Audiolics Anonymous Chapter 13
Phono Stages
Article by Bill Gaw

  Hello, fellow Audiolics, welcome to another meeting of Audiolics Anonymous. Today, we’ll be discussing a technology which most of those 30 or younger may never  have heard, i.e., vinyl records. Those old black discs you young whippersnappers look at  as something from the dark ages, in a good playback system, will still sound better  than CD’s in the best of systems. Yes, there are the pops and clicks, surface hiss, and the background tape hiss, but the sound that comes out is still superior to the best CD’s, and much closer to the original sound from the master analog tapes, than that from CD’s derived from the same masters. And the sound of CD’s derived from analog tapes is also superior to that from digital tapes. And remember, Perfect Sound Forever crowd, the masters of the recording world are now letting you know that that BIG LIE was just that, with their push for the new SACD and Audio DVD standards. The original 16/44 standard was picked not for the beauty of reproduction, but because that was the best that could be done back in the early 80’s with the chips and lasers of the time, and still be able to be transcribed to a disc that was easily transportable. Except for possibly SACD, which I haven’t heard yet, analog tape still beats the best digital systems, and the vinyl record is superior to the CD for reproducing those masters in the home. I have to agree that it can be more of a pain in the butt to obtain the best sound from vinyl compared to digital, but the result is definitely worth it.

Analog Playback

What does one  need for analog playback?

First, the records. Compared to CD’s price of 10-20$ per, one can easily obtain some of the best old vinyl for  0.50-1.00$ per  at used record stores, yard sales, flea markets, etc. I recently picked up a collection of about 100 Boston Pops records for $40, almost all played only once or twice, all in excellent condition and sounding wonderful. And the best new vinyl cost about the same as the best CD’s, although here, one may not be able to get everything new on this ancient medium.

Second, a record cleaner. This is a necessity, as vinyl does attract dust, which gives records the bad reputation of sounding noisy. But when properly cleaned, if the recording wasn’t played in the past using a chisel instead of a needle, they will sound amazingly quiet. I have had a VPI record cleaner which I purchased 18 years ago for $350, still costs around $450 today, and except for a motor change it has done its job faithfully. It is the oldest piece of equipment that I own, and I wouldn’t part with it.

When first received, each record is washed with a mixture of 90% distilled water, 10% isopropyl alcohol, vacuumed, followed by a second wash with DISC DOKTOR record cleaner and vacuuming. This solution cleans, kills mold that is growing in the grooves, and preserves the disc. Then each disc is treated with GRUV GLIDE anti-static spray, which cuts down on ticks and pops from areas of static electricity that build up on the surface of the recordings. These treatments are a one time deal if the records are kept in clean sleeves. While this sounds like a lot of work, it is no more tedious than the washing, carving and degaussing that has to be done to every CD for best sound.

Third, the turntable and tonearm. This is the platform on which the record is spun, and its main job is to keep as constant a speed as possible,  carry away reverberations from the mechanical interface of the record with needle, suppress external vibrations from the surroundings, act as a support for the tonearm,  without adding extraneous noise in the form of bearing chatter. The tonearm holds the cartridge with its stylus and needle in such a way as to allow it to track the grooves of the record to obtain as much information as possible without adding distortion. One can pay anywhere from $350 up to $72,000 for one, with even the cheapest outperforming equally priced CD players. Over the years I have had a Garrard, AR, Gem, Merrill, and Sota turntables with various tonearms, including those supplied with the turntables, a Morch, ET and Graham, and all have given sound I have been happy with until the urge for change occurred, and all of which I have tweaked to my hearts content. I have finally settled on the WALKER PROSCENIUM air bearing turntable and straight tracking arm with which I am obtaining sound which is very close to the second generation master tapes I used to play through an Ampex 350 tape deck.

