Metropoulos Forum

Guys this might be a novice question, I have a metroamp jtm45 that I built myself running at 16 ohms into a 16 ohm cabinet a 4x12.

Now would it be okay to turn the selector switch on the back of my metroamp from 16 ohms to 8 ohms and still run it into a 16 ohm cab?

Would it damage the amp in any way? Would this reduce the volume or just take away tone?

I ask because I'm looking to buy an attenuator and there is a Weber Mass Lite for sale but here is the description on their website,

"MASS Lite with 100 watt rating. 8 ohms. May be used on 4, 8, and 16 ohm amplifiers. Includes MASS bypass, line out, extra output jack, and range switch. This is one of our most unique MASS units in that it has two power level controls, one for the bass-mid frequencies and one for the upper mids-treble frequencies. They may be adjusted independently for the best tone at all levels of attenuation. These controls affect the actual signal going to the speaker, not just a line out signal like in our other units. So, it is like having high level tone controls. The controls are very effective and the tonal combinations are virtually infinite. Because a MASS motor is employed, a more realistic interaction between the attenuator and the output circuit of the amp occurs. The attenuation is continuously adjustable from zero to over -70db using speaker control and the range switch. Like all Weber attenuators, setting the speaker control to minimum (maximum attenuation), allows the MASS Lite to be used as a dummy load for testing or for DI use. "

And Im not sure if this translates into, its safe and not going to damage my amp. The line "100 watt rating. 8 ohms. May be used on 4,8,16 ohm amplifiers" doesnt make sense to me because of the mention of 8 ohms right after the 100 watt rating.

Thanks guys

harkkam08 wrote:Guys this might be a novice question, I have a metroamp jtm45 that I built myself running at 16 ohms into a 16 ohm cabinet a 4x12.

Now would it be okay to turn the selector switch on the back of my metroamp from 16 ohms to 8 ohms and still run it into a 16 ohm cab?

Would it damage the amp in any way? Would this reduce the volume or just take away tone?

I ask because I'm looking to buy an attenuator and there is a Weber Mass Lite for sale but here is the description on their website, ...(snip)....

Thanks guys

I've used a Weber mini-MASS with my amp/cab for several years and love it. With the mini-MASS, I can set it to match the amp head impedance selected and then run ANY impedance cabinet. My cab is 8-ohms, but I can set both the amp and mini-MASS to 16, 8, or 4 ohms and run my 8-ohm cab with no problems. FWIW, it does make a difference in tone as to which impedance is selected. 16 ohm, being the 'top' of the OT secondary winding, seems a little louder and articulate, but I like the 8-ohm and usually use it. I've rarely used the 4-ohm . I'd be surprised of the MASS-Lite didn't operate the same way.

harkkam08 wrote:Now would it be okay to turn the selector switch on the back of my metroamp from 16 ohms to 8 ohms and still run it into a 16 ohm cab?

Would it damage the amp in any way? Would this reduce the volume or just take away tone?

Yes you can run an 8 ohm head with a 16 ohm cabinet. It does affect the volume and tone. Generally the amp will not be as loud and the highs will be attenuated.