You have a "Medium" output Glider at 0.9mV and 24 ohm coils. Folks running a Glider below 200 ohms typically have the "Low" output version, at 0.3 - 0.4mV depending on series (e.g. L2 versus current SL) and 12 ohm coils. Therefore there are different loading requirements between "Low" and "Medium" (and "High") versions. (Note: the L / M / H versions may have been introduced in later series succeeding the original Glider -- the Glider goes way back!)
I have a "Medium" Wood SM, which is basically the same as a medium Glider in a wood body, and in my system it seems to like ~ 470 ohms best. But it’s still excellent at 220 or 1K. Below 200 ohms, you will start sacrificing some of its performance (due to loading losses), though it’s subtle at first. BUT if you like 1K in your system with your ears, then it would be wise to choose a phono stage which can achieve that (or thereabouts).
Some MC phono stages will lock the loading at 100 ohms. Yeah, I find that extremely annoying and limiting. It will be fine for a Glider L but a bit suboptimal for a Glider M, and very bad for a Glider H! The Benz PP-1 phono stage (sadly discontinued) is locked on the other side, at 22,000 ohms, but works great with all Benz (except the Ebony TR) and in that case it’s easy to bring the loading down to whatever you like with a DB Systems loading kit (which I’ve done). However if a phono stage only offer 100 ohms, unfortunately you cannot bring it up from that without internally modifying the unit or getting a different phono stage.
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@mulveling,
I think I'll play with the loading again and reevaluate. The MoFi has plenty of settings and maybe I'll find out that 1k isn't the optimum setting anymore for my ears.
Thanks for the response.
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What Mulveling wrote is relevant information, but if you know that you prefer a 1K load with your particular version of the Glider, that is the dominant information. If you plan to keep your Glider for the foreseeable future, then it is almost certainly possible to modify any phono stage so as to present a 1K load to your cartridge. At worst, this amounts to opening the chassis, removing whatever load resistor, and replacing that resistor with a 1K value. No big deal. Any good tech can do this for you. Try either an Audio Note tantalum resistor, Caddock TF020 (avaiable from Michael Percy Audio), or Texas Instruments TX2575. I happen to like the last one best, but you will like any of these brands in 1K value. No need to convince yourself that you now prefer some other loading option, just because you cannot find a phono stage that offers an option of 1K ohms.
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@lewm,
Thanks for your response. I now dropped the MoFi phono pre down to 900 ohms. I know not much of a difference but it’s a start. Next down (or is it referred to as up?) is 500 ohms.
It would be nice to go with a phono pre with as many options as possible though.
Makes me wonder why a lot of them don’t have at least 7 or 8 options for loading.
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I once had the HO version, yeah, the original 2mv, actual rating 1.9mv. This I ran like an MM, at 47.5K.
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I personally would use 47K ohms for a load with a HOMC cartridge. I agree. Reason why not many phono stages offer multiple choices for cartridge loading is that the switching mechanism itself, unless done rigorously, can add noise, etc. It's a purist approach not to use switching (also cheaper for the manufacturer, of course).
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@nicktheknife When dealing with a cartridge of this type the loading is for the benefit of the preamp, not the cartridge!
What is going on is the inductance of the cartridge is in parallel with the capacitance of the tonearm cable. Whenever inductance is in parallel with capacitance you get a resonance. In this case it can be from about 50KHz up to about 1 MHz depending on the capacitance of the cable and the inductance of the cartridge. If it goes into 'excitation' (a Radio Frequency term meaning that the resonance is oscillating and is making a signal) then that signal is injected into the preamp. Audio information can send the resonance into excitation even though its not the same frequency!
The result is RFI is being injected directly into the preamp and could be overloading it. This would cause distortion (brightness). By 'loading' the cartridge, you detune that resonance and excitation can't occur- the problem goes away.
If the phono section designer understood how this happens, the phono section won't be sensitive to RFI at these frequencies and so won't care about the loading either- it won't affect the sound.
However, when the loading is used, you are asking the cartridge to do more work! Normally it has to drive 47,000 Ohms but now its only 1000. nearly 5x over a magnitude more work- and that work comes with a price- the cantilever, which does the work, becomes harder to move. This causes the cartridge to have a lower compliance than the spec sheet says and may lead to tracking difficulties if you were paying attention to that when the cartridge was bought and set up in your arm!
In addition the stiffer cantilever may make higher frequencies harder to trace.
The bottom line is when you see a preamp that has loading options on a switch it means the designer did not think about the implications of an inductor in parallel with a capacitance (which is your first week of electronics 101 class). Take that for what its worth...
So not having such a provision is not always a bad thing. It might mean the designer knows what he's doing 🙂
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@atmasphere
I don’t want to appear ignorant but I’m not sure how the info you provided helps me in deciding what phono pre I should look for other than listening of course which really isn't an option when buying used. One with a 1k loading option or not?
