Low output moving coil cartridge

Hi

I had a similar if not exactly the same situation years back. The answer was a phono stage that has a gain of up to 70dB. My Dynavector XX2 at the time needed 65dB to get my system working correctly so I would get the extremely low noise and a normal 10-11 o'clock listening level on the volume pot. My Koetsu Red was 0.6mV and needed just 60dB to get the same. The preamp I had was also tube based then BUT just did not have sufficient gain in the MC section to handle a low output MC.

Change to a good out board phonostage.

regards Rob.

Wow, thanks again guy's. You summed it up pretty good as I think I understand it now (for the most part). Johnbrown, yes I would prefer the lower wattage amp if I can get away with it. I did turn the volume up to max- of coarse with the arm resting in holder- and I hear no hiss or noise so hopefully this will work out.The only reason for not switching to the other amp right now is purely out of laziness, however I will be doing extensive comparisons as soon as the new cart gets here. I also have a 2nd armtube on the way so I will be able to compare carts pretty fast.

I agree with 'Almarg', but will make one more point, or maybe try to clarify: many phono pre stages have adjustable gain in order to more closely match a given cartridge's output to volume attenuation. Since, as a general rule, the noise floor will increase the higher the output gain, it's best to keep the output gain as low as possible while still having acceptable attenuation at the preamp (of course, phono preamps will vary as to their noise floor at similar gain levels-some very quiet, some....not so much).

Since the gain at your stage is set, your noise floor will not change from cart to cart-though, as 'Almarg' says, audible "hiss" may increase the further you turn the volume knob. You can try it right now-with no input from your tt, turn the volume knob to '12', listen for noise, now try it at higher volume levels. I'm wagering that you'll hear very little difference, and as 'Almag' said in his initial post, you won't need much more 'volume' to make up for the new cart's lower gain. Therefore, since I'm assuming that there's a (presumably sonic) reason that you're using the smaller amp, you should be fine with it's continued use.

Of course, all of this is academic, since you can simply insert the higher powered amp into your system and compare for yourself. Let us know what you come up with.

Correction: The first sentence of my previous post should have been "More often that not the answer would be NO, but not necessarily." When writing my answer I forgot that you had expressed the question as a negative. :)

In other words, more often than not you WILL have to turn down the volume control, but not necessarily.

Best,
-- Al

Are you saying that if I have the 30 watt amp hooked up with the .5mv cart and I have a comfort listening level at say 12:00 position on the control, then I switch amps to the 60 watt (with the same .5mv cart), that I will NOT have to turn the volume control down somewhat to achieve the same listening level?

More often that not the answer would be yes, but not necessarily. The effect on volume control setting of changing the power amp would be dependent on the gains, or input sensitivities, of the two power amps, meaning what input voltage is required to drive the amp to its specified output power. Typically a 60W amp could be expected to have higher gain than a 30W amp, but that is by no means always the case.

But the only significance any of that has is that the amp gain should match up with the gain of the rest of the system such that the volume control does not have to be used near the extreme top or extreme bottom of its range.

The fundamental benefit of a 60W amp vs. a 30W amp, everything else being equal, is simply that it will be able to handle louder peaks without clipping.

The major concern with going to a lower cartridge output, again, is that hiss levels do not become excessive. Yes, by staying with the 30W amp you would be turning up the volume control to a higher setting than you presently use for the higher output cartridge, and yes if you were to change to the 60W amp you MIGHT not have to do that (depending on its sensitivity or gain). However, that would be irrelevant to the hiss level -- if the 60W amp has higher gain and greater sensitivity than the 30W amp you would not have to turn up the volume control as far, but at that lower volume control setting you would wind up with the same volume of both music and hiss as you would with the 30W amp at a higher volume control setting.

That is because the hiss level is determined, as I said earlier, by the amount of noise which is generated at the front end of the phono stage (all electronic devices generate some amount of noise, and the noise generated at that point in the system is what is critical because it is amplified by everything that follows). While strictly speaking the critical parameter is the noise performance of the phono stage (which can be defined as "signal-to-noise ratio" or "noise figure" or "equivalent input noise"), with high quality equipment that will correlate with the gain of the phono stage, which is why the others discussed the issue in terms of gain.

Good luck with the new cartridge!

-- Al

Thanks guy's for the great responses. I keep learning from your valuable information. I am looking forward for the arrival of my new cartridge for some experimentation. I am still a little puzzled as to how a more powerful amp will not help the gain situation. Are you saying that if I have the 30 watt amp hooked up with the .5mv cart and I have a comfort listening level at say 12:00 position on the control, then I switch amps to the 60 watt (with the same .5mv cart), that I will NOT have to turn the volume control down somewhat to achieve the same listening level?

Depotec-

Let's see, top of the head...

a) AcousTech PH1-P

b) Steelhead Phono Pre

c) EAR 834P

d) Klyne 7Px2

d) the phono pre inboard on my BAT 3xi

All the outboards bested the BAT (as to be expected). I kept the Klyne and the EAR, but if I had to have just one I'd prefer the Klyne-but I've yet to try some good SUTs with the EAR, which is supposed to be a big improvement.

In the Denon 103 world I've got the 103, 103r, 103r w/VdH type 1 rebuild, and a ZU 103r. At some point I'll have SoundSmith rebuild one of them, and I also want to try a 'Uwe' Panzerholz body.

Johnbrown,

I agree 66db should work pretty well. Thanks for pointing that out!

Johnbrown, what phono stages have you used for your DL-103?

Mapman-your cart output may be similar, but another quick search shows the SP-16 with a 55db phono stage gain. i.e., your preamp is different than the OP's, at least in regard to the gain at the phono stage. I have a lot of experience with the D103 variants with many phono stages, and it's true that 55db is marginal-though workable. 66db, however, is fine and jim-dandy, and I'd wager the OP will have no issues.

I'm using a similar low output MC cart (Denon 103R) with an ARC sp16. I tested without one at first but a step up device was required to get to proper levels with low background noise with the sp16.

What's relevant in your situation is not the power rating of your amp, but the gain of your phono stage. A quick look seemed to show 66db gain, which is plenty for that cart. Should be no problem.

No. You haven't lost any power at all by going to the lower output cartridge. All that you've done is to change the position of the volume control that is required to reach the 30W power capability of your amp, and by a modest amount (about 6db, since the cartridges differ in output level by about a factor of 2).

The main question is whether the background hiss at the higher volume control setting will still be acceptably low. That is a function of the noise performance of the preamp's phono stage, not of the power amp.

Regards,
-- Al