Fourth, the cartridge. This is the transducer that changes the mechanical vibrations of the needle induced by its traveling through the groove, into electrical energy. This is the place at which the most distortion can occur in the typical system. The needle must track the groove as closely as possible, the stylus must transmit that information without change, and the coils and magnets, forming an AC generator, must change that mechanical into electrical energy so that it can be transmitted as cleanly as possible. Next month’s column will discuss this part of the chain.

Which finally brings us
to this month’s discussion:

Fifth, the phono stage. This unit has two functions. First, it acts as a voltage amplifier to raise the micro and millivolts from the cartridge into volts to supply the later amplifying stages, hopefully without adding too much noise to the signal. Second, it acts as a reverse equalizer for the RIAA curve. What is that you might ask?

All of the music information is recorded as hills and valleys of differing width and depth in the vinyl groove. The needle on the cartridge must  track through these grooves without gouging into or jumping away from the walls. There are three limiting factors which interact to determine how well this interaction produces the music. First, the noise floor- the inherent noise that an unmodulated groove imparts to the cartridge, which gives the lowest level of signal information. Second the maximum movement that the cartridge can track before the G forces drive the needle to leave the track. Third, the fact that there is far more energy in low compared to high frequency information both in total amount in the music itself, and second in the relative mechanical motion in the groove necessary to record that information. The sum total of these give the maximum differences between the quietest and loudest sounds that can be recorded without too much distortion occurring. In order to maximize the amount of information which can be used, the signal is equalized in the recording chain to increase the high frequency information to bring it above the noise floor, and decrease the low frequency information to decrease the maximum groove modulations. The phono stage then has to reverse this equalization to get back to the original signal. Prior to the mid 50’s, each record company did this differently until the RIAA finalized a standard which is still in use today.

The phono stage has the most difficult job of  the electronic reproduction chain in amplifying and equalizing the signal without adding electronic noise and distortion. I have had many of these in the past, including tube units from Luminescence, and NYAL, and three from Perfectionist Audio Components, and solid state units from Curl, Benz, and PS Audio, and each worked very well, but with each having some minor problem. I finally had Alan Wright from Munich, Germany, www.VacuumState.com, build  me a phono stage, based on his balanced tube-solid state design, which has all of the characteristics which I have found important:

1. Adjustable gain of about 40 to 60 dB. Easier to use different cartridges of varying output.

2. Ultra quiet. Even with very low output moving coil cartridges of 0.2-0.3 mV., no noise can be discerned at the speakers with the preamp set at high gain. S/N ratio of greater than 96 dB.

3. Extremely flat RIAA equalization. This unit is flat on a scope out to beyond 100kHz.

4. Balanced input and output, so that it is very easy to reverse absolute polarity.

5. Low distortion.

6. Neutral. Neither tubby-tubey, or steely solid state.

7. Fills in all of the spaces. Unlike digital, the best analog will reproduce the feeling of space between and around the instruments, and the feeling of space in the hall. The room becomes pressurized when the needle hits the groove, just like in the  concert hall. This is the low level information which is always around us, and is sorely missed with 16/44 digital.

The Wright preamp is the only one which I have heard which does all of these things well. Which brings us up to my component of the month:

Camelot Technology Lancelot Pro

One of the few pieces of equipment that I fondly look back on that I should never have sold, was my John Curl SCP-2 solid state phono stage. This was a wonderful piece of equipment, which gave me almost all of the qualities of the Wright unit, except for a slight decrease in the space thing. Shortly after I bought the unit, John’s house and lab were destroyed in one of those California brush fires. Unhappily, he never put the units back in production, and he had difficulty repairing them, so I sold mine. But I can still remember  the beauty of the image which it presented. Of course, they were very expensive, costing $3000 in late 80’s dollars.

