16ohm spkr in Deluxe Reverb?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by dognmoon, Feb 23, 2006.

  1. dognmoon

    dognmoon Supporting Member

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    I stumbled upon an ebay Auction for an Eminence Swamp Thang with 1 minute left and a great price. I bid as quickly as I could only to read the fine print (after winning, of course ...DOH!) to see that it was a 16ohm instead of the 8ohms that a DR calls for.

    My DR is a ptp reproduction of the ab763 circuit using a repro chassis but current production aftermarket trannies. The guy who built it for me says that there wouldn't really be any problems using a 16ohm speaker (and I trust him implicitly) but I'd like to get anyone else's thoughts on the outcome.

    1. Would it cause extra wear on tubes or trannies?
    2. Will it adversely affect the sound?

    thanks in advance.
     
  2. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    It's not going to sound the same as the correct ohm rating version of that speaker. The question is how much different it will sound. The 100% mismatch can be done without harming the output tranny (as you builder/tech has already told you), but whether it sounds the same is another thing, as I imagine there will be some difference.

    Whether it hurts the OT, the tubes or whatever is also something your amp guy should know...it might depend on his circuit, or OT (and what it "likes to see" for an ohm rating out of the OT).

    I'd probably defer to your tech on that one, and also get another speaker with the 8 ohm rating and see for yourself. The Swamp Thing isn't all that expensive through Avatar or Weber VST, if I remember right...
     
  3. donnyjaguar

    donnyjaguar Member

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    You have a couple of options. Check to see if your output tranny has a 16 Ohm winding and use that if it does.

    Strap a 16Ohm power resistor across the speaker. I think a 15Watt would be adequate on a Deluxe.

    Third option is don't worry about it. The 16 Ohms won't allow your amplifier to run at its most efficient, but I seriously don't it would put it into peril either.
     
  4. John Phillips

    John Phillips Member

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    You might be amazed by this, but actually 16 ohms is a better match for a Deluxe Reverb than 8 ohms is. Really! Fender made them like that for some reason... the actual 'correct' match going by the OT turns ratio is somewhere around 13 or 14 ohms if I remember rightly, but 16 is close enough.

    No, I didn't believe this at first when I read about it either - but I checked it using different loads and metering the output power at each. Sure enough, more power was produced at 16 ohms than 8, which indicates a better match. In fact, the stock 8-ohm load is a better match if you put 6L6s in the amp...

    Assuming the OT is an exact reproduction of the old spec, what you should get is slightly more power, and a tighter, more controlled and even tone with less flub at the bottom end when it's pushed hard. And definitely no risk whatever.
     
  5. donnyjaguar

    donnyjaguar Member

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    This is quite believeable. One of my compatriots swapped the 2x 6V6 in his Deluxe with 2x 6L6 and the net result was it worked much better.
     
  6. dognmoon

    dognmoon Supporting Member

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    regarding the OT, this is what he (the tech) had to say:

    "a pair of 6V6's want to see 5000-8000 primary impedance & the OT is 6600."

    I dunno, what those numbers mean, but maybe they give you a clue how close to the original trannies these repros are(?).


    Thanks for the help, guys.
     

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