Tiny, low volume cab for 20/20?

[Major Dick]

Hi!

I'm trying to find a "bedroom" cabinet and still use my 20/20 rather than spend another grand on a mesa combo. I need to preserve a big part of Mesa into it.

Right now I am using the V-Twin into the computer running cabinet simulation software to spend my time tweaking the many pedals I got at home. I want to keep using the 20/20 but at low volume with a small cabinet. If I buy an EL84 5 watts combo amp (like an epiphone valve jr) with its own poweramp and ditch the 20/20 the problem is the difference in sound color, and that I might get surprises once I go on stage or rehearsal and use the 20/20.

What are the smart ways to get a low volume from the 20/20?
What smaller <10" cabinets are there out there that don't need to be cranked to get a flat EQ?
Is using a 16 ohms cab a reasonable solution to help decrease the volume?
Could the 20/20 kill an 8 ohms speaker for it being too small? lol

Here's something I found, 6.5" ohms cabinet for up to 100W:
http://www.ztamplifiers.com/products/lunchboxcab.html
But since it was designed for the ZT Lunchbox 200W I'm afraid it will be louder than a regular 8"... am I mistaken in my logic?

Thanks in advance!

 

[elvis]

Getting a smaller speaker will not fix your volume issue, but it will change the tone. Just turn down the amp volume and use your normal cabinet. No matter what you do, the tone will be different quiet than loud. There's no reason you can't run a 20/20 just as quietly as any other amp. If you want the best preservation of tone and dynamics, get one of the power-brake type products to dissipate some of the output power as heat instead of sound.

 

[Major Dick]

Thank you for your reply!
It was interesting and helpful because it showed how little I knew about where the volume came from. Normal cab at home it is then.

Now people say a 16 ohms speaker cabinet will reproduce "half the power" of the 8 ohms amplifier, making it necessary to push the volume knob further on the amplifier... So I wonder: Will I get less or as much tone loss with a 16 ohms cabinet as with a 8 ohms at a given low "ear" volume?

 

[elvis]

There are an awful lot of misunderstandings about power amps and speakers. First, half the power sounds like only a small change in volume to the Human ear. Second, and more importantly, the power specified for an amp has very little to do with the power it produces. Yes, you can get 20W at about 1% distortion from your 20/20, but only if you put a continuous sine wave in it. For actual music signals, the continuous power is much lower than the peak power. Think of it this way: if you are not playing constantly with heavy gain, you are only pushing the amp a small fraction of the maximum possible amount, with a peak once in a while when you hit the strings real hard. In effect, you are only asking the amp for a few Watts, even if it's capable of many more.

By turning down the volume, you send less signal to the power amp, so it produces less power. You can run a 100W amp at only 1W by turning the volume down.

It is true that you will get a different tone from running at low volume. Most people blame this on "not pushing the power tubes hard". That is only part of the story. Other equally true issues are that the Human ear has a differnt frequency response at low volume vs. high volume, and the physics of sound in the air change relative to volume as well. The speaker, output transformer, power transformer, etc all have different effects on tone at low volume. If you change something so that you can raise the signal level and push the amp harder, you will eliminate some of those variables, but not enough to really get the sound of a pushed amp. Ultimately the output tranny, speaker, physics of the air, and the response of your ears will limit the ability of 1W to sound like 20W.

If you change the speaker load impedance, you will change the volume knob setting for a given volume level, but you will actually drive the output tranny and output tubes LESS hard, and you will also change the bias, so that the speaker (still low volume) and the overall tone will be different, and not necessarily in the right direction. And again, you will not change the volume substantially, as it is a logarithmic function, not linear.

That is why people use power brakes (or equivalent). Almost all of the amp parts will run just like at high volume: Power tranny, preamp tubes, power tubes, output tranny, all cranked up. The differences then are limited to low volume in the speaker, low air pressure, and change in frequency sensitivity of your ears at low volume.

 

[crane]

That is why people use power brakes (or equivalent). Almost all of the amp parts will run just like at high volume: Power tranny, preamp tubes, power tubes, output tranny, all cranked up. The differences then are limited to low volume in the speaker, low air pressure, and change in frequency sensitivity of your ears at low volume.

I'll add that a lot of power brakes change tone in some way. "L" and "T" power brakes (resistor placement) tend to eat some high frequencies. I've never used one that use a speaker "motor" to brake power, but it seem to be the bests.