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Everything posted by agedhorse

  1. The "gain factor" of a tube does not necessarily translate into circuit gain. It depends very much on the circuit itself. There are circuits where a tube with "higher gain" will result in a circuit performing with LOWER gain. It really does depend on the circuit the tube is used in. Forgive my use of the word tube in place of valve...
  2. Hopefully, being asked to turn down and your divorce don't have anything in common...
  3. From my experience designing amps, this is generally the most accurate description of what's really going on. And to add... conformation bias is very much a real thing that can be a frustrating source of "non-difference".
  4. In pro audio, mutes can be used for a variety of applications, not just to kill a channel. For example, most pro audio consoles have mute groups, where a number of channels assigned to a mute group can be muted with a single switch. The most common application for this is on effects returns for killing the returns between songs for talking. They can also be used for groups of instruments, where say there's an acoustic set and an electric set (or songs) and to switch between them the unique instruments would be assigned to mute groups so say the acoustic guitars and say mandolin could be muted during the electric set. Why not use subgroups for this? You can if you are not mixing monitors from the FOH console, because the pre effects sends (monitor mixes usually) would not be muted so the benefit is not there. Of course this has all been made a little less relevant with multi-input digital consoles, VCA/DCA's and input to channel patch duplication (main and post eq/fx monitor mixes from the same channel).
  5. It's typical for the bass market to lead the guitar market in useful features and technology, guitarists often have a mute feature in their tuners (when they choose to use them).
  6. See my post above, just because something "works" doesn't mean that it's correct and not causing a problem (or a problem that will rear it's head down the road). For those who claim that all failures in an amp under warranty is because the amp is defective, this is a good example of why this statement is not always true.
  7. This is why amp designers spend so much time and effort designing protection circuitry, but even so, protection circuits are not perfect and failures can occur.
  8. Different players, different needs and different tastes for their "at home" application.
  9. The send impedance isn't going to matter much, it's the return impedance that dictates the effectiveness (based on orders of magnitude and the position of the elements in the circuit.) It's a good exercise to do the math, then it becomes obvious WHY. Return input impedances run anywhere between 10k and 100k, there will be a lot of effect at 10k and almost none at 100k.
  10. A 56k resistor is series will work ok with some amps and not with other amps depending on the topology of the loop. I was just pointing g out a more correct solution for those who care about such things.
  11. Neither, those topologies are used for impedance matched networks. All you need is a simple voltage divider.
  12. Using a resistor like that depends entirely on the input and output impedance of the effects circuit. Generally, a more predictable result comes from a true series/shunt pad where the variables are defined almost entirely by the external circuitry rather than varying based on what is inside the amp.
  13. If there are no bleeders designed into the circuit, or if there is a failure with the bleeder circuit, caps can store charge for a surprisingly long time if there's no load (like a typical plate circuit).
  14. This is something that sound guys deal with daily.
  15. The answer is in part that "it depends", but in practice far field cabinets that are designed to work together (reasonably similar math and phase response) generally will not have any more negative impact on the audience sound than "perfectly matched" speakers as these differences are WAY too far to the right of the decimal point to be a significant factor. I'm sure somebody could dream up some wild combination that would be a factor, but I'm talking about REASONABLE choices here.
  16. I should have qualified my comment, because the smallest venues I typically work in start at about 1000 seats. A bass player fighting the sound guy in larger venues is absurd because the sound difference out in the house is SO different than what it typically is on stage (especially in proscenium houses). Also the tools I have in a typical PA are MUCH different (typically) than even the biggest bass rigs. multiple double 18" subs alone completely change the low frequency extension equation. Often a player will want more extension than what their on stage rigs are capable of, so they will boost the low end in an attempt to get more extension, yet all this does is generally muddy things up (especially on stage). The better choice is to allow the PA to do the heavy lifting and concentrate on their stage sound and how the entire band is impacted by it. With a little bit of coordination, often the sub bleed from the PA will fill in the missing lowest octave just fine on stage anyway.
  17. Wait a minute, that's not true at all. The amps are the same width, the holes are in the same locations. The rack ears are identical, with the exception of the size of the screw holes which are about 0.1mm smaller in diameter. The holes on the rack ears can be opened up with a suitable size drill bit.
  18. Of course the quality of the sound will vary from venue to venue, it will do this even if you have a single cabinet. Each venue has completely different acoustic properties, different absorption coefficients, different boundary conditions, and different combinations of path lengths. The PA and a (qualified) FOH engineer will take the bass signal off the stage and do what is necessary to work in the acoustic environment of the auditorium which will always be different than what is happening on stage. The better the engineer, the better the translation of the desired stage sound to the audience... and it has to happen in context with the rest of the mix also.
  19. Everything within the Subway line is (of course).
  20. There are a LOT of differences, including just about every parameter that applies to compliance, resonance, moving mass and then there's the design differences that account for cone (and suspension) break-up. Generally, the frequency that the high frequency rolloff occurs is quite a bit higher than with a bass speaker, and HOW it rolls off is different too.
  21. It's not a crap shoot because there are manufacturers who do know what they are doing, and have a well established track record of doing so without issues.
  22. It also allowed for the blood to pool at the front, sparing much backstage inconvenience
  23. Yes, it is a myth when the speakers are designed with this in mind (and have the engineering/math to back it up). None of the efficiency equations contain any variables related to the size of the driver. Mixing drivers CAN be problematic, but it doesn't have to be problematic and in fact can provide the (knowledgeable, skilled) designer the ability to develop a range of voicings that is not possible (or practical) with a single driver.
  24. In practice it MAY cause issues IF the cabinets were not designed with similar acoustic properties. This means sensitivity, power balance, phase response, complementary voicing, etc. The issues of acoustic summing occurs regardless of similarity of the speakers, it relates to identical speakers also, based on the number of point sources and the distance between the sources. Then there is the (usually) greater issue of boundary conditions, how the reflections within the room combine and the frequencies that each boundary act on (and at what level). The myth of only combining identical speakers without the considerations of all underlying factors that affect the summed response needs to be put to bed rather than be perpetuated.
  25. agedhorse

    Pre amp

    If the Roland amp states that using the headphone out as a recording or aux output, that means that the designers determined that it was safe to do so. Different circuits can behave in unpredictable ways when used in ways the designer did not intend. This is why using a headphone output MAY not be safe unless stated so by the manufacturer.
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