In my previous phono pre’s 1k or close seemed to work the best. Some phono pre’s don’t have this option as I’m sure you know.
I have two MC cartridges and one MM. I like to swap them out fairly often.
I guess I should be looking for something that’s more flexible/adjustable than some of the others out there.
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I can suggest:
The Hagerman Trumpet MC is very flexible, easy to adjust in gain & loading with front knobs, sounds great, and doesn’t cost much. Its main limitation is lack of adjustable capacitive loading for MM. It has a warm sound that goes GREAT with Benz cartridges. Due to a bit of noise floor, it’s best with the 0.4mV and higher models.
The Benz PP-1 (discontinued but available used) has a fixed 22K input load that can be used with splitters and loading plugs (e.g. the DB Systems Loading Kit) to hit any target load without internal modification (this loading plug technique can be used with any non-SUT based MC phono stage with a sufficiently high input impedance). The PP-1 is not as warm as the Hagerman, but only just. And it’s a bit quieter. For a Solid State unit, it’s quite warm and sweet! Unfortunately, it’s MC only. It’s a PERFECT match for the 0.4mV models. It still works great with the medium output models like your Glider, but I find the Hagerman a bit more optimal at that level. I.e. I find the Benz Wood SM (0.9mV) better on the Trumpet MC, but the Wood L2 (0.4mV) is better on the PP-1.
The Rogue Ares Magnum and Herron VTPH-2A are also good options (Herron uses loading plugs, Ares uses DIP switches for loading), but I find them tonally brighter / leaner versus the above options. My preference is usually with the sweeter stages.
MC stages with a SUT front end are generally not going to be very flexible with loading (Rogue Ares being an exception to this), as their loading is usually dictated by 47K ohms divided by the square of the step-up ratio.
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I don’t want to appear ignorant but I’m not sure how the info you provided helps me in deciding what phono pre I should look for other than listening of course which really isn't an option when buying used. One with a 1k loading option or not?
@nicktheknife You will have to listen. Designers are not in the habit of letting you know whether they know what they are doing or not. My point was that 1K isn't needed if the phono section is properly designed; the industry stock standard of 47K should be fine.
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@atmasphere
Thanks for your response and patience. I'm not as technically knowledgeable as someone as yourself but it's nice to soak up as much info as possible.
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@mulveling
I'll look into some of your suggestions. I think I mentioned earlier that I had a Hagerman Piccolo that I built from a kit. I liked it very much and wish I still had it.
I also took pride in the fact that I built it and could put quality parts into it.
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Before breaking my Glider, I recall loading to 1000 ohms made the cartridge "less hot" (as a friend described it). I had forgotten that my then Pass Labs Ono had loading options was it was like getting a free upgrade! My Clearaudio Discovery wound up at about 400 ohms. Then I got a Atmasphere preamp and in short order had the terminals installed to allow loading. I don't recall there really being a sonic difference when I did and about a year or so ago I removed them altogether and thusly defaulting to the 47,000 ohm standard. I want to say the sound is a little "more open" but won't swear to it. I'm certainly no worse for it and if anything, another "thing" has been removed from the path which is always good, IMO. Perhaps Ralph is correct about it not making a difference in his preamp. By all means experiment, but don't be afraid to try no loading at all.
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Perhaps Ralph is correct about it not making a difference in his preamp.
@voolston You can imagine that if I'm aware of this issue facing all phono sections that we would make an effort to see to it that our phono section didn't have a loading problem...
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@atmasphere
For sure! I used the word "perhaps" because I'm in no position to judge such things. You seem to be alone in your thoughts on this and good on you not to persuade folks to use loading of a cartridge to make your phono stage sound good, rather, letting it stand on the design merits alone. Of course, I see why you have made loading a possibility because some folks probably are just conditioned to or insist on doing it.
Question - any benefit of having the loading terminal option removed from my MP-3? Might its existence allow for noise?
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@atmasphere,
I borrowed a friend's Parasound JC3 Jr. Already it made my analog rig with the Glider sound much better and it doesn't have a provision for 1K loading. 50- 550 or 47k for MC cartridges. I'm using 47k at the moment and it sounds great so I'm beginning to understand what you were saying about a well designed phono stage and the 1k loading option not needed.
I don't know if the JC3 Jr. is considered well designed but it sounds pretty good from where I'm sitting.
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Question - any benefit of having the loading terminal option removed from my MP-3? Might its existence allow for noise?
No- it can act as an antenna for RFI, but the input of the MP-3 is built to reject RFI.
I borrowed a friend's Parasound JC3 Jr. Already it made my analog rig with the Glider sound much better and it doesn't have a provision for 1K loading.
@nicktheknife That preamp is designed by John Curl, who knows what he's doing 😁
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