Kern IP-777 preamp

I owned one last year and it was one of the best preamps I've ever had. It works esp. well with Acme cabs, but I didn't think it was voiced well for Eden cabs. Preamps are funny that way, IME.

One of the things I loved about it was the headroom. It sounds so open without any compression. It does have some of the low end of the Alembic F-1X, but not the same EQ capability - the Alembic has a lot more in that dept. If you want classic, balls-to-the-wall fat low end, it is hard to beat the Alembic. Now others have said the Kern is fatter, but I didn't notice a lot of fat being added when the bass EQ is maxxed out. The Kern seems more restrained as far as EQ is concerned.

Like the Alembic, flat on the Kern is with the mids at 10. The front panel power and standby switch should be the model for all other preamps mfrs. to follow.The latest models have an internal power supply - no more wall wart. Yay!

The Kern is not stereo and doesn't have a crossover, but it does have two output jacks for convenience when using a stereo power amp and two cabs.

For biamping, get the rackmount Rane crossover that bgavin has.

Hope this helps. Let us know what you think when you try it.

Nightbass

 

Sorry, I didn't mean to blow your boat out of the water! The Kern is is a great preamp - it and the Alembic are my two favorites.

My experience, and that of other Kern owners, is that the Kern works best with 10" speakers. People with hi-fi cabs such as Acme, Euphonic, Bag End and Glock seem to be the happiest. I was using it with 12's and 15's and thats when the muddiness seemed to creep in. If you have a D-410XLT, you should be just fine. But your ears are what count, not mine.

The tonal balance of the Kern is only one aspect of its sound... it is also open, articulate, and has headroom for days. When you pluck a note, it seems to jump out of the speaker in real-time, and sounds like it is coming from the room and not the speaker. Way cool!

Nightbass

 

From this discussion, it sounds like both the Kern and the Alembic are using the Fender Showman circuits (bass=boost, mids=cut, treble=boost).

It also sounds like both get muddy with speakers that are capable of producing lots of lows, such as 15". As I play my F-1X out more, I'm finding tremendous lows, and what I think are not enough mids. Mine is dialed in 1-10-1 which is the maximum Mids configuration.

I'm wondering if both preamps were designed to compensate for cabs that couldn't produce lows, by accentuating the lows in the preamp EQ circuits?

 

HEY! I live near you (Boca) and bought my Kern from Jeff at M.A.E. in Ft. Lauderdale which I assume is where you are going. Thank goodness Jeff turned me onto the preamp. I love it. Except for not being able to distort, it is wonderful.

I used it live and record with it. Incredible tone and punch: beautiful top end, massive defined bottom, and verstile mids from scooped to warm and thick. The tone controls are extremely effective and powerful yet the preamp is simple to use. I have no amp GAS since I got the Kern.

The Kern's DI works very well straight to my RME AD/DA converters into ProTools. Great sound for rock, funk, metal, jazz.

Get Kern to put in the IEC plug and power supply so no wall-wart and the ground lift switch. I use a Crown K2 amp bridged mono into a Euphonic Audio VL-210 cab.

I tried Eden, SWR, Fender, Ampeg, and a few others about 2 years ago before getting the Kern. WOW!!!! Talk about clarity of tone. Go for it!

 

From the Bass Player review it looks like the Kern is a very solid built piece of gear! If memory serves it's built point to point on eyelet boards (like old Fender's) rather than circuit boards. I've thought about getting one and A/B it with my SWR IOD (ultimate clean and grind) but so far I'm just digging the SWR.

Bgavin, I've also heard that the Alembic stuff is patterned after the old Showman heads (don't know about the Kern?). Although the bass and treble are not boosts but cuts as well; nothing on the old Fender's were "active" boosts, the tone stacks were loss derived.

Tapp

 

That's correct. I've read this in a number of places, and have also looked inside mine to verify it.

Yup, that's what I've found.

You're probably right. The Alembic was designed 30 years ago, back when dinosaurs roamed LaBrea and JBL was hot stuff. The circuit does have a lot of low end boost and mid cut, and probably worked great with the cabs of yore. But this is 2001 and we have flat to 31Hz...

The Kern seems to be a close copy of the Showman, and as such, is probably "tuned" to yesteryear's cabs. That must be why I like it best with a hi-fi 2x10, 3x10, or 4x10, and not with a 2x12 or 1x15.

