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Early impressions: Manley TNT 2-channel mic preamp used with bass guitar

Discussion in 'Amps and Cabs [BG]' started by Snaxster, Nov 5, 2016.

  1. Snaxster


    Nov 29, 2008
    Below is what I wrote to someone who asked about my new Manley TNT mic preamp. Among other things, he asked how it compared to Millennia and Avalon. Note that as of tonight 1. I believe there is no problem (with electrical interference) having the Manley TNT atop the Glockenklang Blue Rock in a rack, and 2. this setup sounds fantastic.

    In the photo you can see a power strip tucked on the right side of the amp. Not visible is an sfx micro-Thumpinator on the left side of the amp. I used whatever patch cables were around and would fit, just for proving out the setup. Eventually I'll have proper cables made for it, and I will velcro the small items in place.

    The rack is an SKB 3U iSeries Fly Rack, model 3i-2217-103U (whose rolling, waterproof, anti-shock hard case is huge and quite cool).

    The Manley TNT is not an obvious choice for use as a bass guitar preamp. In that role it is heavy, expensive, and not flexible in the ways that today's bass guitarists expect. But it is a very high quality device. And its cool channel can make sounds that no conventional integrated bass amp can (no amps that I'm aware of, anyway). For the player seeking something different, or who likes "the transformer sound" usually associated with high end recording studios, the TNT could be just the thing.


    “Friday and today I played the Blue Rock at higher volumes. I alternated between the Greenboy F112 and MA Soundworks MAS-112 cabinets, and between the Blue Rock A channel straight vs. B channel driven by either the Kern preamp or either channel of the Manley TNT.

    Man, but this is an excellent bass amp.

    There are other pathways to test, but one of my goals is: bass guitar > hi-Z in TNT cool channel > +4 unbalanced out > HPF > Blue Rock B channel in > DI out > mic in TNT tube channel > XLR out (as DI).

    That could include using the Blue Rock’s loop for utility (compressor/limiter) or drive or spatial processing.

    The Manley TNT is very interesting. Recently I got mine in new condition for about 31% below street. So far I will say that the cool channel alone is worth that price of admission. By chance I own nothing else that sounds remotely like it. Maybe if I owned API, Neve, etc., the TNT would seem less distinctive. (Several years ago I had a Neve stereo analog tape emulator. It was perfect for mixing. Useful for tracking, too, I don’t remember it sounding as good for bass guitar in the way I’m using the TNT now. But a Shelford Channel on the other hand…)

    I’ve heard it said that the size of a transformer doesn’t matter for audio, but the composition, design and quality do rather. That may be true, but the way the TNT’s circuit uses its enormous cool channel tranny justifies its weight. What a sound; what a range of sounds, really.

    That’s one of the keys to the Manley TNT’s power: range, variation, difference.

    Critical to tapping that power with a bass guitar is using traditional passive pickups and onboard electronics connected directly to the TNT with a guitar cable. Anything other than that direct connection will negate how the TNT can let you vary the load on the pickups. That’s true of tube guitar amps and many other devices, too, of course. But the TNT is designed to capitalize on and rely on that relationship. It has no EQ after all. The savvy player with the right type of bass won’t miss EQ, though. And depending on the TNT’s settings, they may not miss compression either (thanks to natural tube compression in the tube channel or transformer compression in higher “iron” values in the cool channel).

    Yet as in the studio, there is nothing wrong with judicious equalization of a DI signal from a raw instrument preamp output. And the TNT does sound raw. It can sound as smooth and clean as almost nothing there, but it always sounds raw. That should be unsurprising in a device meant to convey the full dynamic and spectral ranges of fine microphones, I think.

    For bass amplification, the Blue Rock EQ shines post the TNT. Today, in that application I found the Blue Rock’s EQ to be understated yet quite effective, and to be as sweet and clear as you could ask for in a MI amp. It let me affect slight corrections to room sound, then add endorphin-inducing thickness and low end. The F112 and the MAS-112 conveyed it all, each in its distinctive way.

    What about the TNT’s tube channel? A deep, clear, beautiful sound. But with a high noise floor in my experience so far. I’ve been working on it with Manley tech support. Swapping in tubes of mine helped a bit, but the circuit seems to be what it is. That said, in the bass amp application no-one would notice the noise through the speaker cabinet. My concern is recording or FOH.

    I never owned Avalon. Maybe I played an Avalon DI once. Though I owned a Millennia TD-1 for a while, I played it only a couple of times before eventually selling it. Yet it made an impression. The TD-1’s tube mode was good, though it didn’t immediately win me over. Its solid state mode, however, was one of the few best bass guitar preamp sounds I could recall ever hearing. And that Millennia equalizer… geez. They deserve their rep, and I can see why Euro-classical recordists like the brand.

    But for MI amplification, what I described above gets me most of the way there (TNT or Kern into Blue Rock). And I don’t think that the TD-1 can do the “heavy” part of the tranny sound range that the TNT does.

    The risk with the TNT is that it won’t play nice sitting atop a high output power amplifier. Manley warns about this. It’s the cool channel, I think. Once I noticed it reacting audibly to the QSC amp, even though the Kern and rack were in between the two. Come Saturday I’ll have a new rack for testing that setup with the TNT and Blue Rock. Here’s hoping.”
    fast slapper and beans-on-toast like this.
  2. Snaxster


    Nov 29, 2008
    For those who like this kind of thing, here is some vintage tube pørn (a shot of my tubes in the TNT) and a shot of the stock TNT internals.

    The tubes are a 1964 RCA USN CRC 12AT7WB and a 1957 Sylvania RAN 6189/12AU7WA. The RCA was new in the box; the Sylvania had no box, but possibly was unused.

    Per Manley tech support I swapped a 12AT7 into the 6414 slot (I own some fine 6414, but they are in storage). Per me, I swapped a 12AU7 into the 12AT7 slot. I may try 12AT7 there instead, and per tech support I could try 12AX7 there, too, so I might.

    I noted that each channel features a particular model of Lundahl transformer for at least one of its inputs, and of Manley transformer for at least one of its outputs (or maybe the reverse, since I don't know how to trace the circuit). In the cool channel there is the Manley Rapture amp, and of course the "big iron" transformer; both made in house, I believe.


    Passinwind likes this.

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