Headway EDB-1 Two Channel Preamp

[ljguitar]

Hi folks...
My EDB-1 (Headway) preamp from UK arrived yesterday.

This will be a preliminary report to be followed by a review and updated news...

First off, this is one great sounding preamp...but it is not a standard dual-source preamp. By that I mean it is not a single cable plug-n-play dual source preamp for a guitar equipped by an internal mic which needs phantom, and a passive pickup. It is plug-n-play for two passive sources, and it is also setup to easily use an external condenser mic focused on the instrument and an internal pickup.

The EDB-1 sounds as good or better through an amp at first listen as my DTAR Solstice with my K&K pickup. Amazing clarity, full, fat, and very good tone and headroom, even with all controls set flat. I'd like to report on the internal mic, but I cannot at present get it to power the K&K internal mic (working on the technical side of that), with the standard K&K wiring configuration. But I have powered up an external AT-2021 condenser mic via the XLR input with +18Volt, and run it in tandem with the pickup on a separate channel, and it sounds/works very well for that. In fact it sounds very much like my guitars that way...

This is one of the configurations which is recommended by the inventor/company who doesn't believe internal mics in instruments are a viable consideration (we are exchanging e-mails and he did print this in the original website details on his preamp). I'm not interested in changing his philosophy of amplifying acoustic instruments, just want a simple solution to join my rig with his...

Now for pics...note the size of the unit side-by-side with an LR-Baggs ParaDI...this fits perfectly on top of my UltraSound amp and will fit in the compatment inside a standard guitar case...




There is no conventional way I have discovered so far to plug in a standard 1/4'' TRS cable into both the guitar and EDB-1 and have it send the +12volt phantom to the mic and place it on one channel while dividing out and sending the pickup signal to the other channel. It is not configured for that option, despite some early speculation in another discussion that it must be - most assuredly it is not.

Channel 1 is for +12volt internal phantom, and Channel 2 for single or dual passive, and XLR for +18volt phantom. Channel 1 can also provide non-phantom access to a pickup (the phantom power is switched). I am searching for a way to feed the mic on channel 1 while directing the pickup to channel 2. Both channels have switchable impedance on the input.

It is against the philosophy of what the inventor considers proper amplification of an acoustic guitar to use internal mics, so no provision is made for what I'd consider a fairly conventional dual-source configuration. This is why no provision is there for TRS insert/split.

That said I am exploring ways to either rewire my cable or the internal setup of the K&K dual source rig I'm using to accomplish this. I'm fairly certain it can be done fairly simply.



Above:Full input view and individual inputs...

If I can figure out how to separate eveything properly and power up the internal mic on channel 1 while not sending phantom to the pickup and sending it to channel 2 via a separate cable (mono). I'm exploring a rewired split cable, or rewiring the ends of the cable or rewiring the internal input of the guitar...it seems there should be a work around which is simple...I'll keep you posted on it.

In fact if any of you out there have ideas, my email is here [email protected] and I welcome your input.

Below-Full input section with adjustable impedance,
and separate volume for each channel plus gain...



I plugged a mono cable into the guitar and into channel 1 to run the pickup and the condenser in XLR in with phantom switched on, and it will be a great option for fairly quiet gigs...an external condenser of course will sound more natural than an internal mic. Just not workable for noisy environments like coffee houses where close proximity to grinders, blenders, steam wands and ice crushers make it tough to work at low enough volumes to utilize it.

[Vikki]

Larry...
If you feed two pickups into the unit can you eq each one separately or do the eq controls just give a combined eq?
Vikki(uk)

[jaskofall]

Hey Larry,

thanks for the prelim review.
I have the trinity in one of my guitars and am trying to find a good, multi purpose blender to blend the trinity and also other dual sources in other guitars. eg, dtar wavelength & K&K combo etc
I have emailed dieter, and he said it wouldn't work with the trinity, He recommended the quantum blender.
John from headway also said that he wasnt too sure that it would work with the trinity as the mic needs between 5-9v and the headway only supplies 12v from channel 1 (this 12 volts is more to supply a internal preamp instead of having a battery in the guitar when using a UST than a mic) and channel 2 supplies 18v Ph P but only via the xlr insert.

Im sure there is a way to power the internal mic with the K&K, Its just a matter of finding out how to do it.
We have lots of clever, clever people here (including yourself) and im sure someone will have a suggestion.

Im sure this preamp will work really well with all my other configurations, but maybe not the trinity.

