Low End Mic Pre with Socket mounted OPAMPS for rechipping

[virtualsamana]

So far I have only heard about people talk about rechipping their presonus MP20. Are there any other low end mic pres with socket mounted opamps that people have rechipped with good results?

[RefD]

So far I have only heard about people talk about rechipping their presonus MP20. Are there any other low end mic pres with socket mounted opamps that people have rechipped with good results?

as covered in TO a few years back, the Eureka lets you do this as well.

but it's more of an all-in-one strip and not just a pre.

[Sean Sullivan]

Symetrix SX202, I believe.

[getreel]

I rechipped a Bellari RP 503. I guess it sounded better. Had less gain. I sold it long ago.

[lancebug]

I rechipped a Bellari RP 503. I guess it sounded better. Had less gain. I sold it long ago.

Ditto, I have a re-chipped re-tubed 503, but don't know it any other way, so I can say what the difference actually is. I use it a lot for mic'ing bass cab. I think the Bellari MP-105 is the definitive ultra cheap mic pre that can be improved with new chips and tube. As far as chips go, I have really been digging the terra chips lately.

[wren]

Rane MS1/MS1b.

Presonus VXP (predecessor to the Eureka; apparently it's basically an M20 preamp in a channel strip).

[@?,*???&?]

The Bellari MP110 is another those pres that can be opamp upgraded.

[Jim Williams]

Yamaha MLA7. It doesn't have sockets, but they can be easily added as it's a single sided pcb. These go for very cheap. The SX202 is double sided without sockets, the mic pre chip is not an opamp and cannot be replaced without redoing the entire mic preamp.

[losthighway]

How much does the opamp determine the sound quality? Mostly, or only somewhat?

I got a modded Presonus MP20 with Burr Browns. Sounds really good, but I don't know what it sounded like with the stock opamps.....

[Jeff White]

How much does the opamp determine the sound quality? Mostly, or only somewhat?

I got a modded Presonus MP20 with Burr Browns. Sounds really good, but I don't know what it sounded like with the stock opamps.....

It sounded thinner, definitely. I did the mod myself and noticed it got thicker. does yours have Jensens? Mine does not.

Jeff

[losthighway]

It claims to in the manual, but it could have been photocopied...... I didn't open it up, and I haven't researched serial # = year made etc.

I'm gonna go ahead and just ASSume that it does and try and tell you mine is better, without really knowing....

[Jim Williams]

MP-20 users typically like the OPA627 (very expensive and not worth it IMO), the LT1357 and some new stuff like the National LME49710. These are all + - 18 volt opamps. The MP-20 is set to + - 20 volts, too high. There are trim pots for the power supply and test points to measure it. Then you have the surface mount quad opamp for the insert (an LME49740 is a good replacement) and a through hole dual opamp for the balanced outputs, a National LM6172 works very well there.

Jensen make the original transformer for these, it's available for only $30. Call Dave Hill and order some. You won't be disappointed.

[jv]

Yamaha MLA7. It doesn't have sockets, but they can be easily added as it's a single sided pcb. These go for very cheap.

Jim,
What op amp do you use as a replacement for the MLA7? I have one of these and I like it stock, but I've been thinking about buying another one to try some mods on to see how it compares.

[trodden]

Symetrix SX202, I believe.

mine is modded with sockets for chip swap. I like the 2604's in it. I have the choice of those, 1469's and 2134's.

[Jim Williams]

I have the MLA7 set up for auditioning opamps. It's a good test bed for that as you can compare 8 in a row. I replaced the input transistors with Hitachi and added some psu bypass caps and a couple of phase compensation caps to maintain stability with wide bandwidth opamps. I've installed LM6172, LT1358, all the BB parts, LME49720's, AD8599's, etc.