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Unregistered guest | I've just bought a new Rotel RA-1062 amp (sounds great!). But the output level I'm getting via the phono input is considerably lower than that for CD. Not just a bit lower, significantly lower. I am using an old 70s Monarch turntable (very obscure Aussie mid-fi model) with a newer magnetic cartridge (Shure/Radio Shack R25XT). Have had excellent levels from the turntable with a previous Rotel 1060 Integrated with an Acurus phono stage (the previous Rotel 1060 didn't have an inbuilt phono stage). Have also had averagely good (not fantastic) levels with an old JVC integrated also. Can anyone suggest how this problem might be remedied? I would like to use the inbuilt dedicated phono stage if possible. I know a possibility might be to use a phono pre-amp and go through an aux input but I want to avoid having another 'box' if possible. The ground wire is thin but it's the same one as used previously with no real issues. Could it be that this older magnetic cartridge has too low an output for the modern phono stage input? Any help much appreciated. |
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J. Vigne Unregistered guest | Phono cartidges vary considerably in output voltage from one model to the next. If this is a new cartridge that you have not had through any of the previous phono stages you can probably trace the situation to the output level of the cartidge. You can compare output levels by looking at the specs on the cartridge, Like speakers the specs on a cartridge tell you little about its actual performance; but, output voltage and loading resistance and capacitance are things that are important values to observe before purchasing a phono cartridge. A qualified audio salesperson should be able to guide you in selecting a cartridge that is compatible with your system. If you have used the same model of cartidge through all of these phono stages then that is not the problem. If the same cartidge gives different amounts of volume through different phono stages then you have to look at the output voltage of the various phono stages. Since part of the job of a phono section is to step up the voltage of the cartridge's millivolt output, by design there is considerable variance in how much gain is involved in different phono sections. You can also find this number in the specs of your pre amp section. If a phono pre amp only boosts the level by 60 dB it will not output as much voltage to the power amplifier as a phono section that has a gain of 65 dB. This means the lower gain is going to have the volume control advanced more for the same volume level at the speakers (in this case by a goodly amount). CD's almost always have a higher output level to the power amp than a phono section. Most CD players can output 1.5 to 2 Volts (or more in some cases). There is minimal, if any, gain in most line stages because of this high input voltage of line level sources. So a CD, DVD, tuner, tape, etc. will usually play louder than a phono input for the same volume control setting. This is not a problem as long as the desired levels can be reached with each input. The only danger is when you switch between sources and don't lower the volume level beforehand. If you can't get the desired volume level from your turntable/cartridge (and the desired volume is within the capablity of your system on other inputs) then your solution is to buy a higher output cartidge or a higher output phono section. |
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J. Vigne Unregistered guest | Phono cartidges vary considerably in output voltage from one model to the next. If this is a new cartridge that you have not had through any of the previous phono stages you can probably trace the situation to the output level of the cartidge. You can compare output levels by looking at the specs on the cartridge, Like speakers the specs on a cartridge tell you little about its actual performance; but, output voltage and loading resistance and capacitance are things that are important values to observe before purchasing a phono cartridge. A qualified audio salesperson should be able to guide you in selecting a cartridge that is compatible with your system. If you have used the same model of cartidge through all of these phono stages then that is not the problem. If the same cartidge gives different amounts of volume through different phono stages then you have to look at the output voltage of the various phono stages. Since part of the job of a phono section is to step up the voltage of the cartridge's millivolt output, by design there is considerable variance in how much gain is involved in different phono sections. You can also find this number in the specs of your pre amp section. If a phono pre amp only boosts the level by 60 dB it will not output as much voltage to the power amplifier as a phono section that has a gain of 65 dB. This means the lower gain is going to have the volume control advanced more for the same volume level at the speakers (in this case by a goodly amount). CD's almost always have a higher output level to the power amp than a phono section. Most CD players can output 1.5 to 2 Volts (or more in some cases). There is minimal, if any, gain in most line stages because of this high input voltage of line level sources. So a CD, DVD, tuner, tape, etc. will usually play louder than a phono input for the same volume control setting. This is not a problem as long as the desired levels can be reached with each input. The only danger is when you switch between sources and don't lower the volume level beforehand. If you can't get the desired volume level from your turntable/cartridge (and the desired volume is within the capablity of your system on other inputs) then your solution is to buy a higher output cartidge or a higher output phono section. |
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Unregistered guest | Thanks for your advice. Have tried a couple more things to pinpoint low phono output problem. I don't have voltage specs etc for the (Shure/Radio Shack R25XT) cartridge but tried a few experiments. 1. Changed ground wire to something more substantial (no difference). Still low levels. 2. Switched (Shure/Radio Shack R25XT) headshell/cartridge with that from an old Technics SL23 - Output levels improved to an much improved level but still not equal to that of CD/Tuner. 3. Switched the Monarch Turntable with the Technics SL23 through the RA-1062 phono and levels were even better. CONCLUSION and possible solutions: Might need to get a better/higher output cartridge for the Monarch (because it is a much much better sounding turntable than the old Technics SL23). OR buy a phono stage box (more expensive??). ANY suggestions are very welcome! Regards, Colin. |
