My preamp solution for a K&K-equipped Martin... and it's not what you'd think.

[000M]

So I've been on a bit of a journey to find the sweetest sound for my Martin 000M. I settled on a K&K Pure Mini and got it installed a couple of years ago. The helpful advice, provided by this forum and others, was that if I wanted the best sound I should invest in a line driver/preamp/active DI with a 1M ohm input impedance. Well, it turned out that it wasn't as simple as that...

I tried these 1M ohm devices:
- Crowther Hotcake
- Boss LS-2
- DOD Bifet Boost 410 (3.9 M ohms)
- Diamond CPR-1 Compressor
- MXR M87 Bass Compressor
- Caline 10 Band EQ (not sure of input impedance actually)
- Fire Eye Red Eye
- DTAR Equinox (5.6 M ohm though)

Besides the exceptions mentioned above, all manufacturers' specs claimed 1M ohm input impedance.

...I think I've found my solution.

FWIW, these results are on only one 'inexpensive' Martin guitar so YMMV. It's possible that my guitar/pickup needs more sound sculpting than other K&K-equipped guitars. However, I will say that the my impressions are based on each preamp in its 'dryest' possible active setting - eq set in the middle, compressor threshold up and out of the way.

And the winner is...

A tie between the Equinox and the Bifet Boost!

Bifet Boost seems to really sweeten the mids while providing the best balance across the frequencies. Perhaps a little rolloff on the low end but not enough to thin out the sound.

Equinox does something great to the highs. They're definitely there in an appropriate quantity, but they're evened out or slightly subdued or there's a slow transient response or something. If it's a rolloff it's a rolloff for good! It would be easy to assume that the impedance 'mismatch' had something to do with it, but I get the same silky top-end if I run it after the Bifet...

Who knows what's going on there. Whatever the silky cause, the Equinox is clearly the most expensive of the lot. I happened to find a sweet as-knew used deal for 40% of the retail price so it wasn't that different $ from my pedals. I don't know how often deals like that come up, but keep an eye out It clearly it has very comprehensive EQing capabilities, but I did my best not to let that bias my impression. I liked it the best (equal) and it was still silky, even with the EQ and Notch buttons bypassed.

The Diamond has a tilt EQ but the Bifet Boost + its tilt EQ still sounded sweeter and flatter to me, so once again I don't feel that the EQ on the Bifet biased my opinion.

The biggest surprise for me (or lack thereof) for me was the Red Eye - it just sounded thinner than I like. Don't take that as a knocking the quality of it though. It seems really well designed and built. But maybe my guitar (000 laminate body) is weak in the low-end to begin with. Turning down the Treble knob wasn't enough to compensate in my case.

I guess what I'm saying is that there are a range of K&K solutions out there, and what may be the best solution for lot of guitars might not be the best for yours. So keep experimenting if you're still unhappy, and sometimes an unusual brand/device/price may be the right solution.

Personally, I'm going to stick with both of my 'winners' for now. I'm using the EQ of the Equinox but the Volume knob on the Bifet is too convenient to let go of just yet.

Happy to answer questions on my experiences with the others, but I figure I've written enough in this post.


EDIT: Corrected Bifet Boost input impedance. Don't know where I got 1 M ohm from.

[tbeltrans]

Looking up the Bifet Boost 410, it seems to be discontinued (though I am sure they can be found on the used market) and also DOD lists its input impedance as 3.9M ohm. So if you already have one, you are all set. As far as input impedance, K & K recommends 1M ohm impedance, but that is certainly not written in stone. Whatever works and sounds good to you is the main criteria. Interesting post, thanks for the info about your experimentation and results.

Tony

[The Kid!]

Cool comparison.

[guitarwebguy]

Interesting and useful comparison - thanks for sharing! I’ll suggest another option (although it is expensive and you appear to have a result that works for you) and that is a Grace Design Alix which would give you all that you need and more in terms of options https://gracedesign.com/products/ins...plifiers/alix/. I use the big brother (Felix) for all my guitars which have a variety of K&K pu’s installed.

[jonfields45]

I have been using passive SBTs on and off for years on many guitars. ToneDextor by far is the best of the preamp options I've tried. However, what I've learned the hard way is what sounds great in my living room does not translate well into every performance space.

So to critique your two winners... The DOD has no EQ knobs and the DTAR has too many.

[varmonter]

Originally Posted by guitarwebguy

Interesting and useful comparison - thanks for sharing! I’ll suggest another option (although it is expensive and you appear to have a result that works for you) and that is a Grace Design Alix which would give you all that you need and more in terms of options https://gracedesign.com/products/ins...plifiers/alix/. I use the big brother (Felix) for all my guitars which have a variety of K&K pu’s installed.

This.. but the felix is a grand but i love it.
Interestingly i have a diamond compression my pedalboard. i use to run it in line with all the efx into my felix and out to the board. I never tried running the kk equipped taylor just through the diamond comp. more fun stuf to try

[Villamarzia]

With my HFN equipped guitars, I found the compressor Cali 76 to work very well with its internal preamp. You can keep the compressor at almost zero and use the preamp stage, eventhough I like a bit of compression. Very unusual, very effective.

[000M]

Originally Posted by tbeltrans

Looking up the Bifet Boost 410, it seems to be discontinued (though I am sure they can be found on the used market) and also DOD lists its input impedance as 3.9M ohm. So if you already have one, you are all set. As far as input impedance, K & K recommends 1M ohm impedance, but that is certainly not written in stone. Whatever works and sounds good to you is the main criteria. Interesting post, thanks for the info about your experimentation and results.

Tony

Cheers for picking that up Tony, not sure where I got the idea it was 1M. I've edited the post.

