Question re power amp

[John Orange]

Hello there,

I have a quick qestion.

1. Background: I have a RKII and an MKIV, both heads, each with its 2X12 cabinet. As I posses some stereo effects, I would like to use them at their best potential, i.e. in stereo

On the background above, the way I figured to run these effects in stereo was to use each of the power stages of the RKII and MKIV as Left and Right respectively.

Curently, I am considering to add a stereo power amp to the two amps above, to ensure sound uniformity.

2. Question:

If I decide to use a Mesa 2:90, which of the knob functions of the amps (e.g. volume, presence, Eq (in case of the MKIV)) will no longer be available as a consequence of skipping the power stage of these amps?

Many thanks for taking the time to look into this.

Best regards,
JO

 

[mrd]

I'm fairly certain that the only knobs that are part of the power amp (on both the MKIV and the RKII) are master outputs and presence.

All your tone knobs, gain, channel volumes, EQ, blah blah blah, is all in the preamp. Having no presence knob is kinda lame, but the 2:90 should have that, yeah?

 

[NoGlassNoClass]

Both of your amps MUST have a speaker load connected at all times...even (in the Mk4) if the silent record feature is used. Failure to maintain a load on the amp will fry it in short order.

Working with what you already have, you could run one side (either left or right) of your effects in the loop of the Mk4, and the other side thru the loop of the RoadKing like so:

Mark FX send > FX input left , FX out left > Mark FX return
RKII FX send > FX input right , FX out right > RKII FX return

If you want to add a power amp, you will also need more speakers... a stereo 4x12 would work, but 2 separate cabs would work better for stereo spread. Hook it up as above, but do not return to the main amps loops. Instead, go from the FX unit outs to the inputs of the power amp, which drives its own cabs in stereo. This is what's known as wet/dry/wet...or in your case W/D/D/W. If you have the cash and are willing to deal with the mountain of gear, there is nothing better. Depending on the situation, you could run one or two heads dry into 1-4 cabs, and have your stereo FX in up to 4 more :shock:

Your soundman will hate you, your chiropractor will appreciate the extra business, but the sound....oh yes the sound 8)

 

[John Orange]

Dear all,

Thanks for taking the time to respond.

Question: Do you happen to be aware of a product that would act well as a dummy load?

For the moment I am not planning in investing in two more cabs. So in my mind I planned to use the 2 2X12s for the stereo amp and have no cabinets attached to RK and MKIV.

Alternate scenario: Now that I am thinking, I could use one of the speakers in each of the cabs for Dry signal, and one of the speakers for the power amp signal. This would still allow stereo from the power amp and would ensure there is a load on the RKII and MKIV. It would also run the system in W\DD/W.

What do you think?

Best regards,
JO

 

[NoGlassNoClass]

Dummy load... THD HotPlate, or Weber Mass. Sequis Motherload (nice but very expensive)...I think Palmer makes something as well.

Alternate scenario: IMO a much better way to go, both for versatility and tone. Make sure you have speakers that can handle the extra juice.