Concerned about my cart/pre pairing

I thought I covered this in my earlier post.  We mentioned that 58db of gain applied to the 0.3mV output of your cartridge would yield a ~0.24V output from your phono stage.  Adding to that the 9.5db gain of your linestage would result in a net signal voltage output from your whole preamplifier of ~3 X 0.24V = 0.72V.  (9.5db translates to about 3X voltage gain.) The calculation gave a different result the first time, because I was working with a putative 7db gain from your linestage, as opposed to 9,5db.  Given that we now know the sensitivity of your amplifier is 1V and also given that you disclosed the fact you use powered subwoofers, which presumably relieves your main amplifiers of the power demands required for deep bass response, I would say you ought not to be suffering from lack of gain adequate to drive your speakers. 


"Faint background noise" can be what is known as "tube rush".  Sometimes that happens when you crank the gain on your tube preamp, which you are not really doing.  Maybe your tubes are going weak.  Also, was Chakster correct in stating that your phono stage uses two 12AU7 tubes, only?  If so, there has to be either a SUT built into the MC input stage OR there are solid state devices adding gain.  You cannot derive 58db of gain from two 12AU7s alone. Below is a useful website.

http://www.sengpielaudio.com/calculator-gainloss.htmhttp://

@lewm 

Thanks for breaking that down for me! So sounds like everything from the cartridge through to the power amp matches up well. Could there be any improvement by getting closer to the full 1 volt rating? By the way, I use a powered sub, but the mains are still running full range off the power amp. The sub is being fed by the preamp. You probably already realize this just wanted to point it out. It's my understanding that to relieve the mains of the work of producing deep bass you need to add a crossover or filter? Again, still learning all the different setups. If I remember correctly the RP1 uses a tube output stage, the phono stage may be solid state, I'll have to look into that. 

I assumed that if you are using powered subs, usually those products have built-in electronic crossovers.  I guess I also assumed that the crossover is also driving the main amplifier you use for upper frequencies.  That's very worth doing if you don't mind spending the money.  As it is, then of course your main amplifier is working full range and the power demands on it are greater than I thought.  What you say about the RP1, which I know zero about and which I cannot even find on the internet (albeit I did not look very hard), makes more sense, if the phono section is solid state.  Technically, I think you should be OK so far as driving your amplifier to power the speakers, but the proof of the pudding is in your listening.  The symptoms you describe do fit the description of a lack of adequate gain somewhere in your chain.  Maybe try to borrow a preamplifier with more overall gain from phono input to linestage output, and see what that gets you.  Or borrow a 1:20 SUT.

If you try using a SUT to solve your problem, keep in mind that you need to attach it to the moving magnet inputs of your phono stage, not the MC inputs..

@lewm, I think the OP can kill two birds with one stone by getting an active two way crossover for his subwoofers. It will cut the bass to his main speakers and add some more gain to the preamps output. 
jin78, check out MiniDSP I do believe they make such a crossover. It will improve your system performance quite a bit with less distortion in your main speakers, better subwoofer integration and more gain. 
As for as your phono stage is concerned the real limiting factor is the signal to noise ratio. If you are hearing noise I consider that to be a problem. I think it is unacceptable to hear any noise at the listening position at the highest levels you listen. If you hear noise then the solution is a quieter phono stage or a cartridge with higher output. 
Low output in a moving coil cartridge is an advantage because the coils are lighter (fewer turns) which gives better tracking and a higher resonance frequency pushing the high frequency response of the cartridge up higher. The problem is having to use a phono stage with high gain and a very low signal to noise ratio. These are obviously expensive. Moving Iron cartridges like the Grados and Soundsmiths have no such problem. With phono stages that have gain below 60 dB they are the superior choice IMHO. The are now some excellent moving magnet cartridges from Audio Technica, Clearaudio, and Goldring that have performance comparable to many moving coil cartridges if not better in some ways. I have never heard a moving coil cartridge as dynamic as the Charisma from Clearaudio. I think any of these would be a better match for your system. IMHO moving coil cartridges are over rated and over priced. The ones that I really like are $5k and over, a lot of money for a perishable item. If you check out my system you will see that it is pretty serious stuff and I am more than happy with cartridges made by any of the above, so much so that I have sold all my moving coil cartridges!