ScumBomb 412 Cab Two Mono Jacks

[ldanmartin]

I set the Amp at 4 ohms, when running both pairs in the same 412... right?

412:
16 Ohm + 16 Ohm in parallel = 8 Ohm into Mono Jack#1
16 Ohm + 16 Ohm in parallel = 8 Ohm into Mono Jack#2

Above 412 running all 4 speakers, using two speaker cables into 2 jacks at the cab, and 2 jacks at the Amp = 4 Ohms?

Details here:
I don't like the sound of my Marshall AVT412 cab. It has a single round jack plate cup, with a single jack.

I don't want to cut the cab in anyway, so it can be put back to stock later, if needed.

I removed the jack cup, made a new flat wood jack plate, drilled 4 holes to match the corner mounting screws, and drilled two holes for the two 1/4 mono jacks. The current opening in the back of the cab is a 2 1/4" hole.

These are the jacks I ordered from here: http://www.guitarnucleus.com/gnstore/elec_jack.html" onclick="window.open(this.href);return false;
GN0055LEL-000 Switchcraft # L11

GN0055LEL-000.jpg

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I don't want any PCB, or switches or switching jacks... just hard wired, soldered 16 AWG stranded wire.

I want to wire two pairs of speakers in a X Pattern, using two Mono jacks.

I couldn't decide what to buy for speakers, so I bought the Greenbacks and Alnicos... from Scumback.

I liked the M75, H75, H55 and Sumnicos and couldn't decide. I figured the H55 might be too dark for a closed back cab.
That left the M75, H75 and Scumnico's.

I couldn't decide between the M75 and H75... so I got both... to provide the M75/H75 Greenback pair.
I was going to get two of each of those... but I like the Scumnico too...

So I bought two Scumnico's also.

1 - M75 Series Speaker, 16 ohms 65 watt, 97db
1 - H75 Series Speaker, 16 ohms 65 watt, 99db
2 - Scumnico 12" Series Speaker, 16 ohms 65 watt, 98db

Facing the front of the Marshall AVT412 cabinet:
I will run the X Pattern with the Greenbacks in the Upper Left and Lower Right corners.
I will run the Scumnico's in the Upper Right and Lower Left corners.

I will wire one pair of 16 Ohm speakers in parallel to a single Mono jack creating 8 Ohms. (Greenbacks)
I will wire the other pair of 16 Ohm speakers in parallel to the other single Mono jack creating 8 Ohms. (Scumnicos)

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I also bought two 6' speaker cables from MetroAmp.

Amps I will be running: Metro JTM45, or AVT50H, or 12XXXX series Marshall.

When I want to hear the Greenbacks... I would plug in only 1 speaker cable from the Amp to 1 mono jack at the cab and set the Amp at 8 Ohms.

When I want to hear the Scumnicos... I would plug in only 1 speaker cable from the Amp to 1 mono jack at the cab and set the Amp at 8 Ohms.

When I want to hear all 4 speakers at once from 1 Amp... I'll call it the "ScumBomb" X Pattern configuration... I would plug 2 speaker cables from 1 Amp to 2 mono jacks at the cab and set the Amp at 4 Ohms.

Is the last part correct?

Essentially Two 2x12 configs at 8 Ohms each in one 4x12 cabinet running out of the cab via two mono jacks, using two speaker cables, into one amp = 4 Ohms? (All speakers are 16 Ohms, 65 Watt).

Since I couldn't decide on speakers, I hope this works and sounds good... hence the 412 ScumBomb X Pattern configuration.
(Speakers should be here next weekend after Jim gets back from the LA AMP show and does the FBI)!

[908ssp]

Yes that is correct. I have a cab done close that but I arranged one pair on the right and another pair on the left. A vertical pair will give you a wide dispersion of sound then an offset pair. I also divided the cab in half inside but I started with a full size cab so I had more room seems to your cab is a bit smaller.

[ldanmartin]

Should I put the M75 in the Upper Left Corner and the H75 in the Lower Right Corner of the X Pattern?
Anyone have a preference or recommendation?

Thanks,
Dan

[ldanmartin]

This is how my original Marshall AVT412 cab is wired, it's also 18 AWG.
I am going to wire two separate pairs in parallel with two mono jacks when the new Scumbacks get here.

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[ldanmartin]

My Scumbacks just arrived! 1-M75, 1-H75, 2-Scumnico's (all 65 watt, 16 ohm). The order looks correct!

Now to remove the old AVT412 speakers, and put these in!