New Fender Pwr Tube Hold-Down Clamps stiffer than usual?

[nevetslab]

I have a new Fender 65 Deluxe Reverb reissue on the bench, that came in with Tube/distortion issues. Put it up on the bench, found the output sounding quite distorted, far more than normal. Both Channels exhibiting the same, so I swapped V4 to see if that made any difference. No change. Powered down, went to remove the two 6V6 Power Tubes, and found the Bear Trap base clamps seemingly much stiffer than normal, and was having trouble releasing them with my right hand fingers while attempting to unplug the tubes. Got the tubes out, installed my bias probes, and geting them into the sockets seemed a real chore as well. Plate current was sitting at 24mA each, seemingly a bit high, and dropped it down to 18mA. When I went to remove the bias probes and plug the tubes back in, getting the clamps to open was a real bear on both tubes.



I got one tube in, while the other one, I was now fearful I'd break the tube with my gloved hand, risking injury not being able to depress these clamps enough to let the tube base properly seat fully.

Is my right hand getting weak, or is it my imagination that these clamps are now a lot stiffer than before. Granted, over the years, this style (and the other Y-shaped clamps being much weaker), have been a constant source of power tube noise from inadequate holding force. I do use Kevlar gloves for handling hot tubes, but haven't yet had a tube break on my trying to insert it. YET.

I did find the source of distortion was the driver tube. Replaced that, now have all the restored gain and drive that was missing, without the severe distortion that I was hearing.

[g1]

Are they marked 'Belton'? I've found those new ones to be much stiffer than anything else. Very tough to work with.

[The Dude]

......Is my right hand getting weak, or is it my imagination that these clamps are now a lot stiffer than before......

Nope. Your right hand is fine. The new clamps are definitely stiffer and make it tougher to get tubes in and out. The thing I find most annoying is that with the older clamps, you could press the tube into the clamp/socket slightly and find the key just by rotating the tube with slight pressure until it sunk in a bit. With these stiffer clamps, it's harder to find the key by feel. You have to be sure (by eye) that the key is lined up. Even then, the clamps are so tight that it feels like you don't have the key lined up when you try to insert the tube.

[Bloomfield]

I have found the same thing with the last few sets I have bought too. I ended up pushing them down, enough to flatten out the bends a bit, and then squeezed them back together until the tension felt about right to hold a tube base. Kind of a bother for something that should be easy enough to make right in the first place.

[drewl]

Yup, new normal.

I'm sure they'll loosen up in forty years or so!

[Mick Bailey]

Apart from the very stiff retainers, the last two new DRRI amps I've had in have had considerable gaps between the octal tube bases and sockets - the retainers only just about gripping on the edge of the phenolic. These amps are just a few months old with their original tubes. I tried different tubes but they wouldn't seat either and the individual sockets looked clear. They must have thought this was OK at the factory. I would have usually investigated further but the customers were only paying for noise fixes.

[nevetslab]

Nope. Your right hand is fine. The new clamps are definitely stiffer and make it tougher to get tubes in and out. The thing I find most annoying is that with the older clamps, you could press the tube into the clamp/socket slightly and find the key just by rotating the tube with slight pressure until it sunk in a bit. With these stiffer clamps, it's harder to find the key by feel. You have to be sure (by eye) that the key is lined up. Even then, the clamps are so tight that it feels like you don't have the key lined up when you try to insert the tube.

Glad it isn't just me finding little hints of aging setting in. Interesting you'd mention it harder to find the key in the socket. On one of the tubes, I did manage to miss the registration of the key, and got the tube installed, though not all the way. Powering it up briefly revealed no heater glow, and I shut down immediately without any damage. Got it rotated, then got heater glow after powering back up.

I'll have to open up the road case and remove the upper rear panel to see if there's any mfgr name stamped into the clamps. I didn't notice anything, but then, I didn't remove the chassis from the cabinet.

[The Dude]

I know this post is a bit old, but I just got in a pair of Deluxe Reverb RI's with the stiff retainer clips, so thought I'd update the thread. The retainers are indeed marked Belton.