Weak ROTEL phono section

Hi all,
Have a Rotel rc1090 preamp...former top of the line...with balanced ins/outs.
Despite using a very powerful 6.5mv cartridge, the output seems a weak and flat. The volume knob on the Rotel has to go far (almost 2 or 3 o'clock) on some recordings to get a satisfactory volume.
I have no problem with cd playback, plenty of power using that input.
I'm using the Rotel with a McIntosh 252 amp. Again, sounds great(and powerful) with CDs.
Any insights or advice greatly appreciated.
How about trying to change the angle of your tonearm..Sometimes tipping the backend lower could help...Its worth a try..
Are you sure your preamp has a phono section? If you can use a CD player with the input, it is likely that it is a line level input. The marking may say Phono or Phono/Aux but you may need a phono board option. My Cambridge Audio int. amp has an input marked Phono/Aux but is a line level input. To use with a TT, you need to add a phono board inside.
One way to tell is to open up the top to see if the input traces to a phono section in the preamp.
Also it will lack the RIAA equalization curve, which will make it sound strange. If you can use a CD into it I don't see how it could possibly have a phono stage. If it did you would be grossly overloading it and it should sound very distorted.
Double check the wiring to your cartidge.With the unit off,cycle the MM/MC switch a couple of times to see if it is not making a good contact.Make sure you have it in the correct position before turning the unit back on.Last resort,hopefully you have another TT to try in place of that one.Owners manual link>>[http://www.rotel.com/content/manuals/rc1090_multi.pdf]
I use the same preamp with (modest) Project turntable. No issues, loudness correct.

It seems to be some problem in catridge itself, or perhaps wiring, as someone alredy mentioned.
Hi Zormi,
Can I ask you...are you using the Rotel with the balanced outputs to your amp or the RCA outputs? Wondering if related to this.
All my wiring is correct and I don't think it's the cartridge.
Thank you much for your advice.
I don't think that there is a problem (apart possibly from the "flatness" you mention, which I can't offer an opinion on). Having to set the volume control to 2 or 3 p.m. for phono, and much less for cd (say 10 a.m.) is very common.

If you look at the specs for the RC1090 in the manual for which HiFiTime provided a link, you'll see that for 1 volt out the preamp requires 2.5mv input in mm phono mode, while for line level sources it requires 150mv input. Those numbers presumably are with the volume control turned all the way up. Your 6.5 mv cartridge exceeds the 2.5mv by 8.3db. If your cdp puts out the 2 volts or so that is typical, that would exceed the 150mv by 22.5db.

So your volume control will have to be set (22.5 - 8.3) = 14.2 db lower for cd than for phono, if everything else is equal (including the level of the recording relative to full scale). That is a very considerable amount, which is also fairly common due to the high output levels that cdp's typically have.

-- Al

I strictly use RCA outputs of the RC-1090 (and RCA inputs of RB-1090) cause these Rotel designs are pseudobalanced, so no any benefit from XLR connections.

Perhaps Almarg is right - you have to accept differences in loudness between CD and turntable as purely normal. Such a difference in some normal amount exists in my system too.

If the cd works ok,there shouldn't be any problems with the balanced outputs to your amp,otherwise the cd would show the same characteristics.If your new to vinyl,it maybe the difference in dynamic range.When cd's first came out,I thought I was going to blow my speakers(plus have a heart attack)the first time I played a cd at home.I imagine if I was new to vinyl,I may think it sounds weak at first if I was used to cd's only. If its a new cartridge,it may sound different from your old one.I don't have all the knowledge like Almarg does,but I've been through a lot of different audio equipment also,and like he says,the volume difference has been common for me also.Hopefully its nothing so you can enjoy the music.
Thank you for these excellent, helpful posts.

I think you're both right, but I don't know, having to put the volume at 3 o'clock with such a "hot" cartridge doesn't quite add up.

I'm not expecting "cd volume" but a little more would help.
You're welcome! Another contributing factor is that the power amp, according to the specs in its manual, has an input sensitivity (for full power, and for the unbalanced inputs) of 1.6 volts (3.2 volts for the balanced inputs), while the specified output of the preamp is 1 volt. That results in having to set the volume control higher (for both phono and cd) than you would have to if the preamp had a higher output and/or the power amp had a lower sensitivity number.

Using the balanced inputs won't change that -- you'll probably have 2 volts out of the preamp (between the "hot" and "cold" signal polarities, instead of 1 volt between signal and ground in unbalanced mode), but the power amp sensitivity changes correspondingly (from 1.6 volts to 3.2 volts).

-- Al
Thanks all.
Thanks Almarg,
I'm wondering if an outboard phono preamp might help. Success would depend on whether the phono output is higher than that of the Rotel.
Yes, a properly chosen outboard phono stage probably would help.

The phono section of your Rotel presumably amplifies a 2.5mv input up to the specified line-level input sensitivity of 150mv. That corresponds to a gain of 20log(150/2.5) = 35.6db, which is somewhat less than the 40db or so that typifies moving magnet phono stage gains.

The line stage of your Rotel provides a gain of 20log(1/0.150) = 16.5db, which is fairly typical (although the gains of preamp line stages vary widely from model to model).

So if you were to obtain a phono stage that provided gain in the low to mid 40's in db terms, while also providing 47K input impedance to be compatible with your moving magnet cartridge, you could reduce the volume control setting by the difference between that gain and 35.6db. Keep in mind the rough rule of thumb that a 10db volume increase corresponds to a subjective perception of "twice as loud."

Audio Advisor has a selection of phono stages you may want to consider.

-- Al