How important is ext. adj. for cartridge loading

Hello Folks,

A New Phono Preamplifier will soon be introduced - MSRP around $1750 - $2000

A small "focus group" questionnaire - On a Phono Preamplifier how important is it to you that MC cartridge loading is adjustable from the front panel of the amplifier? How often do you "fiddle" around with loading ? Enough to warrant the cost increase, probably about $200 for the additional switches faceplate machining etc. pricing the preamp towards the higher end of projected price?

Same goes for MM/MC switching Would external selection be preferable to a internal Jumper setting ?

Is a MUTE function desirable on the front panel as well?

MC loading is at 100, 220, 330, 500 Ohms and 47K Ohms, do you think these are OK or would you like other values?

We have designed the unit so it can be used as a fully differential unit as well with one balanced input and one balanced output, you'd need two of them for stereo, do you find this desirable? Would you prefer this mode of operation to be selectable from the outside (switch on back) or would internal jumper selection be enough?

Thanks in advance for your thought on these questions

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Hi Peter-
I pretty much agree w Viridian.
Front panel switchable loading for MC would be great.
If X-former MC, then I would recommend post for easily
insertable resistors to set loading precisely.
Internal jumper for balanced/SE (or maybe rear panel
toggle switch)
I personally do not need nor do I envision needing 2 or
more phono inputs, but a rear panel switch for
mm/mc OR separate input jacks for mm and mc is good.
Hopefully we have not blown the budget ;~)

At that price point I would prefer the money invested in higher quality piece parts. However front panel or even remote control adjustable loading is becoming de rigueur at higher price point(e.g. Manley and ARC Ref phono.)

For MM/MI consider load options 47K>100K. These higher-than-spec values can sound much better with some MM-- and very few if any manufacturers understand this.


Front-panel switching would be a huge influence for me to buy the preamp. Worth the price difference. If I had several candidates that were otherwise nearly equal, this would swing your unit into favor, for sure.

I'd also scrap the balanced option and replace it with multiple gain settings instead of just mm/mc switching.

One suggestion: Do a search of the various analog forums for "Mono." See all those posts? Put a mono switch on it instead of the mute. Mono shall rise again!


I would like 1k loading and a mute switch on the front. The rest are conveniences and at this price point I'd rather have higher quality parts for the small hassle of rear or internal adjustments.
100R, 1K, 47K, 100K resistive loading, switchable from the front or rear panel. There is really not much difference in sound for loads between 100R and 1k, IMO. You could add 10K, if space permitted.
Switchable capacitative loading would be nice too, for MMs. For example, zero, 100pF, 250pF.
Switchable phono gain, between, e.g., 40 to 50db and 58 to 65db, would be icing on the cake.
Avaliable MM Loading of 20K, 47K, and 100K. These would realy set this unit apart for those with HOMC, MM, and MI. Rear switch for the MM to MC would be best as previously noted. External access, front or back, for all adjustments since many individuals change cartridges often and opening the unit for each change may not desirable. Ultimatly quality components over all these convenience choices.
Mono Switch, even on the back, would be a great feature.

Not that I listen to that many true mono records, but there are a large number of early stereo rock and jazz records with horrible L-R pan that sound great in mono.

I would have preference for exterior loading but putting them in the rear is fine if that is cheaper.
As a middle ground option, consider switching on PCB via in-line micro-toggle switches as per BAT VKP10. This is more convenient than jumpers and keeps the signal path short, albeit degraded by switch contacts.
I have the ARC SP-15. It has front panel switchable impedance loading. It is a nice convenience having it there, but the only time I turn that knob is when I change cartridges. Once the cartridge loading is dialed in, no need to change it. I fiddled with cartridge loading years ago, but each cartridge has an optimum setting and just doesn't sound right when using other values- at least to me. I'd say it is desirable and a priority to have an easily adjustable knob. It is a secondary priority to have it on the front panel vs. the rear panel. The rear panel would be kind of a pain, but still better than soldering in resistors.
Thanks for your insightful answers - please keep them coming.

A few questions was raised - Ill try to answer them

Reason for rise in cost for adjustable selectors is of course cost of parts and the time it takes to install them - A 3/8 " Aluminum faceplate with holes etc for knobs switches cost more than a blank one because of increased machining time etc. they are made with a CNC Mill.

The unit is to be produced "in house" like all our other products and deliberately targeted to a lower price point than our Olympia Amplifiers, but of course with technology influence from them.

This is not a "Hollow State" Amplifier but a Solid State amplifier. Active devices are all FET devices - input is based upon the Toshiba 2SJ74 and its mate the 2SK170. Output is the Hitachi 2SJ79/2SK216. It's a 2 amplifier approach with the first amp having 20 or 40dB of gain depending on feedback resistor setting (MM/MC). The second amp have 24dB of gain at 1kHz and active bass boost to RIAA standards. A R/C network between the two amps provides the RIAA roll off.

Gain is set at 44dB MM and 64dB MC, as a mono block gain is 50dB and 70dB respectively.

