Removing tubes to convert to 50 w

[Marshallman]

Did any of you ever removed two power tubes out of your amp head to convert it from a 100 watts to 50? I saw a vid on you tube of a guy who did that on his Randall Lynch Box and I am tempted to do this on my Carvin since it is such a loud bastard. Thoughts??

 

[Mudder]

Typically you'd remove the two outer tubes, then use 16ohm speaker out instead of the 8ohm. I think.

 

[Anonymous]

You can do it, but it's really not going to lower the volume very much, if at all.

 

[just42dave]

I thought you drop the homage to 4 if 8????

 

[glpg80]

Typically you'd remove the two outer tubes, then use 16ohm speaker out instead of the 8ohm. I think.

thats incorrect.

you pull the two outer or inner tubes and half the impedance load, not double it

16 ohm cabinet set the amp to 8ohm, 8 ohm cabinet load set the amplifier to 4ohm.

 

[Anonymous]

And...no real noticable difference in volume but..Real noticable difference in bass response etc....

 

[Marshallman]

Mmmmm.... so it will just lower my bass and bottom end response then and do nothing for the volume.... guess will have to keep playing loud.

 

[Anonymous]

Mmmmm.... so it will just lower my bass and bottom end response then and do nothing for the volume.... guess will have to keep playing loud.

Thought about an attenuator?

 

[just42dave]

Typically you'd remove the two outer tubes, then use 16ohm speaker out instead of the 8ohm. I think.

thats incorrect.

you pull the two outer or inner tubes and half the impedance load, not double it

16 ohm cabinet set the amp to 8ohm, 8 ohm cabinet load set the amplifier to 4ohm.

This!

correct you half the ohmage per Andy Fuchs and in this thread..

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Re: How to turn the Vh100r into a Mesa
by Owczar » Thu Oct 09, 2008 9:31 pm

Hi
Laney vh100r is my first valve amp, and i have a questrion:
Is removing pair of powertubes dangerous for amp? When i remove pair i will have 50w and impedance half down (from 16ohm to 8ohm etc.)? I must remove exactly V8 and V9?Owczar
Mortal


Posts: 1
Joined: Thu Oct 09, 2008 9:26 pm
Yes.

 

[tituba]

if i remember right. the lynch cab is 8 ohms?. remove the outer 2 tubes and set your amp setting to 4 ohms, or plug into the 4 ohm o.p. easy peezy lemon squeezy.

 

[johnnyjellybean]

Be careful....although most amps are setup in push-pull pairs as an inner pair and an outer pair, some amps have the push-pull pairs setup staggered such as a Bogner Ecstasy in which case you would have to pull the 1st and 3rd tube to half the power.(the Ecstasy has a switch) Either ask someone who knows your amp or pull the chassis out and check which tubes are wired to which.

 

[mrbobo]

Something else to consider- I have noticed the bias changing allot when doing this, I forget which way.