Carvin MTS 3200/3212 Combo tube amp

[JKW]

I am seeking some technical advice about my newly acquired Carvin MTS 3200 2x12 combo amp.

I am running the amp in the 50 watt mode. To my understanding this essentially takes two of the power
tubes out of the circuit.
I'd like to remove the two tubes that are not in use and store them in safe keeping.
Is this possible?
If so which two tubes would I pull? All four still glow as though powered up even in 50 watt mode?

I will attach a link to the schematic in the hopes that it will show which tubes are not used in 50 watt mode.

http://www.carvinmuseum.com/pdf/amps/MTS3200REV-E.pdf

Thanks in advance,
JKW

[Jazz P Bass]

I would leave all of the tubes in.

You could always call Carvin & ask them.

[guitardad]

Looks as if they open the cathode circuit of V6 and V9, so other than heaters on the tubes, they will not pull any current. You shouldn't have to remove them.

[Jazz P Bass]

Thanks for that GD.

Now I see it.
S2 lifts the ground to two of the tubes.

So yeah, leave them in.

MTS3200 Cathode Switch.pdf

[JKW]

Hey guys,

thanks for the info. and I totally see what you are talking about.

However, is there any harm in pulling the tubes from V6 & V9 since all they are
doing is pulling heater current when the switch is in 50 watt mode?

My reasoning is, why pull heater current to two unused tubes if I don't "have" to and the tubes could be
kept safe in storage waiting to be my replacement tubes for the remaining tubes that are in use.

Is my reasoning unsound?

JKW

[Jazz P Bass]

My gut reaction is 'leave it be'.

Pull the tubes & then you have unterminated voltages floating around.

[g1]

Also, removing those heaters may increase the heater voltage to all the other tubes.
It's very uncommon for heaters to burn out, so the unused tubes should still stay "new" compared to the ones in use.