Bass amp build

I’ve built several speakers in the past; decided to try my hand at designing and building a bass cab! Now that I’ve been playing for a minute, I know now what kind of tone I’m looking for: Mostly high-fidelity, with deep, sonorous lows, clean mids, clean highs.

My plan so far: I’m going to use 2x FaitalPro 12PR320 12" woofers, and a FaitalPro tweeter. Since I know jack about passive crossover design (but learning), I decided to take a unique road… Make this an active speaker. I’ll use a Hypex plate amp that has 2x 250w amps + 1x 100w amp. The Hypex amps have onboard DSP; 15 filters per channel. I can use this DSP for active crossovers, smoothing EQ (or tonal adjustments to make it sound like a more traditional cab), time alignment, etc. The Hypex amp is meant for PA cabs, and thus has a line-level XLR input.

To feed it, then, I intend to use something like the Mesa Subway+ preamp/DI box, which has a line-level balanced output.

On the other hand, as cool as this all is, finding a particular preamp that ticks all my boxes is proving difficult; so, I may just take a stab at a passive crossover, since I’ve discovered some software (XSim) that makes it a bit easier.

What do you all think? For practice right now, I either plug in to my studio monitors, or a little Peavey Max100. The Peavey is a cool little portable amp, but the studio monitor/sub setup just sounds big and magnificent.


Oh this sounds very interesting!
If you could keep descriptions of the build to dummy level I would be most grateful

Sure! Is there anything in the original post you’d like me to clarify on?

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I’ve read it a couple of times and sort of get a percentage of where you’re coming from but a build thread with pics would be cool :sunglasses:

What boxes are you finding to be missing?

yeah I was wondering that too. For me there are very few cases where simply fronting a transparent power section with a Darkglass VMT Ultra would not be perfect :slight_smile:

If you wanted an actual tube there you could go with something like an EBS ValveDrive or Two Notes le Bass.

Personally if I wanted an amp at all, I would not want to have a preamp built in to the amp at all at this point and just go with a power section and interchangeable preamp via pedal. But that’s just where I am at, YMMV.

What I’d like in a preamp:

  • XLR line out, +4 dBu nominal
  • FX loop that is instrument level
  • Good clean tone with flexible EQ
    Everything else is a bonus.

So far I’ve looked at the Mesa Subway pedals, which are the closest, but the FX loop is line level (?!). The EBS preamp pedal sounds really nice, but it only has a microphone-level output (-20 dBv), so won’t feed a power amp. Too bad, because it’s got some neat features. The TwoNotes Le Bass is more of a distortion box; its clean sound is quite uninspiring.

My Yamaha basses, though active, have a passive output level (unless I dial up a bunch of EQ boost). I’ve found that’s not quite enough to get proper grunge out of, say, a Microtubes B3K… Hence why I want to run it in an FX loop. OTOH, if I put a compressor in the chain (like the Hyper Luminal), that could certainly add some beef going into the B3K.

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That’s what I do (or did) - basically front my Microtubes X (and other pedals) with a compressor with nice clean boost earlier in the chain. I always want a compressor anyway, and it’s always first in line after the tuner, so it was never an issue for me.

I actually own a ValveDrive and it is a fantastic preamp, highly recommended.I’ve actually sold all my other pedals besides it, my compressor, and tuner. I do everything else in the DAW.

For the power section you could always front it with a neutral preamp that does nothing but gain from instrument to line level. I would much rather do this than have a dedicated preamp in the amp. Were I to need an amp what I would want is basically a PA.

To be honest I will be selling the compressor and ValveDrive as well since I have found amp sims that sound as good or better than real tube amps for my own needs, and my compressors in the DAW are way more capable than almost any pedal as well. Since I don’t care about playing live this is fine for me, obviously not what would work for others though.

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Ooooh, this one ticks all the boxes! …Do I skip a couple car payments to afford it? :stuck_out_tongue:


Whoa, the filter selection on that thing is insane. HPF for a low cut, parametric low, mid and high shelf that go +/- 12dB, and a notch filter. Nice.

Wait… No. The DI output doesn’t have a level control. Gahhhhh! The “Amp” level control only sets the level on the amp/tuner/headphone output, but NOT the DI output. The Gain control adjusts the instrument level throughout the pedal, and crucially, the output level of the FX loop, so that can’t be used as a volume control.


If you save up a bit more, you could go for the Bergantino B⎮Amp, which seems to be able to do all those things that you want. It’s a full amp, but you can also use it as a pre-amp :slight_smile:

You can download the user manual for the details!

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LOL! Well… I think I’m going to go with the Mesa since its only fault is line-level FX loop… And since I only wanted the FX loop to properly drive a distortion pedal, I’ll just put the compressor in front of the distortion pedal, and that in front of the preamp. I think that’s ultimately going to be the best and least crazy-expensive solution. Also, the Mesa has a line output, AND a DI output… Would make it easier if I’m ever on stage and plugging in to a PA.

But I’m also starting to think maybe I should just build the speaker with a passive crossover and just use a standard bass head. But what fun would that be?? Hahaha


I hear ya.’ I haven’t found anything that really checks all my boxes either, except for that B|Amp that @joergkutter found. If I were starting from scratch I’d probably go that route and just ignore that it has a power stage when I’m not using that part.

This is my favorite at the moment. It has enough gain on its knobs that I’m not finding I need any boost with a passive instrument. There’s a pretty wide range of tube adjustment from gentle to crunchy depending which channel you are in and where the switches are set. For me it’s missing a sweepable frequency midrange. To remedy that I also have a Mooer Radar. Although it’s marketed as a cab/mic sim, it has a 5 band parametric EQ buried in there that can be used while bypassing all the other stuff it does.

The blackbird has line level balanced out on 1/4" TRS through a transformer. No effects loop though.


That thing looks great!

It sounds amazing. It’s the most musically pleasing and lovely overdrive to my ears. Although I was groaning about your EBS find after I had already bought this.


The EBS is great but that thing looks amazing :slight_smile:

So, you are using the Blackbird (marketed for guitars) on your bass, specifically for its overdrive and the tone it gets you for your bass!? I am asking as this is related to a question from another thread on how easily/well you can use guitar effect pedals for bass (or not).

Their website claims it’s good for bass because it doesn’t cut low end. They also have some demo samples posted with just bass that sound fine.

I bought it primarily for the tube sound which is really good. I effectively have a hybrid amp head with this.

The tone controls are more guitar oriented, but I don’t really care since I have other places to adjust EQ. The EQ is usable, but probably doesn’t cover some things bass players want to do all on its own.


Is that thread on Bassbuzz? I probably have a post and a question for that one.

I’ve found that many guitar pedals are just fine for bass. Also, bass does has some special needs that pedals don’t always consider in their design and consequently those aren’t as useful. I bought the Sugar Britches pedal so I could put the low end back into any pedal that doesn’t pass it. JHS did a show on this recently where they promoted a solution to bump the low on an EQ pedal to get the lows back from any guitar pedal that has low end tone suck. I don’t like the idea of trying to recover something that’s been filtered down. Rather, I like the parallel path method of mixing the preserved lows back in for that purpose. The Sugar Britches also lets me send a high passed signal to another pedal keeping the low from muddying things up in the effect. This is the same strategy as pushing the XOver button on an MXR Bass Chorus, except that I can set the crossover frequency point and use it with any chorus or anything else. I don’t have to depend on the pedal designer to put a bass x-over into their design and not even all bass pedals do this.