Members iloveespguitars Posted May 22, 2011 Members Share Posted May 22, 2011 Say... my tube has PC: 31 and TC: 964 labeled on it Do I use the PC to buy a matched set somewhere so I don't have to rebias the amp? Link to comment Share on other sites More sharing options...
Members Oblivion DC Posted May 22, 2011 Members Share Posted May 22, 2011 I believe the TC stands for transconductance. From the wiki: For vacuum tubes, transconductance is defined as the change in the plate(anode)/cathode current divided by the corresponding change in the grid/cathode voltage, with a constant plate(anode)/cathode voltage. Typical values of gm for a small-signal vacuum tube are 1 to 10 millisiemens. Not really sure what the PC is, but if you need to replace tubes just go ahead and get a whole set and be done with it. It'll save you a load of trouble in the future. Link to comment Share on other sites More sharing options...
Members mbarn3065 Posted May 22, 2011 Members Share Posted May 22, 2011 PC: is plate current and TC: is trans conductance Link to comment Share on other sites More sharing options...
Members diocide Posted May 22, 2011 Members Share Posted May 22, 2011 So heres a dumb question, if you got new power amp tubes, with similar or even exact TC and PC as the tubes in your amp, would you still have to bias them? Link to comment Share on other sites More sharing options...
Members Nerine Posted May 22, 2011 Members Share Posted May 22, 2011 I would have thought so. Link to comment Share on other sites More sharing options...
Members isvoid Posted May 22, 2011 Members Share Posted May 22, 2011 pc = pretty convincing axefx emulation index, tc = totally convincing axefx emulation index Link to comment Share on other sites More sharing options...
Members mbarn3065 Posted May 22, 2011 Members Share Posted May 22, 2011 pc = pretty convincing axefx emulation index, tc = totally convincing axefx emulation index This! Link to comment Share on other sites More sharing options...
Members Rampage Posted May 22, 2011 Members Share Posted May 22, 2011 So heres a dumb question, if you got new power amp tubes, with similar or even exact TC and PC as the tubes in your amp, would you still have to bias them? Some people say that you don't have to rebias if you can get a new set of power tubes that are an exact match to the brand/ratings you had before; however, I would still rebias the amp. Link to comment Share on other sites More sharing options...
Members FourT6and2 Posted May 22, 2011 Members Share Posted May 22, 2011 Yeah, it only takes like 10 minutes to bias an amp. So I don't understand why people are always trying to find an excuse to NOT do it... Link to comment Share on other sites More sharing options...
Members diocide Posted May 22, 2011 Members Share Posted May 22, 2011 Yeah, it only takes like 10 minutes to bias an amp. So I don't understand why people are always trying to find an excuse to NOT do it... I don't have the tools or knowledge to do it. It hasn't really been an issue because my main amp for the last 6 years was a fixed, non adjustable bias, but my newest amp is adjustable. I may need to look in to this... Link to comment Share on other sites More sharing options...
Members knope Posted May 22, 2011 Members Share Posted May 22, 2011 Cathode Biased FTW! Link to comment Share on other sites More sharing options...
Members Rampage Posted May 22, 2011 Members Share Posted May 22, 2011 I don't have the tools or knowledge to do it. It hasn't really been an issue because my main amp for the last 6 years was a fixed, non adjustable bias, but my newest amp is adjustable. I may need to look in to this... Look up the Amp Head Dual Bias Tester MPD. That, along with a cheap Multimeter, will allow just about anyone to bias a tube amp. Just follow the directions carefully and pay attention to what you are doing. Link to comment Share on other sites More sharing options...
Members FourT6and2 Posted May 22, 2011 Members Share Posted May 22, 2011 I don't have the tools or knowledge to do it. It hasn't really been an issue because my main amp for the last 6 years was a fixed, non adjustable bias, but my newest amp is adjustable. I may need to look in to this... The only tools you need to bias an amp are a meter (which you can get a radio shack) and a screwdriver. The specific method you use, however, will depend on the amp. Link to comment Share on other sites More sharing options...
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