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Sujet T-Bone SCT 800

  • 12 réponses
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1 T-Bone SCT 800
The tube "lampe" in the T-Bone SCT 800 is NOT a 12AT7 but a 12AX7 at 100%. The 12AT7 is a 60% output tube. I recommend you change the tube of origin i.e. a Silver Dragon China 12AX7B for a 12AT7. I put in a EI 12AT7 (Yugo) and it is incredible. It is a copy of the old Philips design from the sixty's.
2
HI Benjikan,

First of all cool: Another guy who experimented changing the tube in the mic. If you go on "astuces" you can read my experience with changing the original tube with a ECC 83 Telefunken NOS.

Citation : The tube "lampe" in the T-Bone SCT 800 is NOT a 12AT7 but a 12AX7 at 100%.



How do you mean? the very short T-Bone notice claims it is a 12AT7 tube. What makes you think it is a 12AX7?

Also if there was an 12AX7 inside, I think it would be problematic to use a 12AT7 because of the lesser output. Whadayathink?

In the meanwhile I put a telefunken ECC801S, which is great.
3
I have two SCT 800's. When I opened the T-Bone there is a Silver Dragon "CHINA" 12AX7B in the microphone. The information on the spec sheet is a typo error. The 12AX7 is too hot for this microphone and like the MXL V series it should be using a 12AT7 or a 6072. I changed mine to the EI 12AT7...What an improvment!
4
I spoke with Gotham Audio in Canada and they change all of the 12AX7 tubes in the Feilo z5500's i.e. SCT 800's to 12AT7's. You get at least 6 db more headroom and less noise. It also relieves the strain on the transformer. The MXL V series is exactly an SCT-800 and they use a 12AT7 in there microphone. I think the choice to use a "CHINA Shuguang 12AX7B" is a question of cost. You will not notice a big difference in output. You might augment your output at the pre-amp stage. At 10 kHZ it will be much smoother as there is a boost at that frequency and the reduction of output allows that frequency to come through more smoothly. Just look at the "lampe" tube you removed from the T_BONE SCT 800. It says "China 12AX7B" on it...
5
Ha man, this is so funky!

The tube I took out of my SCT800 has NO-THING written on it! Also, to remain objective in comparing the sound of the original "12AT7" with the Telefunken, I kept exactly the same gain setting on my preamp. The recorded sound level was almost identical with both tubes! If I had exchanged a 12AX7 for a 12AT7, I would definitely have noticed a change. Don't you think so?

Do you think it is possible that they had different "builds" or series? Maybe they just changed the tube at one point and didn't bother to change the "notice"... or even better forgot to do so!
6
You definately had the China 12AX7B. It is a very very good tube. One of the best out of China. Some high end Hi-Fi amplifiers use them by choice. Many of the China 12AX7's have no markings at all. I also did not notice a radical change when I went to the EI 12AT7. I was pleasantly suprised. I think the change is more evident in Guitar Amps for example at very loud levels. I just set my mic trim up about 2 db at that was the same as the original. As I have two SCT 800's I could compare them in real time. Literally no differnce in output, but definately much smoother with the "EI". Just type in to Google "China 12AX7" tube and you will see a photo of it. It will be the same as the tube you removed. I am certain!

Ben
7
Hey Ben,

Well if you are sure...

By the way I didn't mean there was no difference, the Telefunken sounds really better compared to the original tube. It was just talking about the recording level.

The sound didn't become smoother but gained in dynamics with more present transients, the high end seems more "open" and the muddy/overpronounced bass dissapeared.

Have fun with this cool toy,

A/D
8
Thanks for taking the time to write. Imagine if the name on the microphone said Neuman or Telefunken...The Price would be astronomical...And yes I love recording with this microphone. I also really appreciate my SC 1100's...

Good Day
Ben
9
Quelle est la difference entre des tubes 12at7 et 12ax7?
Devata from nowhere
10
12AX7 100% output 12AT7 60% output egal 40% plus de niveau (headroom) Je changer mon lampe 12AX7 pour le Yugo EI 12AT7 stereo matched pair pour mon deux T-Bone SCT 800's. Pardon mon Francaise je suis Canadian Anglo.

https://www.audiotriodes.com/fr/shop/browse/category/12at7.html