I just had a disappointing trial of "daisy chaining" my two Rumbles, and I need some advice...
I think I remember past references on this forum regarding stacking and connecting a Rumble 100 and 200 together, but it didn't work so well when I tried it.
I've had a Rumble 200 for four years, and love it. Sounds great for the gigs I've played (classic rock and country in small venues and on outdoor patios), although at the last patio gig I would have liked just a BIT more output. The amp sounded OK, but you could HEAR that Delta-Comp working!
A few month ago I bought a Rumble 100, to use the few times a year I have to schlep it to practice sessions (in a guy's basement)...
Anyway, yesterday I decided to see how it would work if I chained the two amps together.
Would it goose the 200's output enough to make a difference?
240 total watts!
I wasn't sure whether to use the Rumble 200 as the master and the Rumble 100 as the slave, or vice versa, so I did some tests to check out how the Rumbles' preamp sections compare.
I used a sine wave generator and my JMJ Mustang as input signals, and observed the output levels and waveforms on an oscilloscope.
I also input pink noise, and compared the frequency response using my old ADC Sound-Shaper SA-1 spectrum analyzer.
It turns out that the preamp sections of both Rumbles are identical in operation. There is no difference in output or response when the controls are set the same on both units. It doesn't matter if you look at the SEND outputs or the headphone outputs, all levels and frequency response are identical.
So, I went ahead with daisy-chaining the amps, using the Effects SEND and RETURN jacks, and using a 1/4" TRS cable.
The amps worked together as expected, in that both power amp sections are controlled by the Master amp's preamp settings, with none of the Slave's controls having any effect.
BUT...
The sound output of the two Rumbles is NOT equal. The output of the 200 is NOTICEABLY louder than the 100, no matter which amp is used as the Master.
The difference in output (estimated using a sound level meter) is about 6dB!
The difference is in the gain of the two power amp sections.
The 200 is always 6dB louder than the 100, even if both amps are driven by identical signals directly into their Effects RETURN jacks.
I doubt combining the two amps would be noticeably louder at a gig than the 200 alone!
SO, has anyone else tried daisy-chaining a Rumble 200 (or 500) and a Rumble 100 together?
Any suggestions as to how to make the two amps more equal in level, to put the Rumble 100's 100 watts to better use?