Two Cabs, A Suhr RL, and a MosValve Power Amp

[TheJudge]

I need some guidance regarding impedance setting on a 77 Marshall JMP 50 watt (2204).

For recording purposes, I have several options:

1) Head running one speaker out to the Suhr RL for a direct signal into Logic using IRs;
2) Head running second speaker out to a MosValve power amp connected to two 8ohm 2x12 cabs;

One 2x12 speaker cab is down a long hallway and in a closet and mic'd up with an SM57 and a Senn. MD421, and the other 2x12 cab is in the control room with the player. The 2x12 down the hallway has much more volume via the gain dial on the MosValve than the 2x12 in the control room.

The Suhr RL is 8ohm, and as far as I know, the MosValve MV-962 does not care what the impedance setting is on the Marshall head. So, I have the Marshall head set for 8ohm load.

Is that correct?

Thanks for the help.

 

[TippyRacer]

I have read your post 3 times and if it is written correctly, how you have it wired makes absolutely NO sense to me. Are you sure you described it right?

1) Head running one speaker out to the Suhr RL for a direct signal into Logic using IRs;
2) Head running second speaker out to a MosValve power amp connected to two 8ohm 2x12 cabs;

 

[TTripp]

Sounds to me, and I could be wrong, that you want.to run the second speaker out IN to the Mosvalve power amp. That is a big no-no, you need a load between the Marshall and Mosvalve (line out from said load feeding the Mosvalve.)

 

[GilmourD]

If I were you I would find out if you can run both the balanced XLR DI and unbalanced 1/4" line out simultaneously, unless your goal is to have a fried MosValve and possibly toasted power tubes, output transformer, and other various parts.

 

[TheJudge]

I do have the Suhr ISO box between the second speaker out and the MosValve providing the line level for the MosValve input.

 

[TheJudge]

Since a load is already provided by the Suhr RL, I don't need another load on the second speaker out. All I need is a line level which is what the Suhr ISO box provides.

I am really just looking for the correct impedance or ohm setting for the amp. I think it should be 8ohm. I am just not sure.

 

[TheJudge]

Using both the XLR and the 1/4" out of the RL is an interesting idea. I wonder if I could use both simultaneously. That would eliminate the need for the Suhr ISO.

 

[TTripp]

Ah, well, your original post doesn't mention the Suhr ISO. In that case, set the Marshall to match the Suhr Reactive Load (8 ohms).

 

[TheJudge]

You're right! My mistake. Thanks for the help.