The Amplifier is set up in Dual Mono configuration with two identical channels each with their own power transformer, on board discrete DC power regulators etc. Parts quality is very high, Dale RN60D 1% Metal film resistors throughout, Nichicon UHE series capacitors, 1% Panasonic Polypropylene film capacitors Etc.

Regarding Mono - The admittedly few Mono carts I've experienced have all had two outputs so using them with a Stereo amp was straight forward.

I have cosen only one Capacitive loading 220pF but it can be disconnected with a internal jumper making it "zero" , maybe 100pF could be added as well.

Input for several Turn Tables is a good idea - but I feel that adding a switch in series (which is how it would have to be accomplished) with the very low signal form the cartridge is not advisable.

Thanks again for your valuable input it is greatly appreciated.

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Just my thoughts. An Aesthetix Rhea meets my needs almost perfectly. The "almost" is due to absence of a mono switch on both my phonostage and linestage.

Essential to me are:
* multiple inputs (preferably 3, at least 2)
* variable loading
* variable gain (My "standard" settings are 38dB MM and 56dB MC)

Front-panel access is not that important, tho I confess that being able to do everything from the remote is a nice convenience.
Front panel loading is certainly nice and allows you to adjust on the fly to improve the sound of any given record. Rear panel RCA plugs are a bit less friendly, but still allow an easy enough adjustment. Pulling the top and replacing a resistor sucks.
I have never had it, have recently sold a Blue Circle which had rear panel RCA plugs and a Dynavector 75 which had internal switching which my aging eyes had fits with. Currently using a MF Kw phono stage with back panel RCA plug ins. I find these satisfactory, they have the advantage of you being able to customize loading plugs, but if good quality parts were used and the price increase was in the order of $200 or less I think many would be willing to pay for the connivence and quick comparison ability of front panel switching.
Just to clarify, my desire for a mono switch is not for running a mono cart but for playback of stereo LPs (early stereo late 50s - mid 60s) that sound better in mono. Like Dopogue I lack this on my phono and line stages.

In general replacing resistors and moving jumpers sucks, micro-toggle switches at a minimum if you go internal for the settings.
A MONO switch also reduces surface noise greatly when using a stereo cart on mono records.

For the loading options, I find flexibility more important than convenience. The phono board in my BAT has plugs to allow me to use any resistors I want for loading.
Years ago (25 yrs. ago) when I bought my first really good preamp I had a PS Audio IVH. Remember the resistors you placed a certain value into the sockets to tailor the sound of the cartridge you were using. That was a very useful feature. It was my first time being exposed to it. I remember setting the loading on my Talisman S MC cartridge and It embarrased many more expensive cartridges during that time. I have had several other preamps over the years with and without loading cababilites and I did not have that success. I prefer some degree of
control or loading when using different cartridges. Some settings will brighten your sound and some would flaten your sound but there would always be a setting that was neutral and the sound simply played music perfectly.

So at least 60 db of gain, cartridge loading and cable resistance is important to me.
DB Audio makes a box that does just this at a very reasonable price. It was featured in one of the major stereo magazines this year I think Stereophile. Just my little old opinion.
Hello Folks

Seems like a LOT of features are wanted, so if we made the Phono Preamp with 5 adjustments/ selectors on the front panel as follows

1. Mute / Operate / Mono

2. Impedance 25, 50, 100, 500, 1K, 10K, 22K, 33K, 47K, 100KOhms

3. Capacitive Load 0, 50, 100, 150, 220, 330pF

4. Gain 40, 44, 48, 60, 64, 68dB

5. Input 1 / 2

Would that meet most folks requirements - and would a $2500 price point make you vote for it with your pocket book too ?

Peter, I'm happy with my Rhea, but that sure sounds like an attractive phonostage. Dave
You seem to have covered all requests and indicated what they would cost. IMHO the real question is your last one stated i.e. the pocket book vote. Going back to your original high quality sound minimal extras may actually target a buying segment better than catering to all wishes. Possible RCA plug loading options for the back, MM/MC switch, and internal capacitance or a set single capacitance and just focus on the sound. The sound quality is what will be talked about and shared, leading ultimately to us parting with what is in our pocket books.
If the preamp included all the features mentioned in you last post, then, yes, I would seriously consider buying it. Sounds too good to be true, yet I'd want a 75K impedance setting.
05-11-10: Pbnaudio
Hello Folks

Seems like a LOT of features are wanted, so if we made the Phono Preamp with 5 adjustments/ selectors on the front panel as follows

1. Mute / Operate / Mono

2. Impedance 25, 50, 100, 500, 1K, 10K, 22K, 33K, 47K, 100KOhms

3. Capacitive Load 0, 50, 100, 150, 220, 330pF

4. Gain 40, 44, 48, 60, 64, 68dB

5. Input 1 / 2

Would that meet most folks requirements - and would a $2500 price point make you vote for it with your pocket book too ?

