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The importance of buffering your guitar output before a soundcard or audio gear

From http://web.infinito.it/utenti/b/bizzetti/dsprt/faq.html

Interfacing a soundcard with guitars - The Line-In and Mic-In inputs of a soundcard or home stereo gear are typically low impedance, which loads the guitar pickups to suck away treble.  Connect your guitar to a high impedance input - a guitar preamp.  Turning down the guitar's volume pot helps by adding series resistance between the pickups and the soundcard input, but that requires increasing the gain at the Mic-In stage (e.g. +20 dB boost plus volume all turned up), adding noise

Soundcard Mic In jack has e.g. 5VDC to power electret mics. Some sound cards have a 3-conductor Mic connector: "left" +1.85V and sound input, "right" +5.0 volts, no sound signal. [great info, see page]

You really should use Mic-In only to connect electret/condenser microphones, and use the Line-In (or Aux-In) for all the rest (including preamplifiers). These kinds of microphones are anyway generally low quality, so if you're using DspRT to process vocal or ambience sounds, your best option is to use a preamplifier to the Line-In, and a dynamic mic.

[he argues that an external preamp generates better S/N ratio than internal.  For this reason and to preserve treble, use an external preamp such as a BOSS EQ pedal in bypass or flat mode, or another non-full-bypass pedal in Bypass mode. -mh]

Before you buy an expensive preamplifier with a lot of features that you don't want/need (e.g. tone controls, multiple inputs), I have here for you some schematics and instructions to build your own, extremely low cost, but highly clean and effective preamplifier. So you will be able to connect your guitar / bass to the soundcard in the best way, both for tone (impedance match), and for background noise.

You need a very simple preamp with flat frequency response, without any distortion. The simpler, the better.

You may use a multieffect unit as preamplifier, but I discourage it, since even keeping it into a "neutral" position it much probably still color the sound someway, or anyway it goes through an analog->digital and then digital->analog conversion, degrading the sound quality (even more if you think of the amazing 64bit double-precision always used internally by DspRT, and by its sample rates up to 48000Hz, 96000Hz (or more, depending on the soundcard in use) versus 32000Hz normally used in those multieffect units).

You may also use a pedal effect as preamplifier but, again, I have to discourage it: for example I experienced that even the one that seemed to me the best choice to do this (a Boss CS-3 compressor, with the knobs set to be transparent and not change the sound) in reality wasn't transparent.. [no, try using it in "Bypass" mode, or use a BOSS EQ, flat.  For levels, watch out for clipping the stompbox's input; you may need to reduce its gain control when pounding on a humbucker - mh]

If your instrument has got *active* pickups, you may get a good tone even without a preamplifier. I haven't been able to test this by myself, though.

End of section from http://web.infinito.it/utenti/b/bizzetti/dsprt/faq.html

http://www.tuckandpatti.com/guitarsound.html - excerpts:

On ballads we wage, and sometimes barely win, an ongoing EQ war when boosting high end (tone vs. hiss coming from the EQ'd buffer preamp noise floor, given the relatively soft attack and sustained chords without fresh attacks to mask guitar hiss).

I haven't used a guitar amp in about 20 years, and given that I basically just use one tone with the goal of a crystalline orchestral sound...

The buffer preamp [in my guitar] is amazing. Guitars are invariably impedance mismatched relative to whatever follows them, with a substantial loss of clarity right off the bat. We all grew up hearing and therefore loving that sound, but I have come to prefer the sound of the more theoretically correct approach. I have not tried it yet, but Bill Bartolini designed an onboard buffer preamp using my Carrotron as a reference, and feels that he surpassed it in all respects, so this would be worth checking out. Even a foot pedal such as the TC makes a big difference and makes it easy to compare to the unbuffered approach without rewiring, but the closer [the preamp circuit is physically located] to the pickup, the better. This is very unscientific, but I would estimate that about half of my sound is the pickup/preamp, and the other half the extreme EQ we do (discounting the effect of the fingers, of course). In recording that is combined with a very transparent recording path not coloring the sound any more than necessary.

 

My Blazer guitar sounds brighter when its volume is at 5; it sounds duller when at 10 (I removed the cap that is supposed to dull the sound when at 5 to compensate).  Overall, the guitar sounds brighter when driving the BOSS EQ with good input buffer than when driving the ancient Kay amp directly.  The Kay has poor input impedance.  So I put the BOSS in between the guitar and amp, in "Bypass" mode (or engaged).  If I want a dull vintage or jazz sound, I plug straight into the amp and turn the guitar's volume to 10.

