SF Bassman head mod/speaker questions

Discussion in 'Amps and Cabs' started by bluelew, Jan 3, 2008.

  1. bluelew

    bluelew Member

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    2 questions:

    1. What are some companies that mod Bassmans and is there anyone here who has had them done? Any reviews/thoughts? I have heard of a company that will mod the bass side of a Bassman into a hot rodded plexi and mod the normal side to blackface specs. Any idea on what companies would do something like this?

    2. Any thoughts on speakers/speaker cab. I have looked at Avatar's cab with a vintage/celestion gold combo. Any ideas much appreciated. I have focused a lot on pedals and don't know much with regard to amp mods or speakers.

    I play an American Strat with a Pearly Gates HB in the bridge and 2 Texas special SC in the neck and middle. I love a good Fender clean (other amp is a Deville). Dirt boxes include a Fireball II, maxon OD-9, and Line 6 Dist Mod for real heavy stuff. I play a variety of styles from blues, Praise and Worship, to pretty heavy stuff.
     
  2. portcitymusic

    portcitymusic Supporting Member

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    I would decide on which mod(s) you will have done on your amp then work on speaker choice. How much gain will be added along with the amount speaker break up you want will play a huge factor in the decision of which speaker to use.

    Daniel
    Port City Amps
     
  3. hasserl

    hasserl Member

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    What you're asking about is very common and not technically difficult to do. Most any amp tech that has been working on amps for awhile has probably done this at one time or another, and can do it for you too. Just ask around locally.

    As far as speakers, And amp like this would benefit from speakers that would work well with both channels, the Fender side and the Marshall side. IME Eminence makes some great speakers that fit this bill, the first IMO being the Tonker. A great speaker that adds little coloration and let's the amp do most of the breakup, it's bright and clear with bell like tones. But a second choice would be the Texas Heats, they will also deliver great clean tones (not as sweet as the Tonker IMO) but when pushed they will breakup more and add some compression that also sounds really great. A modded B-Mass thru a pair of Texas Heats would do Billy Gibbons style tone with ease, a really great sound IMO. The Avatar cabs are also really nice, nothing wrong there. You might also want to check with JD Newel on a cab that would match the Fender Cosmetics.
     
  4. blackba

    blackba Supporting Member

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    I am working on doing some mods to my '67 Bassman with the AB165 circuit. Allen amps had some cool bassman mods, but they aren't doing them anymore. There is a guy in Texas doing them, I don't have his contact info.

    I am doing these mods: http://blueguitar.org/new/schem/fender/modnotes/mga-aa864_vs_aa165.pdf

    I am waiting on parts before I can give you feedback on how it went. Any tech should be able to do these mods....
     
  5. bluelew

    bluelew Member

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    Thanks for the replies. I will definately take a look around locally. Anyone have any web sites to direct me to with regard to modding and speakers? So far I've only been to Avatar and haven't found any with regard to mods.
     
  6. scott1568

    scott1568 Member

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    Try Andrews Amp Lab in Atlanta. His name is Jeff. He turned my '67 BF from the AB165 circuit to the earlier AA864 circuit. I did not do the Marshall mod though, but I am sure he can handle it. Great guy to work with, quick turnaround, and great results too.
     
  7. bluelew

    bluelew Member

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    I will give that a look. Thanks Scott.
     
  8. sl1960a

    sl1960a Supporting Member

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    On SF Bassmans I've always liked converting the PI to Blonde Bassman specs. Makes them really roar (if that's what you want).
     
  9. Texsunburst59

    Texsunburst59 Member

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    My local amp guru does the Allen mod or the Allen/master volume mod on the Bassman heads. David Allen regularly directs customers that want these mods to my amp guy. PM me and I'll get you in touch with him. Here's my '66 Allen/Master Volume modded Bassman head that my amp guy modded for me.

    [​IMG]


    You can find a lot of Allen/Master Volume modded Bassman head clips on my soundclick page.

    http://www.soundclick.com/bands/default.cfm?bandID=633883&content=music
     
  10. bluelew

    bluelew Member

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    Very cool stuff! I liked the tone of this one a lot: Bad Sign BT '66 Allen/MV (Plexi) Bassman Do you remember how much gain you had dialed in on the amp? What exactly does the Allen mod do? How much and what kind of gain does it get?

    Thanks!
     
  11. Kelly

    Kelly Member

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    Mike from kcanostubes (blue_strat) mods them.
     
  12. Texsunburst59

    Texsunburst59 Member

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    I had the gain at about 3 and the master at about 3 for the Plexi setting. Here's what the Allen mod does to a Bassman.

    BassmanĀ® Head conversion - there are lots of 65-70 BassmanĀ® heads with the odd AB165 circuit which was quite a departure from traditional Fender circuits. The BASS channel is not really voiced well for guitar and is often not used. This conversion rebuilds the entire circuit board so the NORMAL channel is the more desirable AA864 circuit (about like the NORMAL channel of a Super Reverb) and the BASS channel becomes a really cool lead channel with a tweed/Plexi flavor to it. The DEEP switch goes between the huge cathode bypass capacitor associated with the 5F6A Bassman to the much smaller capacitor used with the Marshalls. This channel has an extra gain stage, is more aggressive and has more harmonics for a great lead channel. You can use an A-B switch to switch between the two channels with each having its own volume and tone controls. It makes a much more usable amp for guitar. Many end up preferring the BASS channel to the classic tone of the NORMAL channel. The conversion is $199 plus anything else that might be needed as part of normal service such as new filter capacitors, tubes, grounded power cord etc. I have done several of these and they are very popular. The modifications are reversible and there are no holes drilled or controls not properly labeled.

    My amp guy just adds the master volume to the Tweed/Plexi side to be able to dial in heavier gained tones. You can really get some nice singing overdriven tones with the Master volume mod that you can't quite get with the regular Allen mod.:D
     
  13. bluelew

    bluelew Member

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    Thanks guys. Any other ideas with regard to speakers or mods?
     
  14. bluelew

    bluelew Member

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    Bump for speaker opinions?
     
  15. blackba

    blackba Supporting Member

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    I am going to go with a 4ohm Weber 12F150 for my '67 Bassman for my 112 cab. I have used my bassman with my '62 Fender 212 cab that has Weber 12A125A's and it sounds great. I didn't care for the Celestion Classic Lead 80's with it not surprisingly.

    I have the parts in for the mods, but I haven't gotten to it yet....
     
  16. operanonverba

    operanonverba Silver Supporting Member

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    I'm curious.. is there a foot switch available so you can go back and forth between channels with the Allen mod?
     
  17. sfarnell

    sfarnell Gold Supporting Member

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    Here's mine. The cosmetics are ratty but the sound is beefy and it's a lot of fun to play. Bill Krinard did the mod, I painted the faceplate :dude

    [​IMG]
     
  18. blackba

    blackba Supporting Member

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    Standard AB switch should work fine.....
     
  19. smolder

    smolder Gold Supporting Member

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    That's really awesome!


     

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