[Nayyte]

…. If OTL tube headphone amplifiers are ‘nerve racking’, perhaps it’s AAA THX 789 time … little suspense, little music .

The first 3 mins of the NOS 6AS7G was like a space heater running inside my headphones! Some metal tinging noise every 20 seconds. Its died back now but still loud when the music goes quiet. Still it sounds great! I'm really not used to burning things in

 

[jonathan c]

So says the guy with rechargable batteries

… Here is one way (of four circuits) by which I get recharged:

[ ]

 

[Toonartist]

The first 3 mins of the NOS 6AS7G was like a space heater running inside my headphones! Some metal tinging noise every 20 seconds. Its died back now but still loud when the music goes quiet. Still it sounds great! I'm really not used to burning things in

When I turn on either of my tube amps I first plug in an unimportant pair of headphones and then leave it 20-30 mins before listening. They're not solid state and need to warm up. The tubes will give off little tinkling sounds every now and again as they do so... bit like stretching as they wake up. Also, I unplug my good headphones before turning off.... just in case. When I use a tube for the first time I check over the pins etc for obvious damage and use a little wire wool to remove any crap from the pins if necessary and if possible, use a multi-metre to do a continuity check before plugging in a tube for the first time. This is less important if you buy tubes from a good trusted source.

For me it's all part of the "Tube" lifestyle. It's not a turn on and listen straightaway sort of mantra but more of a prepare, relax and then enjoy. Maybe chuck in a beer or a single malt, unwind and then listen

 

[Pharmaboy]

For me it's all part of the "Tube" lifestyle.

Well said!

 

[ben8ding]

Anyone have any experience with the Atticus and the WA 6 SE? I’m wondering if anyone’s really loved the pairing or if I should invest in an OTL.

 

[jonathan c]

For me it's all part of the "Tube" lifestyle.

Then you should dress accordingly!

[Some of us Head-Fiers have these! Courtesy of yours truly … ]

 

[Pharmaboy]

Then you should dress accordingly! [Some of us Head-Fiers have these! Courtesy of yours truly … ]

Where on earth did you get these pix?

(I must have this shirt!)

 

[jonathan c]

Where on earth did you get these pix?

(I must have this shirt!)

• I had the t-shirts made a couple of years ago. I sent them out to a number of Head-Fiers, many of whom were active in the Schiit Mjolnir 2 thread.
• Basically, the summer of 2021 was the Summer of Footscray:

“ those were the ‘Scrays my friend, we thought they’d never end…”

 

[Pharmaboy]

• I had the t-shirts made a couple of years ago. I sent them out to a number of Head-Fiers, many of whom were active in the Schiit Mjolnir 2 thread.
• Basically, the summer of 2021 was the Summer of Footscray:

“ those were the ‘Scrays my friend, we thought they’d never end…”

genius!

 

[Tchoupitoulas]

I don't usually do this but given the interest in it, I thought I'd post to let ZMF fans know that I'm selling my V281 amp. I enjoyed it very much with my Vérité and Atrium, as well as other headphones (especially the Final Audio D8000).

 

[goldwerger]

I don't usually do this but given the interest in it, I thought I'd post to let ZMF fans know that I'm selling my V281 amp. I enjoyed it very much with my Vérité and Atrium, as well as other headphones (especially the Final Audio D8000).

Recently picked one myself. It a super fun and very powerful amp with a small footprint. Very cool

 

[ethelthefrog7]

Anyone have a recommendation of a good amp pairing for Auteur Classic that comes with a remote? somewhere under $2K? Tube or SS?

 

[GridIroN]

I said I would update the thread with some tube roll impressions to go along with my brief review of both the Cayin HA-3A and the Icon Audio HP8 Mk.II Signature Edition. I purchased a significant collection of tubes locally, all NOS. I've spent about 2 days getting acquainted with what each tube offers. I found a lot of combinations produced similar results, but I've tried not to sound repetitive.

