|
Post by John E. on Sept 25, 2018 9:28:27 GMT -7
Where I live, there aren't any amp techs around that I can regularly use. The only one I know of does it as a side job and his turnaround time is about 2-3 weeks usually just cause it's not his main gig.
So if I buy a matched set of power tubes for like a 50 watt fixed bias EL34 amp, could I just switch them out without having to rebias? Opening up amps scares the crap outta me cause I just know that with my luck, the first time I open an amp, I'll touch the wrong thing and end up a French fry.
|
|
|
Post by headshrinker (Marc) on Sept 25, 2018 9:41:49 GMT -7
Unfortunately no. Tubes have different electrical characteristics. I don't have the knowledge to go into them. When they match tubes they make sure that those characteristics are the same, or close, for those tubes. But, the matched characteristics for the next matched set will be the same between them, but different than the previous pair. Technically, if you have a listing of all the values for the match on one set, and get another with those same ones, you should be able to just plug them in and go. In practice that is hard to do.
|
|
|
Post by daddyelmis (Greg) on Sept 25, 2018 9:59:57 GMT -7
unless the amp is cathode biased, then perhaps not (as I understand it). I don't know of many cathode biased el34 amps -- I think matchless has some. Not sure if the Doc has any. The EMS is fixed bias el34 I believe.
|
|
|
Post by purpletele on Sept 25, 2018 10:08:35 GMT -7
unless the amp is cathode biased, then perhaps not (as I understand it). I don't know of many cathode biased el34 amps -- I think matchless has some. Not sure if the Doc has any. The EMS is fixed bias el34 I believe. Did you get your quad tester from China yet. I am thinking about buying that one as well.
|
|
|
Post by zpilot on Sept 25, 2018 10:08:39 GMT -7
Yes, with a caveat. You will need to have the amp biased with a set of tubes from a vendor who tests and sorts their tubes to a consistent standard. A supplier like Groove Tubes. Those tubes will be labeled with a number or color. So if your amp has, for instance, #5 range tubes you will know that a replacement set of that range will draw the same current. So all you will need to do is always install the same make and range tubes from that vendor.
There is a downside to this though. Obviously you will be limited to using that particular tube and it may not sound the same as the tube you are used to using. It is nice though to be able to change output tubes at a gig if one fails and be assured they will work properly.
|
|
|
Post by daddyelmis (Greg) on Sept 25, 2018 10:34:57 GMT -7
unless the amp is cathode biased, then perhaps not (as I understand it). I don't know of many cathode biased el34 amps -- I think matchless has some. Not sure if the Doc has any. The EMS is fixed bias el34 I believe. Did you get your quad tester from China yet. I am thinking about buying that one as well. Not yet - apparently it’s “on the water” from Hong Kong. May take a couple more weeks. I’m not in a hurry, especially to save well over $100-$150. I did just order new JJ 6v6 and a sovtek 5ar4 so I’ll be ready. I’ll post update and review once the stuff all gets here.
|
|
|
Post by mudman on Sept 25, 2018 11:03:10 GMT -7
Yes, with a caveat. You will need to have the amp biased with a set of tubes from a vendor who tests and sorts their tubes to a consistent standard. A supplier like Groove Tubes. Those tubes will be labeled with a number or color. So if your amp has, for instance, #5 range tubes you will know that a replacement set of that range will draw the same current. So all you will need to do is always install the same make and range tubes from that vendor. There is a downside to this though. Obviously you will be limited to using that particular tube and it may not sound the same as the tube you are used to using. It is nice though to be able to change output tubes at a gig if one fails and be assured they will work properly. Some tube sellers will sell you sets matched for that though- KCANos did that for me with anos tung sols matched to Mesa specs
|
|
|
Post by Chilly Gibbons (Todd T.) on Sept 25, 2018 14:13:13 GMT -7
You’ll want to either learn and become comfortable with biasing or have it done. Over their lifespan, tubes will drift out of optimal bias anyway so knowing how to adjust this will save you some hassle. Plus, you’ll want to experiment with biasing to get the optimal sound you want out of the amp. You might like a slightly warmer or colder bias in some amps. Won’t damage anything to be off a bit from the recommended bias point, just don’t red plate.
|
|
|
Post by zpilot on Sept 25, 2018 14:30:55 GMT -7
Yes, with a caveat. You will need to have the amp biased with a set of tubes from a vendor who tests and sorts their tubes to a consistent standard. A supplier like Groove Tubes. Those tubes will be labeled with a number or color. So if your amp has, for instance, #5 range tubes you will know that a replacement set of that range will draw the same current. So all you will need to do is always install the same make and range tubes from that vendor. There is a downside to this though. Obviously you will be limited to using that particular tube and it may not sound the same as the tube you are used to using. It is nice though to be able to change output tubes at a gig if one fails and be assured they will work properly. There are several reasons why you should learn to check/set the bias of your amp, but as I understand it, you have no interest in doing that. That's OK. Perfect is the enemy of good.
|
|