Johan is at it again!!! 17 preamp tubes compaired

I don't get that he used a micro terror for the comparison. A micro terror runs the 12AX7/ECC83 in what is known as "starved plate" mode, so called because the valve's plate (or plates in this case) is "starved" of B+ voltage. A micro terror puts all of 9 ~ 10VDC on the tubes plates. In the past I've made "starved plate" 12AX7 dirt boxes for people (I've run them on 18 ~ 24VDC) & while different tube types will sound different in them, they don't (by a long shot) show anything of the tubes true characteristics.
And to think he had a superlead behind him in the video. Wouldn't you have used that for the comparison. Cheers
 
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ivan H said:
I don't get that he used a micro terror for the comparison. A micro terror runs the 12AX7/ECC83 in what is known as "starved plate" mode, so called because the valve's plate (or plates in this case) is "starved" of B+ voltage. A micro terror puts all of 9 ~ 10VDC on the tubes plates. In the past I've made "starved plate" 12AX7 dirt boxes for people (I've run them on 18 ~ 24VDC) & while different tube types will sound different in them, they don't (by a long shot) show anything of the tubes true characteristics.
And to think he had a superlead behind him in the video. Wouldn't you have used that for the comparison. Cheers
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I've always been a little wary of the starved tube thing.

I have a BK Butler pedal that uses the starved-plate format. It does sound different with different tubes but I kinda doubt they respond the way they would at full power. So I think it would be a poor way to compare tubes. However the pedal does sound pretty good. I don't use it much because it requires AC power.

It certainly seems to me that the Marshall would've made a better test bed.

He may have had his reasons, either practical (volume) or electronic - maybe the Terror preamp section uses fewer tubes and he figured the change would be more apparent vs a pre with more stages? I don't know anything about the Orange lunchboxes myself - had no idea they used a starved-plate circuit - so I'm just spitballing. But I'd like to think that as an engineer he was aware of it.
 
eclecticsynergy said:
I have a BK Butler pedal that uses the starved-plate format. It does sound different with different tubes but I kinda doubt they respond the way they would at full power. So I think it would be a poor way to compare tubes.
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Exactly. The "micro" terror has only the one 12AX7, (operating in starved plate mode). Due to the extremely low B+, the tube will not have the dynamic response of a tube operating at high voltage. A "tiny" terror would have been a better choice as it's a full tube design & all tubes are operating at proper voltages. Cheers
 
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