what all is this hurting, and how much?

[drew_half_empty]

well, today i got bored & plugged my hotrod into the cab I'm using for the bassman

knowing that the bassman cab is 4 ohms, i put an empty plug in the extension speaker jack of the 'rod to knock it down to 4 ohms, sounded okay i suppose, pretty much exactly what i expected it to sound like

then, out of curiosity, i took the empty plug out & ran it, now making it like an 8 ohm head running to a 4 ohm cab

and the tone was AMAZING, thick bassy distortion practically shot out of the speakers, I got more articulation, more bass, better mids, and perfectly EQ'd highs. It was truly MY tone, the tone i've been looking for, the tone that fits me perfectly

but, knowing that running an 8 ohm head into a 4 ohm cab is a big no no, well, how exactly would it hurt the amp?

If it just cuts tube life a little I'm gonna definately continue doing this, but if it pretty much cuts it in half or more, or affects something else, well, maybe i'll rethink it

so what exactly am i hurting by doing this?

 

[TheJangus]

Re: what all is this hurting, and how much?

Check out the link in this thread:
https://forum.seymourduncan.com/showthread.php?t=27679

With tube gear it's better to have the speaker impedance lower. Connecting a 4 ohm load to an 8 ohm amp may be OK, but connecting a 16 ohm load to an 8 ohm amp is probably not. Connecting a 16 ohm load to a 4 ohm or 2 ohm amp is begging to destroy the amp. Running too high of a load on tube gear can fry anything (and occasionally everything) in the outputs, including tubes, transformers, resistors and tube sockets.

 

[Gearjoneser]

Re: what all is this hurting, and how much?

Don't worry about it. It won't harm anything going between an 8 ohm amp and 4 ohm speaker load. If anything, it's a tad louder and may drive your tubes just a little harder, but those are good things. It's not adviseable to run anything thats 16 & 4, but 8 to 4 won't kill the amp or speakers. I did it for years with a head and cab and it didn't do anything but sound good.

 

[msplines]

Re: what all is this hurting, and how much?

Well, well. looks like it's mismatched cab and tube amp night. I was given a cool link by Darrin about half an hour ago for my Selmer/Marshall cab problem:
http://aga.rru.com/FAQs/general.html#imp-1
If it sounded sooo good, why not check out the real (rather than nominal) impedances, you might have less of a mismatch than you think! I'm sorry, but I don't know how to do this.

 

[drew_half_empty]

Re: what all is this hurting, and how much?

the hotrod has a 50 watt version of the eminence legend 125

the cab has 2 of the real em 125's, rated at 75 watts, the cab is wired for 4

you can change the hotrods impedance to 4 ohms by putting an empty plug in the extension speaker jack

so basically I've tried an 8 ohm speaker into it running at 8, a 4 ohm cab into it running at 4, and a 4 ohm cab into it running at 8

and the last one sounds best, so I HAVE tried

and thanks guys

 

[TheArchitect]

Re: what all is this hurting, and how much?

Plugging an empty plug in the other jack doesn't knock the impedence down. Its the load of what you plug in that does that. If anything I would have though it would have created an open circuit and cooked the transformer. No expert, but I think you got lucky.

 

[drew_half_empty]

Re: what all is this hurting, and how much?

umm no, the owners manual says you can do that

infact it reccomends that for a 4 ohm load

 

[mrid]

Re: what all is this hurting, and how much?

Plugging an empty plug in the other jack doesn't knock the impedence down. Its the load of what you plug in that does that.

That does make sense, but maybe the HRD has a special transformer?

 

[Jag513]

Re: what all is this hurting, and how much?

It's got a 4-ohm tap. According to the owner's manual, it's perfectly safe to run an empty plug into the Internal Speaker jack, and a 4-ohm cab to the External.

 

[Hellion]

Re: what all is this hurting, and how much?

That's the great thing about tube amps, you can mess with the resistance of their load to a certain degree and it won't affect anything at all. I routinely ran my Fender 75 with a 4 ohm load (recommended no less than 8) and the only thing that happened is that I got a better tone by pulling more out of the amp. That's all that happens really, when you run a lower impedance (can't do too much lower, mind you!), is that you make the amp work harder by pulling more out of it.