Anyone use one of these?

[RejectionNinja]

The short answer:

A master volume knob reduces the signal sent to the power section.

Adding a volume knob in the effects loop duplicates the master volume function. It will behave exactly as a master volume does, with the exact same benefits and downfalls, because it is exactly the same thing.

Putting the amp's master on 10 and turning the knob in the loop halfway* is the same as having no knob in the loop and the master halfway down.

*"Halfway" meaning a 50% attenuation of signal, the physical positions of the knobs may well differ.

This is all basically true.

However, if you have a tube amp and you can't turn up the existing "post amp" or "master volume" knob past 1 (out of 12) because it is deafening, you're not really using the amp properly. An audio taper pot doesn't *JUST* decrease the perceived volume, it also affects the tone.

If you install one of these volume knobs in the effects loop, you can open up that master volume knob (say 50%) and control the overall volume in the effects loop (say 50%) and you'll have a much better sound.

It's still the same level signal reaching the power amp (on average), but it's not being choked to death by a frequency-ignorant barely-open volume knob. The whole conversation about reactive dummy speaker loads applies to any resistor in the signal chain, to some degree.

*SHEW*. THAT was what I was trying to express in this whole thread and it got way out of hand. My apologies.

It doesn't matter if it's on your strat, your preamp, or your master volume knob - a variable resistor at 5% open affects your tone, and usually in a bad way.

If you're normally running that master volume at decent settings (like anything from 3-10) then this volume knob in the effects loop isn't going to do much for you.

I only jumped into this thread in the first place because my friend hated his Classic 50 because it was so loud that it was basically useless indoors. He got one of these volume knobs and the amp went from worthless to priceless in his opinion. Under the right circumstances, they're very useful.

 

[RejectionNinja]

Yay! a consensus!! Group hug?

I may be a $#%@ sometimes but I have no problems admitting when I'm wrong.

But convincing me that I'm wrong might leave scars, because I'm a $#%@ sometimes.

 

[ggunn]

Not volume but gain, gain and volume are two different animals

Well, yes. Gain is the increase in amplitude of a signal when it goes through an amplification stage, and volume is the SPL of a speaker output.

When it comes to the power section of an amplifier (again, with nothing in the circuit between the power tubes and the output transformer, or between the output transformer and the speaker) they are one-to-one linked. You cannot change one without changing the other by the same amount until you begin to push the power tubes into saturation, where the tubes are passing all the instantaneous current they can (which is the definition of saturation and is the onset of clipping) and they cannot produce a wider swing of AC voltage across the primary windings of the output transformer. At that point the amp is as loud as it can get without producing a distorted waveform. If distortion in the power section is what you are looking for, you have to push it even harder.

[EDIT: The above is not technically correct, strictly speaking. The gain is the ratio of output to input signal and is really a fixed quantity in both the preamp and power amp stages and governed by the tubes and the way they are implemented in the circuit. You don't really change the gain by turning a knob; you just change the input signal level. I used the term "gain" rather loosely. -G]

Yes, of course, you can insert another gain stage in the effects loop to push the power section harder, but it won't make the power tubes go into saturation at a lower volume. A lower volume setting on the front of the amp, sure, but not a lower actual volume from the speakers.

Some folks think of "gain" as the "fatness" of the sound, because when you turn up the gain knob, the sound gets fatter past a certain point, but that's just because you are using it to drive the preamp tubes into saturation. It doesn't sound the same as power tube saturation because they saturate at much lower current levels and clip "harder" (less rounded off near the rails) than power tubes.

I don't claim to be a tube expert compared to the guys who build and work on them every day, but this stuff is pretty much Tubes 101.

 

[Roguetitan]

this unit works exactly the way I thought it would

I emailed the omnisonic guy and he gave me an honest answer and pretty much confirmed what I already assumed how the box works.

"The tube tone comes from two parts of the amp, the preamp and poweramp. All of the EQ and tone controls, as well as a significant portion of the tube distortion (indeed, a lot of the 'color' of the distortion) is in the preamp section. The volume box lets you set the EQ, tone and preamp distortion where you want to and have that rich tube tone at lower volumes. It is not identical to a power soak or hot plate, but it is remarkably similar, and considering how much it does for the price, I think it's well worth the price. If you require the ability to fully attenuate the preamp and poweramp sections at once, a hot plate might suit your needs better. If, like most players, the issue is that you can't ever play your amp at a reasonable level and still have that great distortion, the volume box is an excellent solution for you".

 

[didgijimmy]

I emailed the omnisonic guy and he gave me an honest answer and pretty much confirmed what I already assumed how the box works.

"The tube tone comes from two parts of the amp, the preamp and poweramp. All of the EQ and tone controls, as well as a significant portion of the tube distortion (indeed, a lot of the 'color' of the distortion) is in the preamp section. The volume box lets you set the EQ, tone and preamp distortion where you want to and have that rich tube tone at lower volumes. It is not identical to a power soak or hot plate, but it is remarkably similar, and considering how much it does for the price, I think it's well worth the price. If you require the ability to fully attenuate the preamp and poweramp sections at once, a hot plate might suit your needs better. If, like most players, the issue is that you can't ever play your amp at a reasonable level and still have that great distortion, the volume box is an excellent solution for you".

Thats what I figured, but I think I'd still want to drive the poweramp, so i'll prolly get a Weber.
Thanks for all the research man.
ARe you gonna get one of these?

 

[Roguetitan]

Thats what I figured, but I think I'd still want to drive the poweramp, so i'll prolly get a Weber.
Thanks for all the research man.
ARe you gonna get one of these?

Ya, I am getting one for my sons Crate V33 head, the gain knob is very sensitive on this amp and this box will remedy that problem. and also he can use the gain on a higher setting on the amp and still be able to have some control over the volume output.
that is all I was needing anyway.
another reason is: I was being kind of energy conservative minded because when the attenuator is in use it is using electricity so anything to do to save a few kilowatts is a big load off of the power bill here at the house.
besides any time he plays out he uses the Peavey Trans Tube 100 Supreme and a 412 cab or the valve king combo the valve king requires the Weber attenuator.

I play Bass in my band so I don't need any of that crap