I have a Fidelio X1 & OTL tube amp (from MBP)... how do I proceed?
Feb 6, 2015 at 2:42 PM Thread Starter Post #1 of 18

Torashin

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I don't usually create recommendation threads but I really can't make my mind up so here goes!
 
The amp is a little bear P8, and was a birthday gift, so I can't really return it. There aren't too many details available for it, but I'm assuming it has a rather high output impedance. My main question is; is it worth spending money on a DAC to go with it if it's not a good fit for the X1? I'm very tempted on getting a Modi 2 Uber (I also have a PC with optical out), which would cost north of £140 with delivery and cables.
 
A little more detail:
The amp is advertised as being suitable for 32 - 600 ohm impedance cans, and when I emailed a seller on eBay regarding output impedance he replied with "output impedance: 32 ohm - 200 ohm for your headphone." I'm not sure if he understood my question, could that really be right?
 
As it is, it sounds warm but unremarkable (albeit kind on the ears, which have been having a hard time of it recently), though I've got some new tubes on the way (a 6N13S & 2 6N3Ps).
 
I've also been eyeing up getting some NAD VISO HP50s instead of a DAC. I'm wondering if closed cans would be more suitable for the music I mostly listen to (melodic dubstep, prog house, d&b, glitch hop etc.) as I quite enjoy the intimacy of my CAL!s, which can make the X1's seem too distant & airy by comparison. Again, only for electronic music.
 
 
So what do you guys think I should spend my money on?
 
 
P.S. I'm using a lower impedance cable for the X1.
Thanks for your time!
 
Feb 6, 2015 at 3:20 PM Post #2 of 18

kramer5150

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Generally 6N13S/6AS7/6080 tubes like you say "prefer" to drive high impedance loads.  But it would be completely wrong to judge a product based on the tube type lone, circuit design, component value selection, and listener preferences play just as important role.
 
You're trying to evaluate something with no real baseline for comparison.  Try this... do you have a home theater receiver or iPhone?  Plug into that and use that as a baseline for comparison.  A/B compare back and forth between the two... using the same source and music material of course.  Most HT receivers have very robust headphone outputs, and my experience with my Denon and Sony theater units is that the designers voice them on the warmer/groovier side of neutrality.  Which makes sense, given that they are primarily for DVD movie watching.  That ~35 ohm philips is an easy load for all but the weakest headphone jacks.
 
Try that and compare... if it sounds good then it is good!!
 
Feb 6, 2015 at 5:17 PM Post #3 of 18

Torashin

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I've been comparing it with the macbook it spends most of it's time plugged into and an iPhone 5s. It isn't a massive improvement over the iPhone, if any. Just warmer. Anything is better than the mac though. How much difference do you think a DAC would make?
 
Feb 6, 2015 at 6:26 PM Post #4 of 18

kramer5150

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macbook Pros have very robust headphone outputs at ~32 Ohms, and their internal DACs aren't too shabby either (based on my listening impressions).  I sit here with my HF1 plugged into mine as I type... no desire to amp or source up anything.  IMHO MACs are neutral, flat, spectrally accurate... at times boring even.  The fact that your amp warms up the sound a bit doesn't surprise me... thats what a tube amp (generally) does.  What you are hearing is even order harmonic distortion, and probably added coloration from the filter capacitance and other elements of the circuit.  So even though your tube amp is more of an attenuator than an amplifier... it still may be beneficial to you if you like what you are hearing.
 
We also should not rule out the psycological effects the eyes have on our hearing perception.  Glowing tubes are going to "look warmer sounding"  than a solid state OP amp, transistor or discrete components.
 
As far as amplification and signal gain goes, I think you are fine running straight out of the MAC.  As far as coloring the sound and flavoring it to taste... thats a wide open book that you are just starting out with a new tube amp.
 
Good Luck!!
 
Curious... I've been eye-ing that little bear.  Does it play loudly / cleanly enough for you with those philips cans?
 
Feb 6, 2015 at 6:43 PM Post #5 of 18

kramer5150

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Quick google-foo turned up this little discussion regarding the capability of the MBP headphone circuit... which kind of further backs up my commentary above.
 
http://apple.stackexchange.com/questions/57186/what-is-the-impedance-of-the-line-headphone-jack-on-macbook-pro-retina
 
Feb 6, 2015 at 6:48 PM Post #6 of 18

Torashin

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OK, thanks for that information!
 
I can safely say volume is never going to be an issue! With the mac at full, I barely have to turn the amp dial (which feels nice btw) at all to get a normal listening volume. We're talking a tiny amount here!
Probably the biggest fault with it is the transformer. It does hum a bit, and low level noise can be heard through the X1's with nothing playing. This is far worse with the CALs, which are more sensitive. Mine has the toroidal transformer; I don't know if the square version is any better.
It also gets rather hot, but this hasn't caused any issues so far.
 