Man did I ever get ripped off!! My phono stage cost more than twice your suggested price and the only front panel selector/adjustment is a stinkin' Mute/Operate button.......DAMN!!!

Seriously though, it does sound intriguing, good luck Peter.

This is a great post. Thanks to Pbnaudio for coming to the forum to ask.
Above and beyond everything is sound. Not too long ago I switched to a 30yr old headamp and phono stage where the mfr moved heaven and earth to reduce EMI within the circuitry with exotic materials and manufacturing techniques used (call it super-tweaking). The results are blatantly obvious. That is what I want in a stage. The rest is something I'll deal with somehow. But, as that stage/headamp combo has 1, 2, 3, 4 on the list, the only one I am missing is multiple inputs. I wish I had that.

My commentary would be as follows:

1. Mute/Operate/Mono
Mono good, but then it begs the question if it is real mono or faked mono of a stereo cart. If real mono, it might be better placed in #5 (i.e. Input1, Input2, InputMono). I don't need a mute on a phono stage. If it is 'fake mono', this could be a button/switch next to your input selector (out/in (or up/down) = stereo/mono).

2. Impedance. Lots of choice is great but with so many choices, you'd need a bigger knob. Don't ignore the low end of impedance. I have a couple of carts with <2ohm internal impedance and one cart I lust after has internal impedance below 1ohm.

3. Capacitive Load
My gut is you don't need that granularity but if it costs nothing to get it, go for it.

4. Gain
Everyone will have a volume knob so no need to go overboard. I would think 2 should be fine, 3 would be a luxury, 6 choices is overboard.

5. Input 1 / 2
My preference would be for 3 inputs plus a mono input (real mono).

6/7 If you do real mono, I would suggest doing turnover/rolloff points to provide equalization curves. Maybe that is a special version with a different faceplate and you charge an extra amount for real mono with different equalization curves - if layout was designed right, it would not be a difficult add-in I expect so could be upgraded later, or be added in as a 'module' when building it, tacking on a different, more expensive faceplate. Some would want it, some would not. Those who would want it don't have many commercially available choices at the high end.

The real problem with all of this is that it means lots of switches/connections in the circuit. An input switch is probably the worst offender so has to be the best quality.

As to price... as long as it is the quietest thing on the road, there would be plenty of buyers at that price.
If you have a mono cart with a single RCA output on the leads and you run this into one channel of the input then select the 'Mono' switch that sums the signal and sends it to both channels gain stages...isn't that 'real mono'?

I guess I want fake mono for my stereo cart, but seems like that is compatible with a true mono cart.

At the $2500 level for a phono stage I want something that will grow with me through different, having all the flexibility to make it work in different systems would help justify the cost.
Good question. Will the circuit which expects a stereo signal be OK with one RCA? Maybe I am overlooking something simple...
Hello Folks

A MONO selector would be implemented as a 4 position switch as follows 1, 1MONO, 2, and 2MONO, all it would do is feeding the input to both channels of the amplifier.

I have taken all the great suggestions into consideration an am working on the additional switching arrangements, it will be made as an additional circuit card mounted on the inside front of the amplifier to reduce internal wiring.

As it stands currently the selector choices will be as in prior posting, I have chosen the very high quality US made Grayhill Series 71 for switching. Im awaiting samples from Grayhill of these custom made switches, of which there will be 3 different configurations needed to implement the requested features.

One last question - any one interested in BETA testing of the amplifier once we have a ready to ship unit, you will of course be required to return the unit along with a detailed report of you impressions :-)

Let me know

Some form of loading options, whether front panel or not, is helpful. As far as convenience is concerned, switching by remote control is the best because you can make an instantaneous comparison (my Levinson No. 32 preamp allowed such change, the unit I currently use does not).

However, a switch of any kind is always less than ideal, even when it comes to loading. Companies, like Artemis, offer an internal spot to insert the chosen resistor which is then securely clamped. This is really NOT cheaper than a selector switch, but, it is better for the sound.

My current phonostage (Viva Fono) has no provision for loading change. What I have to do is open the chassis and very carefully solder in a resistor between the hot and ground at the back of the RCA jack (an area full of hair thin wires). This approach means I am loading on the primary side of the step up transformer. I suppose this is done for sound quality reasons; at this price level, I doubt that the lack of convenient switching is a cost saving measure. I have made my own external load resistors using radio shack resistors and RCA jacks to test different loading. When I find what works, I can then hardwire in better quality resistors and remove the extra jack.

I like the loading options offered in the new model described by the original poster-- 100, 220, 330, 500 and 47,000. It is more important to have smaller incremental steps near the most useful part of the range wich is around 100 ohms. Ideally there would be more choices in that range, such as 125 or 150, and maybe something near 1,000.
T bone, shoot me an email with your address and I will ship you a unit once we have one ready

I would be up for Beta testing as I am actually looking for a new phono stage at the moment and having a mono option is one of criteria.
Hi Nick

Shoot me an email with your ship to address as well and yo can be part of the group too