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December 14, 2019, 11:07:09 AM

Author Topic: Tube rolling thread for Stereomour II  (Read 1001 times)

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Offline oguinn

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Re: Tube rolling thread for Stereomour II
« Reply #15 on: June 22, 2019, 01:25:51 PM »
Alright, finally! After about 10 days of no forward momentum on my first shipment from TubeDepot they sent along a second package of Electro-Harmonix Gold 2A3s and Mullard NOS 12AT7s (CV4024).

I'm rolling both in this week and I'll share some impressions. I started with the Mullards and noticed a flash at the bottom of each tube on startup that I never noticed with my previous tubes. Anything to be worried about there?
Jameson O’Guinn

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Main System: Schiit Bifrost MB, U-Turn Orbit, Reduction w/ Integration, Smash w/ Smashup & SmashQuiet (replacing w/ BeePre), Stereomour II w/ DC Filament & Shunt Regulator (replacing w/ Kaiju), SEX 3.0 w/ C4S, Blumenstein Orcas, HD6XX

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Offline Paul Birkeland

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Re: Tube rolling thread for Stereomour II
« Reply #16 on: June 22, 2019, 01:50:59 PM »
That is the Mullard flash, and it's normal for Mullard tubes.
Paul "PB" Birkeland

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Offline oguinn

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Re: Tube rolling thread for Stereomour II
« Reply #17 on: June 22, 2019, 01:53:05 PM »
Thanks, I wasn't aware that was a thing. Just like I wasn't aware that Sovtek and Electro-Harmonix are the same company so I basically paid a little more for a different brand name.
Jameson O’Guinn

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Main System: Schiit Bifrost MB, U-Turn Orbit, Reduction w/ Integration, Smash w/ Smashup & SmashQuiet (replacing w/ BeePre), Stereomour II w/ DC Filament & Shunt Regulator (replacing w/ Kaiju), SEX 3.0 w/ C4S, Blumenstein Orcas, HD6XX

Desktop System: Crack with Speedball

Offline Paul Birkeland

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Re: Tube rolling thread for Stereomour II
« Reply #18 on: June 22, 2019, 01:57:32 PM »
I don't believe the Sovtek 2A3 has the gold plated grid wire. 
Paul "PB" Birkeland

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Offline oguinn

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Re: Tube rolling thread for Stereomour II
« Reply #19 on: June 22, 2019, 01:59:15 PM »
Ah ok, so there's at least one difference. Money well spent! The Mullard are sounding great so far, though.
Jameson O’Guinn

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Main System: Schiit Bifrost MB, U-Turn Orbit, Reduction w/ Integration, Smash w/ Smashup & SmashQuiet (replacing w/ BeePre), Stereomour II w/ DC Filament & Shunt Regulator (replacing w/ Kaiju), SEX 3.0 w/ C4S, Blumenstein Orcas, HD6XX

Desktop System: Crack with Speedball

Offline Raymond P.

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Re: Tube rolling thread for Stereomour II
« Reply #20 on: July 26, 2019, 02:01:45 PM »
I've had my newly built SII for about 2 weeks now and was able to compare the stock GE 12AT7 to a pair of Tungsram ECC81's. I've attached a couple of pictures comparing their physical constructions, with the GE on the left. Soundwise, here's a quick description: They are very similar in bass and mids. Bass is impactful and quick, and the mids sound natural and neutral. The highs are the distinguishing characteristics. The GE highs are a bit harsh and peaky, whereas the Tungsram's are smoother, more even, but without loss of detail.
Raymond P.

Offline Paul Joppa

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Re: Tube rolling thread for Stereomour II
« Reply #21 on: July 26, 2019, 05:35:50 PM »
Sweet - thanks for sharing!

If you got them recently, please post again when they have some burn-in time (especially the GE) - sometimes there is a break-in effect, but not always. Even tubes that are used but have sat unused for years might still need to be run in for a while to be at their best - it would be great to get more data.
Paul Joppa

Offline Raymond P.

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Re: Tube rolling thread for Stereomour II
« Reply #22 on: July 27, 2019, 06:52:32 AM »
Sweet - thanks for sharing!

If you got them recently, please post again when they have some burn-in time (especially the GE) - sometimes there is a break-in effect, but not always. Even tubes that are used but have sat unused for years might still need to be run in for a while to be at their best - it would be great to get more data.