So as far as the preamp and eq stage goes its on par or better than the others? (solstice, para di etc)

Linda - yes, you only have one eq available for the 2 sources

Thanks again Larry,

Jasko

[ljguitar]

Originally Posted by Vikki

Larry...
If you feed two pickups into the unit can you eq each one separately or do the eq controls just give a combined eq?
Vikki(uk)

Hi Vikki...
The EQ is only on the output, which I was inquisitive about, but it actually works quite well in my preliminary tests...

[ljguitar]

Originally Posted by jaskofall

...I have emailed dieter, and he said it wouldn't work with the trinity, He recommended the quantum blender.
John from headway also said that he wasnt too sure that it would work with the trinity as the mic needs between 5-9v and the headway only supplies 12v from channel 1 (this 12 volts is more to supply a internal preamp instead of having a battery in the guitar when using a UST than a mic) and channel 2 supplies 18v Ph P but only via the xlr insert.

Hi joat...
Actually I have it in writing from Dieter (today) that the K&K mic is fine from +1.5 to +12 volts, and have indeed been supplying it with +12 for years in three of my guitars with great results and no damage...

Dieter indeed thinks his preamps work a certain way, and John from Headway has designs on his equipment as well. How we actual users in the field approach it is often a bit different from how it is conceived.

I will be doing the equivalent of powering a K&K Trinity system with the EDB-1 when I get it solved...and will publish the process and our results....Dieter also said it could impair my rig if I used the Raven on it, and suggested the same with the DTAR Solstice - actuality has proven to be quite different...both are outside of K&K's designed 'specs'.

I'd expect him to take that line, and I took the risk with all three of my rigs and none suffered anything in the nearly 5 years I've operated them outside of spec.

John is not thrilled to have to do the homework with his tech on this, but I'm not asking Headway to change anything about their unit. I just need to know a couple technical details both from K&K and from Headway before I alter cables.

[leehwd]

Hi Larry,

Did you notice any difference among different impedance settings? How about the range (i.e., bass vs. guitar vs. violin)?

I tried this unit at a local store last Friday (Victor Litz @Gaithersburg, MD), finding this unit clean, but I was not able to hear any difference amogn those settings. Maybe, it was very subtle, so I couldn't tell the difference. The EQ seemed versatile in tone shaping, but, frankly, I was not that much impressed, given that it costs twice as much as the LR Baggs DI or other similarly priced DI/preamps. Just my 2 cents....

[jamison162]

Nice review Larry. I received a demo EDB-1 last week and spent alot of time with it this weekend. I have not posted my review yet because I am not done evaluating it and haven't had time to write an adequate review.

But my thoughts are on par with yours and others. I was gladly surprised that this unit was not much bigger than the PADI. Also, while it does sound better than everything I've compared to it, it didn't "blow me away" in that it's not gonna totally transform your whole rig into something it's not. It does get me noticeably better tone though. Also, I did not notice ANY difference in the impedance settings either which confirm my thoughts on the whole K&K impedance issue that has been discussed to no end over the past few yrs. It doesn't matter in this application, i.e. not an issue.

I had trouble with the inputs with my K&K Trinity as well and have corresponded with Jasko about this. I find it a little confusing even though I am a tech and do a lot of signal routing and custom controllers/amp switchers, etc. (Mainly with electric guitar rigs - partime; fulltime Civil Engineer).

My assumption from reading the manual was that both Ch.1 and Ch.2 were stereo inputs. With the K&K, the tip is the Pure Pickups and the ring the mic, so I thought plugging into CH.1 would power the mic via the 12v phantom power on the ring.....I was having a lot of feedback issues so I am thinking the pickup and mic were indeed both on but only on Ch.1; the Ch.2 gain was ineffective. Plugging into Ch.2 routes the ring to Ch.1, but no phantom power is availble.

My suggestion would be to make a special cable that splits from a 1/4" TRS at the guitar (tip: K&K pickup, ring: mic) and then split the two signals at the other end to one 1/4" Mono and one 1/4" TRS plug.

The 1/4" Mono will be the K&K Pickups from the guitar end and will plug into Ch.2. The 1/4" TRS will be the mic signal from the ring at the guitar end and plug into Ch.1.
On the 1/4" TRS at the preamp end, wire the mic to either tip or ring, doesn't matter, and wire a jumper connecting the tip and ring. This way the signal is fed from the tip and get's power from the ring. If you use a 1/4" mono for the mic signal, the phantom on the ring will just be grounded.

The only thing I am not sure about here is if phantom is supplied on the ring on Ch.1; does the signal from the ring feed that Ch. or only the tip signal. If the ring does feed that Ch. a signal, (then the mic should be powered when you plug in a standard TRS) you would not have to wire it to the tip at all, leave the tip empty.

