Removing Tubes

[OlinMusic]

What would happen if you removed every other tube instead of the OUTER PAIR or INNER PAIR like you are supposed to?

I always just do what I was told, never totally understanding the whole push/pull thing.

 

[STRATDELUXER97]

Re: Removing Tubes

You have to remove either both outer tubes or both inner or the push/pull circuit won't work...

 

[Gearjoneser]

Re: Removing Tubes

SD97 answered it, but just make sure you cut the ohms in half on the head, when you pull two tubes. Amp 8 ohm, plugged into 16 ohm cab, when 2 tubes are pulled

 

[OlinMusic]

Re: Removing Tubes

ok AND WHAT WOULD HAPPEN if you only pull every other tube, in other words do it wrong. Would it blow up the amp or something?

 

[STRATDELUXER97]

Re: Removing Tubes

ok AND WHAT WOULD HAPPEN if you only pull every other tube, in other words do it wrong. Would it blow up the amp or something?

The amp won't play.....No sound...:smack:

 

[OlinMusic]

Re: Removing Tubes

I tried it
the amp played, sounded kinda stiff and smelled like it was burning hahahah
oh man!

 

[Scott_F]

Re: Removing Tubes

You can pull one tube from a 2 tube amp, but it's not going to sound so hot.

So did it start smoking?

 

[OlinMusic]

Re: Removing Tubes

lol no I shut it off

 

[drew_half_empty]

Re: Removing Tubes

i've had every other tube pulled on my bassman for weeks now

sounds the same way it did with all 4

is mine just a different design or what?

 

[stonabus]

Re: Removing Tubes

whats this tube pulling pratter?

 

[PUCKBOY99]

Re: Removing Tubes

If a 100w amp with 4 tubes has a 1/2 power switch.....you pull 2 tubes(inner or outer), does it cut it to 25watts

OR

Does the 1/2 power switch just kill 2 tubes anyway, knocking it down to 50w ?

 

[OlinMusic]

Re: Removing Tubes

Good question
I would htink it keeps it 50w
You need a pentode/triode to go to 25

 

[OlinMusic]

Re: Removing Tubes

I had to add, off topic
my Marshall always has a kinda burning smell to it.
I run it with a Variac, and I never do anything but 95 - 105 on avg. I am direct into the wall.

It's not like a horrible burning smell, it could just be the way an old amp smells with the tubes lit up. It plays fine, gigs fine, and goes for hours at a time. hmmmmmmmmmmmmmmmmmmmm

Then, my Framus doesn't really make much of a smell at all with the tubes sizzling.

 

[drew_half_empty]

Re: Removing Tubes

ok this is weird, i switched from the every other tube to the middle 2, and it sounds exactly the same

what's the deal?

 

[Scott_F]

Re: Removing Tubes

If a 100w amp with 4 tubes has a 1/2 power switch.....you pull 2 tubes(inner or outer), does it cut it to 25watts

OR

Does the 1/2 power switch just kill 2 tubes anyway, knocking it down to 50w ?

For the most part, a 1/2 power switch kills off two tubes in a four tube configuration and in the case of the DC30 clone I just built, the cathode biasing resistor is changed at the same time to accomodate the swtich from 4 to 2.

 

[ErikH]

Re: Removing Tubes

For the most part, a 1/2 power switch kills off two tubes in a four tube configuration and in the case of the DC30 clone I just built, the cathode biasing resistor is changed at the same time to accomodate the swtich from 4 to 2.

Would the tubes not in use still glow as if they are still "in-circuit"? Reason I'm asking is because my amp's 1/2 power switch (or High/Low) leaves them all glowing. It's a Marshall JCM900 MkIII. Here's what the manual says about the Output Mode switch:

"Switches the amplifier from high to low power output. The “low” setting configures the output stage to “triode” operation, which gives half the rated output (i.e. 25 Watts on 50 Watts models - or 50 Watts on 100 Watt models). The “high” power position gives “pentode” operation for the full rated output."

 

[Scott_F]

Re: Removing Tubes

The heaters in the tubes are still getting juice, so yes, they'll still glow.

 

[HolyDirt]

Re: Removing Tubes

ok this is weird, i switched from the every other tube to the middle 2, and it sounds exactly the same

what's the deal?

Bassmans are freaking tanks, thanks what the deal is. Haha :laugh2: . It kinda like how a lot of old cars can run of corn oil, but try it with something new and... boom.

 

[drew_half_empty]

Re: Removing Tubes

well i'm kinda wondering which is the correct way to do it now

if it sounds the same both ways, then how do i know?

 

[HolyDirt]

Re: Removing Tubes

The mechanic that I am is asking this:

What old cars run on corn oil?

I got an old old, nearly dead chevy to run off of corn oil. Probably the most productive thing I've ever done... :laugh2: