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Eminence Big Ben - how does it do in a blackface Fender amp?

Discussion in 'Amp Central Station' started by 63 vibroverb, Mar 20, 2018.

  1. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    Interesting.....don't just watch the graph curve but read the freqs and db's. Most difference might be in between 1k and 2K...but that isn't a big difference, is it? I like both the LEgend 1518 and the Big Ben.....great speakers, imho. I had a Legend 1518in my proto BF Pro before I bought the '63 Jensen C15N for it. The change to the C15N was perhaps less of an effect on sonics and more for cosmetics and accuracy...since the C15N would have likely been the speaker that would have been put in that when it was built. The Legend could hold its own against the C15N, imho. I used Big Ben's to replace some JBL's in a SF Dual Showman Reverb......big warm sparkly, rich......great in that application.


    http://www.eminence.com/pdf/Legend_1518.pdf

    http://www.eminence.com/pdf/BIG_BEN.pdf
     

  2. homesick345

    homesick345 Poster Extraordinaire

    Jan 20, 2012
    Beirut, Lebanon
    it gets WAY better with time - but - as you remarked; you are starting from a good, healthy base. THe highs will settle down, more mids will be brought forward.

    You need to be planning your break-in procedure; like, yesterday. This is a 225watts rMS speaker, you really want to get it moving non-stop for 48 hours (that's what I did)

    The fizz disappears completely. Yup.
     

  3. Wyatt

    Wyatt Tele-Holic

    913
    Nov 3, 2004
    Its a BF amp designed for steel guitar; I'm pretty sure the speaker isn't what lacks mids. Seems to me a a pair of pots would solve the problem with change back on a sawbuck.

    Source...the guy with using a Legend 1518 with a '66 Super Reverb modded to use a 100KA Middle pot.
     

  4. 63 vibroverb

    63 vibroverb Tele-Holic

    625
    Nov 4, 2014
    Lititz, PA
    I definitely hear it happening. I've never broken-in a speaker using other ways besides playing and time, haha. But it could be something to consider if I wanna speed it up. A lot of the fizz went away just today already.


    I don't know how really specialized it is for steel guitar besides the 15" speaker. It has the "Nashville" mods and the NFB loop removed. The middle pots on this amp are 10k too. What are you suggesting with the pair of pots?
     

  5. Wyatt

    Wyatt Tele-Holic

    913
    Nov 3, 2004
    I like 100K Audio, that way 0-5 works just like 0-10 on the stock amp, but from there you can dial out the tone stack a little for more mids. But I don't think Fender offers a 100K pot on the PCB-mounted pots, they do offer 250K, but that would turn it into a RAW control.

    Or, you can bump up the Middle cap in the tone stack from 47nF to 22nF (stock value in BF Super Reverbs and most Borwn Fender combos), but that has a bigger impact in the lower mids.
     
    Last edited: May 14, 2018

  6. 63 vibroverb

    63 vibroverb Tele-Holic

    625
    Nov 4, 2014
    Lititz, PA
    Interesting. I may look into that, as 15" speakers are more scooped by nature. I'm quite happy with the amount of mids on the amp now though, I was just saying how the Big Ben has less mids than the Red White Blues. There is a "Fat" switch on the Guitar channel that bumps up the mids, but it's too much and gets clanky.


    You're much better at interpreting these things than I am, Wally. What's it saying? Looks like the 1518 is more efficient, heavier magnet, smaller voice coil, and less power handling than the Big Ben. EQ range is a bit wider on the 1518 as well. Perhaps if I spent more time with a 1518, I'd learn how to work with it more. The Big Ben gave me the goods right out the gate though.
     

  7. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    The Cusom Vibrasonic differs from a TR in that ‘customer om’ Channel that I set up for steel in that they did away with the bypass cap in that steel channel...decreasing gain for a steel. The tone stacks in both channels are classic AB763 stacks, aren’t they?
    But then....this amp is modded so we don’t really know what has been done. On channel can be voiced much differently and gain increased so as to have a more versatile amp with a BF channel and a hot, tweedier ...more midrange....type of channel.
    I don’t like to remove the NFB but rather use a pot in series with the top resistor to again yield more versatility.
     

  8. 63 vibroverb

    63 vibroverb Tele-Holic

    625
    Nov 4, 2014
    Lititz, PA
    I enjoy both channels for what they are. The steel channel is crystal clear and gorgeous. Guitar channel is hotter and fatter. As far as I know, I don't think the amp was modded outside of the Fender Factory - I've been told Zinky made some tweaks to the circuit that are commonly known as "Nashville mods". Sorry for the confusion.

    I may consider getting an adjustable NFB pot installed someday.
     

  9. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    Okay, 63VV, I went back and looked at the pschematic...focusing on the Guitar channel. Zingy did some of the tone stack mods I was talking about to that Guitar channel. That is why you sense that Fatter and hotter’ thing there. IMHO, he should have changed the slope resistor as well.....and perhaps gone with a larger midrange pot as Wyatt suggests.
    If you wanted to have a TR channel in that amp, a 25Mfd/25v bypass cap added to the input stage of the Steel channel gets that done. As it is, that gain has been reduced in order to control the big low strings on a pedal steel.
     
    63 vibroverb likes this.

  10. 63 vibroverb

    63 vibroverb Tele-Holic

    625
    Nov 4, 2014
    Lititz, PA
    What value would you change that slope resistor to, Wally? What does that actually do?

    I think I’ll leave the “Steel” channel as is.
     

  11. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    63VV, that slope resistor can be changed to say 56K. This will move the midrange just a tad in the tweed direction. IF I had that amp, I might also like more mids. That is a 10K pot. IF one had a 25K pot that fit there, that would do it for me. One could perhaps tag a 6.8K resistor there in series with the pot to ground and add that much to the total resistance. That would give you the 6.8K of a BF with no mid-controls to a total of 16.8K.....a bit 'hotter' and more aggressive....if there is a place to do that.
    Imho, it is odd that they did not reduce the input signal to the first stage in that Steel channel. That would make that channel a much friendlier place for a big steel string...like in the C6 tuning. I once setup one of the very early 4 x 10 Bassman amps....December 1954...for steel. I reduced that input signal strength.....as I understand Cesar Diaz did for the SRV Vibroverbs....among some other things. When the fellow was trying the amp out with his pedal, I asked him how he liked it. He looked at me, put his bar on up the neck on the low string on the C6 neck,hit the note and slid the bar all the way down and opened the string up...big and firm. He looked at me and grinned...saying.."I never could do that!" That input is just fine for most guitarists.....but SRV's big low E almost demanded that something be done there at the input...prior to the preamp gain stage. IT helps keep a big guitar signal from overpowering that first triode.
     
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  12. 63 vibroverb

    63 vibroverb Tele-Holic

    625
    Nov 4, 2014
    Lititz, PA
    Thank you, Wally. I’ll request these changes to the tech. I’m bringing my amp to him to address the background hiss that’s been present the whole time I’ve had this amp. I don’t want to add an NFB loop, and I want to keep the reverb on both channels. Don’t want to go to lower gain tubes either. Hoping there’s a way to get rid of the noise without changing the sonics.
     

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