You may have a stereo cable that you can just rewire one end of. I use Canare Star Quad Mic Cable for my stereo cable, 4 wires, one for hot tip, one for hot ring and 2 separate but common grounds. Butch at Bayou Cable could make you a custom cable like this; I am currently out of Star Quad.

I'm not sure why John designed these inputs this way, I don't see how any application would work without this specially wired cable.

[jaskofall]

Hey Jamison,

was the quote in bold a recommendation from John or yourself

Thanks

Jasko

[jamison162]

That's my take on how to make it work. Only way to know is for someone to try it. I don't have time this week and will be sending the EDB-1 on to the next guy tomorrow.
But...I will be purchasing an EDB-1 and the Headway HE2/G UST for myself.

[ljguitar]

Originally Posted by leehwd

...Did you notice any difference among different impedance settings? How about the range (i.e., bass vs. guitar vs. violin)?
...I tried this unit at a local store last Friday (Victor Litz @Gaithersburg, MD), finding this unit clean, but I was not able to hear any difference amogn those settings. Maybe, it was very subtle, so I couldn't tell the difference. The EQ seemed versatile in tone shaping, but, frankly, I was not that much impressed, given that it costs twice as much as the LR Baggs DI or other similarly priced DI/preamps. Just my 2 cents....

Hi lee...
I am not prepared to do an exhaustive analysis yet, as I have only tested this unit for a couple hours. I want to put it in the field as part of my testing, which I think is a huge real-world test of equipment...

To attempt to address your points and casual observations...
The impedence settings are:

• Ch 1 Input Impedance: +Hi=>20 MegOhm, Hi=>5 MegOhm, Active=>1 MegOhm
• Ch 2 Input Impedance: Hi=>5 MegOhm, Instr=>1 MegOhm

I'm not sure how you test the effects of switching this...perhaps you have a suggestion as to what I should notice different at each setting? I'm not sure what to expect when a 1 MegOhm source is plugged into a 5 or 20 MegOhm configured input or vice versa.

As to the High pass filter settings for Bass, Guitar, and Violin the frequency shifts approximately an octave upward with each setting progressively beginning with Bass (allows more bass & begins shelving at a lower freq point), Guitar and Violin. It raises the beginning frequency of the shelving approximately an octave at each setting.

Having run a small production studio and doing mic arrays for guitars almost continuously for that time, I heard this high pass change very plainly, even on my UltraSound amp. It would be even more pronounced through a PA system, mixing board or system with capability to produce low bass frequencies.

This could potentially be noticeable in recording and live situations where, if the bass isn't shelved, it can result in subsonic ''bumph'' creeping into sound reproduction...or low frequency feedback when an over-zealous sound tech adds too much bass in the house mix.

Let's compare Apples with Apples...
Yes the EDB-1 costs twice what a ParaDI does, and it does more than twice as much as a ParaDI. It does everything the ParaDI does except for powering it with phantom power and there no effects loop on the EDB-1.

The things the EDB-1 does which exceed the ParaDI capabilities include:

• supplies phantom power to condenser mics or other phantom powered sources (in two voltages at two locations)
• two input channels
• true mute
• XLR input
• 1/4'' mono and TRS input
• high pass filtering
• switchable impedance matching
• switchable in/out notch filtering
• switchable power (on/off by a switch not a plug)
• ground lift
• can be powered by power supply or two 9 volt batteries.

Since I own both, I can tell you that the EDB-1 - even with my cursory testing - surpasses the audio quality of the ParaDI, and audibly exceeds the quality of both the K&K Trinty belt preamp, and the Raven PMB preamp as well, and it does it all in a battery powered unit which is 1/8 the size of my DTAR Solstice.

Headway says it is planning to bring a single channel model to the market next year and that would be more fair to compare it to the ParaDI or other single source preamps (K&K Pure XLR, Fishman Platinum etc).

If you are in the market for an improved preamp, there are other choices that are higher dollar which frankly would potentially produce an even higher quality system if you have the equipment to reproduce it - like the Pendulum preamp rack units which go for around $1000-1200 used.

What I am waiting for before fully reporting on the EDB-1 is to play and hear it side-by-side through identical amps (I use a pair of UltraSound AG-50s), and to put it in the field for some gigs using the internal mic and pickup.

