Replacing preamp tubes (tips?)

[cesjr]

I'm going to re-tube my preamp section. I want to put the quietest tube in V1, so how should I go about doing this? Currently I have the stock Sovtek 12AX7's in my Mark IV, and I'm replacing them with SED 12AX7's. Should I just swap the V1 with each SED tube until I find the quietest one, and then replace the rest? Also should the amp be turned on and on standby when swapping tubes? Is that safe?

 

[Russ]

Swapping tubes can be fun but it takes a while. First, the tubes get hot to the touch and you need to let them cool before handling them. Second, it is not a good idea to be moving tubes around while hot because the contents of the tube do not like to be moved while hot. Third, you should power down before changing tubes. Keep a fan nearby to help cool the tubes faster between changes. Take your time also because if you are too hasty you might not seat a tube completely and run into problems. If you want to use the quietest tube in V1 I would say that you are right to want to swap them through until you find it. This is something that I do for chasing a tone usually or for a touch more gain but it is feasible to do it for noise also. Most better tubes will be pretty quiet. If you are that concerned you might want to buy prescreened tubes for the position. Just remember that with more gain and output you will risk more noise. I have found that Sovtek 12AX7WA's can be pretty quiet but leave a lot to be desired as far as other qualities. To me they sound pretty lifeless. They do their job just not like others can.

 

[bscfo1]

I agree it IS fun, and if you really want to do it, go ahead. I went crazy with it for a while and spent hundreds of dollars on high-end NOS tubes for my preamp. While I thought they actually changed the sound dramatically, once I experienced problems with them, and put my amp back to stock, those small characteristics that used to bother where not there. My amp sounded better too.

I have a EJ strat and a Mark IV. With the stock Sovteks in the preamp and power amp, I can get his singing violin tone and the crystal cleans Eric is known for out of one amp. Tip for the Mark IV: Use 6L6's, simulclass, triode, tweed power. All pull pots are pulled except for the presence. DON'T dial in so much treble (5 is good) and use 0 presence for Rhy 2 and Lead. Use the graphic EQ in the classic "V." With delay, it's truly inspiring. Have fun.

 

[MikeKCA]

I'm going to re-tube my preamp section. I want to put the quietest tube in V1, so how should I go about doing this? Currently I have the stock Sovtek 12AX7's in my Mark IV, and I'm replacing them with SED 12AX7's. Should I just swap the V1 with each SED tube until I find the quietest one, and then replace the rest? Also should the amp be turned on and on standby when swapping tubes? Is that safe?

Sounds like a good plan! Swapping on standy is OK, but I generally recommend turning the amp off completely.

 

[Rayder]

i would say turn the amp off completely. i dont kno about the mk4, but in a triaxis there is no standby switch for it, so there is always current flowing through it when its on. best to turn off completely.

 

[harryjmic]

Ever pull a pre-amp tube thinking you put the amp in the standby mode? Man, that's a startling experience. I usually just put the amp on standby and then pull the tube, I don't like blasting the power tubes so much, I'd rather they stay warm during the pre-amp pulls.

 

[Guitarzan]

i would say turn the amp off completely. i dont kno about the mk4, but in a triaxis there is no standby switch for it, so there is always current flowing through it when its on. best to turn off completely.

+1 Turn it off bro.