Audio Note Oto Phono SE Signature tube rolling

Hi folks, long-time lurker, first time poster here... First of all, thanks so much for all the Audio Note expertise on this forum - I've been an Audio Note convert for going on 6 years now, and I've found this forum an invaluable resource!

I just wanted to post as I've recently been tube rolling my Oto Phono SE Sig, and wanted to post my initial results for others' benefits, since there isn’t too much out there already - and get tips on next steps.

For background purposes, my system as it stands is:
AN DAC3 (old skool, late-90s era, with the Burr-Brown PCM63s, plus a third-party tube power supply mod)
AN TT2, Arm Three/II, IQ3
AN Oto Phono SE Sig
AN-E LX HE (hemp cones, high-efficiency)

Wires are AN-V from the DAC, AN-Vx from the TT, and Lexus LX80 to the speakers.

So far - on Peter Qvortrup’s advice - I’ve focused on rolling the phono section. I got the TT-2 (as above) last summer, and while I’ve enjoyed it, I still feel I’m in the tweaking phase (I am ham-fisted as hell) and it’s had some sonic weaknesses. Overall it’s more fun, lively, present, and real than my DAC3, but compared to the DAC it has sounded a bit light and thin, lacking scale and weight and a touch of midband richness. Treble has also been a touch less refined.

So I bought a bunch of NOS/ish 6DJ8 and 12AX7 types to try. I also had a few interesting items leftover from previous tube rolling escapades on other amps over the years. Some of what I tried:
- Amperex USA 7308
- Amperex Holland 6DJ8 pinched waist (Rogers branded)
- Mullard Holland E88CC
- Mullard UK E188CC
- Siemens 6922
- Siemens Cca (grey shield)
- Telefunken 12AX7 smooth plate
- Mullard CV4004

I tried them in various combinations, including with the stock Sovteks. (It was interesting how much the sound of each differed depending on which tube was in the other socket!) So much of the outcome was synergy - either sound synergy, or (probably) electrical synergy.

As the only 12AX7 I had to roll initially, I stuck the Telefunken smooth plate in straight away and kept that in for most of the initial 6DJ8 rolling. Never rolled it in on its own, so not sure what improvement it made over the stock Sovtek. Seemed bright.

The first one that made my ears prick up was the Amperex 7308. A bit too soft and warm, but wonderful resolution, midrange tones, and refinement. (My unit might be a bit worn out, def not NOS.) The next most promising was the pinched waist Amperex - top-end lively and engaging (not rolled-off at all), and tonal balance great overall, with good groove. And then the Mullard Holland (I guess it’s an Amperex really?) E88CC - much like the pinched waist, but even better all-round! Unfortunately, these last two were old ones from previous amps and both had some nasty noise going on - made me fear for my woofers on occasion! And while they were great, they still had some splashiness up top and a lack of refinement.

So out went the Telefunken 12AX7, and in went the Mullard CV4004. Helped smooth out the splashy highs… but still felt a tad “rough” and unrefined. Paired up the CV4004 with the Mullard UK E188CC - best combo yet! But still couldn’t knock that sense of lack of refinement - and the combo, while super-engaging and exciting to listen to, had a bit of a treble sheen that became wearing over time.

Then I remembered I had bought a Siemens Cca for my DAC3 a few months prior, and it had transformed it… So in it went to the Oto instead, alongside the CV4004. Eureka! ****, this is good! Lack of refinement totally gone - and everything else is just “right”! (As any Audio Note fan will know, sounding “right” is the highest compliment one can pay a hifi component! ) And it’s engaging and upbeat without being wearing at all! Foot-tapping, but also seductive. Mmmm. Overall frequency balance is very neutral, but tons of midband tones and texture, and nice juicy bass. I had a real cheesy-grin moment listening to a track from Allen Toussaint’s The Bright Mississippi (hell of a record btw, and a nice reissue) which had some quiet foot-stomps - they just sounded totally real, and not like “hifi” at all!

So that’s where I am currently - Mullard UK CV4004 plus Siemens Cca. Neither is at all cheap (I paid almost $200 for the Mullard, and $300 for the Siemens!) but in the context of a multi-thousand dollar Audio Note system, it seems easily worth it. It’s taken my turntable from “good with some weaknesses” to “plain magnificent” for a tiny fraction of the cost of just about any other upgrade I could consider.