 

 

http://www.google.com/search?q=guitar+preamp+buffer+hiss

includes reamp technique.

 

http://www.virtualstudio.org/arch/guitar/guitar.txt

 

From:   vs880

Sent:     Thursday, October 09, 1997 12:32 PM

To:       vs880

Subject:            Re: Loud Guitar on the VS-880

 

 

In a message dated 97-10-05 21:16:04 EDT, Lapjoint at aol.com writes:

 

<< Hello,

      It is possible to get that "hair standing on end" sound going straight

 into the VS-880.  Simply re-record what you DI'd into the VS-880 back to the

 VS-880 later on using your favorite amp and speaker and mic(s) combination.

  It sounds just like you played it live:  raw, loud, and massive as it wants

 to be. >>

 

Well the only problem there is you miss the tone interactivity of playing with the amp the first time around. A good amp will break up and interact to your playing style, and controlled feedback of course is another realtime phenomenon that you cannot get from a either a time delayed performance nor through a amp sim in headphones. So lots of times amps are good things to have around as the music is being created, although your neigbors may beg to differ.

 

But the DI'd signal through real amps and speakers and real air and mics is still a good technique.

 

From:   vs880

Sent:     Wednesday, October 08, 1997 5:41 PM

To:       vs880

Subject:            Re: Loud Guitar on the VS-880

 

Categories:       effects, guitar

 

Mega,

I don't think it's gonna work feeding a Marshall - considering you'd need instrumentlevel and have line level. The only way I can see this work would be to run the out into some kinda multieffectsbox(i.e. Digitech etc.) that has switchable in & outs (-20 & 4 db). Run the dry guitarsignal out of the VS into the effectsbox (into linelevel) out of effectsbox(instrumentlevel) into marshall. That would be the only possibility I can think of.

 

ciao Eddie

http://www.geocities.com/~nudeguitars

home of bebop-metal

 

From:   vs880

Sent:     Wednesday, October 08, 1997 2:16 PM

To:       vs880

Subject:            Re: Loud Guitar on the VS-880

 

Categories:       guitar

 

In a message dated 97-10-05 21:16:04 EDT, Lapjoint at aol.com writes:

 

<< Hello,

   It is possible to get that "hair standing on end" sound going straight into the VS-880. Simply re-record what you DI'd into the VS-880 back to the VS-880 later on using your favorite amp and speaker and mic(s) combination.  It sounds just like you played it live: raw, loud, and massive as it wants  to be. >>

 

The last time I tried this I got a bunch of noise and hum. I'm not an impedance guru or anything like that.... just how do you get it to work going into a Marshall?

 

MegaChew

 

From:   vs880 [vs880 at mooncafe.com]

Sent:     Sunday, September 14, 1997 1:19 PM

To:       Roland VS-880 Mailing List

Subject:            Re: O.T. telecaster Re: [VS880] FX Card

 

Eddie Muhlbauer wrote:

>

> Re: getting a convincing Tele sound out of a Strat... you might also consider putting a capacitor and resistor in your guitar to avoid changing the tone once you turn down the volume knob.

>

> Ciao,

>    Eddie

 

 

In fact my secret (?) is to use a 250k volume pot with a 1000pF cap and a 150k ohm resistor in parallel across the two "hot lugs" of the Volume pot. Th old Schecters (Dire Straights) were wired this way. This maintains an even tone throughout the volume pot's range. Stock Fender Telecasters have used several diferent wiring schemes over the years. The typical Roy Buchannan tone is achieved with a 1 meg volume pot with a 1000pF cap (no resistor). The Cap has no impact when the Guitar is cranked full up. But the cool technique is to roll the guitar volume to around 7, and play through a cranked Super Reverb on 10! This really cuts through a mix like an "ice pick"! Use the VS-880's effects board's "Vintage Tweed" patch, or try a Bixonic Expandora on a conservative setting between the Guitar and the VS-880.