Feb 6, 2015 at 7:38 PM Post #7 of 18

kramer5150

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Yep... completely confirms my suspicion that you are using  a tube amp as an attenuator and in essence an equalization device to COLOR the sound.  Its not really amplifying anything.  All my amps are more for attenuation, impedance matching between stages and coloration... they don't do anything really in terms of amplification and gain boost.
 
yes a tube amp, with properly driven tubes will get hot.  In addition to the tube itself, its the power resistors for the 6as7, and the main power supply-input resistors.  In my Darkvoice 337 the tube resistors get far too hot to touch, like a scalding cup of water thats just brought down from a boil.  I am not sure why Little bear put those resistors so close to the tube?  There's no reason for that, they need as much air and circulation as possible.
 
Yeah I noticed two different power X-formers.  I thought one was for 110 and the other for 220.  It should be covered by a metal can, securely earth grounded through the chassis though.  Not sure if that would cut down your noise, but I don't think it would hurt.  Tubes themselves can also be noisy.  Rolling in different tubes could also quiet things down a little.
 
Feb 6, 2015 at 7:39 PM Post #8 of 18

Torashin

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Reading the comments by grizzlybeast here I've come to realise I was right on the money regarding the X1's not suiting electronic music:
 
 The problem is that you always desire to turn the volume up to fill in the air with stronger sounds. However, it just doesn't happen. It gets loud but then feels like its going to cook the drivers.

 
This is pretty much what I've been torturing my ears doing for the last year or so. I think I was in denial  
redface.gif

 
Looks like new headphones it is!
 
Feb 6, 2015 at 8:04 PM Post #10 of 18

kramer5150

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  Yes it came with this can which just loosely plonks over it. The humming is quieter without it but then the output noise is louder  
rolleyes.gif

 
 

LOL... OK thats pretty lazy on their part IMHO.  I would drill / tap some holes in the box and get that can grounded properly.  I don't think it really does anything to contain RFI / EMI if its not chassis-earth grounded.
 
Feb 7, 2015 at 1:22 AM Post #11 of 18

Yummerzzz

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Have the same sort of music taste as you, I found the Fidelio X1's also gave it a strange airy for of empty feel, sold then on pretty quick, I've found IEM's are great for EDM. The AKG K550's with a CmoyBB was great too, but not quite there, getting a pair of Sound magic HP150's tomorrow to compliment my RHA T10's will let you know how it is!
 
Feb 7, 2015 at 8:07 AM Post #12 of 18

Torashin

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  LOL... OK thats pretty lazy on their part IMHO.  I would drill / tap some holes in the box and get that can grounded properly.  I don't think it really does anything to contain RFI / EMI if its not chassis-earth grounded.


Haha yes I'll do that at some point!
Have the same sort of music taste as you, I found the Fidelio X1's also gave it a strange airy for of empty feel, sold then on pretty quick, I've found IEM's are great for EDM. The AKG K550's with a CmoyBB was great too, but not quite there, getting a pair of Sound magic HP150's tomorrow to compliment my RHA T10's will let you know how it is!


That would be very interesting, as I've has numerous sound magic IEM's over the years.
 
Have either of you listened to beyer DT 990 Pros?
 
Feb 14, 2015 at 11:31 AM Post #14 of 18

Torashin

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Well as it turns out the DT150's were a disappointment and I will be returning them - the bass is too tight and doesn't extend anywhere near low enough for my tastes. However the new tubes are little beauties! They're not overly warm like the Chinese ones, and have made my X1's much more sweet and enjoyable yet less fatiguing than straight from my phone or mac.
 
How are the Soundmagic HP150's Yummerzzz?
 
Feb 14, 2015 at 12:13 PM Post #15 of 18

kramer5150

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  Well as it turns out the DT150's were a disappointment and I will be returning them - the bass is too tight and doesn't extend anywhere near low enough for my tastes. However the new tubes are little beauties! They're not overly warm like the Chinese ones, and have made my X1's much more sweet and enjoyable yet less fatiguing than straight from my phone or mac.
 
How are the Soundmagic HP150's Yummerzzz?

Tube rolling makes a difference too.  They just sound different, and its a very effective way to fine tune sound to your tastes and different headphones.  The tricky part is we all hear things differently.  Some people are more sensitive to frequency alterations, while others are more sensitive to harmonic resonances.  Some listeners are highly acute to distortion and AC wave altering characteristics.  Different tubes will result in sonic alterations along those lines.  Figuring out what your hearing senses are most sensitive to is just as important as the tubes/headphones themselves.  As you've discovered not all tubes sound good.  I have Telefiunken ($$) ECC86 tubes in my earmax, and frankly I prefer the Holland Amperex for their thicker/warmer sound.  Just because your amplifier doesn't actually "amplify" anything... it still can be beneficial for system synergy. 
 
Come to think of it that Chinese 6N13S might be something I'd want to try in my Darkvoice.  Nice thing about this tube is there are a lot of rollable equivalents.  6080, 6as7G, ECC230
 
Not sure about the Soundmagic HP150... never heard them before.
 
Come to think of it with that amp and those tubes a DT990 might suit you well.  Get the 250-600 ohm model.
 

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