Peavey 3120 output troubles, please help

[Reeltarded]

You noticed the speakers weren't serial between the pairs, but did you notice that one jack is a switcher and they are tied together? That is what should be stock in that cab.

It left the factory in the above configuration. It had to.

OOPS! NOPE I see a spider 4x12 stereo only. Open it up and put those pairs in series with each other.

[cryptic Kitten]

From Peavey amp owners manual (link posted above):

CABINET IMPEDANCE SWITCH
This three-position switch allows appropriate selection of speaker cabinet impedance. If two enclosures of equal impedance are used, the switch should be set to half the individual value. For example, two 16-ohm enclosures necessitate an 8-Ohm setting, while two 8-ohm enclosures would require a 4-ohm setting. Minimum speaker impedance is 4 ohms.

Yeah? They are just saying it's a parallel connection. I can only use one of the jacks on the amp though. Unless I feel like taking the thing apart and electrocuting myself to fix it.

[cryptic Kitten]

You noticed the speakers weren't serial between the pairs, but did you notice that one jack is a switcher and they are tied together? That is what should be stock in that cab.

It left the factory in the above configuration. It had to.

Neither was tied together, nor were there signs of that. It is also indicated on the back that each side is 8 ohm and in no way implies that one side could be used for anything other. It's a cheap cab. They didn't go above and beyond with it, but it works for me. Also, I could tell nobody ever had the back off of it when I had to take it apart. It's from the spider ii era. It's not like one of the higher end valve cabinets.

[Reeltarded]

See above. You are right. They did make a stereo only to go with their stereo heads. They saved $1 on a jack and a wire and cost themselves $30 in having to shuffle two styles.

[NickC]

Nothing besides left and right input. It's a cheapo line 6 cab. It sounds okay, with the celestion seventy 80's.

I guess it wouldn't be to hard to mod it. Could do a series AND a parallel jack. Would be nice if they just made a cable to save me time though.

I hate 1/4" switching jacks in speaker cabs. Two reasons:

(1) Switchcraft released some with high failure rates. If the switch fails, leaving your poor amp OT all-dressed-up-with-nowhere-to-go ..... it'll give-up-the-ghost.

(2) There isn't enough metal in those switching-tab connectors for good contact when you're pushing a lot-o-watts.

I used to use the big, fat Switchcraft 1/4" TS plugs with 12 gauge cable soldered very soundly, for years. Nowadays I've replaced most of that with Neutrik Speakon™ connectors.

[Reeltarded]

Imagine what my cable case looks like. Failures? Nah.

[cryptic Kitten]

Yeah, I guess I'll just run them in series. My amp is 120watts so running it in series should quiet it down a little, no?

[NickC]

For a 16 ohm cab, follow this:

[img:640:542]http://i254.photobucket.com/albums/hh10 ... Series.jpg[/img]

4 x 16 Ohm speaker = 16 Ohm load
[img:300:213]http://www.avatarspeakers.com/pictures/wirserpa2.gif[/img]


If you want a 4 ohm cab, go this way:

Wiring Configuration for 4 Speakers in Parallel
Four 16 ohm speakers = 4 ohm load

[img:310:61]http://www.eminence.com/wp-content/uplo ... allel4.gif[/img]

[Reeltarded]

Don't mismatch. Open the cab and serialize the paralelled pairs together. Safer to rewire and parallel series pairs, but hey..

[cryptic Kitten]

Didn't understand that last post tarded. I'm pretty good with wiring, used to do sound systems.

[Reeltarded]

I typed while Nick was posting pocs of what I was saying.. except for the talk about s/p vs p/s.

If the jacks are wired series to two pairs and a pair goes down you have no load was the message about which way to wire for those just in case moments.

[cryptic Kitten]

Oh, they are wired in parallel so I am going to do series at the jack.

[cryptic Kitten]

Tech just called about my amp. He said there was bad resistors and the bias was all over the place so it is going to need all new tubes. He quoted me $200. Good bad?