I've been using an Aqvox Phono 2 CI for about 11 years now. Not a phono stage for everyone as it: 1) is a totally balanced phono stage that really should be used with balanced cabling and a phono cable terminated in XLR's 2) is a current mode (as opposed to voltage gain) phono stage that totally dispenses with loading MC's and presents a very low impedance load, almost a short circuit-to any moving coil cartridge attached to it. 3) probably tends to work best (as a result of #2) with low output moving coil cartridges with fairly low internal impedance (ie. 20 ohms or less). Depending on the internal impedance of the cartridge attached the Aqvox will deliver between 55-75 dB of gain and has two gain pots on the front panel (one per channel) to infinitely vary the gain within the range (ie. there are no incremental 1 dB or 2 dB changes-they can literally be adjusted in any position to optimize gain). Both of my cartridges are low impedance designs, an AT 33 Mono with an output of .35 mV and an internal impedance of 10 ohms, and an Accuphase AC 2 with a spec'd output of .18 mV and a quite low impedance of 4 ohms. In looking at the final settings I've chosen with the gain pots it would appear that I'm running the AT 33 Mono with just under 58 dB of gain and the Accuphase with just over 66 dB of gain. The integrated amp I use in this system has a "high-ish" 375 mV line level input sensitivity so I need to turn this system up and typically run at about 75% or slightly more of max on the volume control (or about 3-4 o'clock in clock terms on the volume control). But there are no noise issues and it is deadly quiet. I have a secondary system in the house as well with an AT 120 E (with a 5 mV output) on a Pioneer table run into a DB Systems moving magnet phono pre which has 37 dB of gain. These are run into another integrated with 250 mV line level sensitivity and I rarely get past 30% of max volume on the integrated in that system-it would likely sound better (and certainly offer much better control of volume adjustment) and be quieter with a higher sensitivity spec at line level on the integrated. Or the AT might be outputting even more than 5 mV (not really unusual for cartridges to output a bit more than spec'd) and I could do with 2-4 dB less gain at the phono input. Everyone's systems and ears are different but in any system that I've ever run (all active mind you-no passive preamps) 70 dB of gain with a .35 mV cartridge would almost certainly make my ears bleed. Always best to have a lot of ability to adjust gain IMO. Would be a priority for me in any future phono stage.
Cheers for that excellent info blakep and other members.. lots of options to go with for when I go that road.
I’ve been running my Rega Ania into the rca inputs on my Parasound Halo JC 3 Jr phono stage, with it set for MC gain, supplying 60db. The Jr will add 6db to the gain specs if you use the balanced outs. The Ania outputs .35 mV and calls for about 69db of gain, so I’ve always been curious what swapping to the balanced would do. Finally snagged some cables (thanks forum classifieds!) so I could give it a shot. Now that I have the hardware swapped around I’m gonna spend the day spinning records to see how I like it.
Could use a sanity check on this from the gang here.... I've been using a Soundsmith Paua with my Zesto Andros 1.2 into my Leben CS600 integrated. Paua is 0.4mv, Andros is 67db on MC and the Leben has 900mV at 2ow stated input sensitivity. Everything sounds great and no issues. I'm now trying an MM cartridge that has 6.5mv sensitivity into the Andros 1.2's MM stage which has 47db of gain and then into the same Leben CS 600. Using the formula above, and assuming various starting points, I get the following: For 1v, approx 44db of gain needed (43.74 to be exact) For 1.5V, approx 47db of gain needed (47.26 to be exact) My question is how does the input sensitivity of the Leben play into all of this? Do I need to use 0.9V as the starting point to the formula? Or does the Leben stated distintion of "900mV @20 W" factor into this? Does that mean that at approximately 2/3 power output it needs 900mV to not clip? If I use the .9 as the starting point, I get 42db which is 5 db under what the Andros is putting out. I'm asking this because and starting here because the 6.5mv output is the highest gain cart I've used on this rig and I'm getting an audible buzz from the EI of the TD124 motor. I'm wondering if my gain being too hot is a possible culprit? Again I have no issues with the much lower input of the Soundsmith so I'm scratching my head here.
900 mV is the minimum signal strength input that the Leben needs to produce its stated full power - 20W. More than that helps. The 0.4 mV cart into 67 dB phono gain gives you 895.5 mV - nearly there, so you're OK. The 6.5 mV cart into 47 dB gives you nearly 1.5 V - more than needed. If it sounds fine and you hear no bloating - thing are fine, too. EDIT: I've read your post to the end. It does appear you have too much gain with the 6.5 mV cart, if you are hearing noise.
47dB of gain is typically going to be on the high side for 6.5mV cartridge. If your phono stage has sufficient headroom, it may not be a problem, but on a hotly cut record it may cause issues with the input of the integrated depending on the input sensitivity. 47db of gain equals a factor of 223.872 - let's just say 224 to make it easy. 6.5mV * 224 = 1456mV That would be enough to give me pause. I would talk to the maker of your integrated and see what they have to say.
