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Genz Benz Shuttle 9,2 tube swap

Discussion in 'Amps and Cabs [BG]' started by jake bassist, Apr 4, 2014.

  1. Hi,

    I have Aquilar TH500 and Genz Benz Shuttle 9.2. Prefer the clean sound of Shuttle more than TH500 but GB is lacking in gain structure compared to TH and therefore the dB loudness of TH500. Simply put , when opening gain more TH retains clean, or at least unchanged sound much longer(dialing further) than GB. With GB I can't dial tube gain more than 9-10 o'clock max in order to keep it clean but then I miss on power.
    My question is ....is it posible to raise distortion threshold of tube gain by puting some other tube? So I can have more of the clean signal going into power section and consequently have more power on tap.
    Thanks for your time,
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    This is a very good question that opens up the whole subject of gain structure.

    Every amp is designed with an entire range of operating levels in mind. These ranges can overlap within the various stages inside the amp to allow a wider variety of tone and playability. Amps are also designed with their controls having a particular taper to them, taper being the output per degree of rotation of the control. It's most impressive to design an amp with a lot of gain in the first part of the rotation because when customers compare between amps ina busic store the one that gets loud the fastest is "more impressive", even though that may not accurately indicate which amp is really the loudest when the entire gain structure is taken into account. Our choice for the Shuttle was a fairly linear feeling gain versus rotation, less impressive at the lower end but gain continues much farther through the rotation. Why? Because it's more useable and feels better to the more experienced player.

    That said, there's a lot of gain available over the "input gain" control's rotation, this is so that the amp can work with both low and high output pickups, and still get into overdriven territory. In order to be able to scale this wide, the volume control next to the gain control, as well as the master volume can be used to jhelp moderate how much (if any) preamp tube overdrive is available. To reduce the overdrive, decrease the input gain and increase the volume and master volume controls.

    You might also taka a look at the manual, there is a block diagram in the back, as well as a discussion about gain structure.