Best Op amp for transparent boost?

[seedlings]

The only way to hear a proper guitar signal is direct into an Audiolab preamp, through an Icon monoblock amplifier, and some Martin Logan electrostats, and don't forget all Hosea cables.

CHAD

[karbomusic]

I'm certainly not knocking the audiophile culture

Allow me then .

LOL, made me giggle.

[karbomusic]

To Fiveseven:
Who said I was alone? When you A/B-ing you can hear very well the Difference, and I am not alone in this world...

You certainly aren't alone but none of that makes it real nor addresses his very important and always diverted point. A/B means nothing if you are both the one throwing the switch and doing the listening. Our own perceptions and expectations will skew the results every time without our knowing it. That is what perception bias is, it's been studied, it's been proven. You may hear it but you can't prove it (even to yourself) while sitting there A/Bing on your own. I've done it myself and seen many a sound engineer tweak a treble knob on a track that isn't even on thinking it is making a difference - perception bias.

Now beyond all that, I kind of don't get the idea of "as transparent as possible" for a guitar signal because based on the chain and how/why guitars sound good, none of us have likely even truly heard and very possibly do not actually want a perfectly unaltered signal. What we want is for it to sound good and that sound is a sum of all parts including the room and the air in that room not to mention the person playing that guitar having a major influence on how it sounds.

[PRR]

Late to the original question:

> using this Texas Instruments INA103 for a clean boost?
> interested in finding an op amp with a very low noise to signal ratio.

Then learn how to read hiss specs.

TI is very coy in this datasheet. *EVERY* "low noise" device has an "Optimum Source Impedance" for low hiss. If the source impedance is far off this range, hiss will be high. But TI neglects to boast this number.

However TI does say

"NOISE PERFORMANCE
"The INA103 provides very low noise with low source impedance. Its 1nV/rt-Hz voltage noise delivers near theoretical noise performance with a source impedance of 200 Ohms. Relatively high input stage current is used to achieve this low noise. This results in relatively high input bias current and input current noise. As a result, the INA103 may not provide best noise performance with source impedances greater than 10 KOhms. For source impedance greater than 10 KOhms, consider the INA114 (excellent for precise DC applications), or the INA111 FET-input IA for high speed applications."

Lookit Page 2, "Input Noise". Take 1KHz as an audio average.

Voltage
1kHz 1 nV/rt-Hz
Current
1kHz 2 pA/rt-Hz

The Optimum Source Impedance is, for practical purpose, Vn/In. This works out to 500 Ohms. This is not-far from their claim of good performance with 200 Ohm sources.

It is a mike preamp for 150-300 Ohm microphones.

What is a guitar's impedance?

5 KOhms in the lower audio band, typically rising past 100K in the guitar harmonics range.

100K times 2 pA/rt-Hz over a 20KHz bandwidth is * 28 microVolts * !!

TL072 will do 2 microVolts with the same source impedance! Over 10 times better.

Both numbers will be lower in a 5KHz bandwidth (enforced by typical guitar speaker), but in the same proportion.

The Output Noise is also a serious issue. It is 65 times higher than input noise (at OSI)! This means that gains less than 65, hiss is dominated by the output. But we can NOT run gain of 65 on a guitar preamp (with less than 350V supply). This chip is optimized for very high gain thus very low-output sources. Low-Z microphones.

INA103 is NOT the best part for low-hiss guitar pickup. It is a short fat hose when we need a long skinny hose.

'5532 is also not the best low-hiss part for guitar, though much better than INA103.

TL072 is a wee bit above the "theoretical" for guitar impedances, but so very-close and otherwise cheep-n-cheerful, that it has becomes the go-to for guitar inputs.

A key factor that some folks forget-- you want MINIMUM attenuation between the pickup and the first amplifier. That means keeping the guitar knob on "10", keeping amp input impedance well above 100K, and not stacking crap between guitar and amplifier.

[Haze13]

Just what PRR said: "... and not stacking crap between guitar and amplifier! "
To Karbomusic: A/B means nothing only when you know where is A and where is B. What if you doing the switching, but you don't know which one of them is working? No LEDs or other things? Just 2 boxes and A/B switch. I did "tests" not to fool my self, but to hear the things. Surly I all ready heard what you all say on other forums when others did the same test.

