I know nothing about amps: reason for no fx loop?

forgivenman

Member
Messages
3,029
Because I use delay and reverb from pedals a lot, I’m not interested in amps that don’t have a FX loops. This means that I’ve missed out on some pretty cool amps. What are some of the reasons builders decide not to include loops? Do they affect the tone? Are they cost prohibitive?

Just curious.
 

EL84 Abuser

Silver Supporting Member
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5,696
Effects loops didn't show up until the later 70s and by the mid 80s, were everywhere. Most of the classic amp circuits had already been designed by then and some builders aren't fans of messing with those by adding 'extra' stuff to them. A lot of folks think less is better than more when it comes to pure tube amp tones.

Ever wonder why some amps only have a single volume control?

Pssst. Don't tell Randall Smith.
 
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marshall2553

Supporting Member
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1,616
What kind of amps are we talking about? For non-master volume amps that get their dirt from the power section an effects loop isn't really useful. And I can understand the argument that they can negatively affect tone. I've had a handful of amps where you could hear a difference when the loop was in the circuit even if you just ran a cable from the send straight back into the return. But most of the recent amps I've played have had excellent effects loops. I personally won't buy another master volume amp that doesn't have a loop.
 

hogy

Supporting Member
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12,743
one reason....$$$

That's like saying a Ferrari doesn't come with a tow package because of "$$$". It's a nonsensical statement.

Some of the best, most touch sensitive and harmonically rich amps are very carefully designed to have their individual stages clip in a certain order, sometimes beginning with the output stage. Adding an effects loop here would break that order and drastically alter the tone and response of the amp.

Furthermore, once the output stage overdrives, an effects loop becomes completely pointless, because anything in it gets overdriven at that point.

The solution for such amps is to place your time based effects after the amp altogether. The Komet AmbiKab does just that, in stereo, even.

Hogy, Komet Amplification
 

Mark Robinson

Gold Supporting Member
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8,290
Guy's like Hendrix, Beck, Clapton, Page, and early EVH made it work putting everything up front.
All well and good if you can play scalding loud, and always do so in a big room that sounds good. That ain’t my life, and when I heard great quality digital reverbs with lots of control, I wanted in. So I’ve used loop equipped amps since the 2210 came out. I fully understand that I’m not getting all the Best that tube breakup can deliver, but I also can’t drive a convertible two seat car, it just doesn’t fit my life either. So the utility of a loop is fundamental to me, and the otherwise designs I enjoy in other peoples setups.
 
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12,072
with modern amp and loop designs I don't think it is so necessary to leave loops off, as for one they can be completely switched out of the circuit. But obviously they make the most sense with master volume amps. The Metro zero loss loops are excellent.
 

Glitch Magnet

Member
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2,011
Certainly, any extra feature like an effects loop increases cost. Whether that's $3 or $300 depends on the quality and complexity of the design. Is it just a crude insert between the MV and PI, or is there additional buffering? Solid state or tubes? Ground lift? Transformer isolation? Series or parallel?

I also suspect many amps attenuate the post-preamp send signal down to pedal level, which means gain must then be added at the return to drive the power amp. This all means extra circuitry in the signal chain.

Purists who don't need a loop, don't want anything extra in line to potentially fail or compromise the signal. I've personally witnessed an unused insert jack fail on at least one occasion. Not to mention all those pesky op amps and coupling capacitors robbing me of that pure tube tone. (Yes, I'm being hyperbolic.)

If you don't rely on your amp for heavy overdrive, effects work just fine out front. I run a Vox on the edge of breakup, and my time-based effects sound great with no effects loop. This makes for a simpler, more reliable setup.

I concede, however, even if you rely on power amp distortion, using an effects loop doesn't prohibit that, provided the inserted effects are set for unity gain and have sufficient headroom to handle the signal level. As long as the PI receives the necessary input level, the power amp will distort.

So, if you like an effects loop, there is no shortage of options available. It's a great option to have. Just don't begrudge the rest of us who don't need nor want this feature. Rock'n'roll thrived for over 20 years without it.

Peace y'all.
 

MHG

Member
Messages
5,357
Not a fan of FX loops. Not only does it have a negative impact on the tone and feel of the amp, but it also makes things sound too polished for my taste. I do like them with D-style amps where it allows you to use it as a global Master Volume, but even then, I don't run any effects through the loop. I guess it's a necessary evil if you use a lot of delay with a lot of gain though.
 

Radius

Member
Messages
1,415
I think the advent of effects loops followed music production trends. People want to sound like the record. In the 70's and 80's, studios started putting time based effects after higher gain tones.
 

Gary Brennan

Old cavorting member
Gold Supporting Member
Messages
1,786
Some of the best, most touch sensitive and harmonically rich amps are very carefully designed to have their individual stages clip in a certain order, sometimes beginning with the output stage. Adding an effects loop here would break that order and drastically alter the tone and response of the amp.

Hogy, Komet Amplification
Hey Hogy and others, would appreciate if we can generate a list of which amps are designed in this way. Any suggestions?

Gb
 


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