Stoner/Doom Bassists Thread Pt. 45: Rule 34: Handwired Gear Pronz - Page 20

Lazarus.Bird · #**381** 01-31-2013, 01:09 PM

Nope, definitely don't want to lower my gain! Was just curious if "upgrading" the tubes would be beneficial, but in this case upgrading is really just name brand based and probably doesn't hold much water.

jerrymcdougal · #**382** 01-31-2013, 01:11 PM

Quote:

Originally Posted by dunwichamps

yes. unless for some reason you wanna lower gain then dont bother.

I would normally agree, UNLESS we're talking chinese tubes. In my humble opinion the difference between chinese crap and pretty much any other make is easily noticeable. Chinese designs are quite physically different than your typical JJ/New Sensor physical designs. Just my humble .02 though.

I'd say, for $15 or so, grab a Tung Sol. Worst thing that could happen is you have a spare tube.

JoeVictim · #**383** 01-31-2013, 01:12 PM

Quote:

Originally Posted by dunwichamps

The other thing is that if you only have a sample of 1 tube per brand, its really hard to say if thats how the average tube is from that brand, I just approach stuff like this from a scientific test. You would need to test a good number of each tube, in a blinded way where you didnt know which tube you were swapping and thus could not form a judgment ahead of time. Its often a subconscious thing that happens with A/B testing.

Yes, He had a few tubes from a few different brands and then a few different values. I drank (he doesn't) and had a grand ole time tinkering with tone and trying to understand 12axy vs 12ay7. It was all very fun. Glad I don't have to deal with that anymore. Tubes can add up pretty quickly. Especially if you are one of those NOS golden tone magick tube, guys. Which that guitar player that came over was. He still cringed when I played the Crate, just not as much with the Mullard.

He also had the NICEST PRS I have ever seen.

JoeVictim · #**384** 01-31-2013, 01:13 PM

Quote:

Originally Posted by Lazarus.Bird

Nope, definitely don't want to lower my gain! Was just curious if "upgrading" the tubes would be beneficial, but in this case upgrading is really just name brand based and probably doesn't hold much water.

My buddy was telling me that the build quality is better for even the european tubes. He was basically an anything but chinese tube, kinda guy.

+1 Jerry!!!

dunwichamps · #**385** 01-31-2013, 01:19 PM

Yea swapping different types of 9 pin tubes in the 12aXX family will do lots of difference in gain and tone with 12au7 being the smallest mu (17) (gain) factor and 12ax7 being the highest mu factor (100)

jerrymcdougal · #**386** 01-31-2013, 01:26 PM

If it's of any use, when I tested, I had an assortment of many tubes, not just a new tube and old tube (which would clearly bias be towards the one I just paid for). Not scientific by any means though, I just popped each one in randomly and played the same set of riffs, then slowly sorted them in order of how much I liked them. If I were biased, the expensive JAN/Sylvania/RCA stuff would have come out on top. Like Dunwich says though, this is all extremely relative and ymmv.

I tried: (in no particular order)
Tung Sol 12AX7
Tung Sol 12AT7
JJ Silver short plate 12AX7
JJ Silver long plate 12AX7
EH Silver 12AX7
EH Silver 12AT7
JAN-Phillips 12AT7
Three different Chinese models (don't recall names)
Fender branded RCA 12AX7
Fender branded RCA 12AT7
Sylvania 12AX7
Sylvania 12AT7
Westinghouse 12AX7
Westinghouse 12AT7

Out of all of those, I filled my preamp with Tung Sol 12AX7's (silver).

I have a bunch of 12AU7's too, but those are for pedals, not any amp I own.

**bassboysam** · #**387** 01-31-2013, 01:33 PM

Quote:

Originally Posted by Lazarus.Bird

Nope, definitely don't want to lower my gain! Was just curious if "upgrading" the tubes would be beneficial, but in this case upgrading is really just name brand based and probably doesn't hold much water.

lower gain doesn't mean less distortion, it's just a different kind of break up. I find 5751s and 12AU7s sound more like power tube distortion than 12AX7s. your amp won't become a hi-fi machine.

dunwichamps · #**388** 01-31-2013, 01:35 PM

Quote:

Originally Posted by bassboysam

lower gain doesn't mean less distortion, it's just a different kind of break up. I find 5751s and 12AU7s sound more like power tube distortion than 12AX7s. your amp won't become a hi-fi machine.

Well if you lower the mu factor then the gain decreases and if the gain decreases the amount of clipping for the same given signal will decrease. However 12au7s and others do sound different for several reasons including different biasing (since you are not changing the components for optimum bias for the new tube) and also plate impedance.

**bassboysam** · #**389** 01-31-2013, 01:38 PM

Quote:

Originally Posted by dunwichamps

Well if you lower the mu factor then the gain decreases and if the gain decreases the amount of clipping for the same given signal will decrease. However 12au7s and others do sound different for several reasons including different biasing (since you are not changing the components for optimum bias for the new tube) and also plate impedance.

true but in my experience, I just had to turn the gain control a little higher than I did with the 12AX7. if you are running the gain on full (which come to think of it, Laz might be) then yeah you will notice less dirt. but you may find you like it...

dunwichamps · #**390** 01-31-2013, 01:39 PM

Quote:

Originally Posted by bassboysam

true but in my experience, I just had to turn the gain control a little higher than I did with the 12AX7. if you are running the gain on full (which come to think of it, Laz might be) then yeah you will notice less dirt. but you may find you like it...

oh yea it can sound good. There is probably not a whole ton difference in gain between a 5751 and a 12ax7 since its just a 30% decrease in mu but if you drop in a 12au7 then its 1/5 of the mu, or more than 80% less gain.

Lazarus.Bird · #**391** 01-31-2013, 01:41 PM

While the TB sounds fantastic with the gain practically dimed plugging straight in, I dial it back to around 10:30 when using my pedals.

dunwichamps · #**392** 01-31-2013, 01:42 PM

also remember each tube has 2 triode sections so its possible if you stick in a 12at7 for example you are decreasing gain of 2 stages in the amp by 40% so if they are cascaded it will have more effect then if its a parallel input stage (like subbing V1 in a Superbass)

dozicusmaximus · #**393** 01-31-2013, 01:44 PM

Is there a benefit replacing a 12at7 in the phase inverter (I think is what it's called) spot with a 12ax7?

dunwichamps · #**394** 01-31-2013, 01:46 PM

Quote:

Originally Posted by dozicusmaximus

Is there a benefit replacing a 12at7 in the phase inverter (I think is what it's called) spot with a 12ax7?

well that depends. For one thing if the amp was designed to use a 12at7 properly (components used for biasing it) then it may not really work with a 12ax7 well. However if the component values are more like a 12ax7's then it can work and will increase phase inverter gain. However, it may result in more unwanted clipping because the output impedance of a 12ax7 is larger then a 12at7 and thus if you are trying to swing a lot of voltage to a big load before the power tubes it will clip a lot earlier as a result of loading down the stage