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Gonna build me a bass amp head. Suggestions from any builders?

Discussion in 'Amps and Cabs [BG]' started by frpax, Jan 4, 2017.

  1. frpax


    Dec 15, 2016
    Tempe, AZ
    After building my first guitar amp last Summer (and it turned out fabulous!), I am now thinking of building a bass amp head.
    I would like it to be at least 100 watts (more is better) & I would also like to have a pre-made chassis. An XLR out would also be nice to have. I can do the rest of it myself.
    Oh, and this is important-- I can read a layout really well... schematic, not so much. :)

    Any suggestions from the builders in this forum?
  2. Learn to read a schematic and understand what it says. You are working blind otherwise.

    For bass in todays world, 100W is basically a practice amp. Just remember that a bass amp and a guitar amp are very different animals. I would see if you can find a kit to build. I would consider a SS design - far less voltage for a neophyte to be exposed to.

    If you want to get into amp building as a serious hobby you will need metal working skills. Suitable pre-made chassis are few and far between though they are out there. I had my last batch of chassis made at a metal fabricator. I realized afterwards that I could have had all the holes I needed laser cut at the same total cost!! Hindsight is 20/20! :(
  3. frpax


    Dec 15, 2016
    Tempe, AZ
    I can somewhat read a schematic, that is to say that I know pretty much what everything means. I just have a hard time visualizing it in a completed form. That's where a layout comes in very handy for me.
    I have 4 EL34's on hand and a few 12AX7's and a few other misc. preamp tubes. I understand that with this compliment of tubes, it would be one high powered, rocket fueled guitar amp, but not so much for a bass amp. That is why I'd like to have an XLR out...so I could run out to the mixing board and use my rig as more of a monitor. That's my thinking, anyway. If I were going to go for 200 watts or more, then I'd skip the XLR (probably).
    I'm planning on making my own 2x10/1x15 ported cabinet to run the amp through. But the head comes first.
    I do not plan on making amp building a serious endeavor...just want to make a few for myself, is all.
  4. Then think about a Fender clone. You can get just about everything you need pre-made on the internet. Chassis, transformers, boards etc. Schematics and wiring diagrams are easy to find.
  5. frpax


    Dec 15, 2016
    Tempe, AZ
    Any particular clone come to your mind?
  6. Any of the amps with four output tubes. Just leave out any reverb and tremolo circuits.
  7. frpax


    Dec 15, 2016
    Tempe, AZ
    I have heard that the main difference between a guitar amp and a bass amp is the pot values and some minor circuitry differences. Is this true?
    Also do you think there are any Fenders that I can clone with an XLR out?
  8. Pot values generally are determined by the circuits they work with, not what you hang around your neck.
    The determining factor is more about tubes vs SS, and all of that is pretty much happening in the pre-amp section.
    Where the rubber really hits the road between bass and guitar are the speakers.
  9. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Find a vintage amp that you like and build a clone. Consider a 215 or two 115's. You can't built an amp such as an Ampeg V4B for less than it costs to buy the reissue. Fender has many schematics and layout diagrams on their web site. Same goes for building a Fender. In most cases, building is more of an educational experience than it is a means of saving money.

    For an XLR out, you can take a preamp out via a 1/4" jack and feed it into a DI such as a Radial JDI. This will allow you to adopt designs, even ones without an XLR out.
    Sartori likes this.
  10. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    You're already getting plenty of good advice from many of the usual suspects. Using something like a well documented Fender layout would save you a lot of headaches.

    Be prepared to burn money the first time around, everything costs more than you expect it to. Especially if you do a "white sheet" design, which for me is the only compelling reason to do a DIY build. Or_wink.

    When I decided to finally get a custom case made for my last DIY bass amp, these guys came to my attention just after I had already committed to someone else: Landfall Systems. I'm still hoping to try them eventually for something else though.
  11. bb5000


    May 30, 2006
    Sundsvall, Sweden
    Finding a kit with more than 100W is a challenge..there's always an option to get a chassis with room for four output tubes (for example Weber's 6O100 or 6S100 chassis) and then update the transformers and power supply to something that will handle 200W or more (for example Dynaco's to build a Sunn 2000S, Hiwatt replacement transformers for a DR201)..this will involve some work planning the layout to make sure that everything fits. I usually spend more than 50% of the total build time with the schematics and layout of the amp, finding suitable parts for the bill of material etc.
    I've built five tube amps now, three of them for bass: Weber AB200, Weber 6S100 and Hiwatt DR201. My build #6 is in progress, a rebuild of an old Hagström amp from 1964 (which has no vintage value) to a Dumble-influenced guitar amp.
    Last edited: Jan 5, 2017
  12. frpax


    Dec 15, 2016
    Tempe, AZ
    Old Hagstrom stuff is really cool. A friend of mine gave me a total basket case 1974 Hagstrom Swede. Man it was a mess. But i rebuilt it completely with vintage parts, except for the pots & knobs (pots are nearly impossible to find and vintage knobs are way too expensive!)

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