Omnisonic Preamp attenuator Review

[Roguetitan]

Don't get the Omnisonic confused with an attenuator like a THD Hot Plate or a Weber mass.
A power attenuator attenuates both the power amp and preamp side of a tube amp which goes in between the head and the Cab and dissipates the unused wattage in heat in order for you to get the full tone of both the Preamp and power amp without making your ears bleed.

although this is not a power attenuator it does work passively in a similar fashion for a tube amps preamp side. if you are not sure what I mean by that a tube amp has 2 sides; one side is the preamp side, the other side is the power amp side which is the side that drives the speakers. The preamp side is where a great deal of a tube amp gets its rich tone but the power amp side also contributes to that when the volume or gain is pushed which causes the tubes to compress that creates a vacuum just as for the preamp tubes , anyway this is all tube amps 101 stuff but I just wanted to give others who may not be in the know a basic understanding of how a tube amp works, Anyway....
The Omnisonic is basically a speaker attenuator or for a better term of describing it, preamp attenuator, which works in conjunction with a tube amps effects loop on the preamp side of the amp only. The the Omnisonics' input goes into the amps effects send and the output side goes into the effects return; I also have a multi effects processor in the loop behind the omnisonic (or first in the effects loop) in order to control any volume discrepancies of the effects processor.
you cannot hook this unit up the way you would a power attenuator (between the amp and cab) you must hook it up in the effects loop. If your amp does not have an effects loop then the Omnisonic will not work.
if your tube amp does have an effects send and return then any of the Omnisonic preamp attenuators will work, they are not brand specific.

This little unit allows you to be able to crank the gain on your amp and still be able to get a good rich distortion and overdriven tone without having the amp up so fricken loud you can't stand it.
although you are not getting full tube compression from the amps power amp side the preamp tubes also produce a large percentage of the amps tone but unless you are able to crank the gain you cannot get that tone you want from the amp unless you don't mind your ears bleeding with the omnisonic in the loop you can crank up the gain in order to get that desired tone or very close to it and still have full control of the volume output.

this unit is also very nice to have if you have a touchy gain knob like the one on my Crate V33 Head. this thing was so touchy without the Omnisonic, it was either way too loud or not loud enough to get any distortion at all, it was just hard to get the amp where i could get it to overdrive without it being so loud the neighbors was calling the cops on me and or running the risk hearing loss.
the Omnisonic preamp attenuator solved the problem for me to where I can crank the gain on the amp and still have full control of the volume so with that said I think it as a very inexpensive solution for getting the tone I want out of my amp at low volumes.
it is definitely worth 25 bucks IMO

now if you are needing to attenuate both sides of your amp then you are going to have to dig a little deeper in your pockets and the more wattage your amp is the more you will have to dish out for an attenuator that can handle your amps output therefore Ya this is a very cheap alternative.

 

[rayc]

Nicely done.
My amp (Marshall Superbass MkII) doesn't have a gain section or effects send/return set up so I had to spend some more to by a brick called a TubeCube that does as you described - dissipate power as heat. It works well.
I WISH I had a set up that allowed me to use something cheaper & more flexible such as the one you've descibed.

 

[didgijimmy]

Thanks for the review Rogue, been waiting for it. And I know I counted this thing out a while back, but the more I thought about it, I figured I could definitely use it on the Peavey Classic 50 I almost bought. However, I went with the Fender Deluxe VM as you may remember, which, as an added bonus has linear tapered knobs which eliminate the need for an Omnisonic. For those that dont know, as I understand it, a linear taper allows you to control the amps volume smoothly, so that when you turn it up you dont reach 80% of the amp's volume at 3 and have to fiddle around because its so touchy.

But seriously Rogue, great review.
James

 

[ggunn]

For those that dont know, as I understand it, a linear taper allows you to control the amps volume smoothly, so that when you turn it up you dont reach 80% of the amp's volume at 3 and have to fiddle around because its so touchy.

I think you have it backwards. I'm pretty sure that it's a linear taper pot when it is in a volume control that gets loud very quickly, and an audio taper pot that produces a volume curve that sounds evenly distributed over the range of the pot.

 

[didgijimmy]

I think you have it backwards. I'm pretty sure that it's a linear taper pot when it is in a volume control that gets loud very quickly, and an audio taper pot that produces a volume curve that sounds evenly distributed over the range of the pot.

Thanks double g unn. You are correct. If you want more info (or if anyone does) check this link:
http://www.angelfire.com/electronic/funwithtubes/Amp-Volume.html

The guys at the local shop told me it was called a linear tapered pot, but ithey were confused on the name. I spent forever with that amp and it's definitely audio taper. To me, it would make since that linear would produce an even distribution (since it would be a straight line on a graph). But then again, apparently the way we hear sound is logarithmically, the way an audio taper works.
Thanks man
James

 

[Roguetitan]

RayC
thanks for those kind words about the review

jimmy
you asked about the Omnisonic in a thread a few weeks back got me to wondering if this would be the solution I was looking for for that touchy gain knob and fortunately it is exactly what this amp needed so thanks for inquiring about the device otherwise iwould not have known about it

although there was a big debate about how the device works or doesn't work I can assure anyone who may be considering getting this handy dandy device it is well worth the purchase price and does attenuate the preamp side of the tube amp provided the amp has an effects loop send and return.

I am glad to hear you finally got the amp you wanted, I know you did some diligent research to get the best bang for your buck that would deliver the tone you want.