Road King II 12AX7 tubes task/layout

[ubersam]

In case anyone is interested, the preamp tube task/layout for the Road King II (applies also to the Roadster and RKI) is as follows:

V1A First gain stage
V1B Second gain stage
V2A Third gain stage, Ch1 & 2
V2B Third gain stage, Ch3 & 4
V3A Fourth gain stage, CH3 & 4
V3B Tone stack driver CH3 & 4
V4A Reverb return
V4B Reverb driver
V5A Effects loop send
V5B Effects loop return
V6A&B Driver/phase inverter

EDIT: Apparently, this does not apply completely to the RKI, which does not have a tube driver for the reverb.

 

[MesaDCLP]

What? ... no input stage?

 

[CudBucket]

What? My amp has 12 preamp tubes?

 

[psycle_1]

What? My amp has 12 preamp tubes?

A 12AX7 has two sides to it, hense the A and B when it says V1A, V1B, etc.

 

[ubersam]

What? ... no input stage?

Hhmm.. I got that list from Mesa tech support. V1 is typically the input tube, so, V1A is pressumabye the input stage and sets the amount of gain for the rest of the chain. The other "gain" stages would be the drive stages.

 

[HappyStrat]

Where does the V6 come into play? There's only 5 pre-tubes on a RK I, unless the RK II has 6.

 

[ubersam]

RKII has six 12AX7s. V6 is the phase inverter of the power amp section. RKII also has two series effects loops, as opposed to the RKI which has one parallel and one series. This may have necessitated the additional effects loop send/return 12AX7 tube. Just guessing here.

 

[Flavell777]

The extra 12AX7 on the RKII is for the tube reverb as appose to the RK I's spring reverb.

 

[ubersam]

The extra 12AX7 on the RKII is for the tube reverb as appose to the RK I's spring reverb.

Just a slight correction: The reverb in the RKII is still a spring reverb; however, it is now tube driven. The RKI's spring reverb wasn't tube driven.

http://www.mesaboogie.com/Product_Info/Rectifier_Series/roadking/roadking.htm

 

[HappyStrat]

V1A First gain stage
V1B Second gain stage
V2A Third gain stage, Ch1 & 2
V2B Third gain stage, Ch3 & 4
V3A Fourth gain stage, CH3 & 4
V3B Tone stack driver CH3 & 4
V4A Reverb return
V4B Reverb driver
V5A Effects loop send
V5B Effects loop return
V6A&B Driver/phase inverter

Any idea what the order of these would be for RK I?

 

[Boogiebabies]

The extra 12AX7 on the RKII is for the tube reverb as appose to the RK I's spring reverb.

Just a slight correction: The reverb in the RKII is still a spring reverb; however, it is now tube driven. The RKI's spring reverb wasn't tube driven.

http://www.mesaboogie.com/Product_Info/Rectifier_Series/roadking/roadking.htm

It was op-amp driven. Solid State !!! :x

 

[psycle_1]

V1A First gain stage
V1B Second gain stage
V2A Third gain stage, Ch1 & 2
V2B Third gain stage, Ch3 & 4
V3A Fourth gain stage, CH3 & 4
V3B Tone stack driver CH3 & 4
V4A Reverb return
V4B Reverb driver
V5A Effects loop send
V5B Effects loop return
V6A&B Driver/phase inverter

Any idea what the order of these would be for RK I?

Remove V4A and V4B from the list. V4 becomes the effects loop, V5 is the driver/phase inverter.

 

[Anthony1967]

pressumabye?

 

[ubersam]

pressumabye?

hah. good catch. presumababble. how's that?

 

[Anthony1967]

Xsolent!

 

[fleeced]

Are they labelled up inside?

Want to change V1 for a Tung Sol ... Is it obvious which is which !?

8)

 

[fleeced]

can anyone answer whether V1 is the one nearest the transformer?

Cheers

 

[bgh]

can anyone answer whether V1 is the one nearest the transformer?

Cheers

It should be the one all the way on the left, looking at it from the back.

You can go to http://mesaboogie.com/media/User%20Manuals/Road%20King.pdf to download a copy of the manual.

Hope this helps.