Sonic Frontiers Line 1 - tubed preamp w/Headroom circuit and headphone jack

[Nick Dangerous]

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1349252360

How about that? Balanced inputs, outputs, Headroom crossfeed, remote control, and six 6922 tubes.

Heard it? Tried it? Seen it? Want it?

 

[Nick Dangerous]

Quoted from an Audio Asylum thread (PAY ATTENTION MARKL)

:

http://www.audioasylum.com/audio/gen...es/124479.html

"I found the headphone output to be very good and have never yearned to be able to switch the cross-feed off. It has more than enough drive (would drive Sennheiser HD-600's a lot louder than I could listen) , it's quite, detailed and neutral sounding. I've compared to the Melos Gold Reference, Headroom Cosmic w/Base Station and Musical Fidelity X-CANSv2 w/power supply ...and the Sonic Frontiers was my favorite. Sonically it was the best, and it had a great remote (can swap phase via remote) and lots of inputs/outputs."

Holy crap.

 

[carlo]

nick,
i've auditioned the entire line series (1 through 3) extensively, i must say they're excellent preamps for use in a speaker setup. excellent bass and linearity with just a *touch* of the tube sound to sweeten things up a bit. haven't spent enough time with the headphone out to comment.

good luck with the system btw... looking forward to updates to your site,

carlo.

 

[daycart1]

SlobberSlobberSlobber..... That baby would be mine if I didn't already have three amps and a sack of tubes on the way

 

[TimSchirmer]

that is suh-weet

 

[Dusty Chalk]

Cute remote, too.

Too much good equipment, not enough room in which to put them all.

 

[geom_tol]

The literature says the headamp uses opa2604 opamps. Not the most high end component they could have picked...

 

[markl]

I believe KurtW has/had one, but thought it was so-so head amp.

markl

 

[rsv1k]

New to this forum so don't know if this reply will reactivate the thread or get lost in the archives. I've had a Sonic Frontiers Line1 preamp for 6 months now (not the 'special edition', stock Sovtek 6922 tubes), and a current Headroom Maxed Out Home with Reference modules for a bit longer. With fine sources, cabling and HD600s with AudioArt cable, across a variety of music, I find the Line1 to sound at least as good as the Headroom. This is driving them both teed-off of my DAC or phono stage with identical cables into their respective inputs.

Nobody is more surprised than me as the signal path of the SF is a lot longer, cluttered with a bunch of relays and wiring. I have the schematic: the signal DOES go through the entire tubed line stage before splitting off to the headphone stage. It's not entirely correct to say it's purely 2604 opamp based: the 604s are there as much to implement the crossfeed (very different topology approach to it than Headroom) as drive the phones. All the electronics upstream are beautifully laid out with great parts, but the headphone stage is a basic through-hole PCB with 1% resistors, 4 2604s and wimpy wiring for both power and signal.

As most of you know, the Headroom has very short signal paths, dual-mono SMT boards with the 627 opamp and 0.1% film caps and Vishay resistors.

But with the Headroom set to 'process' and 'bright' (the crossfeed can't be disabled on the SF), hours of comparing over the months consistently show no difference or the slightest nod to the SF. Given how differently the crossfeed is implemented and the huge difference in parts and signal path, it's remarkable how small any differences are, and a testament to SF's prowess. The SF has at times a little more holographic soundstage (crossfeed implementation) and the slightest edge in inner detail and HF resolution. Everything else is below my personal ability to differentiate...

As preamps, the SF has more top-end 'air', along with a tad more HF detail and a 'moister' HF presentation, ie not quite 'liquid' but not as 'dry' as the Headroom. Everything else identical so far as I can tell - bass, soundstage, transients...

So yes, the Line1 is a piece of work as a headphone amp, far better than the schematics or specs would suggest. Plus a full remote, tons of I/O flexibility, etc. I'll hold onto the Headroom as I find it an elegant piece of engineering, plus the ability to drive a pair of phones and disable the crossfeed, as well as probably last forever. Line 1 and 2 on the used market are a huge bargain IMO: consider you get a top-notch preamp and a $1K+ headphone amp thrown in for free...

