Nobsound-HiFi-FU32

Sorry to hear about your NASty firmware event. Music libraries can be rebuilt. DIY tinkering can never be replaced.

You are obviously a recovering basshead since you listed the Grados. Hope your recovery continues.

After 20 years in the studio with various AKG phones, I'm happy to report that my penance is over. I wouldn't buy any new AKG product without extensive audition and a small hammer - just in case. To me the AKG 702 would be a side/downgrade versus the X2. With more or similar unpleasant treble. If it were me (which I did, since it was me), I'd look for a good used pair of 650s  - a much different flavour from the 702/X2. My preference is for clean, smooth midrange detail and tonal balance. It's where the music is and where the 650 excels. No treble daggers. I prefer listening into the music rather than lobbing my delicate sensitivities with an earful of fake detail. 

I could launch into my tirade over unnatural close micing that accentuates high and low frequencies in most modern recordings, that then requires obscene amounts of compression/EQ, but I won't just now. Does the drummer play with his ear 2" from the snare? Multi-mic'd classical orchestras? Don't get me started. LOL!

Compressed V-shaped recordings playing back on V-shaped gear is for.... teenagers. I no longer qualify. By decades. It's the subtleties that engage me musically now, not the wow factor. As an acoustic musician, I've been dismayed at how different (and worse sounding) most recordings of acoustic instruments are. It's why I stopped running on the audiophile treadmill years ago. I'm willing to spend large(ish) on a custom acoustic instrument, not on trendy gear-du-jour neurosis. Been there, spent that. There is no happiness at the end of the audiophile rainbow. Because that rainbow has no end.

While it's fun to read reviews and discuss preferences on the internet, headphone listening is so personal it's like having your own personal music performance in your head. If you're enjoying your current setup, then just enjoy it. If not, then consider what it is you feel is missing - then get a pawn shop guitar, learn some pentatonic scales and write tragic blues songs about the obscene cost of hifi.

That and for another flavour, swap the 12AU7s with more full-bodied NOS 6CG7s. Or 5963s. Or 12BH7s from the 50s. Low cost tube rolling is my last audiophilliac vice. It's a tough addiction to kick. But, it's also one of the more pleasant defenses against the sonic crap that masquerades as professionally recorded digital music.

Sorry, despite my weak-willed efforts it sorta turned into a tirade over my distaste for recording methods since the invention of digital multi-track recording and how we lost the volume wars. Everything MUST be louder than everything else!

High quality closed phone is an auditory oxymoron for me. But, Frans says the new closed Aeon doesn't suffer from closed cup disease, just over-priced mania. So maybe there's a chance. I've used so many closed phones in the studio and even the uber expensive Sony have been disappointing. I seem to be sensitive to low Q resonances or something. Or I breathe through my ears.

Are you sure the driver is dead in the HP150s? They're known for iffy cable connections.  Nexus Intl is the Canadian distributor for soundmagic. Have you contacted them? www.nexusintl.ca/support/
If you want a set of closed phones just for flavour rather than need, you could spend less than $100 on one of the Superlux bass canon variants. Other than isolation, closed phones can best open phones with a big bottom. Everywhere else open phones sound...well...so much more open.

Maybe Frans is saying the P1 can't supply the .6A the 6SN7 requires. That's unfortunate, The 6CG7 is the same specs as a 6SN7 in a miniature 9pin bottle - but requires .6A like its full bodied brother. The 12BH7 is also a .6A tube.

It could be the P1 is limited to supplying < .5A, which means you have to stay in the 12AU7/6DJ8 family. I quite like the black plate RCA 5963 from the 50s. It's a more rugged version of the 12AU7, with a more rugged presentation with more detail - not as laid back as most RCA 12AU7s.

A really sweet 6DJ8 alternate for <$15 is a NOS Tele ECC189. Great details, clarity, low noise, balanced and smooth - not ashamed to compare to the $100+ hipster 6DJ8s. Prefer it to the Amperex and Valvo 6DJ8s I've used in the Solstice. The ECC86/6GM8 is another option, but the audio elite have driven NOS prices just slightly south of the nosebleed section.

I haven't found any low current miniature tube that has the big rich open spacious presentation of the better 6SN7/12SN7 tubes. Especially the older round plate variants in 12V. In the low cost amp realm, only Solstice can use those. It is the cheapskate's tube rolling dream machine.