My Audio Research LP1 has 47 dB gain. My ears have told me the sweet spot for that phono stage is 2 to 3 mV. I had to clear out my MM collection and go to HOMC or LOMC with a 1:5/1:10 step-up transformer.
I have 3.6mV out of my SUT into a tube phono fixed at 40dB gain presumably generating 360mV into a tube integrated with a 750mV input sensitivity. Position of the volume control is 1/2 to 3/4 depending on the record, which is about ideal as I understand it. Would I want more gain? Not that it's an option, but curious.
In my experience it's a Goldilocks sort of thing where you want to kiss that spec on the lips, not miss, not go all in. A little too much gain and you can hear things start to flatten out. Just right and you have better control using the volume pot.
Too much gain or mismatched cart + gain usually sounds grainy and edgy. On hot peaks, you'll hear distortion if the mismatch is bad enough. It's very easy to be seduced by more gain because it will give a bit more "oomph" to the low-end and humans tend to think louder = better but this is misguided IMHO.
Hopefully most of us who appreciate sound quality are well beyond the "louder is better" wow factor. In my system with a particular cartridge too much gain created a non linear response that emphasized the midrange and was slightly edgy. Too little gain is easier to live with but sounds anemic and makes you want more. It has nothing to do with having to turn up the volume compared to other sources and everything to do with missing vibrance and energy in the music. The key is to have the capability to set the gain that makes your system sound its best and often this means using slightly more gain than what is considered conventional. A properly configured vinyl system should approach the energy and dynamics of a quality digital source. If you are putting together or upgrading a cartridge, preamp or SUT vinyl system, going beyond the "one size fits all' school of gain is worth consideration.
I went back to the original TAS article and ran calculations based on their math. According to the writer, I should be using 49dB of gain with my 3.5mV cartridge. I can't say I agree with this at all after doing some basic calculations considering the gear I'm working with. This method won't work with a lot of the music I like, and IME, jacking up the gain like that with this type of cartridge does the system no favors. I'd rather have more headroom for hot peaks on records, and not run up against the max output of my phono preamp. I can assure you there is no lacking in "energy", "dynamics", or anything else with a more modest 42dB gain setting in my case.
KAB has me at 39 dB. The real math is 40.9 dB. I use the 40 dB setting. 44 is too much. My integrated input sensitivity is 390 mV.
the TAS article is not gospel but it is good to have flexibility. one cartridge i had with 5mv output sounded weak at 36db of gain and overdriven at 46db. at 36db headroom didnt matter it simply couldnt deliver any peaks. i really needed about 40db but no such luck. another cartridge with .5mv gain sounded best with 56db and another .5mv cartridge sounded best at 54db gain. having multiple gain settings has been valuable.
Doesn't the "1V" assumption inherently change based on the input sensitivity? @jupiterboy's input sensitivity is 390mV and mine is 900mV for example. @patient_ot what is yours? Because the whole calculation starts with that number right?
dont worry about linestage input sensitivity. they typically have a lot of headroom and can easily accomodate 2.5volts (e.g. a cd player) with margin to spare. shoot for the 1v output of your phono preamp and you wont over drive the downstream amplification. however that doesnt mean 1v is optimum. the multiplication of the csrtridges output voltage, especially that of a lomc, is the sensitive part of the chain with the least amount of margin. when you hear the poor qualities of an overdriven cartrige and phono preamp it is because of the noise of the generator being multiplied too much by the phono preamp, not that signal over driving the linestage and power amp.
That's one of the reasons I moved away from integrated amps - not having to worry about their input sensitivity. Having a separate line stage gives me the flexibility of additional gain that I don't have to have from the phono. For me, optimal output from the phono is 500 mV or close to it, and that's how I do my cart/phono pairing, for both MM and MC. Haven't had any issues with either lack of dynamics or bloating, using that number as my goal.
I recently purchased a Chord Huei Phono Stage. It has adjustable gain and impedance range range settings. With my Linn MC Krystal cartridge, the sweet spot was a medium gain and a 150 ohm impedance setting. Sounds great.
One reason I love my Zesto Allasso SUT - it has 4 gain settings and each one with 10 impedance settings. I can dial in my cartridges pretty much to perfection and yes, there is no "correct" formula. Right now I'm running a 0.5 mV Hana SL with 61dB gain and 400 ohms and know that's perfect to my ears.
absolutely correct but they do get you into the ballpark. the TAS formula for 1V seems to be on the high side, a maximum. the KAB formula for optimum gain is on the low side, a minimum IME. if I was looking for a new phono preamp, multiple gain settings that spanned the range from low to high would be a requirement.
