binky_bass

Before I ran this rig I actually did send both MarkBass and Phil Jones and email asking if it was safe to run both cabs into the Markbass... No response from either. As such I did it anyway, in hindsight a potentially foolish manoeuvre, but hey, now I know!

I still don't feel quite at Ohm with all of this, but I'm learning! (awful I know...)

I used one 8B cab for a good year or so, no volume issues there to be honest. I recently got the other 8B from eBay as it was silly cheap hence the second cab. There is no real benfit to using both for the purposes in which I use them other than having two looks better than having one! Purest self-indulgence I know, for which I could easily have been punished with the blowing up of the MarkBass... So knocking up a series box from about £15 in parts would allow me to continue my (somewhat pointless) amp vanity. Either that, or get a second head for the second cab, or god fobid, SELL the second cab...

So 3 Speakon connectors and 4 bits of wire, wired in series, housed in a non conductive box would essentially do the trick? Weekend project...

So similarly, it would be equally unwise to run four Aguilar DB112 cabs (300w 8 ohm) into a TH 500 (500w @ 4 ohm, 250w @ 8 ohm) as that would also be a 2 ohm load? If the amp has two dedicated inputs for speakers, I assume daisy chaining two DB112 cabs into each input (4 cabs in total) would then be running a 2 ohm load? (I dont have 4 DB112s, I'm just getting my head around safe loads etc.)

Right, yeah I've had a read of that and you are indeed correct. So with these cabs being wired in parallel at 4 ohm each, because of the nature of parellel wiring the load becomes 2 ohm... so if one cab blows the other is still alive. Is it possible to re-wire them as series? This then would see them function at a joint 8 ohm right? ...But with the drawback of them both cutting out if one dies? My brain is trying to absorb everything here!

I've run the rig as in the picture for a good 3 weeks now, probably a total of 10 hours use, running the gain at circa 1/3 and the volume and about 1/2 with no issues at all. No overheating, no stuttering, nowt... The amp definitely says 500w @ 4 Ohm on the rear, and these cabs are definitely 4 Ohm a piece. Running these cabs together, supposedly at 2 Ohm into a 500w @ 4 Ohm head, should I expect derterioration over time or more of an instant death? As I certainly havent experianced the latter. Obviously I don't want to kill the amp, but as yet (in my blissful apparent ignorance!) I have had no problems whatsoever running the rig as is.

Am I right in saying running these cabs at 2 ohms pushes the head beyond it's limit by a factor of 2? So would the head need to be run at a max of half power before hitting the danger zone?

I'm after an education here, so any thoughts would be happily received... What's the potential damage to the amp? From a logical point of view I would see the amp as feeding the cabs, so where does damage to the head come into the equation? And yes, I understand the slightly condecending statement of "The amp doesnt magically double in power to 1200w", I was more inferring to the potential load being recieved by the cabs if functioning at 2 ohm the the resitance is halved. So, with two 4 ohm cabs coming into the amp at 2 ohm, whats the risk of damage if the amp is rated at 600w on the rear panel with the handbook rated power being 500w into 4 ohm?

I'm not great with the wattage/ohm equation. Does daisy-chaining two 8B 4 Ohm cabs then present half that load to the amp? With potentially a 2 Ohm resistance would I be right in saying that the cabs are then much more vulnerable to damage as with half the ohmage it essentially doubles the recieved wattage into the speakers? With each cab being 400w and the head being 600w would it then stand to reason that I could in theory push the 600w to say 2/3 power (say 400w equiviance) based on the 2 ohm resistance effectively halving the joint cab wattage to a combined 400w instead of 800w? So really, I suppose the question is, am I safe enough with running the Markbass at no more that 2/3 volume into both these cabs if they present a joint load of 2 ohm? Techy stuff!

MarkBass Multiamp Mono.

They are both 8B cabs. I've had no issues running the head with both cabs. The cabs are daisy chained with only one being directly linked to the head.

That would indeed appear to be an upside down bridge...

The KL 11 string fretless was in the works when I stayed with Jean all of about 7 years ago! Still yet to be finished I believe.

I actually had the privilege of staying with Jean for 3 days some years ago, I bought his 9 string Pac-Man Conklin and as I flew over to San Francisco to collect it, he kindly put me up for 3 days! The man has a crazy collection of vintage arcade games in his basement. Also has the honour of playing that very bass... it's a savage beast!