Review: Speakeasy Vintage Clone Tube Preamp

by Bruce Wahler

The following are facts and subjective impressions about the Speakeasy 122 Absolute Modeling Amp, which I have owned and used for about six months. I use this product to allow my Korg BX-3 to drive a high-powered (500W) Leslie system.

Overview

The Speakeasy 122 Absolute Modeling Amp (AMA) is a single-channel tube preamp and power amp combination that attempts to perfectly mimic the sound characteristics of the legendary 40W Leslie 122 amplifier, in both a smaller package, and with less output power. Speakeasy makes two varieties: a power-amp-only model for those who already have a preamp or other high-gain sound source; and a version with an included tube preamp (reviewed here). The basic idea is to duplicate the important areas of both the Hammond B-3 organ preamp and Leslie power amp, in order to provide the user with the same sound as a real B-3 and Leslie. When low volume is desired, the AMA can directly supply 10W to an 8-ohm speaker system. When higher volume is necessary, the AMA can be used as a kind of 'preamp' to drive a larger solid-state power amp.

As with any gear, there are pros and cons in the AMA's design, but I believe it is a very effective re-creator of the classic Leslie growl, and while the price is higher than most alternatives, the results are stellar. The AMA is a good choice for keyboard players who want to have the classic Leslie overdrive sound at variable volume levels for different applications.

Compared to a tube preamp alone, the AMA sounds more realistic: &less "fizzy" when distorting, with a more even timbre over small volume changes. Its controls are well tailored to the needs of the organist.

Physical Description

The AMA is a 2U-rack product housed in a very durable, vintage-looking metal cabinet. Like its preamp brethren, the AMA uses a 12AU7 preamp circuit modeled around the Hammond AO-28 design, then adds a pair of 6V6GT tubes running push-pull to drive the output section. The controls are simple and straightforward. As to be expected with Speakeasy, both the preamp and power amp stages are transformer-coupled.

The front panel provides:

A 1/4" input jack to connect to a combo organ.
A Low/High Gain switch, which changes the drive range from classic Hammond Organ to more of a Jon Lord grunge.
Preamp Volume sets the drive level of the preamp stage. A real B-3 doesn't have such a control, but think of it as like the channel volume on a modern guitar amp.
The Bass and Treble controls set the preamp tone. These controls are similar to those on Speakeasy preamps, but seem to have a wider range of boost and cut. In addition to dialing in both the 122 and 147 amplifiers, the EQ has enough range to accommodate an electric guitar.
The Power Amp Volume sets the drive level of the output stage. This is analogous to the volume control on a Leslie Speaker's amp, and perhaps to the master volume control on many guitar amps.
The Lineout Level controls the amount of output sent to a following power amp. Think of this as like a "power soak" with a variable output control.

The rear panel provides:

A 1/4" output jack for directly driving am 8-ohm speaker load.
A 1/4" line out jack to drive a power amp.
An AC mains connector.

The SVTP is manufactured in the USA.

Sound and Listening Tests

Normally, the AMA is used with a solid-state power amp and speakers. The idea is to set the AMA's Preamp Volume to just below the onset of clipping, then turn up the AMA's Power Amp Volume to obtain the desired level of overdrive/grind for a classic Leslie tone. Finally, if the level required is too much gain for the desired output of the solid-state power amp (and it usually is), the Lineout Level is used to drop the output voltage to a more practical level.

This approach has been used by guitarists for years, particularly in the studio. Turning up a tube amp allows one to reach its sweet spot, while using a power soak device brings the volume level back to a practical range. This method can be used with higher-power amps, but setting the levels can become trickier. And besides, who wants to lug around a big, heavy amp just to treat it as a preamp?

Other than the convenience of having all the pieces in one place, though, what makes the AMA better than say, getting a 5-10W guitar amp, loading it with a power soak, and sending the output to a power amp? In theory, nothing. In practice, though, the AMA sounds more like a real Leslie amp, to my ears. The classic 40W Leslie amp has a wonderful overdrive characteristic that many describe as "frying eggs." Most tube power amps have similar sonic properties, but the Leslie amp took a different approach than the majority of '40s-'50s musical instrument amps, which were copies of (then current) hi-fi, "ultralinear" designs.

Put simply, the Leslie's amplifier design trades off maximum output power for lower distortion before it clips; i.e., the amp stays clean longer, but once it overloads, it quickly falls into heavy distortion -- but still in that nice "tube" way. Part of the classic Hammond sound is the selective use of this feature, and the exact tone isn't easy to find outside the organ world. (Anyone who is old enough to have swapped the amp on their 122 or 147 for a Fender, Ampeg, Marshall, or Sunn tube amp knows that the resulting Leslie might have been louder, but it wasn't necessarily better.)

