Speaker Efficiency of Fender Hot Rod Deluxe

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by slhguitar, Mar 22, 2006.


  1. slhguitar

    slhguitar Member

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    I have a stock Hot Rod Deluxe, and It is too loud for me. The speaker in it is a " 12" 8 ohm fender reissue gold label (037617) " Does anyone know what the efficiency on this speaker is, or what another, less efficient speaker would be? Or would my trouble be solved by switching to different tubes, IE 6V6s? To my understanding, the Hot Rod Deluxe does not have a bias trim pot, so how would I go about using these tubes? Any and all suggestions are very much appreciated. Thanks in advance for the help.
     
  2. ES350

    ES350 Member

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    1. turn it down.
    2a. turn it down and stick a pedal in front.
    2b. try an alnico (you have to turn it down to keep from blowing it up).
    3. turn it off and sell it.
     
  3. bob-i

    bob-i Member

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    I dont know what the rating is, but it's not very efficent. I wouldn't swap out the tubes, this amp is designed for 6L6's, swapping to 6V6's would require more changes.
     
  4. Dave C

    Dave C Gold Supporting Member

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    The HRDLX does have a bias adjust , you could run JJ6v6 tubes , but you would lose headroom but maybe not enough volume. The "master" volume pot could be changed from a linear taper to an audio to give better control so it's not so "touchy". A different speaker could make it sound better but probably not too much quieter.
    Dave C
     
  5. krash

    krash Member

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    different speaker will probably make it louder.

    6V6's will require a bias adjustment, maybe even a modification, and only JJ's, EH's or NOS tubes will hold up to the high plate voltage. The amp will sound very different with 6V6's. My warmed-over Princeton Reverb with 12 whole watts and 6V6's is REAL LOUD.
     
  6. John Phillips

    John Phillips Member

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    Unlikely, the stock speaker is VERY efficient. IMO they made it as sensitive as possible on purpose (even at the expense of tone), for the same reason as the stupid linear taper on the MV pot - so that when a kid tries it in a shop, they think "Wow - that's LOUD! And it's only turned up to 3!" Whereas in fact it doesn't get that much louder at 12...


    You could try a Jensen P12Q. That's quite a low-efficiency speaker - 96dB, which assuming the stock one is around 100 (which I'm just guessing at), means the equivalent of less than half the output power. The P12R is even lower, at only 94dB, which is really very quiet for a guitar speaker (I once put one in a Deluxe Reverb and thought there was something wrong with the amp, it was so quiet), but it's only a 25W speaker so you'll fry it unless you do other things to the amp to reduce the power (or run an attenuator set to at least 3dB down).
     
  7. slhguitar

    slhguitar Member

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    how difficult would it be to replace the master volume pot? This seems like it would make the most sense. I like the sound of it, I simply can't get that sound at a reasonable level, because the pot is so touchy. Also, what is the efficiency of a V30? I have heard that those just rip in the Hot Rods...
     
  8. krash

    krash Member

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    P12R?

    I had a Weber P12R in my Princeton Reverb and not only was it ear-bleeding loud (but maybe not as loud as the Silver Bell that's in there now), but also it exhibited a lot of cone cry when even remotely cranked. I'd think you need something with a lot more power rating than a P12R for a HRD.

    Maybe a greenback, those are about 97dB but get into different tone territory. Or an L-pad!
     
  9. slider313

    slider313 Silver Supporting Member

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    Try to find an old ceramic CTS with the C12N size magnet and the original cone. These seem to be a lower efficent speaker than most and will tone down the volume for you. The best years to look for would be late '60's-early 70's. Source code 137 on the rim. For example a '69 would read; 137936 or a '70's; 137018.
     
  10. mbratch

    mbratch Member

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    I have to agree with ES350. If the amp is too loud, you either turn down the volume, or (if turning the volume down has tone issues because of how low it is) you have an amp that's too much power and you need a different one (maybe a Blues Jr?).

    Other than that, perhaps try a 12AU7 (ECC82) in the V1 position.
     
  11. Hamer95USA

    Hamer95USA Member

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    Hey slhguitar,

    I have an Omega Amps modded Hot Rod Deluxe so let me share my experiences concerning this amp. 40 watts can be loud for some people, depending on what your needs are. Jamming in your room might be loud, but for band use, it's perfect. The stock Eminence Legend 125 speaker (50 watts) is an effecient speaker. I would try out installing a Weber Beam Blocker if the speaker's beaminess is the issue with you. You can't switch over to 6V6 power tubes unless you use have an amp tech rebias the amp. You may want to consider the THD Yellowjacket, Blackjacks or other brand of power tube converters, if you wish run EL-84 power tubes. These are pretty cool, plugs into the 6L6 sockets, bias itself for the EL-84 power tubes. It will lower your wattage and give you a different tone.

    Concerning the bias trim pot, it's located on the rear of the amp. You'll have to take off the rear cover, locate a large blue trimpot. That's the bias trim pot. The test point for the bias trimpot is located on the tube circuitboard on the far left. It will have bias test point labeled on the circuitboard. Here is more information on this in detail:
    http://studentweb.eku.edu/justin_holton/bias.html

    I learned how to bias from this article from the Unofficial Hot Rod Deluxe Owners Guide website. Bookmark this website since it contains a lot of useful information about the Hot Rod Deluxe/Hot Rod Deville.

    Guitar George
     

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