2. amps-preamps
  3. 1261675658

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.
Andrew
dordevic
hifitime
715 posts
 
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]
zormi
105 posts
 
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.
dordevic OP
11 posts
 
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.
Andrew
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
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.

Regards,
-- Al
zormi
105 posts
 
Andrew,

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.

Cheers
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