The folks at Speakeasy created a 10W design that copied not only the overdrive aspects, but other sonic features of the 40W counterpart. So, while the term "modeling" doesn't apply it's recent, digital definition, I think it applies here in its original sense: "The AMA is modeled after a Leslie 122 amplifier, warts and all. Does it sound "exactly like a Leslie 122" when driven hard? Truthfully, it would probably fail a direct A/B test with the Real Deal on a few small points. But it's far closer than an Epiphone Valve Junior or Blackheart Killer Ant, or even a vintage Fender Champ. Each of those guitar amps weren't designed with the same output stage, and they have different frequency response and input gain to boot.

An interesting point is that the AMA comes so close to the sound of the Real Deal that it needs -- and wants -- nothing added, tonally, to the chain. Prior to owning my AMA, my rig was:

Korg BX-3 -> Speakeasy VTP w/Barker -> Hafler P3000 -> LowBoy From Hell™

I started out by simply swapping the AMA for the Speakeasy preamp:

Korg BX-3 -> AMA -> Hafler P3000 -> LBFH

I expected nirvana, but it didn't work out that way. The P3000 added its own tube-like MOSFET warmth -- which was welcome in the previous setup, but not with the AMA. The P3000's tone, added to the AMA's own warmth, sounded muddy in the 200-400Hz range. Reducing the bass on the AMA helped the tone, but killed the "frying eggs" effect. Reducing the low end on the BX-3 thinned the sound.

After a few weeks of playing around with EQ and gain everywhere in the chain to no avail, I swapped in an ART SLA2:

Korg BX-3 -> AMA -> SLA2 -> LBFH

Suddenly, the AMA started to shine, and I could put some of the bass back in my setup. Why? The SLA2 is one of the most 'personality-less' amps I've ever owned -- and I say that in a good way. The sound of the SLA2 with a quality set of speakers is just like a very loud set of headphones. This allowed the AMA to dominate the sound chain. The new setup was a huge improvement in the overall character of the organ sound. Clearly, the AMA doesn't need help in the tone department -- only with the volume!

Eggs, Anyone?

This is the real 'litmus test' of the AMA vs. the standard Speakeasy preamp: Can it provide the overdriven growl heard on countless blues and rock recordings -- the "frying eggs" sound? In a word, yes.

In another word: Y-freakin'-E-freakin'-S!!!

I can dial in everything from the dark growl of the Allman Brothers, to the hard-workin' push of Kansas and ELP, to the dying scream of Gregg Rolie's "we were broke, and Leslie was broke, too" road warrior on 'Samba Pa Ti' -- all by adjusting the send level of my BX-3. You want early Jon Lord? No problem. Spencer Davis Band? Yep, we got that, too. Green Onions? It's in there.

And the AMA and a good power amp can provide those sounds at volumes ranging from low enough to allow dinner conversation, to levels that cause items to fall from shelves.

Minor Criticisms

So, what don't I like about the AMA? Not much:

It's pricey -- although I do think that the quality of Speakeasy products is on par with other boutique/niche musical products. Compare its price to say, a Bogner Shiva or Valvetech Hayseed (high-end guitar tube amps), or to any of the studio-quality microphone preamps out there. You do get what you pay for.
While the AMA is technically a 2U box, it really requires 3U-4U of space. The AMA's rubber feet are tall enough to take up another 1/2-space below the case, and both the top and bottom have a series of cooling vents that should not be blocked under any circumstances. (Remember, tubes get very hot!) It's probably possible to re-mount the AMA in two units of rack space, but I wouldn't try it.
The gain range of the "Leslie amp" (Power Amp) section of the AMA doesn't quite reach into Steve Winwood/Gregg Rolie territory all by itself. If, as recommended in the owner's guide, one sets that preamp to the edge of overdrive, then backs the gain down a notch, the power amp gain can't be pushed into Spinal Tap's '11' zone. The only way to nail Steppenwolf's 'Magic Carpet Ride' sound, for example, is to push the preamp into overdrive a little, too. The perfect setting -- mild preamp overdrive that is masked by the power section -- is a little tricky to master at first. Granted, this is a minor quibble, but I wish the second gain stage had more push. Maybe it's the purist in me that's bothered, because the sound seems to be there.

Conclusion

The Speakeasy 122 Absolute Modeling Amp is a great product for those players who want to cross the final bridge to the classic Hammond B-3 sound with their clone rigs, especially if used in very high- or low-volume situations. The AMA is suited to both 'warming' a digital organ sound, and to simulating heavier amp overdrive. It's not an inexpensive product, but provides a great tone for the cost.

No laboratory animals were used during the evaluation of this product!