TONE TIPS FROM THE ROAD
Guitar amplifier effects loops are quite a controversial topic with tone purists. Common
questions go from, Do I run my effects into
the front so as not to disturb the amp’s tone?
and Do I use the effects loop to get better
delay sounds? to the even more drastic, Do I
install an effects loop on my vintage amp?
It’s just another aspect of your rig scene, and
often comes down to personal preference.
There are times when an effects loop comes
in handy on a gig, and others when it can
cause your tone to suffer, all depending on
what you’re trying to get out of your amp.
In a typical guitar amplifier, there is the preamp stage and the power amp stage. The
effects loop is almost always placed right
between the two. The idea is that your preamp channel switches between clean and
overdrive tones, feeds into your effects via
the effects loop, then back into the power
amp stage. Placing your effects after your
preamp works very well if you’re generating
all of your clean and distortion tones solely
in the preamp stage.
On the other hand, effects loops don’t always
work well if you’re generating your overdriven
tones by cranking your amp to get overall distortion and compression from both the preamp
and power tubes, as with vintage style, non-master volume and low powered amps. Inserting
the effects between preamp and power stages
in this case most often impedes their interaction,
and leaves you scratching your head wondering
why you have weird levels, funny buzzing from
your effects, or general tone suck. The preamp
may be sending out such a strong signal that it
hits the effects too hard, requiring you to pull
back the level (if you have control of the input
gain), and then the power stage can’t react
properly since it’s not getting hit hard enough.
Analog-digital-analog effects interrupt that
preamp-power amp interaction, in which case
you’re better off running your rack effects
into the front—or getting elaborate with a
nice, big eighties-style stage rig: the vintage
head into a load box feeding into your effects
rack, then into a stereo tube preamp with two
4x12s. Yeehaw! (But remember: never run your
amp’s speaker output into your effects input,
unless you want to blow it to smithereens.)
Here’s a handful of recommended scenarios:
1. Run your stompboxes into the front, not
through an effects loop. They are designed
and intended for this both tonally and level-wise, and will cause very little change to your
amp’s tone and the power-amp distortion it
generates. In fact, many pedals can improve
your overall tone by their effect on your input
impedance—buffer circuits are designed
to allow longer cable runs without loss of
signal. Plus, if you run your pedalboard thru
an effects loop you’re creating unnecessary
excess cable lengths, which can impede your
tone or cause noise issues.
2. Run your rack effects into an effects loop.
This scenario works best using an amp with
preamp, master and channel switching for clean
and dirty, with your distorted tones generated
by the preamp stage. Delay mix levels generally remain even between clean and dirty. Most
rack effects units have bypass footswitching
ability, as well as MIDI, which really gives you
flexibility using a MIDI foot controller (but be
prepared to pull out your propeller hat).
3. Run all of your effects in the front; feed
pedals and rack effects into two amps for
stereo. This works well if you use a tube-preamp stompbox to generate your distortion and mainly use the amplifiers for overall
tone and volume level. And you can swim in
stereo heaven onstage.
4. Run a rack tube preamp into rack effects,
into a stereo power amp (tube preferred),
into a stereo speaker cabinet or two speaker cabinets for full-on stereo bliss. A lot of
great sounds you’ve heard over the years
have been created this way.
5. Forget all of your pedals and plug
straight into the front of the amp.
(No diagram needed!)
Well, it appears I could elaborate further, so
perhaps I’ll do so in next month’s column.
Until then, happy late night hours twiddlin’
with your tone… I’m right there with you.
Peter is co-founder of 65amps.