16 ohm 6505 combo into 4 ohm Cab?

ghostmutt

New Metal Member
Jun 28, 2011
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High impedance output into low impedance input = Big no-no.
Low impedance output into high impedance input = Fine.

Forum wizards correct me if I'm wrong. Never had problems with such applications.
 
Rewire the cab, there is no way a 412 should be 4 ohms.

Simply put, 8 or 16 ohm out into a 4 ohm load is a big no-no, that is if you hate your power tubes and love replacing them all the time, want to OT to overheat and like your tone to sound like shit.
 
The way I always understood, it's like this:

You can put your car in neutral and floor it = No speaker hooked up to amp

You can safely fit 8 people into a car built to fit 16 = 8 ohm setting on amp to 16 ohm rated cab

You can't fit 16 people into a car built for 8 = 16ohm amp into 8 ohm rated cab.
 
If you want it to explode on you in less than 3 seconds, sure. You WILL destroy your amp doing this.

See, I must have gotten lucky then. :D

Back when I had NO clue that not having a speaker connected was bad news, I ran my Mesa Mark IV recording out into the line in of my computer....for maybe a few hours at a time, multiple times. Thing still works. Did the same with a Peavey Transtube many times as well, but one day, that one did die on me while doing this.

At practice about 2 weeks ago, I set up my rig...plugged amp into power conditioner, flipped conditioner to ON, and while moving my amp back and forth from show/jam spot, the POWER and STANDBY buttons somehow both got switched on....so the amp was on for a few seconds before I realized it and I hadn't connected my speaker cable yet. Still works.
 
I wouldnt mind a definitive answer to this aswell. To be safe I ALWAYS hook up the amp and cab at the same ohmage, but I have heard the car analogy before.
I'd NEVER switch on a valve amp without a load connected. Not even on standby (which I see so many bands doing at gigs)
 
The amp is safe without a load as long as it's in standby. You're fine going uphill (4 into 8, although I wouldn't stretch 4 into 16), but it's best to match it up exactly.

Note that mismatching impedance can affect the tone/response of the amp, usually negatively.
 
Sorry if I hijack, but why are there difference ohms in the first place? Is there any difference between a 4 ohm amp with a 4 ohm cap and a 16 ohm amp and a 16 ohm cab?
 
Sorry if I hijack, but why are there difference ohms in the first place? Is there any difference between a 4 ohm amp with a 4 ohm cap and a 16 ohm amp and a 16 ohm cab?

Convenience and tradition mostly. If everyone could agree what cabinet impedance and wiring config to use, then amps would have a single output impedance. The other thing is that when you start hooking up more than one cabinet at a time, you need to change the impedance on the head to compensate.
 
Krankenstein SST cabs, are only 4 Ohm, got one like that also, they are actually made for the solid state krank amps.

Ah i see. Took this photo of the back. 4 ohms parallel = 2 ohms right?

krankx.jpg


So whats the best option apart from rewiring the cab, a hot plate?