Seventh Circle Audio

The T15 is a transformerless microphone preamplifier designed around the excellent THAT corporation 1512 and 1646 ICs. In conjunction with a LT1013 and support components, they produce a high gain, low noise, low distortion microphone preamplifier that rivals more complex circuits such as the C84. Although headroom and output current capability are not as great as the C84, noise and distortion specs are comparable and the T15 excels in the same sorts of applications. The T15 is by far the least expensive and easiest to build of our preamp kits, and should be great for less-experienced kit builders.

Hey!
good news..

Is this design intended to emulate any other preamps that we might be familiar with? Love the price point!

No, but it's quite similar in topology to many IC-based preamps such as the RNP, DAV BG-1, Trident S20, and many others that use a version of the AD SSM2019 or BB INA103 instrumentation amplifiers. The THAT 1512 is an improved version of these parts and is quite new, so there aren't many direct equivalents on the market. Quite frankly there are none that I'm aware of that incorporate the quality design features of the T15.

I hate asking questions like this, but how does the T15 compare to the C84 soundwise? Just wondering if you can give some general idea of the differences.

I only need a few channels of "clean" pres so I am just trying to decide which would be better.

Thanks!

Having used the DAV BG1, which is closely based upon the same design, I will tell you that it sounds BIG, 3 dimensional, full frequency with extended bass, while smoothing out the transients. It is not a fast preamp. It's not clinically clean like the C84, it's like clean with a layer of caramel on top. It should make a very nice compliment to the other preamps. I'm glad to see this addition since I've missed my BG1 the day after I sold it.

i just finished building my first t15 and i must say im really impressed. i have 2 c84s and i must say that the t15s are a great contrast. wired with the full fader i can push the gain a little for some grit, or in contrast i can choose a more conservative route and ride the gain a bit lower for a clean c84 like tonality. before getting the t15 i was skeptical about it because i thought it might sound a bit too much like the c84. but after playing with it tonight, i realize the this pre certainly has its own niche. right off the bat i would consider the t15 to be a better "all around" pre (imho). simply because its not as sterile as the c84, however it is equally as pleasant. anyway i suppose everyone will have their own opinion. i just figured id share mine. now all i can think about is getting a few a12s!!!!



great job tim!

ps: im selling my dan alexander (neve) preamps on ebay, just so i can buy more 7th circle stuff. life is grand...

Thanks for the post about the T15, I've been watching and waiting to hear some first hand reviews here. I'm planning to order another N72 sometime soon and was considering ordering either a pair of C84's or a pair of T15's as well. The thing about the T15's is they seem simply 'too good to be true'.... nice to here from someone that's built one here that this isn't the case. And your description is very helpful.

Still not 100% sure but reading your report here (and since I already have a Millennia mic pre that I believe is similar in sound to the C84) I'm thinking I'll go for a pair of the T15's.

Thanks again!

Commodor