WTB: SVS Amp Interface by Marchand Electronics

Discussion in 'Archived Threads 2001-2004' started by Jason JS, Jan 27, 2003.

  1. Jason JS

    Jason JS Agent

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    I need one of these really bad. I need more bass !!!!

    Please !!! I will pay top dollar !!!

    SVS Amp Interface by Marchand Electronics, please !
     
  2. Vince Maskeeper

    Vince Maskeeper Producer

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    FYI, this box won't necesarily give you "more bass".

    The whole SVS system of allowing users to gain stage is very dangerous, since no one seems to care enough to understand how a signal chain really works.

    Be very careful with this unit- can do more harm than good.
     
  3. Jason JS

    Jason JS Agent

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    I have my pre amp Adcom GTP-750 turned all the way up (for the subwoofer)and the amp that I am using does not have a gain Adcom GFA 5500

    I just wanted to use this to get a few more db of bass, by using the gain and turning it up a little.

    Is this the wrong reason to get this unit ?
     
  4. Vince Maskeeper

    Vince Maskeeper Producer

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    Well, it's complicated. Have you actually calibrated your system using test tones? Using those tones- how close to ref are you? Are you unable to get ref bass level, calibrated, with your preamp?

    Does your amp have an input indicator? I would guess that since your Amp and Preamp are matched- they are actually designed to work with one another--- so you're problem with bass level is not likely an issue of getting enough juice to the amp, but rather that the amp is not giving enough output.

    Any amplifier has a fixed input level it wants to see at MAXIMUM. The problem with these configs is that every amplifier obeys a different system, and every preamp has it's own output level... thus a box like the SVS magic box might be needed...

    However- given that you have a pre and amplifier made by the same company-- they are likely designed to interface at the same levels, so you're likely already clipping the living hell out of the amp input using the preamp at max level - and adding that box between the two to boost that level will only make that situation worse.

    And thus you see the danger of this type of tool in the hands of someone who doesn't really understand the nature of the signal chain.
     
  5. Jason JS

    Jason JS Agent

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    :b
     
  6. Jason JS

    Jason JS Agent

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    Wow !! That explains a lot. I have not run the test tones as of yet.

    I will run the Avia disk tonight to see what type of output I am getting. And measure with Radio Shack db meter.

    And what are ref bass levels, how many db's ?

    The amp is 400X2 into 4 ohms. I am only using one channel. Also, the clipping lights are not turning on.


    Thanks for all the help in trying to solve my problem and not make it worse [​IMG]
     
  7. Vince Maskeeper

    Vince Maskeeper Producer

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    This too is a bit of a complicated question- the stock answer is that sub output will probably be 115-118db SPL peak output (but this is not how you set your tones!).

    The onscreen instructions in AVIA should help you dial the speaker levels (which is the most important step of getting good audio). If you want some additional instructions, there is a piece in the FAQ and PRIMER, written by this real handsom fella I know:

    http://www.hometheaterforum.com/htfo...553#post650553

    Step one is to get the levels dialed it the proper output. If you still find your processor pegging max Sub output- then we can consider how to fix that problem next.


    Again- the real issue here is that a box like the one you seek solves a specific problem-- and if you don't really have that problem, it creates the potential for serious damage.

    Most people who have little/no experience with audio and chaining several devices together misunderstand the concepts along the way. It might very well be a bad idea to create and extreme signal boost along the way...

    There was a simpson's episode once where bart lined up 20 police megaphones in a row, turned them all on, and made noise into the first. The noise was then amplified, and reamplified until it became giant---

    Well, the truth is, it doesn't work that way. Your amplifier device has a fixed maximum voltage it wants coming in. Beyond that max, you are force feeding it signal and the signal will be distorted-- and distorted signal will damage amplifiers and speakers.

    It is often the case when people don't like the output they're getting that the amplifier is lacking in wattage for the chosen application. Pushing more signal into the amp is USUALLY a very bad idea-- especially if you don't know how much voltage it expects (and especially if it offers no indicator of incoming signal level).

    So, I would say:
    Step one is to calibrate and see where you're at. If you get all the tones to measure even, and you still have the processor sub level cranked to +7 or higher- THEN you MIGHT consider other alternatives...
     
  8. Jason JS

    Jason JS Agent

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    Vince,

    Thanks for taking the time to read into my problem. I have printed out your message and will give it a try tonight or on Wednesday since I have the day off.

    Thanks again what you are saying makes a lot of sense.
     

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