DSL40 CR tube shield

[Mel9416]

Hello all,
New to the forum and new to tube replacement. I recently replaced a preamp tube (V1) in my DSL40CR. Two things I noticed.
First is the the tube was very hard to get in. I had to apply a lot of pressure on it and felt like I might break the tube or damage the pins. I did complete this but the tube still sits a little higher than the others.
Secondly was wondering if the springs in the metal shield should make direct contact with the tube? I feel like when the tube heats up this could cause damage? Should I be concerned about this? Thanks in advance for any advice!

 

[fitz]

Hello all,
New to the forum and new to tube replacement. I recently replaced a preamp tube (V1) in my DSL40CR. Two things I noticed.
First is the the tube was very hard to get in. I had to apply a lot of pressure on it and felt like I might break the tube or damage the pins. I did complete this but the tube still sits a little higher than the others.
Secondly was wondering if the springs in the metal shield should make direct contact with the tube? I feel like when the tube heats up this could cause damage? Should I be concerned about this? Thanks in advance for any advice!

to the forum.
The tube shouldn't sit higher unless it's a little taller than the one you took out.
Try a little wiggling to seat it properly.
If you've never changed the tubes, the sockets are probably just tight.
Some Deoxit on the pins would help for both installation and for corrosion resistance.

Yes, the shield spring should contact the tube.
It's there to help hold the tube in place.

 

[TheKman76]

It's worth noting that the PCB in this amp is pretty flexible, so your caution is well warranted.
V1 is a different valve in this amp and may have different dimensions. I haven't actually looked at them in detail, but to easy your mind have a closer look at them side by side.

I personally use a rotating motion when installed valves in PCB mounted sockets which seems to require less direct force.

 

[fitz]

V1 is a different valve in this amp and may have different dimensions

How so?

 

[TheKman76]

I didn't pay any attention when I've had them out.
Will take some shots later today.

 

[solarburn]

Just like fitz stated make sure tube is all the way in. Don't be hamfisted pushing too hard. The spring will rest against the tube. Don't worry about heat.

I will say I don't use the tube shields unless I hear extra noise happening. I haven't at home play. I'd use them gigging just in case.

 

[Mel9416]

Th

Just like fitz stated make sure tube is all the way in. Don't be hamfisted pushing too hard. The spring will rest against the tube. Don't worry about heat.

I will say I don't use the tube shields unless I hear extra noise happening. I haven't at home play. I'd use them gigging just in case.

Thanks everyone! I’ll try the deoxit and an extra push. Good to know about the shield. Rock on!

 

[Leonard Neemoil]

The problem is the rubber grommet that's in the chassis hole isn't it?

It makes it almost impossible to be sure that the tube pins are properly aligned with the socket because it's so tight around the tube.

 

[solarburn]

Turn the amp on its head So you can see V1 better. Those holes can be tricky. I always turn the combo over for tubing. I have problems with each slot. Not the power tubes. You can move those out of your way while pulling pushing preamp tubes.

 

[TheKman76]

The problem is the rubber grommet that's in the chassis hole isn't it?

Mine doesn't have one on V1. The others do.

 

[solarburn]

Mine doesn't have one on V1. The others do.

Mine is just on V1. I have the 40C combo. I do use tube rings on mine to help with cab/speaker vibrations. Got them from Eurotubes long time ago. Anything to help with tube rattle in a combo.

 

[solarburn]

Th

Thanks everyone! I’ll try the deoxit and an extra push. Good to know about the shield. Rock on!

Also preamp tubes can run fatter than others. Occasionally I'll run into this which can make pushing as well as pulling them harder.

And welcome to the forum!

 

[TheKman76]

I didn't have the inclination to pull the valves, but the photo shows V1 with the shield removed on the left and V2 on the right. Clearly different valves and V1 sits taller in the socket too.

Note V2 has the grommet, as do the rest of the preamp valves, while V1 does not. The Mark I and Mark II are different in this regard it seems?

 

[fitz]

I didn't have the inclination to pull the valves, but the photo shows V1 with the shield removed on the left and V2 on the right. Clearly different valves and V1 sits taller in the socket too.

Original Marshall stock tubes?

 

[TheKman76]

Yup.

 

[solarburn]

I didn't have the inclination to pull the valves, but the photo shows V1 with the shield removed on the left and V2 on the right. Clearly different valves and V1 sits taller in the socket too.

Note V2 has the grommet, as do the rest of the preamp valves, while V1 does not. The Mark I and Mark II are different in this regard it seems?

View attachment 131027

Yep. Seems so. Just V1 on mine.

 

[Mel9416]

Mine doesn't have one on V1. The others do.

Yes V1 has the shield and the others the grommet. I turned the amp upside down and the tubes are easier to reach. The preamp tubes are slightly recessed making a little tricky to line up the pins.