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In the Forum: Audio For Dummies ™
In the Thread: Get, or made up a tube tester, it’s necessary
Post Subject: OK, let dive into 6C33CPosted by Romy the Cat on: 1/8/2007
 hagtech wrote: |
| Please do. I have interest in the result myself and don't mind spending the time. I can post photos for each tube. |
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Sure, let do it. Email me your address and I will send them to you. (Do you have sockets?)
| hagtech wrote: |
| That can only be answered by the end user. Suprisingly, I actually sell more units to afficianados than dealers or manufacturers. You have to be a serious tube guy to even consider such a machine. Many are satisfied with a go/no-go type measurement. However, there are many of us who live in the analog world and cannot divide a grey scale. |
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It is not about the “go/no-go” but the recognition of what a given person would like to get out measurement. Jim as I understand, and correct me if I’m wrong, the trace is a characteristic if the tube design, dimensions, sixes, allocations of the electrons clouds, materials and zillion other things. If a person has two dozens of 12Ax7 or a dozen of different 2A3 tubes, made in different years, by different manufacturers and by different contraction techniques and materials then trace is very nice objective way to differentiate the tube performance. However, in my case, what I use the very same tube in the very fixed operation mode the trice would not be indicative, would be? Well, it possible that a new burned tube will have trace moved but would it say anything about the tube state? I really do not know at this point as I never traced them.
| hagtech wrote: |
| Yes, that's exactly how I measure the transconductance. Except I use a 500Hz square wave. Much easier to sample and hold the peak level of a square wave than a sinewave. Sometimes the voltages can get pretty small, and doing analog division can be noisy. Oh wait, it is different than what you suggest, as I load the plate with (close to) zero ohms. |
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Hm… actually I was thinking to load the tube with the actual load (with choke), the one that it will see in amps… Well, theoretically if your tracer gives exact number of transconductance and the exact number of plate impedance then it is possible easily to circulate gain. Still, and it is what I afraid – did you come across a situation when the estimated gain is not the same what your dB meter shows after you power amp’s secondary?
Rgs,
Romy the Cat
PS: BTW, I had more on it at: http://www.goodsoundclub.com/TreeItem.aspx?postID=2277Rerurn to Romy the Cat's Site