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Buildin an Amp

Discussion in 'Amps and Cabs [BG]' started by Ro_Maniak, Sep 18, 2005.

  1. Ro_Maniak


    Aug 21, 2005
    anyone know how to build their own amp?

    I'd like somethin taht I can carry around a bit easier

    help me out?
  2. mksolid


    Jan 4, 2005
    One of my friends and I looked into building one. If you want to go any higher than 10 watts or so, you need to spend big bucks on the appropriate transformers. And you're probably not gonna be able to build one cheaper than the pro companies can.
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The last time I built my own amp was 1982. Since then prices have dropped to the extent that building my own from parts now would cost more than buying one.
  4. ddnidd1

    ddnidd1 Supporting Member

    Yep. Especially if you're buying parts in very small quantities.
  5. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    I played through a DIY 60-Watt combo for roughly seven years, starting in 1990. It sounded great, and never had a problem. Right now I have a preamp design that I have been using for several months, and a DIY speaker. I am putting the finishing touches on a 140-Watt switching power amp based on the AMP1 kit from 41 Hz Audio (www.41hz.com). In terms of expertise, I have a degree in physics and extensive experience with electronics.

    Here are some general comments:

    1. Forget about saving money.

    2. What do you know about electrical safety? Thermal design? Mechanical design?

    Building small-signal gear, such as preamps and effects, is easy and fun. It is cheap enough that you can afford to carry a spare. Power amps are deceptively simple. Basic circuits are easy to understand, but there is a lot of subtlety involved in electrical safety, thermal loads of various components, self protection, and protecting your speaker from damage. A lot of published DIY designs are unprotected. If you make mistakes, they can be costly or even dangerous.

    One reason for building DIY gear is to tailor your sound. But anything that you can do with the sound of a power amp (especially solid state) can be simulated in the preamp much more cheaply and safely.

    My sole reason is because I am curious about switching power amp design. I have not decided whether I will take my DIY power amp to a gig yet. The new Clarus looks awfully tempting, but so does a Backline 600 head.

    Unless you are compelled to do this by pure hobbyism, you will be better off buying a commercial power amp and saving your time and money for interesting projects with preamps, effects, speakers, etc. A good power amp can be the "reference platform" for experimenting with those other things.
  6. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Aside from all the great points mentioned above (with special thanks to fdeck for mentioning electrical safety!!!!) you should think about resale value as well.

    If you shop carefully for a good used amp, chances are you could sell it later for your purchase price, or even more.

    If you build an amp from scratch, it's likely to have little value to most folks...

    Since your only mentioned criteria is light weight, it becomes even more difficult to build a functional, reliable amp...

    You can also keep it light by buying an amp only loud enough for monitoring and then run through the PA....
  7. Ro_Maniak


    Aug 21, 2005
    well... all that info definatly changed my mind :smug:

    so I'll jus save up for somethin...

    any suggestion for somethin small, light, doesn't have to have many watts...???

  8. FWIW:

    I just completed making a phono preamp (so I can plug my turntable into the computer). Simple circuit, using a single NE5532 opamp, plus a regulated power supply.

    Total cost of my parts: about $16...but I scrounged the power transformer, enclosure, cord, and bridge rectifier from pieces parts around the shop. Add $20 for a transformer, and $25 for a decent enclosure, and I would have over $60 into a gizmo that I can buy commercially-made for $39.

    Also, when I got done, the original enclosure was too small, so the transformer was too close to the main board, producing a minor but discernible hum. (I wound up putting everything in a bigger enclosure, now it's dead quiet ). This is the kind of problems one can run into when you make your own stuff.

    Not to mention that the total project probably took about 10 hours of my time piddling around with it. Actual solder time was much less, but there's a lot of time required to plan, decide where holes will be, getting parts, etc.

    And did I mention the equipment needed? Soldering iron, VOM (volt-ohmeter), wire strippers, drill, drill bits, etc. And get into the hobby a little more, you'll want a signal generator and oscilloscope...

    Now, for a learning exercise, building your own stuff is fun and educational. Keep it small and low-voltage to start with, though. Maybe try some of the small stomp-boxes on www.diystompboxes.com first.
  9. A9X


    Dec 27, 2003
    Sinny, Oztraya
    I agree basically with what fdeck said above. I'm an EE and have been designing and building electronics for a couple of decades both for work and pleasure. It can be a lot of fun to make your own gear, but experience tells me that for a novice builder, unless the project is simple (or better yet) a kit, then the likelihood of it working first time is low and faultfinding requires a base knowledge that most non-techs don't have. Also unless you have a stash of parts then you're not going to be able to better a commercial unit for price. There are a whole raft of reasons why but the big ones are bulk discounts, production line techniques and designs that should already be optimised through testing before it goes into production. You gain by not having dealer/distributor markups, taxes, shipping, warranties etc.

    The two things that are also project killers (and maybe literal killers) for amateurs are earthing and safety with high voltages.

    I'm building my own rig now, basically because it's fun and because I can build what I want, the way I want it and because I still get wholesale prices, can do it for less than I can buy a lot of gear here (Australia) incl importing my own. I also get to select the componentry used for it's performance. However it's time consuming and a PITA a lot of the time as components don't fit where designed, parts are backordered or delayed etc. This one's also all SS which means PCBs and not the easy and fast point to point of tube amps. At the end of it, I'll have a rig that will better everything I've tried and probably cost less than something I could have bought, has some features not seen elsewhere etc, not factoring my design or build time labour costs.

    I'm also using 'digital' amp modules to keep the weight down and because they also sound great when properly done. These modules are easily available and quite cheap but a complete running unit eg the Crate Powerblock I recently mentioned in another thread is still available for less money that my component cost. It also has a lighter weight switchmode power supply, warranty etc.
  10. Ro_Maniak


    Aug 21, 2005
    aiight, so how much would somethin small with low voltage be?