I agree with some of what you've said but not all. Specifically, I do think that the KAB calculator will not deliver for those using passive pre's or running a phono stage directly into a power amplifier (don't know too many people doing this!). Systems with very high efficiency speakers might be another exception, although I'd expect you could perhaps get away with less phono gain in that environment as opposed to jacking it up which seems to be more the focus of the discussion here. But for most solid state based systems (receiver, integrated or pre-power combos) I think the KAB is going to get you into a very good zone. That's my experience anyway, based on using 3 different integrateds (all with pretty different input sensitivities) and 3 different phono stages. I would also agree with you that many analog system related problems are probably created by phono stage/cartridge mismatches. But I think that ultimately, phono stage/cartridge matching is the critical factor. Many analog users (particularly those new to the medium and being primarily used to digital, spend too much time focusing on where they are on the volume pot with analog (in the vast majority of well balanced systems you're going to be higher, sometimes considerably higher, with analog) compared to where they are with digital. And with most decent equipment, volume pots are more linear in their final 50% of travel than they are in the first 50, so it's probably a good thing to be pushing on the volume a bit more . Trying to volume match digital and analog in a system is the ultimate sucker's game IMO. Screw up the interface between phono and cartridge, primarily the gain interface, and all you do is amplify it through the rest of the system.
I would think it would be fine for you. If you are going to use both cartridges and you had the ability spec an exact number, I'd probably go with 39-40 dB but that's probably splitting hairs LOL.
Definition of "input sensitivity": "Input sensitivity is the maximum voltage strength of an input signal that an amplifier can handle and still produce unclipped full output. This is important to understand because not all audio signals have the same voltage. And, when a signal’s voltage exceeds the input sensitivity of an amp clipping and distortion can occur." You don't necessarily have to go to the maximum. Your amp, with its 1V input sensitivity, will handle anything below 1V without distortion/clipping, if we are talking of an integrated amp or receivers. If there's a preamplifier in the middle - then you need to do your math before buying. Example: the input sensitivity of my Yamaha R-S201 receiver is 500 mV. I have a Denon-103 (0.3 mV) running into 60 dB of Pro-Ject Tube Box DS. Using this formula: Phono Gain/20 = N, then 10 to the power of N x cart output in mV = Phono's out to amp, I get [10^(60/20)] x 0.3 = 10^3 x 0.3 = 1,000 x 0.3 mV = 300 mV - this is my phono output going into the Yamaha. It's well below Yamaha's maximum input voltage of 500 mV, and close to KAB's optimal 325 mV. Now, if I had this going into, say, a preamp with 15.5 dB gain (example - Brown Audio Labs SP-1B), the same formula would produce: [10^(15.5/20)] x 300 = 10^0.775 x 300 = 5.95 x 300 = 1,785 mV, or close to 1.8 V output. It would certainly overload a power amp with 1V input sensitivity, so, you would need to have a power amp with close to 2V sensitivity, or choose a preamp with lower gain.
Same Brown Audio SP-1B preamp has an internal MM phono stage with 45 dB gain. So, let's take, say, my Shure M97HE cart, with it's 4 mV output. [10^(45/20)] x 4 mV = 10^2.25 x 4 mV = 177.8 x 4 mV = 711 mV, which would go into your power amp, and be well under the 1V max input sensitivity. According to KAB, though, the 711 mV would be more than twice the optimal value, and may be too close to clipping at musical "peaks."
I'm aware of all the math. The problem is you are only looking at one half of the coin when it comes to input sensitivity. The other half is this. Input sensitivity is also the minimum input that your amp needs to make it's rated power output with the signal. If you are putting in 300mv and your amp is rated at 500mv you will need to turn your amp up quite a bit more than you should. It also results in reduced dynamics. With solid state gear it isn't to big a problem. With tube gear it can be a killer. Even with solid state gear I prefer a much closer match in terms of gain and input sensitivity. With in two db is fine but 4db is pushing it.
You can't take such a statement about distortion and use it without knowing what the preamp gain was set at, what the amp sensitivity is and finally the available overhead on the phonostage.
How can a metric be simultaneously a maximum and a minimum? At the input sensitivity value your amp produces the maximum rated output. Anything above and the amp clips. So it cannot be the minimum, by any stretch of imagination. Do you always need to run at the maximum? Come to think of it, I don't think I ever have, or wanted to reach the max. As far as the Yamaha goes, if I go up to 65 dB, the resulting output will be 533 mV - above the 500 mV threshold, so clipping will be guaranteed. Getting close to 500 will require a value between 60 and 65 db. I'm not sure how many phono's offer that, but I don't feel compelled to start looking. The Yamaha hookup is temporary, it will eventually go with the Cambridge Azur 851A in my main system, which must have a higher input sensitivity, too bad they don't publish the number. As it is, though, I like it with the Yamaha and hear no obvious issues with the setup. Edit: To get closest to 500 mV, my phono gain should be 64 db, giving me an output of 475 mV. Someone mentioned here that in a perfect world gain would be adjusted in 1 dB increments. But, we don't live in a perfect world. Another thing, though - don't you think that getting that close to the max sensitivity figure clipping would be happening at every "peak"?
Hm, I think I have it all out there: the gain is set at 41 dB (phono), the current input sensitivity of the Yamaha receiver is 500 mV. I said nothing of distortion in the phrase you're quoting, but admit to knowing next to nothing about "available overhead".
