RM-4 vs. MCP-33


I have recently purchased the Audio Research MCP-33 phono pre-pre amp, and compared it to my heavily modified Music Reference RM-4 pre-pre(Dynamicaps, Vashay nudes, Blackgate caps, fred diodes, premium power cord, etc) RM-4.
Here is the listening impression so far. My regular phono preamp Counterpoint SA-9 is out to Mike Elliott for upgrads, so I have borrowed my friend's Wright Sound WPP-200C for the audition.

My modified RM-4:
very transparant, lots of details without sounding bright, a little polite sounding, instruments a little thinner than the ARC unit, very smooth and silky, better micro dynamics

MCP-33:
I had to change the tubes to Amprerex Buggle Boy 6DJ8s since the stock Telefunkens sounds too thin and bright to me.
This unit has definitely more macro dynamics than the RM-4, so it is more suited for jazz and pop with rhythm. The RM-4 is more polite and silky smooth sounding, so classical music is good with the RM-4.
So, the MCP-33 has somewhat more apparant (macro) dynamics, a little more foward in the midrange, a little thicker sounding than the RM-4, while the RM-4 is more transparant, smoother and has better resolution and more detail. Occasionally, I felt a little hardness in the high frequency from MCP-33, but I need more listening before I can be sure. Guess the premium parts installed on the RM-4 has paid off (parts alone cost over $1000). The MCP-33 indeed sounds very good, and I am sure stock MCP-33 would outperform unmodified RM-4.

If I had to pick one of them, I would pick the RM-4 because the transparancy of RM-4 is quite addictive. Maybe I would change some parts on the MCP-33 and find out if it gets better.

Any thoughts on the comprasion?

My system is VPI TNT 5/JMW 12.5/Shelter 501 II/Modified Acoustat Servo OTL power amps/Acoustat model 8
Steve
sojs

Showing 1 response by 76doublebass

Thats interesting of the work done on the RM-4.
I use to own a RM-4 for about 5 years when it first came out.
I used it with the ARC SP-8 for moving coil head amp
reproduction.As I recall you could solder in your own resistor to load it too the proper value you needed.
Even stocked the unit has a wonderful bloom in the midband
and a very musical unit at that.Roger Modjeski used very high quality tubes with this unit.
The RM-4 is a great find if u can locate one on the open market used.
I have done many experimental mods using Vishays myself
and I'm very familiar what this resistor is capable of.I.E.
A huge reduction of the noise room floor,A very,very transparent resistor,which opens up this vast 3D Soundstage
that is locked tight with perfect imaging around the instruments playing in this soundfield.
I have not audiotioned the ARC Head Amp your refering too
But I'm sure if this was moded out it would sound much better then the RM-4.
Happy Listening
Don