SSM2019 in X2 channel strip.

ok so i got off my ass this weekend and proto'd an ssm2019 preamp IC onto a small SMD proto board. I threw some wires and a pot on it and proceeded to tear out all the preamp related parts, except for the phantom couplers, the zener protection and impedence resistors, on a spare(bought 5 extra channels specifically to mod!)channel and replace it with the proto preamp. these channels are super easy to mod since everything is marked, V+, V- and gnd are actually printed next to their jumpers and so on. i just ran twisted wires to where the bases of the input transistors would have been, the output to the ouput of the 5532 that was there and voila! working very well right away. the output of the 5532 goes to switching between channel and monitor and then to one section of a tl084 and so on.

opinions:

the sound of this IC is actually very good for what it is. i A/B'd that channel with another channel using the regular preamp setup and i could hear a slight difference in the high frequencies which were slightly soft in the ssm2019 channel, however I believe this to be my 2nd channel since the comparison channel is running matched 2n4403s and a opa2134 in the preamp, then going through 1 stage of an OPA404 instead of a tl084.

more on this and a clip later

does anyone know of a place i can host a small sound file without having to buy space or setup a webpage? some kind of FTP would be cool..

It would be interesting to hack the potted module on the X2 mic input. I remember that they used a "hybrid-discrete" module in the mic preamp -- an op amp with transistors working together for the best of both worlds. Or such was the marketing speak at the time (I worked for Alesis Marketing back then). Anyhow, I remember that they were proud of their H/D module and had a patent on it. The engineer had the patent framed over his desk. Hey, the patent would make it easy to look up the circuit, huh?

Your ISP might give you some free web space, check with them. Or sign up for a trial AOL account and use their space.

hmm maybe they changed their design because there is no potted module on these cards. there is however an input transistor/opamp design that sounds pretty good for what it is. I received a schematic for the preamp but it's not what is on the pcb.. go figure.. :green:

It's more of a potted card. 1.5" by .5" and the width of a circuit board. It has surface-mount components on it and then they shrink-wrapped it or potted it and put pins on one side like an SIP. I think they used it as an op amp in the preamp and the EQ. It would interesting to see the circuit and build it with good components, although I think it was designed as a cheap 990-esque op amp.

I did a patent search and I couldn't find it. I thknk it was patented by the engineeer, not the company, and I can't remember the engineer's name.