I don't want to get electrocuted....

[konstantine RK]

Just began removing the RK from it's chassis... Is it common to turn it on in this way to put preamplifier tubes?

I got a "cocktail" tube package from Dougs tubes and I want to experiment switching them out with these new tubes

right now I have a "Mesa"in V1, a sovtek in V2, mesas in v3 & v4 and something I pulled out of a triple recto with no name but it was the replacement tube that saved my faith in v5

so what steps do I take to be safe to plug in while my RK is naked lol?

 

[212Mavguy]

One of the amps I have is a custom one of a kind boutique amp, on the back the builder wrote: "This amplifier was built to kick ass and take names but beware that it contains lethal voltages that will ruin your day if you carelessly poke around in it!"

Ed Smith, builder, Toad Suck Tones Classic 50.

Keep your fingers out of the inside of the amp's guts...even after shutting it off. If it was mine, I'd stick it unside down on a table so that the side of the chassis that the tubes and trannies protrude out of is facing up. Should be pretty safe due to 3 prong power cord. Remember to connect it to the speaker before powering up.

Happy Thanksgiving, and be thankful for the inspirations coming to Randall Smith on an ongoing basis!

 

[elvis]

Do you actually have to pull the chassis to change tubes??

Mavguy is right - 500-600V inside there, and it stays even when the amp is unplugged thanks to various supply capacitors. They will hold enough charge to zap the heck out of you.

Standard procedure when working with high voltage: keep one hand in your pocket. That way you can't (easily) get a shock that puts current through your heart.

Go slowly, and don't forget the words of Stanley Goodspeed in The Rock: "The second you don't respect this, it kills you."

Keep it assembled if at all possible.

 

[konstantine RK]

OK So when I pull this thing out and turn it on....

I can.... pull out and push in Preamp tubes right?

and what kind of surface do I place the amp on when its time to do this?

Sorry for the dumb questions but this is my baby!

 

[212Mavguy]

Yep, stick it on top of a dry table, maybe on top of a dry terrycloth towel in the manner previously described. Do not be intoxicated while doing this. :wink: Put it on standby during the swapping if you wish to be a bit more cautious, some really nasty noises can happen while inserting preamp tubes when not using standby. DEFINITELY use standby if swapping power tubes and allow a minute for the heaters to warm up while you're at it for any tube type. One time in my early "ignant" days of tube rolling I put in a tube that had not the cleanest set of pins in a socket that was also a bit dirty, the amp had no SB switch, was turned way up, and the sudden, powerful surges going through the circuit caused a cathode bypass capacitor to explode besides put the speaker at serious risk of blowing the voice coil. :roll: Made a big pukey mess all over the guts of my amp. PITA to clean it up, but learned my lesson.

While pulling or inserting, a bit of a circular motion helps things to go smoothly. A piece of old inner tube in the hand helps your fingers get a better grip on the glass, and the tube feels a lot less hot to your fingers if it has been operating for a while, particularly power tubes. Best to turn the amp off for a few minutes before pulling them unless they have been operating for only a minute or so. Handle any tube type extremely carefully after pulling them hot, set them down like the most fragile of eggs, the heat inside makes a tube's guts much more fragile than if they are cold. Once I dropped a hot power tube on the floor, a kt66, it did not break the glass, but it was never the same, had to toss it.

 

[konstantine RK]

Thanks so much! I really appreciate your post 212Mavguy

 

[konstantine RK]

here is what I ended up leaving in today....tung Sol 12ax7 in V1
Mesa 12AX7-A in V2
Sovtec 12AX7LPS in V3
Mesa 12AX7-A in V4
Penta 12AX7-B in V5

I have a "Shaunguang" (lol) pre amp tube, a JJ ECC83S, another Sovtec and two preamp tubes tht I pulled out of a Mesa triple rectifier (no markings but the tube is dark at the top

Im going to give my family the rest of the night off and power this thing down so if you see anything here that you think I sh9ould try let me know

thanks in advance and after a few electronics courses I may flip it over and learn about the guts of the Amp....

 

[konstantine RK]

Well Im happy with the sound so far... Next time I will get some more advice on preamp tubes... I did break a Mesa 12AX7 but I still have plenty of those and one was broken but both of my other Mesa tubes work so I guess that was the bad one....

Im hoping to check out a RK2 so I can hear Channel 1-2 with the lonestar sound....Im also hopeing to plug my pedalboard into a RK 2 to see if the buzz is true about how improved the RK2 is over the RK1

My cleans are very acceptable but the Randall's Blackface module still sounds better though I can live with what I got on my Mesa.

Just dont have the cash to buy a RK2 and accept that my RK1 is only worth 1200 -1500$$$