Boulder "Jensen Twin Servo Mic Pre"

[drummerdan]

Does anyone have this unit or know anything about it? How does it sound? Whats it go for? What you like recording though it (if anything)?

[spiral]

Yup. Right here!
http://www.johnhardyco.com/JTS990Details.html

You could write to John and he would tell you everything you wanted to know, and even more stuff that would probably fly over most people's heads.

And as far as the difference between the M1 and Jensen check out this article:
http://www.prorec.com/prorec/articles.n ... D700669DD0

The main difference between the M-1 and the Jensen Twin Servo is that the M-1 uses one 990 op-amp per channel, while the Jensen Twin Servo uses two. There are tradeoffs in each approach. The Jensen Twin Servo offers somewhat less distortion and wider bandwidth at maximum gain than the M-1 because the gain is split between two 990s. But the M-1 can handle higher maximum input levels than the Jensen Twin Servo (+12dBu vs. +6dBu) because the minimum gain of the M-1 is 12dB, compared to 18dB for the Jensen Twin Servo. I originally made the Jensen Twin Servo exclusively for Jensen Transformers. For the last two years or so, I have been selling the Jensen Twin Servo directly.

[drummerdan]

Thats pretty cool. I got this unit for free. I met a little old lady who's husband died and he did small recordings. She gave me this pre, and told me in few weeks if i helped her clean the house out she would give me all the recording equipment i wanted! nothing to wild, but i did notice a pair of akg 414's, 3 100w power amps, a nice clean DAT machine, and a few wild 12 foot weighted mic stands.

[spiral]

Wow. That's crazy. From what i gathered from the article above, the Boulder project was scrapped and Hardy just built them instead for Jensen. Does yours look like the one above?

Well you just got one of the best mic pres out there for being a nice person. Way to be a good citizen.

[John Hardy]

The "Boulder" version of the "Jensen Twin Servo" mic preamp was introduced in 1986, built for Deane Jensen by Boulder. I introduced my M-1 in 1987 and showed it to Deane on a trip to the west coast. By 1988, there was a falling-out between Jensen and Boulder, so Deane asked me if I would be willing to build a preamp to his specifications using the M-1 package as the basis for it. The result was also known as the "Jensen Twin Servo 990 Mic Preamp", and it was similar in overall concept to the Boulder version, but I think the packaging and metering are superior to the Boulder.

For several years now I have been selling the Jensen Twin Servo directly. The folks at Jensen suggested it, since they were extremely busy just dealing with transformer orders and did not have time to tend to the mic preamp side of things.

John Hardy
The John Hardy Co.
www.johnhardyco.com

[spiral]

Hey. You won't get any closer to the source than that! Awesome.

So is the John Hardy version of the Jensen Twin Servo the exact same design as the Boulder (with updated chassis and metering) or did you and Deane revise it? Thanks.

[John Hardy]

So is the John Hardy version of the Jensen Twin Servo the exact same design as the Boulder (with updated chassis and metering) or did you and Deane revise it?

Both designs use essentially the same input transformer, two 990 op-amps per channel, the same output transformer, "input bias current compensation" circuitry and "DC servo" circuitry to eliminate all coupling capacitors. But there are differences in the way some of those things were accomplished. Boulder packaged the 990 differently than I do. They may have included the input bias current compensation circuitry within the 990 package itself (I'm not sure about that). The input and output transformers were refined in 1991/92, and the model numbers were changed from "JE" to "JT" to signify the improvements.

Probably a bunch of little differences here and there, but essentially the same net result. I recall the "picnic table" discussions that Deane, Bill Whitlock and Steve Hogan had during the development of the Hardy version. There was a picnic table in the area behind the Jensen Transformers building where they discussed things now and then. There were some significant changes in the DC servo circuit at the last minute.

Of course, YMMV.

John Hardy
The John Hardy Co.
www.johnhardyco.com