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J. Vigne Unregistered guest | There is nothing that has a gain stage in a turntable, headshell or grounding wire. If the ground were bad you would hear a 50/60 cycle hum but the level from the cartridge would not be affected. As I laid out in the above post, the difference in gain can only be traced to the cartridge or the phono stage, no wires or tonearm can change that. I will repeat that it is infrequent that a phono stage will play at the same volume as a CD player because of the CD's inherently high output voltage. If that is your goal you may be chasing a phantom. The goal is to have the volume level you require (within the limitations of your system) with all inputs. Beyond that you have to deal with each input having a slightly different volume level for the same setting on your volume control. That's why you have a volume CONTROL, so you can adjust the volume. Before you spend money on anything new you will need to know the output voltage of your present cartridge and the gain of your Rotel phono section. Without that information you have no idea what you need to look for to raise the volume level of your phono imput. As to buying more expensive pieces be aware that often the lower priced cartridges and phono stages have higher gain (for reasons I won't go into here) and as you spend more money it is not uncommon to find lower outputs from these devices. It is possible to find higher output units if you have information to start with, but you must have a reference to start from. |
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Unregistered guest | Thanks again for your advice. Having difficulty finding output voltage of the old R25XT (I don't think it was a particularly expensive cartridge in its day so might find something better instead). Interested to know your opinion on the phono specs for the RA-1062 (Is it right that that the audio shop should be able to match up a suitable cartridge if they have the amp phono specs?) Specs are as follows: Phono (MM) Sensitivity/Impedance - 2.4 mV / 47 kOhms. Input(Phono) overload - 170mV. Also assuming that because this is a brand new amp there shouldn't be too much trouble finding something compatible. I do appreciate your advice to date. I'm learning a lot. |
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J. Vigne Unregistered guest | Yes, the shop should be able to give you some assistance in picking a cartidge for your table. I would take the turntable with me when I went to the shop and ask them to mount and align the cartridge. As a matter of fact I would call a few shops in your area that sell cartridges, if that's possible, and ask if they will perform that service for you before I headed out to make a purchase. You're going to need the alignment guage that came with the table for anyone to do a proper job of alignment. If you don't have that guage ask the shop if they have a universal guage that they will use to get the proper set up. If you have no access to a guage there is one offered on this forum and on the web site "Enjoy the music", sihttp://www.enjoythemusic.com/magazine/. You cannot properly align a cartridge by guessing at where it should go and you cannot use your old cartridge as a guide since a new cartidge is going to have a different stylus overhang. To not properly align your new cartridge is throwing away money and will do damage to your records if it is severely out of alignment. The hassle of disconnecting the table to take with you is well worth the extra effort. Just make certain the stylus guard is on the cartridge, the tonearm is tied down securely and if possible remove the platter are at least put some cardboard wedges under it to keep it from bouncing off and taking out your existing stylus. Also, since Radio Shack uses cartridges made by other manufacturers (usually Shure and Audio Technica) the shop might recognize the cartridge and have some idea what the output might be on your present cartidge. |
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Gold Member Username: John_aPost Number: 2090 Registered: Dec-03 | Just to underline J. Vigne's comment "So a CD, DVD, tuner, tape, etc. will usually play louder than a phono input for the same volume control setting. This is not a problem as long as the desired levels can be reached with each input. " The amplifier volume control position is not important, as long as you get the volume of sound you require. Clipping and other forms of distortion may come in at certain high power values, not gain control settings. You can be on be on maximum gain and still get good clear sound if the signal is small. I now play LPs from a MM cartridge through an NAD 1000 stereo pre-amp at gain at about 3 o'clock and an NAD T760 as power amp at about + 12 dB. You might imagine both amps are up in the red zone, but no, the sound is clear as a bell, with wonderful volume and still some headroom (max would be 5 o'clock and +18 dB). I have never heard distortion from this arrangement. For CD I would probably have 12 o'clock on the pre amp and +9 dB to get roughly the same volume. |
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New member Username: KpdPost Number: 1 Registered: Dec-04 | Similar question regarding phono level inputs here. What I'm trying to do is gauge whether or not I can add an iPod to the only free input left on my NAD integrated amp - the phone input. The connection I'm thinking is mini to stereo cable into the phono input. Would this be do-able? |
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Gold Member Username: John_aPost Number: 2559 Registered: Dec-03 | Kirk, it is do-able but will not sound good because there is an steep slope equalization for phono. Get a mini-jack to stereo RCA cable and try one of the other inputs. If it works and you like it, you can get a 2 into 1 stereo RCA adaptor, or switch. iPod has a low level signal so you will need the gain control higher than with other sources. Following my post of Sept 20 I now use the tape output from the pre-amp to the receiver, using the "Ext 5.1" input on the receiver. The sound is much better; it misses out the A/V receiver's preamp stage. |