Poll

MC preamps and power supplies that I would buy. See features and pricing at bottom of article

I already have a MC cartridge and preamp
8 (28.6%)
I am considering converting to MC and need a preamp
2 (7.1%)
RM-401
6 (21.4%)
RM-402
0 (0%)
RM-403
3 (10.7%)
RM-411
6 (21.4%)
RM-412
0 (0%)
RM-413
3 (10.7%)
RM-414
0 (0%)

Total Members Voted: 14

MC Transformers, Headamps and Cartridges

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Roger A. Modjeski

MC Transformers, Headamps and Cartridges
« on: 3 May 2012, 04:52 pm »
The recent explosion in vinyl interest has spawned a number new vinyl products and internet/mail order catalogs of hundreds of pages. Needle Doctor had 9 color pages in the May 2012 Stereophile. The 2012 Music Direct catalog is 208 pages, 133 of which are equipment/accessories. There are 75 pages of music, fifty of which are vinyl. Cartridge prices approach the cost of a small car.

In the past week I have spoken with several retailers and distributors. There are dozens of MC step-up devices and complete phono stages. Prices run the gamut from a few hundered dollars to over $15,000. Cartridges do about the same with the Dynavector DRT XV-1T at $9,250. I have no idea what sonic improvement one gets for $9,250. I do think that MC cartridges have a lot to offer over moving magnet (most of which are actually moving iron, variable reluctance transducers). I've had a Denon 103 for many years and I can recommend the Denon line as good sounding, robust cartridges that won't let you down.

The technical virtues of Moving Coil are many. They tend to have flatter output when properly loaded. They have less moving mass. The cantilever is better supported and it's far end is tied to the cartridge body as opposed to a slide-in stylus. Theoretically they are better able to handle stylus displacement due to warps or eccentricity as the coil output is not influenced by position as much as in a reluctance cartridge. I have not seen much on this last characteristic and would be interested if readers have any articles on this.

Although several of the people I spoke with encourage me to make a very expensive complete phono stage, which I will eventually do, I presume that many of you have a preamp with a good phono stage and that all you need is a step-up device to make the upgrade to MC. A quiet step-up can make a noisy phono preamp have less overall noise as it puts a lower noise front end ahead of the not so quiet 12AX7 we find in many preamps. As we all know, its the first stage that determines the overall signal to noise. Even the very quiet RM-5 with it's 6922 input tube can be improved more than 3 dB with my headamp. In addition, the selection of tubes for the RIAA section in the existing preamp is relaxed by the 20+ dB gain of the head-amp. This is also applicable to phono stages that are noisy with standard output cartridges.

Although there are many step-up transformers available, it appears to me that they defeat one of the main virtues of a MC cartridge, the fact that there is no flux-varient iron in the signal path. A transformer, no matter how good, re-introduces iron and all it's problems of magnetizing current, core loss and copper loss. The output from a MC cartridge is very small yet it will be asked to drive a transformer with many times it's weight in iron and copper.

The alternative step-up device is a head-amp or pre-preamp. The RM-4 head amp I designed in 1980 did that function in a simple all tube amplifier with adjustable gain and loading. It was very popular and we sold over 600 of them in just a few years... till CDs came on the scene and vinyl took a nose dive. Now that vinyl is back with even more MC cartridges choices than before, it's time for a new head-amp.

Although there are a number of tube head-amps and complete MC phono stages there is only one to my knowledge that are all tube with no input tranformer. These new entrants to the field use a transformer to get the signal above the noise of the tube. They often employ a 12AX7 which is the wrong tube for a low noise stage. The Fosgate has a 6922 input, however it is about 10 dB higher in noise than my parallel 6922 input stage. It sells for $2,500 and is made in China.

After 34 years of using the 6DJ8/6922 tube I have developed a line of 6922 head-amps that are an improvement over the RM-4. A-weighted noise is typically 3 dB lower due to better tubes and a remote power supply. It was not possible to get the last bit of hum out of the RM-4 with the transformer in the box. Now the power supply is separate and done in a wholly different way. For the ultimate in low noise and black background there is a rechargeable battery power supply. There is also a line operated supply with improved filament regulation and a new type of B+ supply which replaces the high-feedback series regulator with something better.

There are many ways to package these products. It is clear that cosmetics have become more than half the price of high-end products these days. Although my dealers want my equipment to follow that model I still believe that a discerning audiophile might still consider sonic value over cosmetics. These new designs run very cool and can be packaged in everything from nice plastic chassis (our plastic "pot in a box" at $135, outsells the metal version at $450 by ten to one).

Here is the tentative line-up. All have separate power supplies and use two SLN 6922 tubes. All parts are high quality, gold jacks, spring loaded, shielded tubes out the back for easy replacement.