Anyway, next I’d like to try rolling the ECC83s and ECC82 in the line stage, and maybe even try a set of NOS Tungsram EL84s… (I’ve already ordered another Siemens Cca for my now-sad DAC3! ) Anyone gone down that route? What where your experiences?

(Also FWIW, most of the above tubes are now for sale, if you’re interested! )

Thanks for listening,
Dunc

 

I have the same integrated. I've been thinking about possibly doing some experimentation with tubes myself. Thanks for posting this.

 

you should also look at trying the IOI cartridge and at least the SUT 3 (preferably the SUT 4). i have the ability to demo both with the OTO and the differences are significant ... especially when you move into the MC cartridges. I think the IQ3 is amazing ... but going to the IOI will
take you to a new level.

 

Check this thread. Might be helpful.

Audio Note Soro Phono SE Tube Rolling

 

I wrote about my experience rolling tubes in the same amp here:

First Step:
Strictly for fans of Audio Note UK..

Final Config:
Strictly for fans of Audio Note UK..

Cheaper tubes than yours, but nevertheless.

And I agree, Telefunken in the Phono 2 position sounded decidedly weird.

 

I also found the TT-2 a piece of work to set up and I've done quite a few hundred turntable set ups and decided to redo my demo unit the other day and finally I got it to sound bloody amazing. The bass this thing produces running an Arm 3 and IQ3 is just ridiculous for a lightweight turntable. 4 hours of up and down, in and out, totally worth it. Years ago I wanted to help Mario from AN set up in Munich and get a better idea on how he sets up a TT but he declined the offer of assistance in order to not share his technique.
I finally cracked it.

 

So AN doesn't want to spill how to best set up their turntables?

 

Glad it's not just me.

My biggest problem was proper leveling. I made the mistake of leveling the suspended platter using a spirit level - this caused the platter to wobble slightly almost continuously, screwing pitch stability and tracking. The fix was to _just_ level the main plinth, and then get the platter exactly level _relative to the plinth_. The platter and subchassis need to be lined up with the plinth, or the suspension can't settle. (This is probably old news to suspended turntable users, but was news to me... Makes sense in hindsight!)

Also have the damnedest time dressing the arm wires so they don't drag on the suspension - the little screw-on clip that comes with the deck is too small for both AN-Vx cables plus ground, so I've resorted to leaving it have screwed in, and just wedging the cables in as best I can - seems to work, but feels awfully janky for such a fine (and expensive!) deck... Anyone figured this out? (Probably deserves its own thread...)

Dunc

 

I switched out the stock EL84s In my Oto Line SE Sig for Genalex Gold Lion. New but from an old design IIRC. As they’re sold by AN, I expect someone put thought into which of the many alternatives to stock.

I’m really happy with the improvement over the outgoing factory fitted Sovteks but to be fair they must have had 8000 hours on them, so maybe not a completely fair comparison. At less than £125 for a matched quad including tax & (UK) delivery it was a cheap upgrade.

 

Interesting! Was running on the assumption the stock EL84s were fine and to focus on the line m-level tubes. But I have been eying a set of NOS Tungsrams...

 

Well Mario didn't. The dumb thing is the combination of that TT, arm and cartridge is popular and the measurements guide as a starting point would be seriously beneficial.

 

Great post. Iv'e upgraded my El84's in the oto to EI branded Nos Tungstrams. Excellent valves . I have not done much with the phono section which had a ECC88 which had no brands name on and a Sovtek 12AX7. I thought seeing that Audionote now use a Psvane 12AX7 as stock as preferred over the Sovtek I'd give one a try. Up to now its sounding awful, one of the brightest valves I have heard in my Oto. I have heard that Psvanes take a while to burn in but this one is so bright I can't ever see it improving. Has anyone else any experience of the Psvane 12AX7 in the phono section of the Oto Phono SE Signature?

 

I'm in the process of doing exactly the same tube roll. My psvane 12ax7 has now lost its brightness and I am running a Telefunken ECC88 Diamond base along side it. Can I asked where you sourced your Siemens CCA grey plate from, the Mullard Cv4004 is easy to source in the uk but the Siemens is proving difficult.