 

I know I have talked the Direct box issue to death, but here is another bit of info. If you have a stomp box that you want to use to augment your tone during your guitar overdubs and you plan on having the effect "enagaged on" during the recording, then a direct box is NOT NEEDED! This holds true for any effects stomp box. The little Boss series units have a buffer that is in the circuit AT ALL TIMES, even in the bypass mode. So if you were planning to get a direct box, but already have an old OD-1 or CE-2 laying around, put a fresh battery in it and plug it in between your Tele or Strat (or SG, Les Paul, More strat,;-) and the VS-880 and leave the effect in the bypass mode. This will act as a direct box, buffering the output from your guitar and isolating the pickups from the 20k Load resistance of the VS-880. (remember, this "compromise" input on the VS-880 renders a dull sounding guitar when its just plugged straight in.    

 

Steve Conrad

 

From:   vs880 [vs880 at mooncafe.com]

Sent:     Sunday, September 14, 1997 11:23 AM

To:       vs880

Subject:            Re: O.T. telecaster Re: [VS880] FX Card

 

Re: getting a convincing Tele sound out of a Strat...

In order to get a convincing Tele sound (neck and bridge together) not only do you need to install a switch, you also need to move the bridge p.u. a 16th of an inch towards the neck. If you want to go for really authentic sound, you need to figure out how to put that metal plate that is around the bridge p.u. on a Tele under your pick guard. Needs to be metal, can't be brass---it needs to be able to magnetized by the p.u.s magnetic field.

 

(That will bring into place an inductance that rolls off the real unpleasant high-end, that we don't like.) Also, the actual high-end on strats is somewhere between 8 and 9 k and on a tele it is about 2 k, so you might also consider putting a capacitor and resistor in your guitar to avoid changing the tone once you turn down the volume knob.

 

Ciao,

   Eddie

---------------------

Forwarded message:

From:   MegaChew at aol.com

Reply-to:       vs880 at mooncafe.com (Roland VS-880 Mailing List)

To:     vs880 at mooncafe.com

Date: 97-10-08 15:25:27 EDT

 

In a message dated 97-10-05 21:16:04 EDT, Lapjoint at aol.com writes:

 

<< Hello,

      It is possible to get that "hair standing on end" sound going straight

 into the VS-880.  Simply re-record what you DI'd into the VS-880 back to the

 VS-880 later on using your favorite amp and speaker and mic(s) combination.

  It sounds just like you played it live:  raw, loud, and massive as it wants

 to be. >>

 

The last time I tried this I got a bunch of noise and hum. I'm not an

impedance guru or anything like that.... just how do you get it to work going

into a Marshall?

 

MegaChew

 

REAMPING:

http://www.virtualstudio.org/arch/guitar/guitar.txt

 

From:   vs880

Sent:     Wednesday, October 08, 1997 5:22 PM

To:       vs880

Subject:            [VS880] Fwd: Loud Guitar on the VS-880

 

Categories:       effects, guitar, mixing

 

>To get the sound I'm looking for on a "loud guitar" recorded sound I simply run [the guitar] straight into the VS-880 (i.e. I record the guitar as it comes out of my guitar) after splitting the signal from [to] a heavily processed but very low volume "3 AM working sound" [not recorded] when working through a small monitor or monitor system (studio monitors). This means my guitar is heavily processed to my ear but the original [direct/dry] guitar signal is going to the VS-880. When I need to fiddle (or change) the recorded but unprocessed [direct/dry] guitar sound which had the feel which I desire with feedback [recorded as part of the direct/dry sound] or whatever from the studio monitors (i.e. run it [the direct/dry signal with optional feedback] through a Marshall or whatever amp [later]) I simply patch an output from the VS-880 into the specified guitar amplifier and mic the signal(s) (I use 2 or 3 mics) [multimiking is good] [mic the Marshall's speaker now] back to the VS-880.

 

Then I stack whatever guitar sounds I have in a pleasing manner which fits the song. I use the direct outs of the VS-880 and I have never really encountered a very noisey situation [though the direct/dry guitar track and its extra noise from being recorded feeds the super-sensitive amp distortion stages]. However, if I did [encounter extra noise created this way] I would use a downward expander or gate, but I've never had to do this. Maybe it's because I've turned the VS-880 output volume down to an amplifier workable level??? Regardless, I try to make the specified guitar amplifier sound as natural as possible by listening to the playback on the guitar amp [a bunch of times while adjusting all the Marshall's controls] before doing any re-recording [to finally capture the reamp'd sound].  Anyway,  the guitar is quite huge sounding (with a little practise).

 

Sincerely,

Douglas.

 


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