I have used Neal Feay Company here in Santa Barbara since Harold Beveridge introduced me to the founder and his son in 1978. Alex Rasmussen, the grandson of the founder, has made significant contributions to the appearance of high-end audio metal work for companies like Aesthetix, BAT, Conrad Johnson, Class A, Constellation Audio and many others. However this level of metal work comes at a rather high cost. I have opted to keep my metal work simple yet of their high quality finish. I am open to your comments

Amplifier units:

RM-401  High impact, textured plastic, shielded box with loading via RCA plugs. Gain 10,20 or 26 db. Gold jacks.

RM-402  Metal chassis with 3/8" Anodized Aluminum front, 17" x 7" x 3.5" chassis with 12 position front panel loading can be changed on the fly to tune cartridge for records that might be too bright or a bit worn.

RM-403  Complete MM/MC phono stage in metal chassis as above, six 6922 tubes 12 position front panel loading and 6 position gain. Second phono input available at extra cost.

Power supplies: 1 meter umbilical cord detaches on preamp end. IEC power inlet, Power switch and indicator. No AC sent to preamp unit.

RM-411 Plastic box matches RM-401. Contains very low noise 12 volt power supply with my High Voltage converter.

RM-412 Metal box matches RM-402. Similar to RM-411 but in metal box with larger capacitors, torroidal mains transformer, separate left and right power supplies.

RM-413 Plastic box matches RM-401 has 12 volt DC input and is powered by battery and charger of your choice. Same power scheme as RM 411 you supply the 12 volt power.

RM-414 Metal box matches RM-402 with 12 volt, rechargeable battery and charger all enclosed in chassis. Will play 10 hours on a charge. Front panel switch completely disconnects unit from AC line or allows play while charging. Battery management circuit prevents complete discharge of battery if left on inadvertently.

Tentative pricing. The plastic cased units are priced for direct sales. The metal units are dealer/distributor/export priced. My foreign distributors have no interest in low cost products.  Perhaps there can be special offers on the metal units to Audio Circle members as I have done with the RM-10 and RM-200 in the past. Balancing internet and dealer sales and pricing is not an easy task.

Amplifier Units:

RM-401 $450
RM-402 $1500
RM-403 $3000

Power supplies:

RM-411 $350
RM-412 $1400
RM-413 $275
Rm-414 $1900

The real deal for the person interested in sonic value is the RM-401/411 combination for $800. Less expensive, lower noise and better sounding than the original RM-4.

Prices are tentative and may change.
« Last Edit: 4 May 2012, 03:44 pm by Roger A. Modjeski »

Ericus Rex

Re: MC Transformers, Headamps and Cartridges
« Reply #1 on: 4 May 2012, 12:18 am »
I thought a lot about this poll this afternoon.  Here are my thoughts.  These days, you have to have a solid looking piece of equipment in addition to having a great sounding piece.  Gone are the days of the simpler, rack mounted style chassis.  Most people are willing to pay more, even much more, for the solid look.  Additionally, I see the headamp only version as having limited appeal these days.  Since more and more preamps are line-stage only I think you'd have more succes with the 403 than with the 402.  But you will have a few who already have a good MM stage and need a head amp.  So I think offering the 401 direct only might be good for those customers.  As for power supplies, since the PS must be as far as possible from the preamp to limit the noise possibility, it will probably get stuck behind the rack on the floor somewhere.  No need to make a fancy metal power supply.  I like the idea of offering both an AC and DC version of the power supply for different folks.  Maybe a cheaper style metal box (instead of a metal box matching the 402/403) could be supplied.  Nothing fancy, just a little better match with the 403 than plastic?

My two cents.

Clio09

Re: MC Transformers, Headamps and Cartridges
« Reply #2 on: 4 May 2012, 03:21 pm »
I would agree with Ericus Rex for the most part. To take it a little further, being on the manufacturing side now I think most audiophiles prefer eye candy at times to great sound. The attitude of, "if it looks great and costs a lot it must sound great." Some of us know better and designers like yourself don't buy into that type of mentality and are a straight shooter when it comes to promoting your products and services.

For me personally I have been seeking a product like 403. However, since I am trying to put together a primarily vinyl system, I am being really picky. Two major things I require are a built in volume control (dual mono or using a well implemented balance control) and a differential balanced design so the unit should have balanced outputs. The only ones on the market I have seen so far that accomplish this that I may be remotely interested in are the Manley Steelhead and the K&K Audio Maxxed Out unit. I would prefer the latter because the volume control is a passive design and I am a big proponent of passive preamps. I do not think the Manley units volume control is passive. My only other option would be an Atma-Sphere full function preamp. This is something I would consider, since as one option I would be mating this phono stage to an Atma-Sphere amp. Of course I own an EM-7 12v and RM-10 MkII so in the end maybe single ended is the way to go. I guess this is what the decision boils down to for me.