The GE's probably have at least 70 hrs on them. Right now I'm enjoying the Tungsrams, but maybe later I'll put the GE's back in for further burn-in to see if there would be any difference.


I should also note that one of the GE's is weaker than the other, as evident from the driver triode plate voltage being ~235V, which is at the high end of the spec'd range. The "normal" tube's plate voltage is ~215V. Swapping sides shows that the other triode of the weaker tube is also weak. So maybe the condition of this weaker tube along with the mismatch between tubes results in what I'm hearing.

Raymond P.

Online Tom-s

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Re: Tube rolling thread for Stereomour II
« Reply #23 on: July 29, 2019, 03:21:12 AM »
GE 12AT7 to a pair of Tungsram ECC81's

As i said on the previous page, the Tungsrams are some seriously obese tubes.  ???

That is the Mullard flash, and it's normal for Mullard tubes.

The "Mullard flash" is also normal on most Philips tubes from other factories (also normal on GEC tubes).
It's a result of the current in-rush property of cold filaments/conductors (the resistance rises with temperature).
Don't worry about it. I've even seen tubes where 1 filament did flash and the other didn't. Never had trouble with any.

I've just started tube rolling with the SII and found one very interesting result. There's tubes that are preferred with my speakers (Klipsch Heresy III's), not with the headphones AKG K1000's and vice versa.
For instance: Telefunken ECC81's, love them with headphones (great frequency extension, huge soundstage, etc etc, a bit much of bass), but with the speakers the voices are placed so far back they sound distant/damped/faint. This difference ain't small and is due to both the transducer (speaker vs headphone) as the effect of the room on sound from speakers.


I haven't found the time yet to compare tubes. Mainly because i'm upgrading some caps in the SII first (done with PS, parafeed and coupling caps, cathode bypass to do). In the testbox there's 10 pairs of Eu tubes at this point: Telefunken ECC81/801s, Hamburg 6201/PW, Blackburn TK1, Heerlen TK1, French 6201's (double and tripe mica), Brimar 6060's and General Electric Company 2900's.

EDIT:

My review for now (with speakers).
ECC81 TK1 Heerlen factory (Foil D getter): Full, warm, detailed; has "musicality"; recommended.
ECC81 TK1 Blackburn factory (square getter): Detailed, more analytical sounding tube, sparkle up top (a bit much for me, crazy prices, not recommended).
6201 Hamburg factory (gold pins, round foil getter): Warm, big soundstage, good details yet musical (found for 50€/pair on that selling website, recommended).
6201 PW Hamburg factory (gold pins, dual support halo getter, pinched waist): very close to normal Valvo, unobtanium, not recommended)
ECC81 Telefunken Berlin factory: Air, detailed, missing midrange some sort, analytical.
ECC801s Telefunken Ulm factory: Air, details placed in good soundstage, nice bass (not cheap +-150-200€/pair, but recommended).
« Last Edit: July 30, 2019, 11:23:26 PM by Tom-s »

Online Tom-s

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Re: Tube rolling thread for Stereomour II
« Reply #24 on: December 12, 2019, 06:20:17 AM »
Rolling output tubes. First up. The RCA single plate. "The original 2A3".

This is a pair i've been waiting to try for very long.

I've changed the operating point on my SII to suit them. I would not recommend using a pair like this in a normal Stereomour.

These are paired with my most used drivers, GEC A2900's.

The warranty band says 20 June 1936.

Only this morning i've tested them for the first time, and both show 80-90% (in the good section) on my EICO 666.

How do these sound? I have no clue how to say this.
Very open, large, palpable in the midrange, easy to listen to.

So, what does this mean?

Detailed on top. Lacking a little bass (compared to Sovtek 2A3 and RCA black plate (single/double DD getter). Bringing out every detail and the music seems more detached from the speakers.

These are like headphones that are so easy to listen to that you just have to turn up the volume.

I like them. If this is the involving type of sound (I obviously don't know how to express myself here) people talk about with EML 2A3 Mesh, those are my next tubes.

Fun fact. Did a picture in the dark. And my camera picks up fluorescense inside the glass bulb of the right example that can't be seen with the naked eye. See picture.