Playing Through Two Amps

[David Doggett]

I still don't get it. Vernon's measurements show an approximat halving of the output when plugging into two volume pedal output jacks, whether we consider the drop from 2.7 mV to 1.4 mV, or the drop from 214 mV to 116 mV, or a drop of 3 db. Yet my perception is that the second amp does not merely double the halved volumes back to the level of one amp, but is much louder, maybe not twice as loud, but at least half again as loud. The slight difference between the two-out voltage and exactly half (0.05 mV and 9 mV, respectively, or about 2-4% increase over the one-out level) does not seem enough to account for the increase in volume supplied by two amps. Something's still missing in this picture.

[Vernon Hester]

Well,David,
Set up your amp and make sure your speaker is postive (Connect the + side of the speaker to the + side of the battery 1 1/2 volt, Make sure the cone moves out when you make connection) Do the same on the second amp to be sure the speakers are in phase!!
Then Plug your guitar into amp one, put a meter across the speaker terminals,(meter set to AC voltage). Set the gains to read 8 volts at the meter.This will give 16 watts of output(4 ohm spkr). Do the same on the other amp.Then use a passive splitter and plug into both amps, do not touch the gains on either amp. Then look at the meter. This will eliminate the ear or human factor.I will make the test the next time I have my amps connected and see if it matches yours. Good Luck
Vern

[John Floyd]

In the 70's We (the Shop where I worked) built a preamp/Splitter for Charlie Daniels to use 5 amps on stage. It was a one stage preamp feeding 5 emitter folowers driving the 5 amps, That worked out very well for him.