I'm looking at picking up an NS in the near future, and realized I haven't anything decent to amp it with.

I do, however, have parts for a preamp. It was originally going to be a dedicated mid-phile level headphone amp, but it wouldn't be difficult to just add an instrument preamp stage and the circuitry to mix the two channels together (I wasn't originally planning on crossfeed). I'd have a pretty killer practice headphone amp then, as well.

For the preamp I have a pair of Penny & Giles stereo faders (need two pairs of pots for a balanced output headphone amp), Class-A J-fet/Bifet output buffer (currently unity gain but I could add gain of about 4 safely). Input stage will be transformer-coupled so it will accept either balanced or unbalanced inputs.

I also happen to have a pair of cabinets I made way back (like, 20 years ago) that I never got around to finishing. The top cabinet is about 2.7 cu. ft. and I was planning on loading it with a pair of Eminence 10" woofers and perhaps a compression driver for highs. The bottom Cab. is 7.19 cu. ft. Haven't decided what I want to put in it, yet.

I could build an amp but it may be just simpler for me to use a simple PA amp. I saw a couple Carvin tube PA amps on eBay the other day...tempting.

Most of my playing would be with our jazz trio (mostly Jazz/Jazz Fusion), and some Church gigs (mostly folk-style worship tunes). I don't want to have to lug the big cabinet around for the small stuff, it's kind of massive.

So, to the questions:

1.) For the preamp, what kind of (quality) input stage do you think would be most appropriate for the active electronics on the NS? I'd like to run the bass clean but I'll probably have some modeling pedal/effects on the guitar side, so I'll need line-level input as well. Should I be thinking about transformer-coupling the output, to?

2.) Any thoughts or alternate suggestions for the drivers in my cabinets? Is adding a compression driver for the highs worth it? The big cab. would take 4 x 10, but I'm not intending on using it all the time so I don't know if I want to spend that much money on drivers.

3.) How about a DIY amp? Suggestions for designs or kits? Tubes or no? Am I just better off going with an over-the counter PA-amp solution like many have suggested for other rigs on here?

I should add I'm not intending to save a huge amount of money by DIY--I just happen to already have some parts on hand, I'm handy with electronics and like being able control the quality of what goes into the things I make.

check out this thread on DIY stereo preamps


viewtopic.php?f=4&t=732&hilit=DIY+Preamp


Randy

Thanks Randy! That's a great thread! Guess I didn't search enough..

If you need the NS to emulate a bass guitar, the Sansamp Bass Driver DI does a nice job. The subtle compression it offers I really like with the NS. EBS also makes so nice items like that.

Hello zaubertuba.

Concerning the 3rd. point on your list:
I have, until recently, been using MosFet power stages for the amplifiers I make for friends (and friends of friends). Though for the three latest guitar amplifiers it has been Class D Power amplifiers from Onlineusa that were chosen. The musicians choose them, that is.

I "cheat" and let them do blind A/B comparisons. If I tell them beforehand that I am using something as sacrilegious as class D or even transistors, we end up in the usual transistor/tube debate. Hence, I cut the crap early by letting them try out different output stages in my amplifier park.

If they want an output stage that distorts when driven hard, then the solution is to install a 1:1 audio transformer. That's where that "wonderfully warmly rounded" tube sound is located for the most part.

I am myself in the process of laying out a rig for the Stick. Perhaps we can have fun with such a project together.
My approach is that the amplifier and speaker chain is to be as linear and without distortion as possible, practically HiFi.

All the best,
Henrik

I certainly don't *have* to have a tube amp. I was attracted to the JISBOS for my headphone amp because it was discrete components. Jury is out as to whether my ears will hear a difference between that and my opamp-based a47 headphone amp. Most people I correspond with think the JISBOS sounds pretty sweet.



Is that due to frequency rolloff in the transformer, or some other factor? If the former, transformer selection becomes a huge factor. I was planning on using Cinemags in my preamp, which spec out very good for frequency response, but aren't as costly as Jensens.



Sounds like fun!



That's my philosophy as well. I'm kind of a "closet audiophile cheapskape," so sensible attention to clean signal reproduction is pretty key.

I always thought adding a stereo/mono switch and output to such a preamp would make sense so you could sum the outputs post pre-amp, but I guess the NS has active pickups, so it wouldn't make any difference.

It could make it easy to run it into a single channel amp if you're playing outside of your own rig much simpler though....

Just a thought

Randy

When you brought this one up Mich, I had to go check on it at a store, where I get to take it apart and look at the service manual.

My personal, subjective and possibly unpopular opinion is that it is no better than the Behringer BDI21. Which can be had for $25 to $ 40. The Behringer is cheap enough that it hardly makes sense to build a copy.
The two are almost clones of one another and there are no compression circuits in either.
Only if one needs line instrument output and/or the XLR line out will it make sense to buy the Sansamp. But it will set you back about $200...
I'd hack the Behringer if i needed those outputs.

I can not show the schematic for the Sansamp, but a trace of the Behringer is available here: http://plexilandia.googlepages.com/tech12bassdriver.rar

Prospective buyers should (as always) do an A/B test and not take my word for it.

All the best,
Henrik

Have have a Behringer Euro Rack mixer that works fantastic - bought one after I seen Greg Howard's last year. Never seen that pedal, does not have all the switches and outputs the Sansamp has, but some of those I don't use. Great suggestion, that Di box is something I use for different purposes as a convenience. A cheap version probably would work fine as well provided it's not noisy.

Great thread, guys. I've been a bit overloaded these days and haven't been able to join in. I'm glad there's more electronics geeks on board. Thanks for the amp links, I'll have lots of questions about them sometime, maybe this summer. I have made both JFET and Mosfet preamps and I like the Mosfet better now. It also have lots of gain and could drive most any input.

I have yet to finalize my preamp design and put it in a good metal box. I have a new colleague at my college who teaches electronics and plays guitar. He has a Ph.D in electrical engineering and we're having fun coming up with ideas for our Stick preamp design. He's an electronics guy who doesn't know enough about computer programming to do everything he wants. I teach computer programming and I don't have enough electronics knowledge to do everything I want to do. We looked at each other one day and said, "Whoa! We need to talk!". We'll keep you posted about what we come up with.

-Eric