Help me get this preamp tube out

[Randall]

Boutique amp, I don't even know what it is, but I do know I can't get these preamp tubes out. They are in very, very tight, with only about 1/2" or less of gripping area.

Anyone have any tricks? I tried wrapping some blue masking tape around one for a better grip, but it won't budge.

[xtian]

Silicone non-slip pad or silicone oven mitt should have enough grip to help you out. Wash the glass with alcohol first.

[nosaj]

How about trying to take the rubber grommet out first or maybe it will take tube out at the same time.
What amp are we talking about?

nosaj

[Enzo]

In my kitchen I have a round rubber disc, thin and floppy with a textured surface, maybe 6" across. They call it a jar opener. And it works. I use it to get a grip on a jar lid to open it. Companies give them away as promo swag, but you can buy them at any grocery store. One of those might get you a better grip.

I also have a sorta cone shaped foam thing made to pull tubes. The small end for 12AX7 and the larger end for larger tubes. Here, like this one:
https://www.ebay.com/itm/VINTAGE-GC-...AAAOSw8Xpe1XrU

[Jon Snell]

To avoid any damage, I would release the pcb from the chassis and in pulling the frame away from the chassis, remove the valve/s from the underside.
There will be fixing screws/clips to release.
Broken glass, from gripping the bottle too hard, is not an option for me.

[Mick Bailey]

I had one like that where the grommet was hardened and stuck to the tube. I worked a feeler gauge around to break the bond but it was still gripped very tight. A good few wraps of cheap masking tape and perseverance got it out in the end, but it took a lot more time than I would have liked. When I thought back I would have been better crushing it with long-nosed pliers and pulling it out by its guts. It turned out it was defective anyway in the end.

[Randall]

Pulling the chassis on this point to point wired amp would be more trouble and time than it would be worth to me, given how many turrets and wires involved. Plus it would be restricted by three preamp tubes and rubber grommets. This is really not an option for an amp I have no schematic for, and don't really know what it is trying to be. I will look for some silicon gripper material as Enzo suggests, and if that doesn't work I will return the amp, and suggest sending it to the builder. Tamerlane is the brand, which is not labeled anywhere on the amp. Oh, and by the way, the power tube sockets are 100% inaccessible, as they are buried under the main board.

[Jon Snell]

From your description, it sounds like a home made, poorly laid out machine.
Shame.

[nosaj]

Maybe ask here
https://www.facebook.com/tamerlaneamps/
nosaj

[The Dude]

Are the grommets really necessary? If it's that hard to get tubes out, I'd consider cutting the grommets out with an exacto knife and tossing them away. It should make removing the tubes much easier.

[nevetslab]

I would very carefully try cutting up the rubber grommets that have bound themselves to the preamp tube glass. I'd be hacking away with a medium-size X-Acto knife blade holder, not the smaller one. if the rubber has hardened completely, I'd try a very sharp wood chiesl to hack up that grommet. Getting that grommet(s) out of there will finally allow the tubes to be unplugged, either by gripping with your fingers, or the textured rubber grip pad Enzo mentioned...I too make use of that in the kitchen. Once the tubes are finally out of the way, I'd make use of some silicon rubber sleeving. I use a specific hi temp silicon rubber tubing, ID being 3/32" and OD being 7/32". Measure the diameter of the opening and calculate the circumference, then cut the tubing to that length, and carefully slit the tubing open. Then, you can slip the tubing into the hole to nicely fit all the way around. I use that tubing on the inside hold of hold-down clamps' top hats to shock-mount the clamp from the tube glass on power tubes.

I buy that material from McMaster-Carr all the time, but could send you some to bypass the cost ($9.63 per 10ft length), plus the shipping cost and tax.

[The Dude]

Not to argue- your idea is a good one. I'll just add, there are plenty of amps with chassis holes for tubes without grommets or anything at all. I don't see why it would be necessary to have anything there. If a grommet fits, there should be plenty of room between chassis and tube glass to avoid any problems.

[Randall]

I finally got the tube out. Since it was on the edge of the board I managed to get a little green screwdriver in the crease of the glass and the socket and gently pry it up until there was enough space to sneak a second one in there. I cringed the whole time I did this. The grommets were not stuck to the glass, it sure made things more difficult. For instance, I would get the tube raised a bit, take the screwdriver away, and it would drop back down the mm of progress I had made. It took about 20 minutes to get it fully out. I removed the grommet while I did a tube swap to check for hum, and put it back when I found no difference in tubes. But when I did, the grommet made this quite difficult. I ended up greasing the tube with a little soap and water, and it slid back in nicely. I let it sit won standby for about 30 minutes before I tested it again, hoping to dry off any moisture that may have gotten to the pins.

This amp is a royal PITA, and I want it gone. Oh, and did I mention the external bias control was cranked up to as far as it would go, putting the 6V6s at 95mA? An aluminum cased power resistor that was meant to be screwed to the chassis for heat sink, but was hanging off the edge of the board in the air was actually dripping little beads of solder from under it's heat shrink tubing.

[Mick Bailey]

Many of the boutique amps I see are really poorly designed and some dangerous. I had one where the terminals of the can PSU caps pointed downwards towards the floor of the head, which was covered with stapled-on roofing foil. The gap was about 1.5mm. I had to line out the bottom with insulating sheet. This was a brand-new amp that came to me directly in its unopened shipping carton. Another kept blowing fuses; a transformer bolt touched a terminal strip used for primary voltage selection. When the top of the combo vibrated with certain notes it shorted the live terminal to chassis ground.

Another amp recently in built to a Twin Reverb style with a Plexi channel was already sagging under the massive extra-huge transformer weight pulling down on the thin aluminium chassis. Just the four through bolts and no reinforcement, or even the three rear lip screws.

I also had a hi-fi amp in for a re-tube a few years ago where the four EL34 output tubes were soldered directly to two PCBs. No sockets.