-sd

 

[KurtW]

I have the Line 2, which has a larger, outboard power supply but otherwise is identical to the Line 1, with Siemens NOS tubes. Its a great preamp, although slightly noisy when used with very high efficiency horn speakers but that is a very tough test. The remote is the best I've used, and its features and controls are all excellent. I almost never use it's headphone jack, only because if I'm in the room where it is I'd rather use it with speakers. I would bet that the Line 1/2 is a better sounding preamp than the MOH but the headphone output itself is nothing special, although not too bad either. The MOH is a bit dry sounding, unlike most tube amps/preamps I've heard.

 

[markl]

Are the SF pre-amps (Line 1 & 2) a potential platform for upgrading/mod-ing/hot-rod-ing to improve parts quality in the head-amp section? Anyone know if it will drive low-z phones (say, 40 ohm?

).

Before I went down the Melos path, I was *this* close to getting a used SF Line 1.

Mark

 

[rsv1k]

There's a factory 'special edition' upgrade that takes the already-excellent passive parts to best-of-best components, overkill IMO ($700 w/ upgraded tubes too). Tube rolling is also done, though I understand the engineering and solid-statish sound of these units make them less responsive to this than other designs. Because all this feeds the headphone stage, it may be worth doing for the ultimate in preamp and headphone sound.

I don't believe any of the 'SE' touches the headphone amp. The good news is it's an easily accessed through-hole board, and schematics are available. Changing the topology to modify or switch out the crossfeed may take some doing, but putting in far better passive parts should be straightforward. Upgrading the opamps would take someone familiar with the biasing requirements of the better models. Wiring upgrades to and from the PCB are mandatory, but the power supply itself is PLENTY hefty.

Driving 40-ohm loads? I do know I've gotta crank the volume up pretty high to drive HD600s, and with a low-output source and a need for high volumes you might be tapped out. Modifications to the headphone board could probably address this too. Whoever takes this project on keep us posted!

KurtW, the most expensive (best?) phone amp I've heard is the Blockhead, so for now my MOHR is my benchmark, which is why I rate the Line1 at least as good and the best _I've_ heard. Looking through this site seems there are now plenty of (better-sounding?) alternatives I've not heard. Yeah, calling the MOH 'dry' would be a fair characterization, though as you know the Line1/2 are drier than other tube preamps.

-sd

 

[kelly]

rsv1k
Welcome to Head-Fi. Thanks for posting about the Sonic Frontiers. I'd read reviews and opinions of it elsewhere but it's very hard for me to take most audiophiles' opinions on headphone amps and headphone sections of preamps seriously because most of them have not heard the dedicated headphone amps we have.

You said that in your comparison you turned process and brightness on. This strikes me as an uneven comparison since it's possible that you just didn't like the crossfeed effect. There are pros and cons to crossfeed and the results don't agree with everyone. Have you done much in the way of AB comparison between the MOH without crossfeed and the Sonic Frontiers?

My taste tend to line up pretty solidly with Kurt's but often lie counter to Markl's so maybe this is a good amp for Mark indeed.

 

[rsv1k]

Kelly, Sonic Frontiers is (was) a licensee for using the Headroom-specific crossfeed process. On the Line 1/2/3 preamps the processing is permanently enabled, you CAN'T switch it out. So the only valid comparison to the Line1 is with the Headroom amp in 'process' mode.

I owned a '99 Maxed-Out Home prior to the '02 model, so I'm pretty familiar with their crossfeed process by now and generally prefer it. But part of the reason I'm keeping the Headroom is that I CAN switch out the processing.

The fact that the sound is near-identical despite their very different circuit topologys to implement the crossfeed is significant, esp that the 'bright' HF contouring is indistinguishable between the two.

Yes, the Line 1/2/3 reviews I've read rarely mention the phone jack at all, and if they do can't offer a critical assessment. But someone at Sonic Frontiers seems to know their headphones for it to sound as good as it does with so much signal path and moderate components on the 'phone board. Having said that, I'm probably not golden-eared enough to offer this as any more than opinion on *this* forum, despite being a lifelong headphone geek. Like I mentioned, there are a lot of non-Headroom amps out there now I haven't yet heard that may raise the bar.

-sd

 

[kelly]

rsv1k
I didn't know Sonic Frontiers licensed the crossfeed from HeadRoom. That's interesting... but... I thought headRoom had re-engineered the crossfeed in the 2001 amps so that it would be different.

You are more than qualified to be offering your opinions here. That you even know Head-Fi exists would put you into that category. That you've owned two high end HeadRoom amps yourself and have had long term auditioning with them makes your opinion far more valuable to me than someone proclaiming golden ears. Please do stick around.