[jamison162]

Upon further review of the manual:

Ch.1 is a stereo jack. The tip source feeds Ch.1, phantom power is supplied to the ring, but any signal on the ring is not fed to that Ch. So a jumper on a 1/4" TRS plug connecting the tip and ring plugged into Ch.1 should get the mic powered and signal fed to that Ch.

Ch.2 is also a stereo jack but has 2 applications:
1) Acts in mono feeding a signal from the tip of a plug to Ch. 2 when there is a source already plugged into Ch.1.
2) Acts in stereo feeding a signal from the tip of a plug to Ch.2 and from the ring of the plug to Ch.1 when there is nothing already plugged into Ch.1.

So....my cable idea posted above should work for you/us Larry. Hope this helps.

[ljguitar]

Originally Posted by jamison162

...Nice review Larry.

...I had trouble with the inputs with my K&K Trinity as well and have corresponded with Jasko about this. I find it a little confusing even though I am a tech and do a lot of signal routing and custom controllers/amp switchers, etc. (Mainly with electric guitar rigs - partime; fulltime Civil Engineer).

My assumption from reading the manual was that both Ch.1 and Ch.2 were stereo inputs. With the K&K, the tip is the Pure Pickups and the ring the mic, so I thought plugging into CH.1 would power the mic via the 12v phantom power on the ring.....I was having a lot of feedback issues so I am thinking the pickup and mic were indeed both on but only on Ch.1; the Ch.2 gain was ineffective. Plugging into Ch.2 routes the ring to Ch.1, but no phantom power is availble.

...I'm not sure why John designed these inputs this way, I don't see how any application would work without this specially wired cable.

Hi joat...
My posts are not really a review yet - just my first impressions, and a catch up on the commitment I made to the group to post when it arrived.

After reading your post I went in and plugged in a dual-source equipped guitar via TRS cable into channel 1 which activates the pickup for sure, so I switched the phantom on and off to test for evidence of the mic being active in the signal, and it is definitely not there. I've concluded after messing with the unit a TRS insert doesn't necessarily assure a ''stereo'' input configuration.

I did the scratch-test on the mic screen directly, the talk into the mic test with it turned way up, and the hold a really loud chord while switching the phantom power off and on...nope it's not there...yet.

I will pass the info on cable wiring possibilities from your observations on to my tech, and see what he thinks (he does PA sound work for arenas and used to run a radio station, and is an engineer for radio stations all over this region). He has repaired and rewired gear for me for years...good friend to have. These may be really helpful. I'll for sure let you know what options we end up using. There may be several ways to skin this cat...

He is coming over Sat to look at everything.

As to why it's designed this way is John sells pickups which match his preamp perfectly - for several instrument types. And he says they are coming out with an internal non-mic active pickup this year. It will be perfectly matched to his system.

By the way, for external phantom powered condenser mic and mono pickup input, it's a perfect little rig. Works perfectly. For a dual source non-active system like and undersaddle paired with a magnetic pickup it's perfect and ready to roll with a simple TRS cable.

The only configuration it seems not to be wired for is TRS supplying power to internal mic with a passive pickup.

[jamison162]

Originally Posted by ljguitar

The only configuration it seems not to be wired for is TRS supplying power to internal mic with a passive pickup.

Which is exactly what John writes about in the manual. Still, my cable idea should work perfectly. Not too hard to make either.

CH.1 works with his HE2 pickup and will power it without having to use the internal battery - which is what he intended I believe.

Edit: Larry, since you have ongoing correspondence with John L., why don't you copy and paste my cable idea and ask him if this will work.
Obviously there are many preamps on the market which supply phantom on a certain input which also feeds the signal. But, John had these
isolated from each other on Ch.1's insert. Not fully understanding phantom and eveything, I would want to make sure this will not cause any damage
to the EDB-1 by linking the signal source and phantom on Ch.1 itself.

[hann]

It looks like a great preamp based on your initial analysis but if it's gonna be so troublesome to match it with a K&K trinity wouldn't that be a deal breaker?

for me at least it is... imaging rewiring several trinity-equipped guitars..

and i wouldn't be able to test future preamps..

[ljguitar]

Originally Posted by hann

It looks like a great preamp based on your initial analysis but if it's gonna be so troublesome to match it with a K&K trinity wouldn't that be a deal breaker?

for me at least it is... imaging rewiring several trinity-equipped guitars..

and i wouldn't be able to test future preamps..

Hi Hann...
If it's a simple matter of making up a new cable, then it's neither troublesome nor a deal breaker for me. It's not a big deal to have another cable around.

I have three such Trinity equipped guitars in my house myself. I'll let this play out and see where it leads before concluding that it cannot be done.