Here's an interesting twist on a compressor review. We have not one, but two Lightning Boy Op-2 vacuum tube powered optical compressors.
In talking with Mike about his work, he offered to send a current version Op-2 and a new version he is delivering. The most recent Op-2 operates at 12 volts DC and at least 400ma, center negative tip. The new version operates at 24 volts DC and at least 170ma, center positive tip. Mike provides appropriate power supplies with his pedals. What's the big deal about the move from 12 volts to 24 volts? Read on.
Claim to fame for the Lightning Boy Op-2 is the two 12AU7 tubes inside for gain, and no transistors or IC's involved. This is true of both the 12 volt and 24 volt versions. Mike sent me a prototype of the 24 volt circuit and it looks identical to the most recent 12 volt version. The two tubes are seated such that there is a bit of give.
It's an attractive pedal in a yellow enclosure, two tubes protruding from the top, and metal rails protecting the tubes from bumps and unintentional jarring.
There are two knobs. One for Compression level and one for volume, essentially makeup gain. There are two switches. One sets the compression circuit to a hard knee (the compressor clamps down on the signal very quickly and hard) or soft knee (the compressor kicks in very gently as the signal crosses the threshold).The second switch is called Turbo. With the Turbo switch flipped up, the compression is louder and more interesting with more obvious harmonic content. With the switch down, the Op-2 is a pretty transparent and soft feeling compressor. The compressor sounds great with the switch in both positions, but my preference was hands down operating the compressor with Turbo on. You get fatness and fullness and nice tubey sound. Another way to say it would be more beefy. The harmonic breakup is subtle. Don't think distorted. When Turbo is activated there are blue LED's that illuminate below the tubes.
When power is applied to the pedal, the center LED lights red. When the foot switch is pressed to activate the compressor, the words "Lighting Boy" illuminate. Pretty neat! There is no LED indicating amount of gain reduction.
The Compression knob controls the amount of compression and it is my understanding that it does so by affecting both ratio and threshold. Because of this, the compressor is going to react differently depending on the output of the instrument you are using.
The Volume knob controls the amount of output, or makeup gain.
I liked playing with the pedal in both hard and soft knee modes. There is an obvious different between the two with soft being very easy, smooth compression. With the compressor operating at hard knee the effect is much more noticeable.
The overall action of the compressor is smooth and polished. You won't experience much at all in the way of dip and swell.
If you are looking for limiting effect, look elsewhere.
I'm not sure how to describe the attack. There is no independent control of attack but to my ear it is neither fast or slow. It's somewhere in the middle. I never really felt strongly that I wish I could adjust the attack but I do think an independent control for attack would make for a whole new level of dynamic variability.
Now here's where things get interesting and different between the two versions.
On the 12 volt version the Compression range (controlled by the Compression dial) is fairly limited. To my ear, the compression effect isn't really noticeable until the compression dial is at noon or higher. In fact, I found my sweet spot at about 3:00. For many compressor pedals, a dial at 3:00 would mean a lot of compression. Not so much with the 12 volt version. Mike speaks to this on his blog where he says this in reference to the 12 volt version:
"The struggle was creating a lot of compression. It was impossible with just 12v."
This doesn't mean the 12 volt version is not unfavorable, but it is relatively subtle which isn't necessarily a bad thing.
Mike goes on to say,
"Before and ever since the release of the Op-2 Comp I have been trying to figure out how to get it to compress more severely without altering its tone, physical size, price, or a variety of other parameters. Its now been over 2 and a half years and many times I said, "this is as good as it gets." But, today everything changed. I felt a stoke of genius hit me today."
Introducing the 24 volt version which is marked "Rev B".
I spent a lot of time with both versions and my conclusion is this. The 24 volt version is easily a noteworthy improvement. The range of compression is wider. The compression is more noticeable and there are more sweet spots along the dial. My sweet spot on the 24 volt version was about 11:00 - noon compared to the 3:00 position on the 12 volt version. There is a trade off though. The overall volume output of the 24 volt version is even less than the 12 volt version. 24 volt trades gain for clarity and more compression. Yes, the 24 volt version is more "interesting" and yet smoother at the same time. It has more detail and just sounds, well, even better. The 12 volt version sounds more "modern" for lack of a better word and more sterile comparatively. The 24 volt version has a complexity to the tone that is addicting. You get noticeable tube tone. It is very satisfying. The 12 volt version sounds good, but the 24 volt version sounds great. If you are looking for transparent compression look elsewhere. I suspect those interested in a vacuum tube optical circuit aren't looking for transparent though.
The 24 volt version also has a lower noise floor. It's not that the 12 volt version was noisy at all. But there is an improvement in the overall noise level in the new version. I did have to have Volume knob at at least 3:00 to be happy.
What changed in the circuit itself? Mike said,
"I changed its location in the Op-2 circuitry, which changes how it responds and sounds. The actual photo resistor part (compression element) is no longer affecting the output directly. Now it directly alters the input volume of the 12AU7 input stage."
Read more here: Op-2 Updates (continued) "REV B"
Bottom line. If you are looking for tube tone, smooth compression, and some added "excitement" in your tone, look at the Lightning Boy. It's not a gimmick. The tube tone is more noticeable than the Effectrode PC-2A I reviewed earlier. Looking inside, the Op-2 is wired point-to-point with no circuit boards. This is true of both 12 volt version (Rev A) and 24 volt version (Rev B). Yes, those funky green things are paper-in-oil caps and they are NOS. Just like a vintage amp!
If you already have a 12 volt version is it worth upgrading? IMHO, yes. You can send your Rev A to Lightning Boy for a Rev B update for $30 (+ shipping).
On the downside, the Op-2 has hefty power requirements making it not the most pedal board friendly. This is to be expected when the two tubes are providing the gain and thus require higher voltage. It is also fairly limited in its control and flexibility.
The foot switch is true bypass. Top mounted jacks and power input. The pedal is heavy and has a very solid feel. When I first opened the box and saw the tube sticking out I wondered how durable the pedal would be. How the tubes are seated means they have a little bit of give and the metal bars will do a great job protecting the tubes. The pedal itself is the size of the original Diamond enclosure and the FEA pedals.
Retail price for Rev B: $359
Size comparison below.
Edit 11/17/18: Mike sent me a pic of new back plates for the 24 volt version indicating he's ready to ship the new Rev B.
Edit 1/1/2019: Mike has made further modifications to the Op-2 now identified as Rev B.1.
I received the updated Lightning Boy Rev B.1 and there are some pretty cool changes. Here are some brief details:
1. Still 24 volts (instead of 12 volts) 2. Visual meter identifying how much compression is going on by way of LED. Nice! 3. Previously the compression knob controlled the ratio and threshold. Now it has a wider range and is controlling the blend of dry and wet signal. 4. The Turbo switch is now a ratio control. Flipped down, the pedal has a very low ratio of 3:1. Flipped up ("Turbo") is more like a limiter. Mike says around 12:1. 5. There is now more gain on tap and it can boost above unity even under heavier compression.
I have found my sweet spot is with Turbo on (12:1 ratio) and the compression dial at about 10:00 which means I have a lot of dry signal blended in. The attack is slowed a bit when using soft knee as compared to hard knee.
The LED indicating gain reduction is a real nice enhancement and works quite well.
In the near term the manual will indicate that the turbo switch is actually a ratio switch and the compression knob is actually a blend knob. Revisions of the casing will indicate the same in the future.
It does take a little time for the pedal to warm up being all tube. This includes the LED indicator. It will work almost immediately upon powering up but it sounds best after 5 minutes or so.