Tube Rolling the Cayin HA-3A​

Starting off on the HA-3A, brief word on the 12AU7 signal tubes: I decided to replace the factory JJ's with E80CC's. Firstly, they look bomb, second, they are famously great sounding tubes so I figured they'd be an obvious first attempt. I wasn't disappointed, they sound fantastic, with a beautiful representation throughout the whole frequency range with nothing sounding biased or out of place. No real need to roll anything more.

On to 6v6 slot tubes...!

Tungsram E80CC’s + Marconi 6v6G "Cokebottles"​

• Good mid tone
• Great body
• Warm “live” sound is gone, replaced with a more traditional sound
• Very smooth transients
• Significant soundstage boost
• Significant treble extension boost
• Note attack significantly less. Significantly reduction of sub-bass
• Detailed, forward midrange
• Very nice holography and separation

Overall, a smooth, mellow, agile combination. Mid~treble focus. Wouldn't generally be my first choice in terms of timbre, but it's very nice.

Tungsram E80CC’s + National Union (SovTek) 6v6GTA's​

• Full bodied
• Clear, and VERY crisp
• Particularly detailed
• Holography and imaging upgrade noticeable
• Bass punch is nice
• Otherwise very neutral

Overall, a fast paced, and highly dynamic; wonderfully neutral.

Both sets of tubes represent a significant improvements over the factory tube set in terms of general listenability. The factory sound as I said previously, was really trying to produce a lively, "live" sound. Both sets of NOS tubes I tried presented more well-rounded, traditional sound profile. I personally and surprisingly felt the Soviet National Union tubes were best and will be using them as my every-day tube roll.

It’s also important to note that all sets of tubes significantly lowered the noise floor. A significant portion of the hum present in the HA-3A seems to come from the not-fantastic modern tubes. That's taking into consideration the E80CC's have more gain than the factory 12Aau7's.

Tube Rolling the Icon Audio HP8 MK.II Signature Edition​

I purchased a few different signal tubes, and received an old Telefunken tube from the extremely generous @Pharmaboy. I purchased a NOS Raytheon military AT7WC, and a NOS Sylvania military AT7WC. Both tubes test higher than normal gain for their type. All 3 tubes were free of microphonics.

Telefunken 12AX7 (NOS West Germany, year unknown)​

• Incredibly bold sound +++
• Articulate ++
• Edgy, tense.

All around superior to the factory ElectroHarmonix. Basically an automatic upgrade for the whole sound profile.

Sylvania JAN 12AT7WC 1979​

• Very smooth
• Tad more air than the Raytheon
• Very nice sparkle up top. Makes up for the trade away of lower end impact.

A tube so mellow, it is perhaps too much so, but can sound good when paired with a complimentary tube.

Raytheon JAN 12AT7WC 1974​

• Very loud for an AT7. Higher mU than expected
• Nicely detailed, very “fine” sound, but rather forward.
• Nice little bump in treble extension
• Adds a bit of decay to the mix.

Nice overall tube that adds a TOUCH of romance, but is overall still clear, crisp, neutral, and impactful. This tube makes the HP8 sound a bit more like the rustic, live sounding profile the HA-3 has from the factory.

Tung-Sol 6SN7GTB “Tall Boys” 1959​

(With Sylvania 12AT7WC)

• Well extended upper and mid range
• Crisp
• Layered
• Details, details, details
• Soundstage depth increase; lots of space between notes
• Bass kick is there, but subbass presence is significantly recessed

TungSol’s give the Sylvania a bit more kick back, but the low end is over-all fast, dynamic, hyper controlled. Not a bass-head combination, but doesn’t sound offensively anemic. Wouldn't be my first choice though.

(With Raytheon 12AT7WC)

• Very complimentary tube selection
• A light, heavenly 'sing-song' sound yet still somehow rich
• Agile. Both tubes sets are quite dynamic, so they boost each other nicely.
• Extension; both tube sets have a touch of extension on the mid/upper mid range.
• Romance; a slower decay at the mid/upper mid range keeps this tube set from sounding overly clinical or “solid state”.

Potentially end-game tube combination for this amp

(With Telefunken 12AX7)

• Lots of space between notes
• Still has a lot of detail
• Punch from the telefunken is very welcome, produces a dynamic and balanced combo
• Nice bass
• Takes the holography from the telefunken and merges it with the detail retrieval of the tungsol.
• Incredible combination.

