Recording guitar feedback

[Lunch Money]

Sympathetic feedback doesn't need tubes.

If you want tubes for your overall sound, of course that's the feedback you want, too; however, if you're using an amp sim that you're happy with, just run it through your speakers and enjoy the ensuing feedback squeal.

All that's happening is that the physical energy of the soundwaves is 'playing' your strings for you-- they start to vibrate sympathetically with the tones and harmonics that come out of the speakers.

Tubes are wonderful in a guitar amp, period. But they're not a vital ingredient for guitar feedback!

Greg

[IIRs]

IMO valves are a vital ingredient in any guitar amp. Even if you get a useable tone with an amp sim, it doesn't feel the same: I've never tried one that made a guitar come alive like a good valve amp does..

[zeoy]

You are both right LM and platinum. You can have feedback with valves, transistors even ampsims. But it's not the same. I think that a valve amp produces more complex but in the same time more controlable feedbacks. The guitar-pickup combo has maybe the more vital role in feedbacks. According to some amp manufacturers even the placement (horizontal or vertical) of the valves is crucial. My amp (Peavey Bravo) has the valves horizontally placed and produces very easily feedbacks at medium volume but I am not sure if this is due to the valves' placement

[Sepheritoh]

You are both right LM and platinum. You can have feedback with valves, transistors even ampsims. But it's not the same. I think that a valve amp produces more complex but in the same time more controlable feedbacks. The guitar-pickup combo has maybe the more vital role in feedbacks. According to some amp manufacturers even the placement (horizontal or vertical) of the valves is crucial. My amp (Peavey Bravo) has the valves horizontally placed and produces very easily feedbacks at medium volume but I am not sure if this is due to the valves' placement

My guess is that the compression used has a greater influence than the placement of the valves.

[IIRs]

My guess is that the compression used has a greater influence than the placement of the valves.

I have a rack-mounted rig: It is a simple matter for me to plug the output of my Pre-amp / FX straight into my soundcard or mixer.. but I don't because no matter what cabinet emulation I dial up, or compression I apply, it feels flat and life-less compared to the Mesa 20/20 power amp: I am utterly convinced it is the EL84 valves in the power stage that make my rig sing like it does..

[Sepheritoh]

I agree that valves have a better feedback. The old time feedback masters like Hendrix, Townsend, Beck etc loved the Mesa(*) and Marshall amps for the feedback. Not an expert myself (I had an Elk 80 valve amp and the feedback sucked) I suspect that the pre-valve of the amps does the compression.

[Edit - If my memory serves right the Mesa boogy used to be popular for feedback]

[Lunch Money]

I love the sound of a properly roaring tube amp, but that's a different argument. This particular topic can't degenerate into a simple 'tube vs. sim' argument or there will be nothing new to add. So, instead, focusing on feedback in general--

If a tube amp produces better feedback, it's directly related to the quality of the amp's sound itself. Some setups will overdrive and produce different harmonics, and harmonic excitement is one of the hallmarks of tube circuitry. So that's not up for debate-- if a tube amp produces (to your ears) a better sound in general, that you will also prefer the sound of its feedback.

My only point is that tubes do not in any way at all create feedback. Feedback is ONLY caused by the interaction of the soundwaves with your strings. It is ONLY produced (well, unless you have squealy microphonic pickups, which is a different story) by sympathetic vibration.

So a tube will not in ANY way affect how easily feedback is produced. I agree that the natural compression is a part of the equation, but if you have solid-state compression you will have the same effect. My point is simply that from a scientific point of view, tubes do NOT equal feedback.

This is not to be confused with an entirely separate point-- you may indeed prefer the sound of feedback generated with a tube amp, and I can't debate that.

Greg

[Sepheritoh]

Greg everthing you say there is true. I did not dispute anything and did not elaborate, as I think most of the facts have been presented in this thread and very well eleborated by you. I was entering into the discussion with zeoy & Platinumears on the topic of why valve amps naturally (without outside FX can create feedback. Maybe I should have started my first sentence with a "to my ears", but that is not the point, as my theory is that the main reason for that valve amps create a easier feedback is because of built-in compression. Also different amps work different.

As mentioned I had a Elk amp before that was really bad with feedback. I have a solid state Marshall now which sound ten times better, but still not as pleasant as Henrix could get with his $100,000 stacks.

There are great plugins that sounds even better than my marshal amp. Personally I prefer Trash. Technically, as was mentioned by yourself, that is not really feedback, but simply sound processing, done in such a way that it can sound great and sometimes almost the same as real feedback (created with strings-and-the-soundwaves method).

[Lunch Money]

Word.

Didn't mean to make it sound like a retort to you specifically. <grin>

Greg

[Sepheritoh]

Word.

Didn't mean to make it sound like a retort to you specifically. <grin>

Greg

[IIRs]

So a tube will not in ANY way affect how easily feedback is produced. I agree that the natural compression is a part of the equation, but if you have solid-state compression you will have the same effect.

Compression does of course affect feedback, as any live sound engineer will be able to tell you.. the valve power stage exhibits a unique combination of non-linear compression and distortion and definitely does make it easier, if not to generate the feedback in the first place, to control it and influence its behaviour.

It is mainly the dynamics of a valve amp that is important in creating the "feel" IMO, but this is an integral part of the way the guitar resonates and feeds back at stage levels.

Here's my rig:



The top unit is the pre-amp / effects unit with a single 12AX7 valve to handle distortion. I have DI'ed this into dozens of different systems ranging from huge soffit-mounted pro-studio monitors, to club PA systems, and the sound is always useable, but the guitar feels dead, and playing it is really hard work. Only when I play through the Mesa power amp underneath it does the guitar seem to start playing itself, and responding to the sound from the cab..

So I would agree with you Greg, you can get anything to feedback, but to produce musical controlled guitar feedback I still say you need real glowing valves! (Or those fancy feedbacker pickups they invented back in the eighties come to think of it.. anyone tried any of them?)

[Sepheritoh]

(Or those fancy feedbacker pickups they invented back in the eighties come to think of it.. anyone tried any of them?)

Are you talking about those thingies that Lindsey Buckinham (Fleetwood Mac) used? I thought that it sounded cool - almost like an guitar voilin / sound, but it did not really sound like feedback.

[IIRs]

Maybe: I just have a dim memory from an eighties guitar shop.. I seem to remember it sat in the neck position instead of a pickup (or was combined with a pickup) and induced the strings to vibrate..

[Sepheritoh]

Ha, the thingy I was thinking about is the eBow.

http://www.sweetwater.com/store/detail/Ebow/

[IIRs]

I think the thingy I'm thinking about works the same way, but its permanently attached to the guitar and you switch it on when you want it..