I picked mine for about $70 used. I think they were only discontinued a year ago so there are a few still around that are new/as new. I see one on Reverb and three on eBay listed as brand new.

For people wanting to experiment, buying used is probably the best way to go though - easier to flip for the same price you paid.

[000M]

Originally Posted by guitarwebguy

Interesting and useful comparison - thanks for sharing! I’ll suggest another option (although it is expensive and you appear to have a result that works for you) and that is a Grace Design Alix which would give you all that you need and more in terms of options https://gracedesign.com/products/ins...plifiers/alix/. I use the big brother (Felix) for all my guitars which have a variety of K&K pu’s installed.

Originally Posted by varmonter

the felix is a grand but i love it.

All of the Grace Design stuff makes me drool! What made you guys choose the Felix over the Alix?

One day when I try a Felix/Alix I'm 99% sure I'll realise how much time/postage/tone I've wasted chasing this sound. Until that day comes I'm going to claim some silly pride that none of my experiments cost me more than US$200 apiece (I'm in NZ). Red Eye was US$150 used (mint) off Amazon. Even the DTAR was US$165 used (ex cond). Definitely made it easier to take a punt. Took a lot of patience to wait for the right prices to turn up though.

Now if I can just get back what I paid for it all...

Originally Posted by varmonter

Interestingly i have a diamond compression my pedalboard. i use to run it in line with all the efx into my felix and out to the board. I never tried running the kk equipped taylor just through the diamond comp. more fun stuf to try

It seems there are few peeps liking them on their acoustics but I just didn't click with it. Not a reflection on the quality of compression; I've concluded that compressed guitar in my monitor just isn't my thing. Tone-wise, the Diamond added a very musical low-mid bump that probably makes it awesome for soloing... I just wanted something flatter as an always-on thing. Great piece of kit though. I'm sure it has earned its place in your rig.

Btw I was mostly testing it with the pedal on but with very little compression (if any)... which you might reasonably conclude is a waste of a good compressor...

[000M]

Originally Posted by Villamarzia

With my HFN equipped guitars, I found the compressor Cali 76 to work very well with its internal preamp. You can keep the compressor at almost zero and use the preamp stage, eventhough I like a bit of compression. Very unusual, very effective.

This is what I mean, especially when it comes to line drivers/preamps first in the chain. All pedals are buffered when they're on. We should think outside the Hammond enclosure!

It can be freeing. If you already have a bit of gear it can reduce GAS-induced bloating. Or it can help to justify yet another purchase...

[000M]

Hmmm, another thought...

If I rank these three from bassiest to trebliest I get
Equinox (5.6 M ohm)
Bifet (3.9 M ohm)
Red Eye (1 M ohm)

... Maybe my guitar is just a toppy beast?

There are so many people out there who extol the virtues of the K&K-Red Eye combo, so maybe it's my guitar? Seems strange though because it doesn't sound that toppy acoustically.

[guitarwebguy]

I went with Felix instead of Alix because: 1) I often play 2 instruments in a set and I can use the Felix as 2 separate inputs which allows me tp preset everything when I need to switch instruments, 2) there are times when I like to use a mic in addition to the K&K pu’s in one of my guitars, in that mode, I can blend the two inputs into 1 output and have both inputs with their own EQ

[ACOUSTICDEWD]

Highly recommend these 1M ohm devices:

Programmable EQ from Source Audio. It's more surgical than any of the plug-n-pray devices. Clean boost alongside visual EQ controls

ParaEQ from Empress Effects. A slightly pricier option and even more surgical. parametric bliss with a great Q selection

GMF Ai1 The most affordable option - has the same shape switch found on Ultrasound amps (same designer) treble/bass controls, phase, ground and a mini headphone out.



....

[Sonics]

Interesting. I've noticed a brand missing from your list of preamps. Personally my first step would have been to consult the manufacture of the pickup and see what they have to offer in terms of external preamps. In theory you should have no incompatibility problems by keeping everything 'in-house'.

https://kksound.com/preamps.php

...and while we're on the subject, this K&K pickup blend system sounds superb...but it's expensive!

[Pitar]

I think the best first effort to making the K&K PWM, and other similar products, perform as needed is to find the best spot for each of the Piezo pick-ups in the array. The bridgeplate, for me, was not the right spot. I say that because I had the same problem on my 1st PWM install. I did not like the balance and tone of the product as-installed on the bridgeplate per the instructions.

On my 2nd install I bought a removable pick-up made by Shadow and located the best spots on the soundboard for each of the Treble, Mid and Bass "bugs" of the array, then extended the conductor lengths of each to reach those places. Then I used the same removable mounting adhesive that came with the Shadow pick-up to temporarily mount each PWM bug to confirm that their locations resulted in a flatter EQ out before bonding them permanently.

The specified bridgeplate location makes all of those products easily installed DIY kits for people. If the instructions dictated a search for the best spot for each bug before bonding it, like I did, it would probably scare away a lot of potential buyers who couldn't be bothered with the extra effort.

The Fishman SA220 amp EQ settings for my first PWM install (Goodall RCJC) had the treble 75%, the mids flat and the bass rolled off to about 25%. The classical guitar I have with the factory installed system on the same amp has a slight mid scoop, which is about normal. My 2nd Goodall RCJC install more closely matched the classical guitar's settings with a slight bass roll off.

I think it would be impossible for the makers of the arrays to have a universal product that performed well across all the guitars produced. It isn't just a matter of EQ'ing the array because the best quality of the sound available from the guitar simply isn't on the bridgeplate. It's outlying from there. Collecting the best sound from the guitar to send to the electronics is the goal, or should be, but the Piezo arrays currently made are not built for that express purpose.