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May 22, 2019, 10:04:39 pm

Author Topic: Tube rolling thread for Stereomour II  (Read 178 times)

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Offline Tom-s

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Tube rolling thread for Stereomour II
« on: May 16, 2019, 03:58:38 am »
Let's start a topic to share experiences with tube rolling in the Stereomour II.

Please share your opinion on different tubes in SII!

SI users are welcome to share aswel!

I'll try to keep this startpost up to date with what tubes to use in SII.

The list of tubes to use in the drivers seat:
12AT7(W)(A)(B)(C)
ECC81
E81CC
ECC801S
6201
6060
CV455
CV4024
A2900
TS65
B309
M8162
7728
6679

Not direct equivalent, optional:
5965 familiy (E180CC = 7062 = CV8431 = 6829 = 6414)
6211


Do note: some have minor electrical differences from ECC81 / 12AT7, but can be used in SII.

The list of tubes to use in the output position:
2A3
5930
VT-95
CV1831
#2A3-40

! 45 (145,245, 345 etc.)

#The extra power available with these tubes not being used in SII.
! Needs some modification. https://bottlehead.com/smf/index.php?topic=11138.0

The 6.3v heater winding is rated 1.5 amps.

The 2A3 filament windings are actually 3.15 volts at 5.5Arms. (The high current rating allows for DC heating, which is an optional upgrade for those with extremely sensitive speakers.) In both AC and DC cases, the filaments have small series resistors to fine-tune the voltage.
« Last Edit: Today at 08:54:31 pm by Tom-s »

Offline oguinn

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Re: Tube rolling thread for Stereomour II
« Reply #1 on: May 16, 2019, 04:06:47 am »
Hell yes, excellent timing as I’m constructing mine now.

Might I suggest formatting this post the same way as the Crack thread, where there’s a section for tubes that can be dropped in with no mods and a section for tubes where mods are necessary (like it seems to be for ECC81/12AT7 - unless I’m misreading)? You could add 45s to the list of “usable with mods,” right?

EDIT: Ha - looks like you edited this right as I posted to add 45s.
Jameson O’Guinn

Offline Jamier

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Re: Tube rolling thread for Stereomour II
« Reply #2 on: May 16, 2019, 12:44:35 pm »
Tom,

     I am not a huge tube roller, but I think the following list are also 12AT7 compatible:

6211
5965
6414
6829
6679
7728
TS65
M8162

I am no expert on these, so part (or all) of this list may be redundant with respect to your list.

Jamie
« Last Edit: May 16, 2019, 12:46:14 pm by Jamier »
James Robbins

Offline Doc B.

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Re: Tube rolling thread for Stereomour II
« Reply #3 on: May 16, 2019, 01:15:33 pm »
A lot of those are not directly compatible. They might be a near miss, but they would need optimization of the operating point to perform at their best.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Raymond P.

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Re: Tube rolling thread for Stereomour II
« Reply #4 on: May 16, 2019, 01:59:09 pm »
Thanks, Tom! I have a SII on order, so I can see this thread to be super useful.
I like idea of categorizing those that are direct drop-ins vs. those that might need modifications.
Raymond P.

Offline Tom-s

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Re: Tube rolling thread for Stereomour II
« Reply #5 on: May 16, 2019, 08:39:46 pm »
Tom,

     I am not a huge tube roller, but I think the following list are also 12AT7 compatible:

6211
5965
6414
6829
6679
7728
TS65
M8162

I am no expert on these, so part (or all) of this list may be redundant with respect to your list.

Jamie

The reason Doc mentioned is the reason i didn't include them in the list.

The 6211, 5965 families are different and need modification.

7728, TS65 and M8162 are special quality equivalents and i'll add them.

A lot of those are not directly compatible. They might be a near miss, but they would need optimization of the operating point to perform at their best.

Offline Tom-s

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Re: Tube rolling thread for Stereomour II
« Reply #6 on: May 17, 2019, 07:30:18 am »
So let's discus the different types.

Because i have to do something while waiting for the SII.

First things first.

The ECC81
Quote from: Radiomuseum.org
Mentioned: Dec1950, Market: 1951.
Twin triode, the European version of the 12AT7, especially designed for VHF, also good to use in audio amplifiers; high amplification, low internal resistance.
https://www.radiomuseum.org/tubes/tube_ecc81.html

It is a direct replacement in SII.
From personal experience, don't look at the label of the tubes, look at the tube factory codes for European tubes.
These tell you more about the actual tube than the label does. 

Tube data: https://frank.pocnet.net/sheets/010/e/ECC81.pdf

Philips tube code: https://frank.pocnet.net/other/Philips/PhilipsCodeListAB.pdf

In the Philips ECC81 collection i've seen:
Delta -> Heerlen (The Netherlands)
R -> Mitcham (England) (Mullard)
B -> Blackburn (England) (Mullard)
D -> Hamburg (Germany) (Valvo)
‡ -> Munich (Germany) (Siemens)
F -> Suresnes (France) (La Radiotechnique)

I've added an example. It's an Adzam (Belgium) labeled, Mullard Blackburn factory build, ECC81 pair (three holed plates are typical for certain versions of ECC81 build in this factory).