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Thread: My "New" Bronco Amp

  1. #1

    My "New" Bronco Amp

    Back about 8-10 years ago I bought a '70s Silverfaced Fender Bronco Amp. For those not familiar with the amp, it is a rebadged Vibro-Champ that was packaged with a Fender Bronco guitar as a "student model" to compete with the imports from Japan that were really improving at the time and beginning to severely cut into Fender's sales. The amp used one 6V6 tube and put out about 5 watts into a very inefficient 8" 3.2ohm speaker. Here's a picture, probably from 1968:



    Well this Bronco had a beat up cabinet that one of the previous owners had decided that it needed a convenience outlet so he installed a wall box to give not one but two convenience outlets on the side of the amp. I put in a Weber signature 8" 4ohm ceramic speaker and it sounded OK.

    Somewhere along the way, I got the idea that I couldn't leave well enough alone. I decided to add a more efficient speaker so I found a 10" Weber California speaker on eBay for a good price. I had read that you could fit a 10" speaker into a Vibro-Champ/Bronco cabinet. Well that is true but not one with a magnet the size of a Weber California. I also thought that the brownface Fender look suited the name "Bronco" better than the silverface look did. About that time, someone was advertising custom faceplates on eBay and I was getting ready to buy one when they had to stop selling them. Bummer!

    So my plans went on hold and then the amp started sounding like crap. No volume, no tone whatsoever. So I put the amp into a corner and went on. I had other great amps to play through but they were all much more powerful.

    Towards the end of last year, I decided that this was the time to move forward with the project. I saw some threads by a fellow that goes by Powdog over at Gretschpages.com. He did some great work on some cabinets and also did nice work on the electronics as well. We started communicating and came up with a plan. He was going to make me a new cabinet that would house the 10" Cali speaker. We arrived at 2" taller and 1-2" deeper. (He said it was 1" but it looks more like 2" to me and I'm too lazy at this point to measure.)

    I had seen some two-tone amps so I decided to do this one with the Brown Western tolex (remember this is a "Bronco" amp) and blonde tolex on the top and bottom with oxblood grill cloth. I thought I had a source lined up for the faceplate but that fell through so Powdog (Cave Valley Amps http://cavevalleyamps.com/home.html) suggested a source and we went to work on that as well.



    Don

    Guild X-170-T
    Guild Starfire V
    G&L ASAT Deluxe Semi-Hollow
    Gretsch 6120 DC
    Gretsch 5422-12
    Fender American Standard Stratocaster
    Fender '90s Custom Telecaster

  2. #2
    Here is the finished Cabinet:



    So I got the cabinet and took it to my local amp tech, Paul Chambers http://www.specialtyguitars.com/. He quickly found why it had been sounding so crappy:



    Well he went through the amp and replaced what needed to be replaced and also replaced the intensity pot with one that switched the tremolo circuit out of the signal path when turned off. This gives the amp more oomph when the tremolo is off. I got the amp back like this:

    Don

    Guild X-170-T
    Guild Starfire V
    G&L ASAT Deluxe Semi-Hollow
    Gretsch 6120 DC
    Gretsch 5422-12
    Fender American Standard Stratocaster
    Fender '90s Custom Telecaster

  3. #3
    Man with that speaker and the larger cabinet it sounded great. More apparent volume and the tone was fantastic. I got a Hall of Fame reverb pedal to use with it and that was just the icing on the cake. But ... that faceplate just would not do with the new cabinet.

    Well with a comedy of errors in getting the new faceplate, they finally got here. I mounted it after several small issues and this is how it ended up:





    And the volume even goes to "11."



    In the process, my $135 practice amp has become considerably more expensive, but it was a project that I had been planning for a long time and it is finally finished. At least until I have Ethan add reverb to the amp.
    Last edited by dbirchett; 01-28-2017 at 02:35 AM.
    Don

    Guild X-170-T
    Guild Starfire V
    G&L ASAT Deluxe Semi-Hollow
    Gretsch 6120 DC
    Gretsch 5422-12
    Fender American Standard Stratocaster
    Fender '90s Custom Telecaster

  4. #4
    Senior Member walrus's Avatar
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    That came out fantastic! Love the "11"!!

    walrus
    1984 Guild D64
    2008 PRS Hollowbody Spruce

  5. #5
    That's really cool!
    Quote Originally Posted by fronobulax View Post

    And I like Harry's approach.
    '66 Starfire I SB bass, '67 Mark IV pear wood, '75 Mark 4 P padauk, '00 Bluesbird black,
    '66 Thunderbird amp, '68 Thunder 1 RVT amp, '70 Superstar Combo

  6. #6
    Super cool! Brown & blonde on a Bronco is just the thing IMO.

    I discovered the "disable tremolo for more guts" trick by accident when I pulled all the tubes in my Vibro Champ, so I could clean the pins & sockets, and then neglected to put the tremolo tube back in. I was amazed at how much the cleaning job had improved the amp's oomph until I stepped on the tremolo footswitch and all went silent. :) (Vibro Champs do tremolo by using one triode of a second 12AX7 tube to vary the amount of signal flowing from the main 12AX7 to the lone 6V6 power tube. It's a unique approach with a unique sound.)

    -Dave-
    1962 F-20 Troubadour
    1970 M-75 Bluesbird
    1971 S-100 "Black Cherry"
    1973 S-100 "Nature Boy"
    1990 Nightbird Custom
    2013 NS M-75 Aristocrat
    2016 NS S-200 Thunderbird

    c. 1971 Foxey Lady

  7. #7
    That is one of the best looking little amps I have seen in a long time. Great choice on the Brown Western Tolex with the Blonde Top and Oxblood Grille. The Brown Faceplate really ties it together nice as well.

    TX
    Guilds
    Hoboken-1960 X175, 1961 SF-II
    Westerly-1971 F612, 1976 G41, 2000 SF-V, 1984 S284, 1993 JF100-NT-CRV
    Nashville C.S. SFIV-3 P90 w/Trem
    Corona-2003 Fleming F47-Brz RW, 2003 D55 50th Ann. Brz RW#10 of 50, 2003 X160 R.B., 2003 SF-III-90
    Conn-2011 GSR D50 Coco, 2013 R30S, 2013 Orph 12 Fret Slope, 2013 Orph Jumbo, 2014 Orph Burst 000-12 Fret 12 String S.H. RW, 2012 F50-DTAR, 2012 F50R Burst, 2012 F50R DTAR, 2013 F512 Burst, 2014 F512-DTAR, 2014 D55-RS

    Amps
    70 T-bird 2x12
    93 Sequoia

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