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Fender 300 Pro questions.. (power draw and overdrive squeal)

Discussion in 'Amps and Cabs [BG]' started by eyeballkid, Mar 2, 2016.


  1. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    Ok.. Ive got two questions about my Fender 300 pro tube amp.

    1) Ive actually got two of these amps. They both work perfectly and have been real workhorse tone monsters for me. The first amp is tubed with Winged Cs 6550s and EHX in the preamp. It has a bit more volume and sweeter tone at identical settings to the other one. The second one is tubed with EHX 6550s and Tung Sols in the preamp. I have a passive jazz and a passive P bass. Whenever I use a passive bass with the second amp on the overdrive channel I get a loud squeal if either I have the overdrive channel drive above 7 or I have the tone on the bass wide open. If I turn the tone knob back about 1/3 the squeal will go away even with the overdrive on the amp turned to 10, OR if I leave the tone knob all the way open and turn the overdrive below 7 on the amp it will go away. Its not a feedback issue from being too close to the amp as far as I can tell.. Any idea whats causing this? It only happens with passive basses and only on one amp. Is it something to do with the gain of the tubes and their voicing? or???


    2) This weekend my band is playing a good old fashioned house show. aaaand like alot of those kinda things the spot we're playing, while known for hosting lots of bands, is not the most adapted to having lots of amps and power draw as sometimes multiple amps are plugged into the same source. SO FAR there hasnt been any issues there where the power has been killed or anything, BUT I have a choice between taking my Fender 300 pro tube amp, OR the Sunn1200s which is a rackmount version of the same amp that runs 750 watts. Which amp would have the lesser draw of power so I can play it safe for the spot?

    thanks guys.
     
    Sartori likes this.
  2. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    anyone?
     
  3. Don't the amps list the power draw/consumption next to the power cord socket?
     
  4. 1. This is a guess, but I think the squeal is an oscillation resulting when the impedances of the bass and pre-amp match up just right. An interesting experiment would be to swap pre-amp tubes and see what happens. "Just right" means in a way that causes this.

    2. Assuming equal efficiency, the 300W amp will draw less power.
     
    Sartori likes this.
  5. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    Doh! I think you're right!
    I'll check that tomorrow.
     
  6. mbelue

    mbelue

    Dec 11, 2010
    Tube vs. Solid State. I expect there's a big difference.
     
    bassmeknik and Sartori like this.
  7. He wrote they are the same amp except for the rack mounting. If they differ in that way then they are definitely not the same.
     
  8. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    Yeah, one is 300 tube watts, the other is a solid state/hybrid rackmount version of the same amp that does 750 watts @ 4 ohms, 1200 @ 2ohms.
     
    Sartori likes this.
  9. How in the wide world of sports is that the same amp?

    One is all tubes and the other has transistors. They are nowhere near the same. Having similar pre-amps does not make them the same.
     
  10. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    Look up the fender 300 pro and either the sunn 1200s or fender bassman 1200. They released two formats of the same design. One is a rackmount solid state version of the other. Same features, same layout, tons of power, one is a solid state power section, one is tube...

    We could argue the finer points, but basically I have a tube amp and the same amp in solid state form for more portability and less worry..

    Im just wondering which is better to take along from a "safer bet" perspective.
     
    Sartori likes this.
  11. This is not a fine point. It is a HUGE point. These are oxymorons ie., complete opposites. It can not possibly be, in even the most vague sense of the word, the same amp if it is solid state. That is just ludicrous.

    Do you know why the solid state amp is lighter? Because it doesn't have a tube-based power section or an output transformer. Those are seriously MAJOR differences. It means that the efficiency factors of the amps are entirely different. A 1200W SS amp and a 300W tube amp are likely to draw close to the same amount of power. That is the ONLY thing even remotely similar about them.
     
  12. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    So do you have an answer for my question or are you here to hassle me over semantics to make a ridiculous point that is obvious?

    Yes I know all that and I could spell it all out to get the semantics perfect for people unfamiliar with these two amps, or I could hope that people that were going to respond were at least partly knowledgeable about them to know what Im talking about.

    Here are the two amps Im talking about and YES, OBVIOUSLY they are drastically different, where one has a big ol honking tube set and iron transformers in it, but they are "two formats of the same design" as I said before..



    300pro. bassman1200.
     
    Last edited: Mar 3, 2016
    Sartori likes this.
  13. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    both have a little box by the power cord that says 120V~60hz and then the tube amp say 900w and the rackmount says 1800w next to it. So I would ASSUME that means the rackmount actually draws more current then the tube amp... twice as much.

    anybody can verify that?
     
    mbelue and Sartori like this.
  14. Identical preamps, is what he means.

    But this really is all semantics. His questions is simple. Which had the larger draw, and which is the safer bet for a venue (in this case a house) with uncertain power.

    Worth noting in this case that this player's band is probably very loud.
     
    Last edited: Mar 3, 2016
    mbelue likes this.
  15. john m

    john m Supporting Member

    Jan 15, 2006
    Right on
     
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  16. jastacey

    jastacey

    Feb 8, 2009
    Houston,Tx
    Did some quick calcations, the Pro 300, will draw about 7.5 amps, which is most likely due to the tubes drawing power for the filaments, the 1200 Pro can draw up to 15 amps, at full power, the spec's don't give a idle current draw, I believe 15 amps is the most that a consumer device be marketed, if it's UL rated, but I may be wrong
     
    Sartori likes this.
  17. mbelue

    mbelue

    Dec 11, 2010
    Or you can just look at their wattages like @eyeballkid did.
    I'm all for working out the math, but sometimes its unnecessary.


    Even though they have separate consumption ratings, and power output ratings, the only time those numbers are accurate is when they are both used at their maximum. Maybe the 1200 is loud enough at much less than full output. Same for the 300 pro. The only way to know conclusively would be to measure each one with an ammeter while in use at their desired volume level, with desired program material.


    Easiest to just compare consumption wattage and choose the lesser. No reason to make things complicated.
     
    Sartori likes this.
  18. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    Cool. thanks guys.. Looks like Im taking the tube amp.

    any other ideas on the squealing??
     
  19. mbelue

    mbelue

    Dec 11, 2010
    Swap preamp tubes between them, or if you got spares.

    Failing that: Tech Time.$ :(
     
    Sartori likes this.
  20. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    It did it with the previous preamp tubes that were in it too. I cant think what they were.. Some audiophile 12ax7s that were in it when i got it. I REALLY dont think there is a fault in the amp like something malfunctioning or busted, of course I could be wrong, but the channel works 100% fine and has no strange behavior on anything but passive basses with the tone knob all the way open while the gain is mostly cranked. Its kinda weird.. If I have an active bass, even with the treble cranked up some I have never gotten the squeal.

    ps to mbelue and sartori... I need to check back in with the stoner thread.. ive been absent tooooo long.
     
    Last edited: Mar 3, 2016
    Sartori likes this.

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