Cab connection FAQ

Speakers and Cabinets, types, manufacturers , what ohm ? questions, DIY speakers ...

Moderators: jim renolds, jimsreynolds, Jackie, Andy

Rick O'Shea
Club Circuit
Posts: 758
Joined: Mon Sep 01, 2008 3:50 pm
Location: Ottawa, Ontario

Re: Cab connection FAQ

Post by Rick O'Shea » Thu Jul 10, 2014 12:45 pm

Yes you can. First discard the PCB and original wiring and remember to label the jacks on the cabinet clearly and permanently.

You can wire the two 8Ω drivers in series, resulting in a 16Ω load. The two 16Ω speakers can be wired in parallel to present an 8Ω load. When both sets of drivers are to be used, hook up the 16Ω load to the 8Ω output on the JVM and the 8Ω load to the 4Ω output.

Sounds confusing I know, but this will be safe with the JVM.
Rick O'Shea
JVM410H EH12AT7 in V1
Diamond Halo Chorus, MXR CAE Wah, Decimator G-String
JCM900 1936 w/stock G12T75s
SG '61 Reissue, '83 B.C. Rich Eagle REG-2

gezza
Private Parties
Posts: 304
Joined: Sat Jan 05, 2008 6:16 am
Location: Birsbane - Australia

Re: Cab connection FAQ

Post by gezza » Sat Jul 12, 2014 12:58 pm

OK,
Last question.

What is the best way or standard way to run 1960a cab.

As the JVM has 2 x 8ohms outputs, I could switch the cab to stereo.

Or is it better to run the cab in Mono at 16ohms.

Many Thanks,

Gezza.
JVM410HJS
Marshall 1936 - Loaded with Vintage 30's.
Fender USA Strat Deluxe.
Fender USA Strat Deluxe FSR Ice Blue.
Fender USA Strat Plus.
Custom Made PRS and Strat.

Rick O'Shea
Club Circuit
Posts: 758
Joined: Mon Sep 01, 2008 3:50 pm
Location: Ottawa, Ontario

Re: Cab connection FAQ

Post by Rick O'Shea » Sat Jul 12, 2014 1:22 pm

Mono 16Ω or 4Ω is normal practice. Stereo 2x8Ω is just another way of presenting a 4Ω load. They all sound the same.
Rick O'Shea
JVM410H EH12AT7 in V1
Diamond Halo Chorus, MXR CAE Wah, Decimator G-String
JCM900 1936 w/stock G12T75s
SG '61 Reissue, '83 B.C. Rich Eagle REG-2

Mr_Moo
Club Circuit
Posts: 642
Joined: Wed Oct 23, 2013 3:33 am
Location: New Zealand

Re: Cab connection FAQ

Post by Mr_Moo » Sun Jul 13, 2014 1:53 pm

Hi Gezza, just to clarify Rick's point there - the JVM is a mono amp, so one JVM won't run the 1960 in stereo. So if you did plug into the two 8 ohm stereo inputs on the cab, you'd need to use the two 4 ohm outputs on the amp.

But if I recall correctly, you have a 410H and an HJS. Lucky bugger [smiley-shreds] So you could set up a true stereo rig if you ran both power amps at the same time, and you'd then plug the 8 ohm output of the H into one side of the cab, and the 8 ohm output of the HJS into the other side of the cab. Could be a good setup if you're using stereo effects, and don't mind being very loud.
Play it like it's the last time it'll ever be heard.

Tonemeister
World Tour
Posts: 2864
Joined: Wed Mar 27, 2013 5:27 pm
Location: Calgary, Canada
Contact:

Re: Cab connection FAQ

Post by Tonemeister » Tue Jul 15, 2014 5:03 pm

Mr_Moo wrote:Hi Gezza, just to clarify Rick's point there - the JVM is a mono amp, so one JVM won't run the 1960 in stereo. So if you did plug into the two 8 ohm stereo inputs on the cab, you'd need to use the two 4 ohm outputs on the amp.

But if I recall correctly, you have a 410H and an HJS. Lucky bugger [smiley-shreds] So you could set up a true stereo rig if you ran both power amps at the same time, and you'd then plug the 8 ohm output of the H into one side of the cab, and the 8 ohm output of the HJS into the other side of the cab. Could be a good setup if you're using stereo effects, and don't mind being very loud.
200W isn't that loud smilie=icon_lol.gif
- Marshall JVM410H: Negative Feedback Mod (33k-500k, linear), Compression Mod, One-Wire Cascade Mod, OD2-to-OD1 Mod, P.I. Boost Mod (with 33k in R52), Plexi Cap Mod (1uF), Modified C83 Mod (1- OFF, 2- 0.68uF, 3- 1.0uF, 4- 1.5uF, 5- 2.2uF, 6- 3.2uF), Gain Reduction Mod, Blackface Mod, Mesa Rectifier Mod, 50W (two tubes: 37.5mV), LED Footswitch Mod
- Laney AOR ProTube 3012 Combo: stock
- 2x Marshall 1960B 4xG12T-75
- 2x Dean DIME (FBD, Stealth #29/50), ESP LTD MH-250HT, Fender MIM Strat
- TC Electronic PolyTune, ISP Decimator G-String, Morley Mark Tremonti Power Wah, Ibanez TS9, MXR EVH Phase 90, TC Flashback X4, TC Hall Of Fame

link to my old band "Systatic" (Line6 Vetta II days) http://www.systatic.ca

Mr_Moo
Club Circuit
Posts: 642
Joined: Wed Oct 23, 2013 3:33 am
Location: New Zealand

Re: Cab connection FAQ

Post by Mr_Moo » Wed Jul 16, 2014 2:34 pm

Tonemeister wrote:
Mr_Moo wrote:Hi Gezza, just to clarify Rick's point there - the JVM is a mono amp, so one JVM won't run the 1960 in stereo. So if you did plug into the two 8 ohm stereo inputs on the cab, you'd need to use the two 4 ohm outputs on the amp.

But if I recall correctly, you have a 410H and an HJS. Lucky bugger [smiley-shreds] So you could set up a true stereo rig if you ran both power amps at the same time, and you'd then plug the 8 ohm output of the H into one side of the cab, and the 8 ohm output of the HJS into the other side of the cab. Could be a good setup if you're using stereo effects, and don't mind being very loud.
200W isn't that loud smilie=icon_lol.gif
Yeah true, how many Marshall Majors did Blackmore use to run on stage? (Actually use, as opposed to sitting there looking pretty).
Play it like it's the last time it'll ever be heard.

Black7Ninja
Garage Band
Posts: 28
Joined: Fri Jan 21, 2011 4:37 pm
Location: Brighton, England, UK
Contact:

Re: Cab connection FAQ

Post by Black7Ninja » Tue Sep 10, 2019 1:25 am

Hi all, this is a really great thread and has answered a lot of my questions. Really good to know that using 2 of my JVM's outputs into a single cabinet makes no noticeable difference.

I have a Blackstar Series1 2x12. It's 8ohm mono and 16ohm stereo. If I wanted to use two cabs (say when gigging) and the house cabinet is only 16ohm, is it still possible do to this given my cab is 16ohm only in stereo?

As a supplementary, if the house kit is a 4x12 what do I need to account for in terms of safety and volume matching?

Thanks

BN

Post Reply