Easy to use Peavey combo amp's head or the speaker separately

Discussion in 'Amps [BG]' started by fnordlyone, Nov 27, 2013.


  1. fnordlyone

    fnordlyone Supporting Member

    Joined:
    Jun 12, 2013
    Location:
    south Louisiana
    I pulled the grill off my Peavey Basic 112. It is attached with velcro (NASA!) Then I unscrewed 4 spots to pull speaker. There are two wires. In this case, they both had connectors, so I didn't even have to unsolder the speaker. I then bought a 2 dollar 1/4" jack. The wires inside combo, with their connectors, fit on the pos and neg of 1/4 jack without soldering. Wrapped with electrical tape.
    My combo head (50 watts rms into its original 8 ohm single 12) now powers my 2x12 4 ohm cab at 75 watts.
    Sounds so much better.:cool: No more farting out when I hit my lows-- the two 12s handle it well.

    Will be testing out my vintage CTS 10 inch speakers in a cab which will be built to early 1970's Ampeg classic sound. I have repaired the rip in the one cts speaker… elmer's glue and toilet paper.
    Oh yeah, I no longer have the 60hz buzzhisst! It is gone!:hyper::hyper::hyper:

    The 4x12 system (16ohm + 4ohm) sounds killer, too. It's going around 5ohms with about 70 watts. Right? :confused:

    If you want to use only the speakers in a combo… get a 2 dollar male 1/4", attach some wires and connect other end to the combo's speaker(s) (enough wire to get it to the head). Plug into jack of your favorite amp head.

    f n o r d !
     
  2. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    A couple of very important cautions here:

    First, if you are using the external speaker jack to ADD a cab in parallel with the existing speaker, the total impedance will be lower than just the speaker that came with the combo. There's a very real possibility the amp will not be able to accommodate the additional load on the amp.

    Second, even if you are disconnecting the combo's internal speaker and just using an external cab, the external cab's impedance may still be lower than the amp was designed for, still risking frying the amp. As noted here, the original speaker was 8 ohms, the cab was 4 ohms...that's asking for twice as much current out of the output transistors.

    Finally, if mixing speakers (or cabs) of two different impedances in parallel, the lowest impedance speaker (or cab) is going to get the vast majority of the power through it.

    I have no idea what combination you are figuring out that nets you 5 ohms. Four 16 ohm speakers in parallel yields 4 ohms. If you plug ANOTHER 4 ohm speaker cab into the amp in parallel, the amp now will see a 2 ohm load. I doubt your amp will survive very long.
     
  3. fnordlyone

    fnordlyone Supporting Member

    Joined:
    Jun 12, 2013
    Location:
    south Louisiana
    Thanks for the response. I have the older model Basic 112 that doesn't have a speaker out jack. Yeah, not sure how I figured out 5 ohms:rollno:. The two cabs (one a 4, the other 16 ohms) together is 3.2 ohms and below the 4 ohm minimum that Peavy rates the head. I won't be doing that again; I'll rewire the 16 ohm cab into a 4 ohm to be used alone.
     
  4. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Just to ease my foreboding, the 16Ω cabinet is a 4x12 correct?
     
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  6. Garden Variety

    Garden Variety Supporting Member

    Joined:
    Oct 29, 2013
    Location:
    Columbus, Ohio
    Peavey stuff IS usually overbuilt, and your Basic 112 might get by fine with the 4ohm speaker load, but placing a 4ohm load on a transformer with only an 8ohm tap is not the same as using a transformer designed for either 8 or 4 ohms, as with the newer Basic 112. These are ok practice amps as stock, but if you huff the tranny it will likely not be worth fixing. Even if the old tranny and new tranny are the same, there could still be other changes in the circuit designed to accommodate the 4ohm load that your amp doesn't have. A simple call/email to Peavey CS would settle it.

    And I would ABSOLUTELY get those speaker leads soldered to the jack. Maybe you think they are ok with just e-tape on them, but just one slip and if the leads short together, again, the amp becomes a boat anchor. Cheap insurance....

    BTW, in case you don't know (seems few do, based on reviews), these have active preamps. The faceplate nomenclature is misleading; a "flat" EQ setting is actually with the knobs at noon, not zero, and you have boost or cut options.

    Jon
     
  7. Steve Dallman

    Steve Dallman Supporting Member

    Joined:
    Mar 5, 2006
    Location:
    East Central Wisconsin
    I've got a Basic 112 that does 75 watts with a 4 ohm load. The original speaker was 8 ohms and there is an ext speaker jack. I put in a 4 ohm speaker and it's a little cranker.
     
  8. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    Note that Peavey changed their Basic 112 design, the older ones don't have an external speaker jack. I'd have to see the schematic for the newer version to see if it's the same power amp as the older version.
     
