What tube preamp to go with McIntosh MC275?

I currently connect my DAC directly into my power amps.  Both my power amps has volume controls.  They are McIntosh MC275 and a customer built 300B.  Actully, I think they sound good, but I am wondering if it can be improved further by adding a preamp.  My speaker is Harbeth 40.1.  I don't need louder volume, so, I am purely looking for something to improve the sound.  If you ask me what I am looking for, I think bigger soundstage, more life-like, and more slam in the bass, I guess.

Any suggestions?  I can see many preamps use 6SN7 tubes, but my custom built 300B already have 4 6SN7s, I am not sure if it will make much difference by adding more 6SN7.  Would 45 make a good preamp tube?
I’m a Mac guy, The best sounding preamp I have is a rebuilt C20 by Mike Samra, Then I added a thing or two. So purest will bellow that nothing in between is better.. BS. That C20 and MC275 are made for each other.. Choose good speakers. They will show EVERY flaw in BAD speakers.

Enjoy life, C20 has a bass contour on the back, complete tone control, and loudness. It may sound a little old fashion. BUT IT WORKS perfect. I added a Zpre3 in the tape loop, that adds sub out and remote control.

Works just wonderfully. It will raise the roof with my 90% efc. speakers
A pair of 12" drivers, one is a MB one is a SUB. That combo has bass all day long...A (200 watt morel) mid dome, inverted dome tweet, and a UHF Ribbon, a 5 way.
VMPS TIISE, with a driver swap. My Macs make them just BOOGIE.
Slam does come to mind... clear to 19 hz + or - 3 db. 100 db or close.

Great rock and roll speakers, or you can get very good results from small planars, speakers, my goto monitor speaker anymore, Planars and ribbons.. I just love um..

oldhvymec1.... So your telling the OP to get rid of his $15,000 speakers!? I think hes asking for advice on a Pre amp?

I would just get a McIntosh C22 mark V and be done with it.

Thanks, I heard good things about c20 and c22.  How does it compared to Audio Research SP8?

i also read many good reviews on Coincident Line Stage preamp using 101-d tube.

i feel it is very hard to choose preamp.  For power amp, I consider the power which kind of determine by the tube.  For preamp, what are the things I need to consider?  The impedance is not an issue since my amps have very high input impedance.  
I have never been happier than with my current setup which includes

McIntosh Vintage Tube Tuner/Preamp mx110z.

I sold McIntosh SS C28 Preamp and bought the mx110z.

Happily, when I went to TT with 2 tonearms, mx110z’s two phono inputs made it easy.


good photos here


good article about it


My integrated Tube Amp gives me remote volume which makes it easier to use Vintage.

Other poster mentioned using the tape loop to get remote volume when preamp does not have that.

only a few around for sale, and they are going up in price it seems



the tuner is fabulous (I have dedicated FM antena, thus good signal which it needs) I have found many/most people have never heard terrific FM, even my audiophile friends. I use the tuner, primarily for my Jazz station, it is the best sounding tuner I ever owned. My Carver Tuner is the best given weak signals, but doesn’t sound as good.

found this when deciding whether to buy

"When operating to spec, the mx110 tuner section is superb. McIntosh engineer (way back then) Richard Moderaffi (who originally designed the MR77 & MR78 tuners) (performs modifications on McIntosh tuners) said there is nothing he could do to improve upon the original design of the mx110 tuner section. It was (and still is) that good."


45s make an amazing preamp.  Check out the KR P-135.  It is an awesome unit.  Here is a review from positive feedback.  


I am a KR Dealer.  If you are in North America PM me if you are interested.  If you aren't in North America, I can help you locate a dealer.  I think this would be brilliant with an MC275.  I know nothing about your 300B but KR makes a couple different 300B amps and this is a good match with them.  

I am considering these three, which one is the best among the three?

1) Luxman Luxkit A3300
I read that this is based on the McIntosh C20, then Luxman do some improvement or changes on it to beat the C20.  This one has recently been serviced with all new caps.  This is the cheapest of the three.  I hope it has better synergy with my MC275.  I like the look of it.

2) Audio Research SP6
I read good reviews on this.  Service history is unknown, the seller hasn’t responded yet.  More expensive than A3300, similar price as the CL34.
3) Luxman CL34
This technically is a higher model than the Luxkit A3300.  Also recently serviced.  I can’t find much information on it.  Similar price as the SP6.

I am getting confused now. I borrow the A3300 from a friend and I don’t like the sound. It seems it filter out something. Music is not as engaging, and got fatigue after a while. I prefer to have my DAC directly goes into the amp, for both MC275 and the custom built 300B. It seems buying a preamp is trial and error?

or could it be the cable?  I only have two pairs of RCA.  One of them gives me that fatigue when I used it to connect my DAC and power amp.  
oldhvymec1.... So your telling the OP to get rid of his $15,000 speakers!? I think hes asking for advice on a Pre amp?

Not at all, I'm saying a 90% speaker with a 275 Mac and a C20 will have all the Umph you'll need.  I have a C2500, very close to the C22 (re)
BUT my C20, will just whip the pants off of the new stuff, just no remote.
MX110, MX120, MX121, C22 (early) 2 C20s, a C11, pair of C8s. I have a few pieces.
The C20 is the BOMB.. When it's right... FEW get even close. 60 years old. Cary, AR, VTL, I've had them all and still do have a few. That Mac, and something about the "Samra touch". (Red sock green sock guy)

Wonderful a Wonderful!!

Just an update, I found out the problem is one of the ICs.  I change it and the A3300 sounds very good with the 275.  I decided to go with it for now, and maybe upgrade later.