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Thoughts on Attenuators?

Discussion in 'Amps and Cabs [BG]' started by keiththebassist, Jan 16, 2012.

  1. Anyone out there using attenuators with their tube amps?

    I've been eyeing the THD Hot plate because I really like the concept. I've found that with my hartke 3500 head, the tone just seems to keep getting better and richer to my ears the higher I crank it. I want to hear that sweet high gain, overdriven warm tube crunch while still retaining the ability to someday father children.

    Also, they seem to now have built in noise suppressors, My amp is quiet but my guitar players Marshall pumps quite a bit of white noise when the gain is turned up. I've seen some reviews with guitar amps but wondering if there are many bass players out there who have used the THD or any other attenuator.

  2. sunbeast

    sunbeast Supporting Member

    Jul 19, 2006
    Los Angeles, CA
    Attenuators all have a maximum rated power input, and as far as I know there aren't any that can handle upwards of 200 watts (most are only rated at 50-100 if I remember correctly). They are also usually used with tube amps so you can get power tube breakup at reasonable volumes, whereas most solid state amps don't really benefit from having their power amps pushed extremely hard. There are some exceptions to this- Mosfet-based solid state power amps can get a certain grind when pushed that is pleasing, as do a few other designs (like the older GK designs), but usually the pleasant grind is coming from the tube preamp being pushed in a hybrid solid state design and not the power amp.
  3. sunbeast

    sunbeast Supporting Member

    Jul 19, 2006
    Los Angeles, CA
    It appears the THD only handles a Max wattage of 185...
  4. Hmmm... Thanks I had never heard that. I wonder why that is. Perhaps thats why it's much more common amongst guitar players? I do have a hybrid tube/ss amp but I am pushing a peak of around 300 watts.
  5. sunbeast

    sunbeast Supporting Member

    Jul 19, 2006
    Los Angeles, CA
    I'm guessing that is because guitarists using all tube amps are the main target for the application, and most tube guitar amps only put out between 20-100 watts. When you crank a tube amp into distortion it is usually putting out more than that though, hence the "continuous rating" wattage limit on the THD of around 150 watts (enough for basically any tube guitar amp apart from the 200 watt HiWatts and a few other exceptions). There probably would be some market for a more powerful version for bassists that play SVTs and other tube bass amps in the 300 watt region that want huge saturation without overpowering the rest of their band, but probably not that great of a market considering the need for a much larger sized heatsink (I would imagine that the powersoak is mostly just a big heatsink with a load attached, so for a larger wattage it would need to be proportionately larger) and increased tube costs (pushing an amp to its limits burns through tubes much faster, and replacing the power tube section of an SVT is much more costly than something like a Marshall Plexi- not to mention the strain it would put on the other components in the power section).

    As far as using it with a solid state amp, have you tried just turning up the input gain and turning down the Master volume? I don't know how well built your amp is, but not every amp is designed robustly enough to put up with being pushed to its limits all the time. If you aren't worried about that aspect, then you could just look for a less efficient cabinet so you would be forced to push it harder to get the same amount of volume. You won't get more tubey overdrive by pushing a soliud state power amp harder though, so you might have better luck just hitting the preamp harder (where the tube is located)...
  6. Yes. I found that out after partially frying mine.
  7. will33


    May 22, 2006
    +1 all around.

    Those power soak, hotplate type devices are nothing but tube killers. As bassists, we have better ways of achieving it, namely smaller amps and/or fewer/less sensitive speakers, which is the approach guitarists worth their salt should be taking. Our problem usually isn't taming ourselves down but rather getting loud enough.

    With an SS amp, follow sunbeasts advice and just turn the master down and the input up.
  8. Good insight, I usually keep the tube preamp at around 75% and the solid state preamp more around 35% with the power amp set pretty low (around 20%). So I'm already overdriving the tube pre. Does the power amp usually give tonal change or does it simply amplify the signal? thanks again for the in depth response. Obviously I'm still new to lots of stuff in the amp world :)
  9. sunbeast

    sunbeast Supporting Member

    Jul 19, 2006
    Los Angeles, CA
    Hitting the power amp can give create a pleasant distortion in some solid state amplifiers to a point (the GK 800RB for example), but usually there is nothing to be gained from hitting a solid state power amplifier super hard except possible damage to your amp and/or speaker (and often some really unpleasant distortion)- and any distortion certainly isn't going to be "tubey", because there aren't any tubes in the power section. An all tube amp has the capability of "tubey" drive from both the preamp tubes and the power amplifier tubes, and you will never get quite the same sound or feeling from an amp with a solid state power amp without some sort of tube power amplifier modeling technology. If you are looking for a more tube-like drive and don't want to invest in an actial tube amp, then you might want to check out a pedal like the Tech21 VT Bass or any number of bass overdrive pedals (though the VT Bass has a pretty good rep on here and would be a good place to start I would think).

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