McIntosh C2200 and C2300 Nudies

[forzaroma]

Alberto......I chose the standard Tung-Sol 12AX7 tubes, primarily because I did not plan to use them in the phono stages. It is only in the phono stages that noise tends to be an issue with almost any tubes. The Tung-Sol 12AX7 gold pin tubes are rated quieter, and as such, would be expected to be very quiet in the phono stage. I did test the standard Tung-Sol 12AX7 tubes in the moving magnet phono stage on the C2300 yesterday. The results were superior to the stock McIntosh issued tubes, and I did not notice an increase in the noise floor. I did notice a more open, airy sound, with very tight dynamics, and a solid bottom end. In the end, the Telefunken 12AX7 tubes were the tubes of choice for both the line and phono stages. The Telefunken tubes are magical, organic, tight, airy, three dimensional, and so smooth from top to bottom, without a hint of grain or glare.

Thanks!

 

[chuckworkb]

In photo #2 in the lower left, I think I see a cold solder joint.

MasterLu, That was very funny.

Dan very nice photos. Your very lucky to have both of these beautiful pre amps.

I like the way the tubes are loaded in the 2300.

I notice that the 2300 Transformer isn't shielded like the 2200. Wonder why?

 

[jdandy]

I would like to see comparison shots of the back of the meters on both units

Sorry about no photos of the backs of the meters, but both preamps are back in service. I installed the LED kit in the C2200, so it is not factory anyway. The C2300 uses LED's for the meters, and a single LED shining into multiple fiber optic runs that are then routed behind the circuit board to the various nomenclature on the glass face that needs lighting. If I have the covers off again I will take the photos you requested and post them.

 

[jdandy]

I like the way the tubes are loaded in the 2300.

I notice that the 2300 Transformer isn't shielded like the 2200. Wonder why?

Chuck.......McIntosh calls this transformer an R-Core transformer, and states that it runs cooler, generates less stray magnetic fields, and supresses mechanical noise. I am assuming that McIntosh uses cases for transformers that are potted to help keep them guiet. The transformer case is needed to hold the potting compound until it sets up, and to keep the transformers attractive looking. My guess is that the quieter R-Core transformer does not need to be potted to control mechanical noise, so no case is needed. Maybe Roc-c will help us out on this.

The neat, orderly, and logical board layout on the MC2300, and the unique tube board that holds the six tubes at an angle to be viewed through the window, is more appealing to my eyes than the board layout on the C2200. I guess it doesn't matter how the boards are designed, both preamps are winners in every respect.

 

[ron-c]

R-Cores run cool and do not make noise or have stray magnetic fields. Therefor they do not need to be shielded. Downside? Expensive when compared to other transformer designs.
Both preamps, C2200 and C2300 are Roger Stockholm designs.

thanks,
Ron

 

[jdandy]

Thank you, Ron.