Building Custom Bass Amp

Discussion in 'Amps [BG]' started by staybobo, Nov 11, 2012.


  1. staybobo

    staybobo

    Joined:
    Oct 6, 2012
    Mercury Magnetics Hiwatt Partridge Transformers: OT HI200-O & PT HI200-P.*
    Preamp tubes: 5751 & 12AY7.
    Driver tubes: 12AX7 & 12AU7.
    Power tubes: 6550.
    Rectifier: Solid State.
    2 Inputs Passive & Active
    Optical 3:1 Compressor/Limiter w/switch.
    Wattage knob to go from 350 watts to 30 watts.
    Master volume per channel.

    Channel 1: 4 band Baxandall Eq. & 9 Band Graphic Eq. *- Clean to Moderate breakup
    Channel 2: Sunn Bass Coliseum Eq.*& 9 Band Graphic Eq. *- Dirty to Fuzzed out
    Effect: Envelope Filter w/Graphic Eq.

    Foot pedal: Channel 1/2, Graphic Eq off/on, & Envelope Filter off/on
    Speaker Cabinet: 1964 Gibson Titan III Speaker Cabinet For Bass.
  2. BogeyBass

    BogeyBass

    Joined:
    Sep 14, 2010
    Cool dude that is alot of stuff is this a kit or do you plan on laying that all out yourself.

    Interested in how your doing the pre and EQ's board? turrents?
    350 watts so....6 or 8 power tubes? plate voltage?

    sounds like a monster, going to need healthy bias current and one hell of a phase splitter.

    cant wait to see this.......
  3. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Interesting. Have you ever built a tube amp before or designed one???
  4. B-string

    B-string Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    3 graphic EQ's? Really? One on one channel maybe IHMO. I find graphic EQ's more destructive than useful, but it is not my amp :)
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  6. JGR

    JGR The "G" is for Gustav Supporting Member

    Joined:
    Jun 29, 2006
    Location:
    Maryland
    Disclosures:
    President, CEO, CFO, CIO, Chief Engineer, Technician, Janitor - Reiner Amplification
    Go with Heyboer instead of Mercury unless you get a discount on MM.
  7. B-string

    B-string Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    BTW the output trans you listed is a 200 watt transformer. It won't due 350 watts.
  8. B-string

    B-string Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Have you tried http://www.magneticcomponents.net/ ? I just installed one of their OTs in a Marshall 6100. It turned out to be not only a good replacement but a tone improvement as well. Creamy OD, more open lows and sweeter highs.
    A "SVT' or 400/400+ OT would be a special order (300 watt plus) but they do special orders all the time and more reasonable than MM?
  9. Bassmec

    Bassmec

    Joined:
    May 9, 2008
    Location:
    Ipswich UK
    Disclosures:
    Proprietor Springvale Studios
    But then again he didn't say how many 6550 tubes he has in his design
    So we don't know a lot, perhaps it's such much:
    [​IMG]
    but starved plate.:D
  10. B-string

    B-string Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    My bet is no, but I have been wrong before. ;)
  11. staybobo

    staybobo

    Joined:
    Oct 6, 2012
    No I haven't built an amp before.

    Mercury Magnetics Hiwatt Partridge Transformers: OT HI200-O & PT HI200-P & Mosfet
    Preamp tubes: 5751 & 12AY7.
    Driver tubes: 12AX7 & 12AU7.
    Power tubes: 5 6550.
    Rectifier: Solid State.
    2 Inputs Passive & Active
    Optical 3:1 Compressor/Limiter w/switch.
    Wattage knob to go from 200W Tubes/450W Mosfet to 30W
    Master volume per channel.

    Channel 1: Tubes 4 band Baxandall Eq. & Switchable Off/On 9 Band Graphic Eq. Clean to Moderate breakup @ 200w.
    Channel 2: Mosfet Sunn Bass Coliseum Eq. Dirty to Fuzzed out @ 450W.

    Foot pedal: Channel 1/2 & Compressor/Limiter.

    Speaker Cabinet: 1964 Gibson Titan III Speaker Cabinet For Bass.
  12. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    The voltage required by a 350W amp is lethal and needs special measures to be taken. Even after 50+ years of working with tube electronics this is a project I would think more than twice about attempting.
  13. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Then if you attempt this you are in danger of losing your life!!! I just can't emphasize that enough.
  14. JGR

    JGR The "G" is for Gustav Supporting Member

    Joined:
    Jun 29, 2006
    Location:
    Maryland
    Disclosures:
    President, CEO, CFO, CIO, Chief Engineer, Technician, Janitor - Reiner Amplification
    They do indeed make great stuff; I have used them for guitar as well. I inquired about an SVT style a few years ago and they wouldn't do it. Heyboer are great and very well priced. I've got five custom chassis waiting for a big amp, and the design is done, but as Bassmanpaul said, it's a huge undertaking.

    To the OP, if you haven't built an amp before - make that several - DON'T start with something this complex and dangerous. .
  15. staybobo

    staybobo

    Joined:
    Oct 6, 2012
    What style output and power transformer should I use?

    Tube/Mosfet bass amp
    Preamp tubes: 3 5751 & 2 12AY7.
    Driver tubes: 3 12AX7 & 1 12AU7.
    Power tubes: 4 6550.
    Rectifier: Solid State.
    2 Inputs Passive & Active
    Optical 3:1 Compressor/Limiter w/switch.
    Wattage knob to go from 200W Tubes/450W Mosfet to 30W
    Master volume per channel.

    Channel 1: Tubes 4 band Baxandall Eq. Clean to Moderate breakup @ 200w.
    Channel 2: Mosfet Sunn Bass Coliseum Eq. Dirty to Fuzzed out @ 450W.

    Foot pedal: Channel 1/2 & Compressor/Limiter.

    Speaker Cabinet: 1964 Gibson Titan III Speaker Cabinet For Bass.

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