Playing mono records properly without breaking the bank - a phono pre-amp question.

Uber, The 2-pin Denon is no problem, if you are content with driving only one of the two stereo channels, without a Y-adapter.  If you used a Y-adapter (so as to be able to drive two channels in mono), there are possible issues with impedance, but the question is equipment-specific.  You could try it.  I'd go with the AT33MONO, if it were my choice.
The mono switch solution allows you (or anyone) to compare the very same stereo cartridge used in either stereo or mono mode on the very same mono LP.  That way, there is no issue with the inherent quality of the cartridge, as opposed to the situation where you compare stereo cartridge A to mono cartridge B.  There you are doing more than just comparing stereo to mono; you obviously have the confounding factor of the SQ differences between one cartridge vs another.  But this must be at least the third time I've pointed this out.  So I'm done.

This thread has become a dog's breakfast of conflicting and/or redundant suggestions.  (I just wanted the chance to use the "dog's breakfast" metaphor.)  Anyway, get something with a mono switch to start with, and then decide for yourself if you like listening to mono LPs in mono mode, or not.  I predict you will prefer it.  By the way, a mono mode selector switch is typically in the linestage or high level circuitry, so stand alone phono stages will not usually have such a switch, but there are exceptions to every rule.


Uber, On the perfectionist level, you ask a good question.  The result of using a mono cartridge into a stereo LP begs a few more such questions.  For all intents and purposes, if the mono cartridge provides 4 pins, 2 each for a left and right channel, then the result should be similar to using a mono switch.  For a 2-pinout mono cartridge, you'd have to make an effort to deliver signal to both channels of a stereo input, like a Y-adapter.  If you use a Y-adapter, then each channel of the phono stage looks back at the output Z of the cartridge in parallel with the output Z of the other channel.  That could have a small effect on tonal balance. I'm getting a headache thinking about this.

Folkfreak and Lubachl, The better experiment, to work around Folkfreak's valid point that when comparing stereo cartridge A to mono cartridge B, you have to guess at the differences due solely to the basic goodness of the two cartridges, is to compare, for this example, your expensive MC cartridge in stereo mode to the very same cartridge with the mono switch engaged.  This is what I do all the time, and I cannot think of an example where I liked the stereo mode better than the mono mode, using a preamp with a mono switch to amplify the signal from a mono LP.  (Of course, I am only talking about "modern" mono LPs, not 78s, which are not LPs at all by definition, or late 1940s/early 50s oddball recordings.)

Elliott, Your experience is slightly different from mine.  I played all LPs, mono or stereo, with a stereo cartridge for the first ~35 years of my audiophilia.  And I agree with you partly, I never felt a crying need for a mono switch or a mono cartridge.  However, the recent interest in mono LPs and mono playback induced me to acquire preamplifiers with a mono switch (I have two systems) and also a mono cartridge.  Since then, using these devices, I have been impressed with the positives of playing mono LPs in mono mode (either by using a mono cartridge or by switching or both). There is less high frequency "hash", for sure, but also there is enhanced clarity and a closer approach to the live sound.  I wouldn't go without at least a preamplifier with a mono switch, these days.  For certain LPs produced in both stereo and mono during the transition phase from mono to stereo, I can even say I prefer the mono version. On the other hand, I wouldn't argue that a casual listener could not be happy in stereo.

No, there is really no "good" external switch for this purpose, because the signal voltage from a cartridge, even a high output one, is very low compared to line level signals, and passing that signal through a switch will inevitably do harm.  Some similarly recommend a Y-adapter placed in the line from cartridge to phono input.  That's not a good idea, because of the impedance anomalies that will result.  (It's too complicated to explain here.)  However, it might "work" to place a Y-adapter in the line between the phono stage output and the linestage input, if you are using separates. Because impedances will also be affected in this topology, you'd have to experiment on a case by case basis (phono stage/linestage combos).


Depends upon the design and quality of the switch.
I don't understand the comment that the DV17D3 per se isn't good for mono compared to other modern stereo MC cartridges.  All modern stereo cartridges should be about the same in mono, for good or ill, and assuming a stylus shape that is "modern", i.e., line contact or modified elliptical type.  A stereo cartridge with a conical tip might do mono slightly better than the foregoing, but such a stylus shape is not very good for stereo in the first place.

Finally, you didn't ask this question, but I wanted to comment that having a mono switch on your preamplifier to my ears gives about the same (good) result as using a mono cartridge.  I have both, and that's my opinion.  This thread will go on and on, so I would also mention here that there are both "true" mono cartridges and mono cartridges that are made from stereo cartridges by bridging the channels internally.  In the latter case, that is more or less like using a mono switch.  Also, IMO, there is tremendous benefit to playing mono LPs in mono, no matter how you get it done.  On the other hand, most mono LPs also sound "good" in stereo mode, if you cannot afford the equipment needed to go mono. You'll just hear more noise due to dirt in the grooves and to recorded hf that amounts to noise and is cancelled out in mono mode.