Overall a great combo. Very much similar tone to the factory sound of the HP8 but risen to a new level, and with attitude.

Sylvania 7N7 rebased to 6SN7GT “Bad Boy” Chrome Domes​

(With Sylvania tube 12AT7WC)

• Detailed & crystalline. Amazing upper range
• Faster roll off than the Tung-Sols
• Nice bass kick
• Subbass feels a tad veiled, & thin; doesn’t sound bad, but leaves you wanting in the lower register.
• Wonderful textured mid range however...
• Airier lower mid range than the Tungsols

Overall a smoother, dark-of-neutral tone with nice air and texture. Again, would not be my first choice though...

(With Raytheon 12AT7WC)

• A more balanced presentation
• Subbass kick
• Impact and note weight
• Mildly mid-forward

Overall a very pleasant, balanced combination. A close 2nd to the next one...

(With Telefunken 12AX7)

• Warm with lots of air
• Full bodied & splashy
• Crazy holography
• Mind-blowing

Story time... I was previously listening on the low gain amp option on the HP8 as my previous review noted I strongly disliked the other gain options. When I first listened to this combination, I didn't like it much. It sounded veiled and...mushy. Something prompted me to see what happens if I increase the gain because I thought "there's no way that's what these tubes sound like. I put a lot of research into these tubes...these should be great". Well, I turned the knob and then.... the clouds parted and the gods spoke to me through the voices of my ancestors and I bore witness to a sound unlike anything I have heard before. I then took a 2nd day to re-review everything I had heard on higher gain. The other tubes did not change much.

Comparing the final tube roll of both the HA-3A and the HP8 SE​

I ended up with a sound I loved respectively from both amps. Both amps are nowhere near their top potential in their factory form, though I would say it's my experience having now experimented on both it is easier, and much cheaper to raise up the HA-3A than the HP8, but the HP8 with good tubes is on a level I do not think the HA-3A can match. Close? Yes, but match? I don't think so. I also think the HA-3A's sound signature changes far more readily and quickly than the HP8. The HP8's sound signature is heavily reliant on the single 12AX7 tube. I tried leaving the factory David Shaw CV181's in, and the sound was still much improved; the DS 181's are well chosen, clean, revealing, transparent and articulate tubes. On the HA-3 I get the impression it would be fine to seek 12AU7's that are crisp, clean and leave it at that. The 6v6's are more than capable of producing a pleasing shift in sound if a user wanted to be conservative with their money. It was VERY expensive to bring up the sound of the HP8 in comparison.

Next I will try some different 12AX7's in the HP8 and see what happens. I have a hunch the reason the AT7's both sounded on the thin side was because the amp really was designed for an AX7 to be driving it.

Update 3: Living with the Cayin HA-3A, & 12AX7 Experimenting and some new 6SN7's for the HP8 Mk.II​

I've been using the HA-3A as my daily driver for a few weeks and I want to note how impressive it is that this thing just always sounds good with some relatively inexpensive tubes. I'm surprised how many people sell this unit on the marketplace without having tried other tubes in it.

That being said, I want to give a brief correction to my first review of the Cayin HA-3A. After using it as my daily driver for several weeks since I bought it, I've never really had to time to do things like game or sim with it (I'm into flightsim). After trying I realized the HA-3A picks up incredible amounts of ground loop from my PC's power supply and GPU (RTX 4080). This wasn't a problem, or at least not nearly as significant a problem with the HP8 for some reason. It remained mostly silent, however the HA-3A produced a feedback that was loud enough to hear over the ambient "start screen" music of many games. This lead me down a path of trying to clean the signal....eventually, I picked up a new powerbar, a 15ft DC cable reconfigured my power and having my amp plugged into the outlet across the room fixed the issue. I also put ferrule cores everywhere, just in case.

So whilst my NOS tube replacements did lower the noise floor of the tubes themselves, try to make sure your amp isn't sharing sockets with high power friends.