  9. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    These are solid state amps, there is no output transformer.
     
  10. fnordlyone

    fnordlyone Supporting Member

    Joined:
    Jun 12, 2013
    Location:
    south Louisiana
    Thank you for the info. Yes, I will email Peavey about this momentarily (I figure since its the night before Thanksgiving it will take them like 10 seconds to get back with absolutely the pertinent information. I'm not being sarcastic, they have the best tech support I have ever encountered by any company). I looked at the literature that Peavey keeps neatly organized on their site. The heads specs seemed the same for my old timer as the newer ones with the ext. out. I will solder the wires and mount jack soon.
    f n o r d !
     
  11. nashvillebill

    nashvillebill

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    Oct 13, 2002
    Location:
    Nashville TN
    Again, this is NOT a tube amp, there is no output transformer!
     
  12. fnordlyone

    fnordlyone Supporting Member

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    Jun 12, 2013
    Location:
    south Louisiana
    Nashvillebill is correct, of course. This is solid state.
    I don't just have e tape covering bare wires, either. The lead wires have heavy duty female disconnects and it takes a pliers and persistence to disconnect from the jack's prongs (not to get sex ed). I put the electric tape as an extra precaution. Maybe the extra insulation of the tape cut out the 60hz bzzzhhsst?

    f n o r d !
     
  13. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    I wouldn't worry about the quick connects coming off the output jack if they went on tight, after all that's how they were on the speaker to begin with!

    The electrical tape on the terminals should not affect any 60 hz buzz. External sources (fluorescent lights, fridge, etc) usually are the source of 60 hz. Or an ungrounded outlet.
     
  14. fnordlyone

    fnordlyone Supporting Member

    Joined:
    Jun 12, 2013
    Location:
    south Louisiana
    Bill from Nashville,
    Thanks for keeping an eye on a 43 year old rookie like me.
    for all…
    da vault of peavey "assets"

    http://www.peavey.com/support/searchmanuals/archived.cfm

    lots of great undervalued old peavey gear out there IMO:)
    get your specs above
    going fishing on craigslist for myself right now… hoping for an old tank to float to the top!
    tis the season, :cool:
    f!
     
  15. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    I've got one of these older Basic 112 amps myself. I added lots of stuffing into the enclosure and replaced the speaker with a Scorpion Ultra12 (still 8 ohm), made a lot of difference.

    I *may* have replaced a couple of opamps with OPA2134 but I can't remember.
     
  16. deathsdj

    deathsdj

    Joined:
    Sep 18, 2010
    Location:
    Wichita, KS
    I have a Basic 112 also. The older one without an external speaker jack. My daughter recently broke off my headphone plug in the jack (my fault, I left it plugged in and she is 3 and loves my bass gear) so it is going to have to come apart.

    Now I'm thinking upgrades, just because I like to do stuff like that.

    Cheers!

    MJW
     
  17. fnordlyone

    fnordlyone Supporting Member

    Joined:
    Jun 12, 2013
    Location:
    south Louisiana
    Here's a pretty well done home made instruction on ripping the Basic apart and replacing/repairing input jacks!



    happy tinkering!
    fnord!
     
  18. Garden Variety

    Garden Variety Supporting Member

    Joined:
    Oct 29, 2013
    Location:
    Columbus, Ohio
    Ouf.....yes, output transistors, not transformer. Still, I know the older model (the one I had) specified 8ohm minimum load (listed on amp and in manual). It was the later model that offered the extension jack, allowing a 4ohm total (and the wattage increase). I wouldn't just throw a 4ohm load on that original until confirming that the output stage was up to it. Being only 50 watts, just about any use of it is going to be running the amp pretty hard. I considered mine useless for even a 2'fer practice with another guitar player.

    Jon
     
  19. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    I agree with you there, I tried using mine (with the stock speaker) at a practice once... I could not hear it.
     
  20. fnordlyone

    fnordlyone Supporting Member

    Joined:
    Jun 12, 2013
    Location:
    south Louisiana
    Hey Jon,
    I am only practicing at fairly sane volumes in my bedroom. Still, I was considering mine useless for its lack of tight bottom. I just don't think the stock speaker can pull it off; damn thing is a WoNkEr:scowl: Since it was useless, and cost me a hundred bucks, I don't mind risking it to be useful. Oh, it sounds so much better through the 2x12 cab (two 8ohms speakers parallel for a 4ohm cab)! I love to practice again… priceless.
    I will check with Peavey Friday, though. What is this you speak of this, "output stage?"
    word's oldest rookie still trying to learn,
    f n o r d !
     
  21. deathsdj

    deathsdj

    Joined:
    Sep 18, 2010
    Location:
    Wichita, KS
    Thanks!

    Cheers!

    MJW
     

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