And you say: none of us have likely even truly heard and very possibly do not actually want a perfectly unaltered signal.
You bought a 6k$ guitar and you just need a booster between your guitar and amp. JUST TO BOOST the signal. Larger Amplitude and higher current of the 6k$ guitar. NO bass, no treble or Mids. More of every thing that your guitar already has. In that situation you will want a Transparent Boost. If you want to alter the signal, that why EQ pedals were made... And that goes to EVERY PEDAL. All of these True Bypass things... Why people love this? Clean signal when pedal is OFF? Not just... It replaces the switching JFETs in a signal path with jumpers (if pedal being modded), and now your sound is much clearer then before since JFETs are not there any more.
Buffers: There are BJT's, Fets and IC's (as unity-gain) and last perform much better in this place - has been proven on this forum (or other). There was a very long thread with bode graphs and calculations.  BJT's just the cheapest.
The whole Idea of pedal Effects started from the point that it should WORK from 9 volts, but no one thought about the sound of it (well the maximum performance of the scheme). Now we can buy with a press of a button what not even existed 40-years ago. All around we hear that more voltage will give you a better tone (EP-booster with 18 volts, Delays with 15 volts, Maxon OD820 with BiPolar power supply, 30volts Overdrive from Freaking Sick Electronics and more, fuzzes with particular trannies, caps for WHAs and Amps...) Newer Marshalls do not sound like these from the 70's or 80's, but the scheme has not changed - the quality is.
Tube amps sounds good because the Tubes works at the voltages that they need - 300 volts for 12ax7, 450 for class AB for EL34, 6l6, kt88 and more. They can work at lower volumes, but the sound will change (it worked for EVH with 100watt when he used it with 90ac after variac). Same as solid State semiconductors will ''sound" better at higher voltages, but no need to extremes. 2sc2240 can operate at 120 volts I need to try that
I think enough for now:) As I said before, just wanted to share what I heard, experienced, read... If you like what you hear, than that how it should be.

[deadastronaut]

If you like what you hear, than that how it should be.

+1

i use a 2cm length gutar lead to amp with no loss..but its a bugger to play..

[karbomusic]

You bought a 6k$ guitar and you just need a booster between your guitar and amp.

What about a 6k guitar makes the signal better, special or more clear than a 1k guitar? Maybe it's a 1k guitar with 5k pickups?   For most  equipment/parts that handle sound... In many cases price makes a worthwhile difference in sound (to a point then we hit the law of diminishing returns very quickly), in many, other cases it does not make a worthwhile difference.  As I said originally, I think anyone should do what they like but I'm hesitant on selling that to others without verifiable proof with proper testing that can be backed up properly that's all. What you say you hear may be exactly right but no one else can count on that without proper testing, period. The original poster deserves that.

@DA

I use one of those solid metal guitar pedal male-to-male plugs and the amp hangs directly from my hip.  

[anotherjim]

I wait on someone to re-introduce those coiled cables with the right angle banjo backed plug on one end. These are directional cables and should be used in reverse with a Strat played upside-down. Rose-Morris sold nothing else. I can't believe anyone spends money on pickups potted in whale blubber and wire insulated with Tibetan Monks' hair without the real deal curly mojo cable.

[seedlings]

I use one of those solid metal guitar pedal male-to-male plugs and the amp hangs directly from my hip.  

What a great idea!  Fernendes, are you listening?  Build a new version of these with a G12M paired with a 1W firefly on-board amp.  Sustain for days.



CHAD

[Mark Hammer]

What about a 6k guitar makes the signal better, special or more clear than a 1k guitar? Maybe it's a 1k guitar with 5k pickups?   For most  equipment/parts that handle sound... In many cases price makes a worthwhile difference in sound (to a point then we hit the law of diminishing returns very quickly), in many, other cases it does not make a worthwhile difference.  As I said originally, I think anyone should do what they like but I'm hesitant on selling that to others without verifiable proof with proper testing that can be backed up properly that's all. What you say you hear may be exactly right but no one else can count on that without proper testing, period. The original poster deserves that.