I can source my own fancy chassis and have a great woodworker who has done some nice work for us to spruce up our products. Any chance you would offer a product for those that would want to drop it in our own chassis? Single ended would be fine if balanced is not something you would consider doing.

jtwrace

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Re: MC Transformers, Headamps and Cartridges
« Reply #3 on: 4 May 2012, 03:24 pm »
I have voted but could care less about the enclosure.  I can make fancy if I want.  Actually, I'd prefer to just purchase the module(s) anyway.

Roger A. Modjeski

Re: MC Transformers, Headamps and Cartridges
« Reply #4 on: 5 May 2012, 06:37 am »
I have voted but could care less about the enclosure.  I can make fancy if I want.  Actually, I'd prefer to just purchase the module(s) anyway.

That's great! I wish more people shared you view. I will soon have the High Voltage power supply modules available at $90. You will need one of those and a well regulated 12 Volt, 1 amp power supply or battery which will run the heaters and the HV supply.  I can supply the parts for the regulated 12 volt supply or you can make one using a 7812 regulator. As to the amplifier part, would you prefer to buy a kit of parts or one that is finished?

airhead

Re: MC Transformers, Headamps and Cartridges
« Reply #5 on: 9 May 2012, 06:00 am »
Personally i would rather have a single preamp that does everything--line stage, phono stage, and mc stage.  Every extra box means another set of interconnect cables to worry about, and another power cord to plug in.  I used to have a separate preamp and headlamp (mc stage), and replaced these with a single unit.  I later had to add a line level crossover, to add a subwoofer, which is a complication I have to live with. 

Ericus Rex

Re: MC Transformers, Headamps and Cartridges
« Reply #6 on: 9 May 2012, 12:06 pm »
That's great! I wish more people shared you view. I will soon have the High Voltage power supply modules available at $90. You will need one of those and a well regulated 12 Volt, 1 amp power supply or battery which will run the heaters and the HV supply.  I can supply the parts for the regulated 12 volt supply or you can make one using a 7812 regulator. As to the amplifier part, would you prefer to buy a kit of parts or one that is finished?


Music Reference Kits!    :o   That's an absolutely AWESOME idea!!!!

Clio09

Re: MC Transformers, Headamps and Cartridges
« Reply #7 on: 9 May 2012, 02:47 pm »
That's great! I wish more people shared you view. I will soon have the High Voltage power supply modules available at $90. You will need one of those and a well regulated 12 Volt, 1 amp power supply or battery which will run the heaters and the HV supply.  I can supply the parts for the regulated 12 volt supply or you can make one using a 7812 regulator. As to the amplifier part, would you prefer to buy a kit of parts or one that is finished?

Roger, if you haven't done so already you may wish to look at how Kevin Carter at K&K Audio packages his phono stage and other equipment kits. Everything from parts to fully assembled modules (with or without enclosure) to complete build. Here is a link to the phono stage section of his website:

http://kandkaudio.com/phonostage.html

I think it would be great if you could come up with a similar approach. as I mentioned earlier, for me taking completed modules and allowing them to be dropped into a chassis of my choice with only the last remnants of wiring things up would be of great interest.

ptmconsulting

Re: MC Transformers, Headamps and Cartridges
« Reply #8 on: 9 May 2012, 04:19 pm »
I personally like the head amp idea over step up transformers. I own a Hagerman Piccolo now and am mostly pleased with it. I see that as your primary competition if you are looking at a kit. It is also adjustable for gain and loading via switches/dials right on top (a very nice and necessary feature IMO).

The one thing I don't particulary like about the Piccolo is that it can get noisy when I turn things way up (a low volume record and very inefficient speakers make this necessary sometimes). It also allows for batteries or a 12V DC wallwart to power it. I would suggest either/both of these options as well as your improved power supply, but I also agree that these sit on the floor so looks are not important there. I do believe an inexpensive aluminum painted kit case for the primary circuit would be better than plastic though.

banquo446

Re: MC Transformers, Headamps and Cartridges
« Reply #9 on: 11 May 2012, 05:39 am »
For those like me who use MM carts, a capacitance loading knob would be heaven. For what it's worth, I couldn't care less about looks.

woodsyi

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Re: MC Transformers, Headamps and Cartridges
« Reply #10 on: 11 May 2012, 02:41 pm »
Unlike Jason, I can't do my fancy metal boxes.  Not only do I not have any tools or skills, I have no time.  So I voted for 403.  I already have the preamp that Roger alluded to and I really like it's performance.  The only down side is that all tubes inevitably means less than black background and I had to use balanced cable to eliminate a hum.  So I am interested in an all tube gain MC phonostage with a BPS and I don't necessarily need to display the PS.  So I voted 413.  I figure I can hook it up to a 120Ah Deep Cycle battery I have tucked away somewhere and be completely off the grid to avoid any  grounding issue.