3,741 of 6,388
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Dan
 
Checked all the info I can for your latest Alpha headphones.....and the only item of concern seems to be for the quality of the original cable (although from your recent video I see you supply short 3.5 and long 6.3). Being in the non returnable UK, just wanted to know if you are able to upgrade the original Fostex cabling if requested? I'm not very techie, to would struggle to fix or replace myself. I'd pay of course....
 
Thanks...Phil UK

 
Hi...   The standard Fostex cable simply suffers from oxidation on the mini plug that goes into the headphone, perhaps because it can't rotate.  The symptom is "static" in one or both channels, or a dropout in a channel that goes away by moving the cable.  I polish the cable tip and treat it with deoxit.  About 1-2% of people call to say they have a "bad cable," fortunately it's easily fixed by wiping it with a microfiber cloth and a little rubbing alcohol, or another deoxit treatment.
 
That said, I also provide the thinner, lighter and shorter V-Moda cable for users with portable players, or wanting a shorter cable on their desktop (you need to provide your own 1/8" to 1/4" adaptor if your gear has 1/4" (6.3) jacks).
 
Should a warranty issue arise worldwide, I pay the shipping to correct the problem.  
 
Dan Clark Audio Make every day a fun day filled with music and friendship! Stay updated on Dan Clark Audio at their sponsor profile on Head-Fi.
 
@funCANS MrSpeakers https://danclarkaudio.com info@danclarkaudio.com
Feb 26, 2013 at 11:40 PM Post #3,742 of 6,388
My stock T50rp cable makes noise scratchy on the 1/4" side.  I love that it locks in place on the headphones end and wish someone would make a similar cable at higher quality.
 
Feb 27, 2013 at 2:59 AM Post #3,745 of 6,388
I have the JDS with stock AC. No one ever told me that I should upgrade the AC adaptor/plug. Why would they ship with a poor supply of power?

You might want to try upgrading your gain opamp to something like an NE5532 or OPA2134. The NJM2068 (which I believe is what's used in jds labs' version) can start clipping at lower gains than the other 2 opamps mentioned...

I am using a 16VAC 400mA power supply with my O2 and do not appear to be having any issues driving the Mad Dogs.  I also have a 2 Vrms input signal from my DAC feeding the O2.  I think the power supply could be a major factor in why some people are getting drastically different results with the O2.  Now that I am using Mad Dogs instead of ATH-M50s at work, I may step up to a 20VAC 500mA power supply.

Edit: Here is a link to a 20VAC 500mA power supply for the O2 from the same manufacturer as my current 16VAC 400mA power supply.

http://www.mouser.com/ProductDetail/Triad-Magnetics/WAU20-500/?qs=LASUwJSZkDkn6JIHWiQclg%3d%3d

The shipping costs almost as much as the power supply.

Hmm, I might always be wrong, but I was told that getting a more powerful transformer would not be helpful, since it's not actually converting AC to DC, the regulators are doing that inside the O2, and they convert to 12vdc, so anything above that number just makes the regulators run hotter...
 
Feb 27, 2013 at 3:17 AM Post #3,746 of 6,388
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I'm likely going to have an opportunity to pick up a pair of Mad Dogs soon, so I will definitely be comparing them to my HE-400 eventually.  I think for HE-400 fans, it is sounding more and more like the best closed companion, so I would definitely report back with my opinion for others that may have the same questions regarding the two.

 
Nice! Please do let me know how you like them.
 
Feb 27, 2013 at 8:16 AM Post #3,747 of 6,388
There may be a slight strain using a 20VAC power supply into the O2, but it is well within the recommended specs and it should not run much hotter than usual. It is the current that is key here. I've seen 16VAC 1A power supplies being used. Higher available current should make a difference on some headphones. I do have a background in electronics only as a Navy Sonar Technician, but it has been nearly 20 years since I practiced this trade. Perhaps Dan can weigh in and give us his perspective on the matter?
 
Feb 27, 2013 at 8:54 AM Post #3,748 of 6,388
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Really? Are you running the O2 with high gain or normal with the HE-500? At low gain, the O2 isn't loud enough. At high gain, it distorts.

If your HRT Music Streamer ii+ is anything like the non-plus version, it puts out 2.25Vrms. On AC power, the O2's maximum gain = 7 / Vinput.  So a gain above ~3.1x is going to overload the input and clip.  The default gains from JDS (and most anywhere else) are usually set to 2.5x and 6.5x.  So high gain will definitely distort.  An O2 definitely gives you enough rope to hang yourself with.  Now as to why 2.5x gain isn't enough, next question...
 
Quote:
I have the JDS with stock AC. No one ever told me that I should upgrade the AC adaptor/plug. Why would they ship with a poor supply of power?

JDS ships the WAU12-200 wall wart.  This is the default transformer listed for the O2, probably because it's cheaper (under $6) than the alternatives.
 
On the O2 details page, it states explicitly that if you plan to use power-hungry low impedance headphones (e.g. Hifiman planars), you should use a 14+VAC transformer at 400+mA.  Specifically, that means a WAU16-400 (16VAC, 400mA) is probably the ideal O2 transformer for the princely sum of almost $11.  You can use up to a 20VAC (with whatever current spec you can find) wall wart with the O2, but anything above a WAU16-400 is likely unnecessary.
 
I suspect running out of supply power is why the low gain is not loud enough for you.  An O2 with 2.5x gain from 2.25Vrms theoretically hits 118dB with HE-500, but I think you run out of (chip) power at around 117dB.
 
But you could eek out a bit more gain with resistor swaps if you need it.  Though it could also be a faulty build, I suppose.
 
Now back to MDs...
 
Got any CSD waterfalls for the Alpha pads yet, Dan?
 
Feb 27, 2013 at 12:21 PM Post #3,749 of 6,388
Anyone have a headphone stand that works well with the new Alpha Pads (so they don't get squashed)?
 
Feb 27, 2013 at 12:24 PM Post #3,750 of 6,388
http://www.amazon.com/Sennheiser-Headphone-Holder-Over--Headphones/dp/B004LPZBD6/ref=sr_1_1?ie=UTF8&qid=1361985819&sr=8-1&keywords=sennheiser+stand
 
This is good if you have a place to clamp it, like the end of the desk or shelf. 
 

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