No I meant the post where the Moody Blues record was distorted at 46 db. You need to know a number of specs about that system to be able to determine the applicability to yours. I have an EAR 834P phono with 48db for MM and no distortion at any reasonable listening volume with either Clearaudio Maestro or Shure V15V. It is run direct to the amp however so no preamp in the circuit. Overhead refers to the amount of overload a phonostage can take for brief periods. It is usually noted in db as in a phonostage having say a 18db overhead at 20kHz. The more overhead the less distortion from brief loud passages or record imperfections. So the same gain with different overhead will produce different levels of distortion.
OK then, you were replying to someone else, but clicked on my name. I wrote nothing of the Moody Blues, and have no phono with 48 dB gain.
No you replied to the poster who mentioned distortion with the Moody Blues record. Thats what I was referencing. I understand you don't have a phonostage with 48db gain. My point was he hears distortion at 46db while I hear no distortion at 48db so you need to know more than simple gain.
I just looked up the input sensitivity of a SET tube integrated amp I'm salivating for: the Cary CAD 300SEI. - It's 420 mV, even lower than my very modest Yamaha receiver's 500 mV! So, when (if) I upgrade to that amp, I may have to seriously reconsider the carts/phono's that will be fed into the Cary. The Denon 103 at 60 dB still works, at 300 mV output, others will have to be carefully calculated. I have a feeling I may have to start hunting for phono's with lower gains, which even sounds strange. Edit: Now I understand why the Leben phono mentioned here, or in another phono gain related thread, has gain of around 24 dB - it is meant to go into SET amplification with very low input sensitivity. If gain isn't low enough, than the choice of carts narrows down dramatically. Although, people running expensive SET gear are probably using super-duper LOMC carts, anyway.
It depends where the volume control is in the circuit. If the volume control is front of the gain stage it will never see the full out put of the phono stage unless the volume is turned up all the way. The 420 mV figure of the 300SEI is the amount that it needs to put out its full power rating to the speakers, not the point where it overloads its input stage. CD players put out 2 volts. That won't overload the Cary's 420 mV inputs unless the Cary's volume control is turned all the way up. The 300SEI needs to see 420 mV for it to put out its full 15 watts into a speaker.
It is and it is a measurement taken at unity gain on the amplifier. I'm not sure what cartridge you need 64 db of gain for. The DL110 to get 500mv needs 49.9 db (rounded to tenths) of gain at it's stated 1.6mv outputs. The Leben phono preamp is actually designed to go with the companies push-pull tube integrateds. Input Sensitivity varies based on the topology of the input stage of the circuit. Some SETs, like all tube amps, have a lowish sensitivity others a high one.
I had my DL-110 at 46 dB (on an iphono) and it seemed an ideal match. Better than the 40 dB option where it felt constrained by comparison. Also tried my M97xe on both and it was rather overblown at 46. Overall, it's a tricky one as variations in design of stages; variations in different systems overall influence on the output (eg using others' findings (and preferences) as a reference); and the fact that even variable-dB phono stages tend do it in large increments... all mean it's hard to be exact and know you've nailed it. Can only use the tools as a guide and experiment where possible.
You mentioned, that at 300 mV from my Denon 103/Pro Ject Tube Box DS at 60 db, I'm short-changing myself, as the Yamaha receiver's sensitivity is 500 mV. My reply is that at next available gain setting, 65 dB, the Yamaha would be clipping already, at 533 mV. To get closest to 500 mV without clipping, I would need 64 dB gain, which doesn't exist in any phono I know of.
Yes it might. But you would still need to try the phono pre in question in your system, with your carts, and your records. I can tell you that I also run a 4.0mv output cart with 42db of gain. Other people might run that a hair lower or a hair higher depending on their system and the adjustability of their phono preamp.
It's not going to clip at regular or even loud listening levels. Input sensitivity is a measurement taken at unity gain, in other words with the taps wide open. Basically its a measurement that relates to your use of the volume control. If the signal you input is to low you you'll lose out in dynamics and have to turn the volume up to high and depending on your amp that can be a problem or not. Typically it raises the noise floor because you are having to over amplify a weak signal. If it's too high you clip the wave form before you get the maximum power out of your amp. If you manage to hit the exact input sensitivity i.e. 500mv. Then you can turn your amp all the way up and only clip it on peaks. Over driving the input section on your amp really isn't that big a problem. To put it in perspective, CD players and DACs typically output around 2v. Ultimately it's a balance game. That's why lots of people on here have said they would like to have an infinitely adjustable gain for their phonostage. Personally when presented with two gain settings like you have I listen to both and decide. Typically I find that I like to keep it within 2 db of ideal with my SEP amp and moderately efficient speakers, with my Cornwalls I can handle coming in 4 db below. With my Fisher 4 db is fine. Usually I prefer gain difference to be on the lower side.
@avanti1960 Based on this, I assume my MS Phonomena II+ would not be a good match with the Art9, correct? Max 60db.
This is way gain staging is as much art as science. How high "should" you turn up your amp? All you're doing with a volume control on a conventional active linestage is attenuating, so you're really not turning it up, you're really turning it down less. To what degree does it matter how much of the gain in the gain stages comes from the phono pre, how much comes from the line pre. Yes at some point along the spectrum you'll experience problems -- at the extremes maybe overload as you bump into one or another of the device's headroom on peaks; or you'll have weak, thin anemic sound at low volume. But we're really more commonly operating not at the extremes and we're not trying to drive our gear to full output, so we're working inside an operating spectrum to acheive the best dynamics and lowest noise and distortion with a variety of sources some of which are louder, some softer. There's a range of possible ways of arranging the gain stages which will work OK. It's a matter of finding a livable range of volume control with multiple sources that has low noise and high headroom without loosing umph and punch and body.
