[thesteve]

do you know what the manufacture of the amp is Bill? I've got a Bell Labs Pacemaker hi-fi tube amp that was converted to a guitar amp (with a 25W Celestion G12M). It's got some work to do on it (a grounding issue, among other things). I'm probably going to start with a set of new tubes for the thing...unfortunately that's going to run $100 or more, which is why I haven't started on it yet.

[BillSPrestonEsq]

Originally Posted by thesteve

do you know what the manufacture of the amp is Bill? I've got a Bell Labs Pacemaker hi-fi tube amp that was converted to a guitar amp (with a 25W Celestion G12M). It's got some work to do on it (a grounding issue, among other things). I'm probably going to start with a set of new tubes for the thing...unfortunately that's going to run $100 or more, which is why I haven't started on it yet.

Nope, There is a plain metal chassis. Honestly, I have no clue. There is no indication whatsoever. Someone wrote down the tube types on the metal in very faded magic marker. (6x4, 6av6, & 6v6) and I got a spare 6x4 and 6av6 for $12 NOS at my local electronics store. (I live 4 blocks from an old school electronics store with tubes, etc all for really decent prices. None of the real common tubes, but they have the stuff for hi-fi and ham)

The only thing technically this thing could use is the volume pot, and the other pot (It might be a tone pot, but I can't really hear what it does too well and the preamp I plan on pairing with it has eq) are a little scratchy. And the input jack is temporarily a guitar input jack I had lying around. I definitely plan on replacing that, giving it a 1x12 or 2x12 and adding a peavey preamp I have around. I tried that rig out, and while the tube glowed white, it was perhaps the best sounding vintage sort of overdrive I have heard.

[Ax]

that's an interesting project... PICTURES WE DEMAND PICTURES... but take your time, no rush...

[wjrhee]

Originally Posted by BillSPrestonEsq

Red is bad, blue is good, but what does white mean? That I am driving the power tube too hard?

the tubes of my blues junior glow orangish red. is this a bad thing then? should i want my tubes to glow blue? what does "good" and "bad" even mean?

sorry for the tangent.. :P

[Major Tom]

Your tubes are fine. The orange-reddish glow is from the metal parts of the tube that are supposed to get "red hot", that's normal. The blue glow that's been discussed is from the gases; its like a ghosty flourescence that appears up close to the inside surface of the glass. I think its only power tubes that get the blue glow, but I'm not 100% sure on that, like I said earlier, I haven't really paid that much attention. I can tell you that not all power tubes get that blue glow, or at least not enough to notice. As I remember, it seems like new ones tend to have less (or none) that ones with a few miles on them.

[wjrhee]

Originally Posted by Major Tom

Your tubes are fine. The orange-reddish glow is from the metal parts of the tube that are supposed to get "red hot", that's normal. The blue glow that's been discussed is from the gases; its like a ghosty flourescence that appears up close to the inside surface of the glass. I think its only power tubes that get the blue glow, but I'm not 100% sure on that, like I said earlier, I haven't really paid that much attention. I can tell you that not all power tubes get that blue glow, or at least not enough to notice. As I remember, it seems like new ones tend to have less (or none) that ones with a few miles on them.

ok, so my tubes have metal parts that glow which make it red, and other tubes have gases that make them blue. so tone-wise what does that mean for my amp?

[BillSPrestonEsq]

Originally Posted by wjrhee

ok, so my tubes have metal parts that glow which make it red, and other tubes have gases that make them blue. so tone-wise what does that mean for my amp?

nothing really. Thats normal.

[thesteve]

Originally Posted by wjrhee

ok, so my tubes have metal parts that glow which make it red, and other tubes have gases that make them blue. so tone-wise what does that mean for my amp?

if they're glowing red, that's generally a bad thing.

as far as tone goes, I don't think it makes a difference. All tube filaments should glow an orangey color (varying from yellow-orange to red orange)...the blue/violet glow is a secondary effect based on gas composition.

[What5647]

this "good" tube filament glow is very much like what you'd see in a low-wattage light bulb.

[nate95366]

Originally Posted by thesteve

if they're glowing red, that's generally a bag thing.

If you meant, "bad," then I'd say "maybe; and maybe not." If the metal parts in the tube are glowing a dull orange-red, that's what they're supposed to do. The metal plates have to be warm for electrons to jump in between them. Warm metal tends to have a dull orange-red glow.

If they are glowing a brilliant, piercing, red-orange-yellow, that might be a sign of a little too much heat and a few too many electrons jumping in between plates (too much current, too little resistance), and that should be just about the time your fuse will blow, if you've got one.

Nate

[thesteve]

Originally Posted by nate95366

If you meant, "bad," then I'd say "maybe; and maybe not." If the metal parts in the tube are glowing a dull orange-red, that's what they're supposed to do. The metal plates have to be warm for electrons to jump in between them. Warm metal tends to have a dull orange-red glow.

If they are glowing a brilliant, piercing, red-orange-yellow, that might be a sign of a little too much heat and a few too many electrons jumping in between plates (too much current, too little resistance), and that should be just about the time your fuse will blow, if you've got one.

Nate

thanks for the correction...I'm surprised I missed it.

What I was talking about is just a red-red...that dying filament color. the orange-red is definitely normal