Moving onto the HP8, in my last update I expressed my hunch that the HP8 Mk.II was designed first and foremost for a 12AX7. I came to this conclusion because the lower gain, though high testing AT7's I bought both had a softer characteristic to the sound they produced with any 6SN7 tube...They both had nice mids and highs, but I had difficulty getting a bass response and richness out of them that satisfied me.

Well, I picked up a few new tubes and have concluded that yes, the HP8 Mk.II SE sounds significantly better, at least to my ears with proper 12AX7's installed. All 3 of my authentic AX7 units produce a superior sound.

Funkwerk RFT 12AX7​

(With the 7N7 Bad Boys, same test 6SN7 benchmark I was using before)
I may have overpaid for this tube, as I later learned it's a relatively common NOS tube, but it’s an excellent unit, with full, intact printing and date code (though, indecipherable to me). NOS from West Germany. Word on the street is they should sound very similar to Telefunken’s units.

• …And it does.
• Slightly transparent, yet “vintage” sound.
• Softer lower end, but not lacking bass weight.
• Slightly forward midrange, but good, slightly wider soundstage vs the Telefunken
• Clear, crystalline, a few times to a fault, but only noticed this once or twice.
• Not as holographic as the Telefunken, but great swing and agility throughout the dynamic range; gets close.
• Basically, sounds kind of like the Telefunken, but more mature/refined.
• NOTE: This tube was got by the vendor in a never-used batch buy. This tube had significant microphonics, but after burning the tube in a short period (1~2 days), it went away.

RCA 6SN7GTB w Ribbed Black Plates & bottom getters​

(With Funkwerk RFT)
Apparently there are several versions of this tube, most of them sounding unimpressive and dull. One of which sounds fantastic with black plates and bottom getters vs the getters in the plate. I believe I’ve managed to find an example of the latter and avoid the former…

• Some sweetness.
• Mid and lower mid focus.
• Surprisingly good.
• Highly impactful. Possibly most full bass of all tested tubes.
• Soundstage shifts to the romantic side; feels a tad smaller than other tubes.
• Warm, washy timbre.
• The only tube I’ve tested that provides a genuinely vintage, “tube” sound.
• Still sounds clear, and agile enough to not lose coherence nevertheless.
• Might be too much for a headphone like the Atrium. VC would love them. Caldera loved them.
• Note: These tubes get REAL hot. Ow!

Sylvania 6SN7GTA Chrome Dome, Green Label​

A quintessential Sylvania tube.

• Well balanced with slight warm tilt.
• Blackness to it’s timbre…lots of space between notes.
• Balanced, neutral, but delicate.
• Sweeter upper range/treble.
• Nice, relatively wide soundstage.
• A perfect “every day driver” upgrade. Great in every way, jack of all trades, offensive in none.

Mullard ECC83 12AX7 (Blackburn UK, April 1966)​

(Tested with several 6SN7 tubes)
Figured I'd try out a Mullard as it was reasonably priced and I needed more 12AX7's to try. I was concerned about microphonics as Mullards are known for being microphonically loud. This unit has none worth speaking of.

• Very round sounded.
• Soft, and lush.
• Not so soft that it sounds thin or anemic like the AT7’s.
• Warm vintage sound with very nice layering.
• Nice tube. Not as edgy as the West Germans.
• This tube is very nice combined with the RCA's. I thought they'd sound very "syrup" together, but the impact and emphasis in the RCA makes up for the rounded roll off in the Mullards.

And that's it. I think this will be my last update as I think I have enough of a variety of tubes to satisfy me (and a thoroughly empty wallet... ). Hope this update sheds some light on the surprisingly mysterious Icon Audio HP8.

I'm really happy I took the risk and bought this thing.

PS. someone is selling one on the marketplace right now for a ludicrous price if my review(s) have convinced anyone to pick this unit up...

 

[oppman99]

I jumped on the unit in the classifieds as soon as I saw it

 

[GridIroN]

I jumped on the unit in the classifieds as soon as I saw it

Glad you got one! I'm extremely jealous I paid so much more, but that's the nature of things.