1) Over on the pickup-makers forum we had numerous discussions with Frank Falbo, formerly of Seymour Duncan Pickups, regarding their silver-wire Zephyr pickups ( http://www.seymourduncan.com/2011products/zephyr-silver-pickups.php ), and begrudgingly accepted that, yes, they can make an audible difference, but generally only under circumstances that only apply to a few.

2) When I had lunch with George Gruhn several years ago - and Gruhn has seen more fabulous expensive guitars than most of us here put together - he conveyed that everything above around $3500 tends to go into cosmetic stuff that doesn't really contribute to better sound.  Good design, good materials, and solid workmanship, can be done for around that amount, without sacrificing anything, and spending more only gets you something you might like better (cocobolo and purpleheart inlays, and Dilbert-shaped fret markers?), but isn't necessarily a better instrument.  Of course, we are talking new instruments, and that is entirely separate from whatever premium someone might pay because something is old and rare, or highly specialized.

[samhay]

I wait on someone to re-introduce those coiled cables with the right angle banjo backed plug on one end. These are directional cables and should be used in reverse with a Strat played upside-down. Rose-Morris sold nothing else. I can't believe anyone spends money on pickups potted in whale blubber and wire insulated with Tibetan Monks' hair without the real deal curly mojo cable.

http://www.voxamps.com/vcc

[deadastronaut]

^ man, they were a nightmare...forever getting tangled and twisted...

[slacker]

Didn't read the whole thread so someone's probably already said this but, even completely clean, my amp adds tons more colouration than any "transparent" booster, that's kind of the point of it. You're talking marginal gains trying to make things more transparent before it.

[samhay]

^ man, they were a nightmare...forever getting tangled and twisted...

Yep, and they were suprisingly fragile too.

[karbomusic]

he conveyed that everything above around $3500 tends to go into cosmetic stuff that doesn't really contribute to better sound.

Good info; that's a little higher that I tend to quote it (I'll call it inflation adjusted). My quote to customers (back in my guitar sellin' years) was:

"There isn't a guitar worth more than $2000.00 where sound is concerned, after that it is nothing more than aesthetics, cost of materials and labor for those aesthetics and build quality".

Obviously that's just a saying but I think and have proven (to myself) after handling thousands of guitars during those ears to be fairly accurate. It's easier to see when one breaks down where the cost actually comes from.

My 3000.00 Taylor 814CE acoustic stopped sounding better way before it hit the 3k mark, much of that price is stuff that isn't related to fidelity. I played and setup lots of >$12,000 electrics and acoustics and with one's head turned no one could say they sounded better than a 2k-3k guitar. It looked, played and felt fantastic, that's about it.

[FiveseveN]

it is nothing more than aesthetics

There's something that people forget and leads to this kind of pointless discussion: sound has aesthetic properties as well.
There are few objective qualities, factors that make an instrument "sound better": susceptibility to EMI, maybe noise if it contains active elements, pops and intermittence if something is very wrong. Everything else is just preference.
On that note, if someone is utterly convinced that only a particular 6 K guitar can offer the "sound in his head" it's his prerogative. Doesn't mean it holds aesthetic (or material) value for anyone else and it certainly doesn't mean it's objectively superior.
Same goes for amps, effects, caps, op amps etc., and even then parasitic properties, oscillation, noise, poor slew rate, all kinds of distortion and so on may be attractive for some people in some circumstances.
And yet the myth of "the best" lingers on...

[seedlings]

Soon the tide will turn and we'll aspire to be mediocre!

CHAD

[FiveseveN]

It looks like we're already there, see this little rant: http://youtu.be/bT9LUiWXkyo

[Haze13]

Totally agree that the price that I wrote was way too high, strange that people think that this was the main reason for the post.

[anotherjim]

Going back to my comment on curly cables...
http://www.premierguitar.com/articles/The_Vintage_Coiled_Cable_Simulator_Mod

Those Vox ones are a travesty. Vintage? With OFC?

The real deal had insulation that cracked easily in order to let the oxygen in!
It had to have the all metal right-angle plug that need a 300w iron to solder the screen to; and with at least one little screw missing.
Oh, and you didn't just use them guitar-pedal- amp. They also functioned as psychic (intermittent) channel switches when connected between I and II inputs of your Marshall and as subtle, but tonally vital, power soaks when used round the back to hook up the cabs.

Sorry if OT, but the kids have a right to know what they're missing.