Dell18 Posted March 4, 2014 Share Posted March 4, 2014 I ordered a full tube ensemble for my main head. 4x SED EL3's, 2 Tung Sol 12ax7's, and one JJ ECC83S. The JJ to tame the gain and smooth it out as per my tech's suggestion. I have yet to try it in my 100/50w head but it definetly did that in my Jet City JCA20. As I was tube rolling in the JCA, I realized I kinda like a Tung Sol in v1. My initial plan was to put the new SED's in my main head, put the JJ in v1 and the Tung Sol's in v2 and v3 but I'd really like to keep one Tung Sol in the JCA. v3 in my main head is the phase inverter. I have 3x Ruby and 3x Shuang that I can put there. Does the PI spot affect tone much? If it's just negligible I'd prefer to just put a Ruby there and save a Tung Sol for the JCA. I've had a Ruby there for like 12 years and it still tests strong so durability isn't really a concern there. Link to comment Share on other sites More sharing options...
tulk1 Posted March 4, 2014 Share Posted March 4, 2014 Interesting question. Especially for those of us that ain't tube/amp experts. Found this doing a quick search. All of your signal goes through the PI, none goes around it. Seems it might be important. On your tubes, I was actually surprised by your statement of using a JJ to tame the gain. I've gone off JJ anyTubes because I couldn't control the gain with them. Not my fav tube. But, if it works for you, then it works. Link to comment Share on other sites More sharing options...
Dell18 Posted March 4, 2014 Author Share Posted March 4, 2014 Yeah, I'm certainly not a JJ fan either but this is their ECC83s I'm putting in place of a 12ax7 in v1. The ECC has lower gain than a 12ax7. I'm sure there are better ECC's but at $11 and my tech's suggestion, I figured I'd give it a shot. I'm ok with it in my JCA, hopefully it responds the same in my Genz Benz. Link to comment Share on other sites More sharing options...
H Posted March 4, 2014 Share Posted March 4, 2014 Fender blackface amps use 12AT7s (also known as ECC81) in the PI position. These have a lower gain factor (60) than a 12AX7. Try one of these perhaps. ECC83 is the British code for the 12AX7 tube. I have Mullard and Brimar ECC83 tubes and they perform exactly as 12AX7's do. They have the same gain factor - 100. Link to comment Share on other sites More sharing options...
slider313 Posted March 5, 2014 Share Posted March 5, 2014 Fender blackface amps use 12AT7s (also known as ECC81) in the PI position. These have a lower gain factor (60) than a 12AX7. Try one of these perhaps. ECC83 is the British code for the 12AX7 tube. I have Mullard and Brimar ECC83 tubes and they perform exactly as 12AX7's do. They have the same gain factor - 100. ^ ^ ^ ^ This The gain factor (100) will be the same. There's no lower gain 12ax7 tube. A 5751 will "bias up" the same as a 12ax7 but has a gain factor of 70. That may work. Different brands of 12ax7's will sound different in the phase inverter spot. Link to comment Share on other sites More sharing options...
Dell18 Posted March 5, 2014 Author Share Posted March 5, 2014 No, I understand ya, but there is definetly less gain with the JJ in v1 than the Tung Sols, Rubys or Shuangs. Those offer tonal differences but the gain level is roughly the same. JJ I believe makes 3 tubes labeled 12ax7 and 2 different ECC83's. I think plate size may be the difference the ECC's. The one I have is the 83S which has been noted to have less gain for whatever reason. I have a 12AT in an amp and 3 vintage 12AU's in another but I just wanted to dial the gain back a little, hence trying out the JJ. Did the trick in one amp, hopefully it does the same in my 100 head. I figured out which slot was the PI. Yep, differences can be heard but the don't appear as noticeable as they are in v1. At least in the JCA20. Link to comment Share on other sites More sharing options...
Dell18 Posted March 5, 2014 Author Share Posted March 5, 2014 Hmmm. Won't let me edit my two typos. As long as I'm reposting I'll point out I do understand the 60/70/100 gain factor of the different tubes. I didn't want to dial it back that much and was suggested the JJ ECC83s. I know it SHOULD have the same output, and maybe it does but to the ear, there is less gain there. At least in this amp. Once my Genz is retubed, I may post further on this but since it's getting a fresh quad of EL34's (God, I wish I had just picked a nice 30-50w head out) and all new 12ax7's there's a lot of variables being changed so..... Anyway, thanks guys. This is my first retube in 15 years of owning tube amps. First 10 years I was a poor SS/hybrid player. I've had this one for 12+ years and pwr tubes are just now getting close to the end. Link to comment Share on other sites More sharing options...
H Posted March 5, 2014 Share Posted March 5, 2014 Fair enough It might be worth getting in touch with someone local to you with a tube tester. You could look for other 'off-spec' 12AX7/ECC83 types which may get you where you want to be with this amp. Link to comment Share on other sites More sharing options...
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