I hope you could help me with a problem I’m facing with my amp.
I have a Hartke HA4000 (400 watts into 4 ohms and 220 watts into 8 ohms) connected to two cabinets in parallel:
The Hartke VX1508 350 Watts @ 8 Ohms and Hartke VX115 300 Watts @ 8 Ohms. But whenever I’m playing (volume 1/10 or 2/10)
the sound is cracking/clipping a lot. I actually went through the manual to check about then cabinets and it was saying
that they would not recommend connecting to cabinets in 4 Ohms but I’m not sure if its the case. I was thinking about connecting
in series but I am afraid to damage the amp as I do not know much about cabinets in general. I hope you could give me a help on it.
Just to make certain I understand your gear what I’m reading is that you have two 8 ohm cabs you connect in parallel. One is a VX1508 the other is a vx115. Correct? And your amp is an HA4000 which will run a 4 ohm load producing it’s full 400w. Correct?
So with both cabs connected the amp is seeing a 4 ohm load (impedance) which according to it’s specs in can easily handle as well as 8 ohm and 16 ohm loads. I also don’t find anything in the manuals for those two speaker cabs that indicates they can’t be connected in parallel. In fact the manual has a diagram showing the proper way to do it.
So all of this seems good yet you’re getting clipping at low volume levels? Correct?
How long have you owned the rig? Did it just start doing this? Are you using proper unshielded speaker cables and if so could there be a problem with one or both of the cables? Do you experience any problems when using the cabs individually? Are you running any effects in line or through the effects loop?
Just trying to narrow down the possibilities from afar.
The problem has happened since I bought the amp two years ago. I’ve tried to connect the speakers separetely using or not effects in a low volume, usually I do not play more than 3/10. Not a ghost!
I apologize if some of my questions seem so basic that they cover stuff you already know and understand but no one here can see or hear what you’re dealing with so if we’re gonna troubleshoot online we might as well cover as much ground as we can. We’re looking for the source of the problem here and where in the signal chain it could be coming from.
You say it’s happens under a 4 ohm load with both speakers connected and under an 8 ohm load when only one speaker or the other is connected. The amp can run any load from 4 ohms to 16 ohms so nothing here seems related to an impedance.
Are you sure you’re connecting the cabs using unshielded speaker cable not shielded instrument cable. I apologize if this is something you know not to do but we’re troubleshooting online here so I want to consider any and all possibilities.
The amp has two input jacks. Does this happen regardless of which one you’re using? Have you tried different basses and instrument cables to be certain the problem isn’t coming from that? If you play a bass with active electronics have you checked the battery(s) and are you using input #2? Does it happen even when the basses volume is rolled back or only when the bass volume is higher or highest?
If you’ve already been through all of what I’ve mentioned so far and if none of the above is an issue and this has been a problem since you bought the amp why haven’t you returned it or contacted Hartke about repairs? It seems as if you may have an amp that needs servicing. In any event a tech should look at it for you.
He’s using two 8 ohm cabs now whose jacks are wired for parallel connection. The same problem exists whether he runs both at 4 ohms or each one separately at 8 ohms. Connecting them in series would require rewiring them and two 8 ohm cabs in series would create a 16 ohm load. I don’t believe that impedance is the source of the problem. It seems like it may be more related to the input stage or improper connection of the speakers.
I have tried to connect the cabinets separately in 8 Ohms using both outputs connection that exists and swaping them as well. I have more than one bass in which are all active. I have used the input #2 for active pick ups and still the same problem has happened. In regards to the unshield speaker cable, I’m not sure as I bought the amp with those cables but they really don’t look like a guitar cable at all I’ll try to get some new cables to see if the problem persist. The thing intriging me is the watts on the cabinets which are 300 and 350 in 8 Ohms. My amp runs in 400 W in 4 Ohms. So I guess the amp is more powered than the cabinets.
Do you know how could I connect them in series? Cause I think it might solute the issue. Cause My amp runs till 220 Watts in 8 Ohms which is lower than the limit of the cabinets. I might try it to see if it solves the problem.
If the speaker cables were supplied by Hartke along with the amp they should be the proper type of unshielded cables. As for how wattage is shared it’s split between all speakers in the system like the following example.
My Genzler Magellan produces 350w @ 4 ohms. If I’m using two 8 ohm cabs with speakers rated @ 300w each one is seeing only 175w. Half the output wattage at maximum power. If I was playing the same amp through a 4x10 cab with 300w speakers each one is seeing 87.5w. The load is always divided among the speakers.
The one of the cabs you have combines a 15" driver with two 8" mid range drivers. It’s likely that cab has an internal crossover that sends frequencies above a certain level to the 8" speakers and the low end to the 15". The other is a straight ahead 1x15 cab. Those speakers are sharing the 400w the amp produces @ 4 ohms so no one speaker is getting more than 200w output tops.
Even if you were to play either cab alone at 8 ohms the amp is only producing 50%-60% of 400w so roughly 200w-240w. You would not be overpowering the speakers then either. The danger here is to your amp if you were to run say three 8 ohm cabs at a 2.67 ohm load. As the manual cautions. That amp cannot run less than a 4 ohm load.
You’d need to rewire the cabs and then you be running a 16 ohm load not 8 ohms.
Do this instead. Call Hartke and speak with someone in their service and repairs dept. Describe the problems you’re experiencing and let them give you some advice. No one should be more knowledgeable about their products than they are.\
If they’re unable to diagnose it over the phone or via email they will very likely direct you to a more local service center to have it all looked at. It could be an issue in the input phase or in the preamp that will require taking the amp apart to test and repair. I would do this as soon as possible to avoid doing any damage to the amp.