What sonic flavours do you favour in tube rolling? More warmth, more detail, more space, richer mids? All of the above? 

"After all, its better to regret something you have done than something you haven't"

Oh that is an awesome and highly dangerous axiom to use in the headphone hobby.

Didn't know it was a $35 headphone amp. That is cheap! Need to hit rewind and get some $0.50 Amperex tubes from 1979.  The NOS Tele ECC189 would be my only suggestion since it's less than 50% the cost of the amp and is the best sub $15 miniature tube I've heard. You didn't elaborate on what you hope/expect to hear from tube rolling.

Good luck on your bargain hunting expedition. Too soon for a Winter Solstice sale tho.

11/11 sales?? Veterans Day sales???

In my tubular experience, the 6SN7 family is where space gets spacious...but for detail the ECC189 is great.  And will work in the P1. In the Solstice it sounds exquisitely detailed. I've asked Frans before by studying the datasheets if tube X will sound better than tube Y in the Solstice. His answer was...it depends. Depends on too many factors that the data sheet can't reveal.  The fun in tube rolling in these little low voltage G1217 gems is in the discovery. Tracking down obscure possibly great sounding tubes and discovering new flavours that improve (or not) one's own system is a big part of the appeal. There is no guarantee that the most revered tube will be the 'it' that you seek. Others can guide you - if you know their tastes - headphone audio is a personal journey. You only have to please your own tastes, no one else's taste can replace your own. Even if the internet desperately wants to.

For me, the problem with OTL tube amps is twofold - three if cost is included.

One, without an output transformer, most OTL tube designs struggle to generate enough current to drive low impedance phones because the tube amp's output impedance is often as high or higher than the phones. In the tube speaker amp world, OTL designs are pretty much reserved for direct-driving electrostatics - Futterman designs excluded. Hence why most tube speaker amps use output transformers.  Can't fight city hall and physics. Driving 300ohm+ phones is where OTL makes sense and can sound great - like the BH Crack.

If you enjoy listening to low impedance planars, tube OTL amp will not likely enhance the enjoyment. Hybrid amp is the better low cost option.

Some say transformers are bad. But they aren't. They're actually really good, except to make really good ones is really hard. When I was in the studio, I enjoyed some good iron in the mic signal path - with $2k per channel mic pres. Even with headphone amps, good output transformers cost serious money - hence the good transformer output amps are $1K+. OTL became the cheap stepsister of tube output amps - not so much a design win as an economic one.

Two....most of the tube magic / sonic differences happen in the input/driver stage. The output stage contributes 20-30% or less depending on the design. It's a diminishing return thing. No budget or home thermal limits, fill the room with glowing orbs of sound.

Three. Cost vs satisfaction. I'm a recovering audiophile. I've built up all tube Audio Research / CJ rigs that cost more to re-tube than buying every G1217 amp. Twice. Spending tens of thousands for an audio playback system is no guarantee of satisfaction. IME, it's the opposite. Instead of enjoying the music, more time is spent on worrying about what is still missing than what is heard. For my OCD predilections hi-end audio is a purgatory padded in temptation, promising auditory nirvana but filled with soul-sucking neurosis.


Now...back on topic. Tube warmth is not a term that ever made any sense to me. The audio canon states when a tube generates more 2nd order distortion it is said to sound warmer. Yet, because harmonic distortion occurs above the fundamental the added harmonics are higher in frequency. Maybe thicker is a better term. Lots of lower order harmonic distortion can actually sound thinner. Higher order distortion sounds harsh - it's where over-driven solid state shines. LOL!

Where warmth as a term makes sense to me is when the interaction of the tube in the circuit causes an early high frequency rolloff. Less highs can be perceived as warmer. Or just dull. Like my current dissertation.

I'll PM you the secret NOS 189 source. Must keep it secret until at least until you and I have ample lifetime supplies. ;-)

I gathered that much

Worth looking any more into them? Seems that it'd probably been much cheaper to just buy the parts and build one myself - probably more fun too.

Probably just hold my cards for the time being, TBH. At least until I can get a Garage or Vali2 (seen some comical pictures of these with totem poles of adapters) that's in my budget. Not much point in buying something new and finding myself wishing I'd waited and gotten something better in the first place - wait did I just contradict my earlier regret claim. The P1 was/is a good cheap entry point for tubes, so it makes sense the next amp should be a obvious step up.