Nightbass

 

When of my buds dug out an old 1994 Bass Player article that detailed the various frequency ranges:

• 25 ~ 100 Hz, Power, Depth, Boom
• 125 ~ 500 Hz, Presence, Definition, Honk
• 630 ~ 2,000 Hz, Growl, Edge, Harshness
• 3150 ~ 20,000 Hz, Brilliance, Sparkle, Noise

I figure I'll tweak up a spare channel on the parametric EQ to center at 1250 Hz with a two-octave Q to see if I can boost the growl.

I'm trying to score a real-time analyzer, then I'll be able to measure for sure, rather than guess. It would be very interesting to feed the line-out from a given preamp into the analyzer and see exactly what EQ curve is applied at the "flat" settings.

 

Hey Bgavin, How 'bout something you can use for FREE! Go to:

http://www.duncanamps.com/tsc/index.html

and download the tone stack calculator. If you've got a schematic of the Kern, Alembic, or even use a Fender Showman and click the Fender tone stack and enter appropriate values. You will see a graphic representation at various "knob" settings.

Remember folks, if the Kern/Alembic tone stack is a copy of the Showman, it is not boosting any of the freq. it is a loss circuit (only cutting) yet it "sounds" like boost when added; because who in they're right mind would dime the bass control on a Showman amp (can you say farty mud!).

Tapp

 

It's my understanding the Showman circuit is Bass=Boost, Mids=Cut, Treble=Boost.

I have it for certain from Alembic that is the way the F-1X operates. No proof of how the Showman operates, but Alembic says the F1-X is modeled after the Showman.

I don't have a schematic of the F-1X, bummer.

Thanks for the tip, and I will add it to my list of reference materials.

 

Here is a shot of the Fender/Alembic F-1X setup in 2-10-2 and 0-10-0 modes:

Screen Shots

It looks like I can get almost flat in 0-10-0 mode. The rest I can probably squeeze out of my parametric EQ.

 

If you want to believe that the Showman is a boost-cut-boost circuit then fine, but I'm telling you that the traditional Fender AB763 tone stack (which is what the Showman is) is a loss stack(there is no active freq boosting going on, just passive filtering). The voltage (from the pickup) is amplified at the 1st gain stage then sent to the tone stack (which loses gain) it is then sent to 1 more stage before hitting the driver/pi. In a Marshall, the tone stack is at the end of the chain feeding a low impedance cathode follower (but I digress).

Did you try the tone stack calculator?

I had (at one time) an Alembic schematic so I'll look around. I don't honestly know how the Alembic/Kern relate to the Showman, but I do know old Fender circuits.

Tapp

 

Bgavin, I just caught the graphs after I posted so cool.

I think our disagreement is a matter of semantics. I think (after reading your post again) that you're referring to attenuated frequencies and in that case you're right that the bass and treb are "boosted" and the mid is "cut" to give a "scooped mid" response. This is the standard "Fender" clean tone that everyone talks about.

When I hear "boost" I think of active circuitry which the Fender circuit (and possibly the kern/Alembic) does not have. The freq response is purely a function of the RC passive networks within the tone stack.

Is this clear as mud (ha ha)? I think we agree.

Tapp

 

Even through I think it's cool that the stack calculator gives the frequency response for an amp with various settings, it's hard to complete the "tonal picture" without the equivalent circuit of the speaker cabinet. Tieing the two together (amp with load) in one tool would be great (getting both schematics would be nearly impossible).

I'm going to the Bass Palace on Friday and I hope they still have the used Kern! They have a Bergantino 310, Epifani 310, and Glock 212 (with a Soul head) and I really want to try driving these cabinets with the Kern. Besides the EA and Acme cab's which seem to be a good fit for the Kern (from previous post), what other cab's have worked well with the Kern?

Sam

 

It was only boost in my mind because the Bass and Treble pots must be wired in reverse. When the Bass pot is at 0, it is at Maximum Cut evidently? So turning the knob clockwise (the "boost" direction) is actually introducing minimum cut into the circuit.

Anybody have the stack trace for the SWR IOD? I'm wondering if those are a lot more flat line (read: HiFi).

[ edit ]

My subs provide such a sold bottom end, I must be getting overdone by using a preamp with scooped mids that favors the lows in such an accentuated manner.

I'd still like to hook an RA-27 analyzer into a preamp so I could actually measure the kind of pattern that comes out. I figure one could use a slider-based EQ to flat line the response to the analyzer pink noise signal, and the slider pattern would be the inverse of the preamp stack pattern.

Thoughts?

 

I chose the EA cab to use with my Kern 777 because it simply sounds gorgeous.

The runner up was an EBS 4x10 but the EA was much bigger and open sounding and more neutral. I tried SWR, Eden, and a few other cabs.

Finally, the EA 2x10 is pretty small and I can carry it around with one hand if needed...I usually use two.