Tubes, Ohms, Series, and Confusion??

[diceman]

I've always just been "plug in and play" with my amps - and never really bothered to learn too much about them. Time for me to learn a little, and I'm looking for some input from you guys that know what you're talking about. I'm about to purchase a "bottom cab" for my 1/2 stack to make her a full - and have some questions.

I've got a Laney GH50L 50watt tube head (single channel, EL34B tubes), which has speaker jacks for 1x16ohms, 1x8, 2x16, 1x4, and 2x8. My cab has 4 Celestion "Rocket 50" 12's in it, has a 200w handling, and 8 ohm impedance. I'm planning on getting a second identical specs cab (strait bottom cab, same speakers, still 8ohm, 200w)

I am wondering if I'm better off to run the cabs in parallel at 2x8 ohms, or in series at the 1x16ohms output jack?

My guitar is an Epiphone Elitist LP, which has the USA 50SR/60ST humbuckers (similar to Gibson 498's I guess) - with this guitar, should I (in general) be running in the low or high input on my head?

This all seems like common stuff that I should know - but will admit that I've never thought too much about. I've always just run in the "high" input without ever thinking twice about it.

Thanks for the help, guys.

[coldsteal2]

I played for over 16 years straight with
all kinds of amps and cabs, never once looking
or paying attention to ohms.
Really never even had a problem either guess i was lucky.
I do remember one amp with a 4ohm 18" reverse horn bass
speaker and a 16 ohm 2 15" cab with a 200 Watt HIWATT head
I have no idea what i set my OHMS switch to in back hahah.
for over two years never a problem.
But i guess you can have trouble from them

But i guess its a good idea to go by the rules

[diceman]

Yeah - I'd sure hate to fry something by being a dumbass (which I frequently am)!

[US Masters]

I Just joined the forum and noticed your post - thought maybe I could help.

Running the two cabs in series will present 16 ohms to the amplifier if you wire the two cabinets in series. The problem is, the outer sleeve of the jack for one of the cabinets will be hot with output signal, so you have to be careful that it doesn't short to anything else. Plugging the 2 cabs into the 2 jacks on the back of the Laney is easier.
For sound you'll have to try both - especially trying to drive more bottom-end through the cabs in order to see which way sounds better to you. The power tube circuit, output transformer and speakers are work together so changing the operating conditions on one impacts the others.
As for the input, again you'll have to try both. Your playing style, strings, how you use your volume controls and the height of your pickups will determine how hard your guitar drives the amp. It is possible to drive it too hard in the high input and have the distortion start to lose its quality.

[drewbertca]

It would require a custom cable to wire them in series so I recommend plugging them into the dual 8 ohm jacks...

[diceman]

Thanks Drew - I'll check out a good cable as well.

US Masters/Dave - First, thanks much for the knowledge - I'll try those things and actually understand what I'm doing! I was looking at your website yesterday (just your amps so far) and am quite impressed with the specs/looks of your amps. I'm looking forward to digging a little deeper - as a boutique amp is on "my list" of gear that I'd like to get in the not too distant future. The fact that you're ready and willing to help those of us out with our gear (from companies other than your own) speaks volumes about your character. Looking forward to talking to you more in the future and hearing more about your guitars and amps.

[Paul]

woops read that wong

[b-squared]

You definitely don't want to run your 8 ohm cabs in parallel to the 16 ohm jack...you'd be sending a 4 ohm load. The burning wax from your Output Transformer would be very fragrant, and the magic smoke would be released.

I'd recommend running the cabs to the 8 ohm jacks. That's why they are there.

BB

[diceman]

Originally Posted by b-squared

You definitely don't want to run your 8 ohm cabs in parallel to the 16 ohm jack...you'd be sending a 4 ohm load. The burning wax from your Output Transformer would be very fragrant, and the magic smoke would be released.

I'd recommend running the cabs to the 8 ohm jacks. That's why they are there.

BB

Will do - 8 ohms in parallel. My bottom cab should be in next week!