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Topic: Speaker/Power Attenuators |
ajm
From:
Los Angeles
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Posted 18 May 2003 8:10 am |
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Has anyone here used one before?
I'm specifically looking at getting either the THD Hotplate or the Weber VST MASS.
Thanks.
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Artie McEwan
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Paul Osbty
From:
Seattle, Washington, USA
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Posted 18 May 2003 8:46 am
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Line 6 also makes one. I forget the name of it.
www.line6.com |
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ajm
From:
Los Angeles
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Posted 18 May 2003 2:22 pm
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Paul, I'm looking for information on a speaker/power attenuator that goes between the amp and speaker. It attenuates the volume that you hear coming out of the speaker while still allowing you to crank the amp and get the effect of the power tubes.
I looked at the Line 6 site and couldn't find theirs. Please let me know what the Line 6 version of this device is.
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Artie McEwan
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Bill Crook
From:
Goodlettsville, TN , Spending my kid's inheritance
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Posted 19 May 2003 6:05 am
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Please be aware.......
Anything you place beween the amp and the speaker to dissiapate sound/heat/distortion will/can drive the power-amp much harder.
This can/will cause early failure of the power-amp section of your system if used for extended time.
Useing one of my "Nashville 400" amps,I managed to actually cause a device (in the amp) to burst into flames by useing a "Power-soak" device.
As I was testing for MAX power output, I manage to fry a 1501 4 ohm speaker,2 output transistors,and the "clippin" chip,u8. I finally wound up with a (believe it or not)with a 7-10 amp @ 27 volt(AC) signal to the speaker.
Of course,the speaker blew out. Even at best, NO speaker can handle this kind of current.
Bottom line here is :
There is a limit to being able to produce a "forced" sound to the final device(aka as the speaker)without doing damage to the power output stage of an amp or the speaker.
Right now, I am useing "Power Mosfits" in my "Nashville 400". I am conducting test to see just how much voltage and AC signal I can actually send to the speaker without causeing damage to the speaker or amp.
These devices are generally use as a "Motor Control" devices to limit or control the amount of energy to the final output device.
If you are not a "Teckie" type of person (and do not have the equipment),I would not suggest that you attempt to modify your equipment for Maxiumn performance. Let someone else do it for you.
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BDBassett
From:
Rimrock AZ
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Posted 19 May 2003 7:21 am
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Good question.
All of Mr Crook's cautions are certainly valid but I don't suspect you are trying to burn down the house, just want a little of the overdrive sound. There may be a low tech, safe and effective solution known as an L-pad. If memory serves, pads are different than pots in that they do not change the impedence that your signal is looking at. For example, if an amp is supposed to be pumping it's signal into an 8 ohm speaker and it is really 'looking at' a 4 ohm load it will run hot and there may be problems as a result. When you try to attenuate the voltage of the signal to the speaker so that it is softer, you run the risk of changing the load on the amp. You don't want to do that because as I said it may cause problems.
So, you want to attenuate the signal without changing the load. That's what an L-pad does.
I used one for many years on one particular monitor speaker. I salvaged it out of an old Shure Vocalmaster speaker cabinet. I was a large ceramic core coil about 2 inches in diameter with a knob that turned just like any volume control. I mounted it into a little metal box with a couple of phone jacks and used it in line with that one speaker.
Worked like a champ for me.
BDBassett |
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Paul Osbty
From:
Seattle, Washington, USA
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Posted 19 May 2003 8:51 am
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Yup, I misread your post. Try a :
Marshall PB100 |
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Dave Robbins
From:
Cottontown, Tnn. USA (deceased)
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Posted 19 May 2003 10:00 pm
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Years ago when I was still using Fender amps, I had a "Twinn" that I had modified for studio work. One of the modifications was the adding of an "L-Pad". This really worked great. I wanted to get the amp down to a reasonable level for studio mic'ing, yet be able to drive it hard. The L-Pad allowed this. I also had a "direct out" added for going straight to the board, which worked good but sounded a little sterile (might have had something to do with the fact I was playing a Sho-Bud at the time with it's stock thin pickups). This was a no master type of Twinn, so I had a master added too, but I think I wound up having that moved to the output of the direct out later on. Great amp for the time. Sometimes I wish I had it back! Sold it in California after I got my first "Session 400" which basically had all the features I needed built in and with it's 15" speaker sounded better (and "lighter!"). But that ol' Twinn sure sounded good for it's time!
Dave[This message was edited by Dave Robbins on 19 May 2003 at 11:02 PM.] |
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Stephen Gambrell
From:
Over there
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Posted 20 May 2003 7:40 am
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| Are you guys talking about using one of these things with a transistor amp? I thought they were only meant for tube amps, transformer-coupled output, to force the power amp tubes into an overdriven state? Cause if you hook this type load on the back end of a power transistor, something WILL light up. Guaranteed. |
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Dan Tyack
From:
Olympia, WA USA
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Posted 20 May 2003 11:22 am
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The THD Hotplate is what you need. It won't break your amp (THD has been selling them for at least a decade and I don't know of any damage). The Hotplate is great because it doesn't change the sound very much until you have the thing almost off. In those cases, there are tone switches to add highs and lows. They are sold to match the specific impedence of the speaker you are running.
I've never tried the Weber, but the Hotplate is the standard.
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www.tyack.com
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