Enter the LANCELOT PRO. This is a dual mono solid state phono preamplifier produced by Mel Schilling of CAMELOT TECHNOLOGY, www.camelot-tech.com, E-MAIL: mas@camelot-tech.com. It uses their CHARM II battery based power supply which gives a pure very well regulated, low impedance DC current to the separate phono unit. The phono unit, designed by Doug Goldberg, consists of two very small chassis attached together by a front and back face plate. Each unit contains a compact circuit board with separate moving coil and magnet inputs with an external switch for each, and one single ended RCA output. Dip switches inside the unit can adjust the input capacitance from 50 to 350 pF, and resistance from 47 to 68 K for moving magnet cartridges, and  the DC impedance of moving coils from 10 to 47K ohms by replacement of the included metal film resistors. The unit is beautifully constructed, and compact, and, weighing only a few ounces, light enough to place right next to or on your turntable. This allows one to attach it directly to your tonearm wires, thus possibly getting rid of one set of interconnects. This is a major advantage as the signal coming from the cartridge is very fragile, in the millivolt range, and an interconnect between the arm and preamp always affects the sound negatively.

The Charm II power supply was originally designed by Bob Whitney for the ARTHUR v3.0 D/A CONVERTER, and can be used to power both units. The unit takes about 12-15 hours to take a full charge, and then is able to power the phono stage on batteries for about 12 hours. While I only listened to the unit for a maximum of 8 hours once, it didn’t run out of steam during that time. The power supply can be placed about two feet away from the phono stage, thus isolating the phono from line noise, and is connected by two DIN type cables.  The price for both units is $995, and the CHARM II unit can be bought separately for $699, a true bargain, and maybe a steal. I’m surprised Sam Tellig hasn’t written it up yet. Throw in the Arthur, at $699, and for under $1600, you can have both digital and analog reproduction.

You may ask, why I spent some time discussing the Curl phono stage in the lead up.  Well, this unit comes extremely close to the Curl in all except one parameter, and at a fraction of the cost, as used Curl’s, when  you can find them, still go for $2500 plus. Used with the Crown Jewel, Lyra  Helikon, and Clearaudio Insider, the unit was dead silent, even with my super high efficient horns. There is no noise floor. While the designer says it has about 40 dB gain for MC, I would put that figure at closer to 48 dB. With the low impedance power supply, the unit’s major strength is extremely fast transients, with tight bass and clean highs. Sounds extend from ppp to ffff with no feeling that the unit is running out of steam. While digital is supposed to have 96dB S/N ratio, this unit makes analog sound like it has more. While the noise floor is already low, with analog, one can hear even lower level information below the noise floor, especially with the best cartridges. This phenomenon is similar to being able to pick out a soft voice in a crowded room. This is also the background information that makes one feel one is in a live space, rather than that anechoic feeling one gets from digital, unless a lot of dither is used.

The soundstage is clean and clear, meaning no veils are present between you and the music. Each instrument has its own space and appropriate size, and one can hear the spaces between the instruments. Little bits of information from the background come through. For instance, the  traffic outside of Symphony Hall in Boston can be heard on the right side of the hall, and the subways under Kingsway Hall can be heard to come in from different directions when the rear speakers are used in surround recovery mode.

Brass and percussion instruments sound especially life-like, so if you like jazz or rock, this unit is the one for you. On Jazz at the Pawnshop, the crowd takes on a life of its own, and one can hear conversations in the background.  And orchestral music is wonderful, with the best recordings almost sounding live over my system. There is a point on the Reiner Scheherazade fourth movement, about two to three minutes in, when the orchestra stops, and just before continuing, one can hear two voices I think in the cello section whisper something. One can only make this out in the best of equipment, and it comes through clearly with the Lancelot Pro. While the above fine nuances of background information may be considered distortions of the musical event by some, I think they add to the feeling of being there, and  go to show how good the Lancelot Pro is at presenting low level information.

Weaknesses? Compared to my Wright, there are two minor ones which this unit shares with all other solid state phono stages that I have heard. First, the space between the instruments lack that last degree of air pressure that one feels in the concert hall. There is no absolute silence between and around instruments, except in an anechoic chamber, although digital sometimes sounds like that. But like the Curl, this unit comes very close to the best tube units in preserving the feeling of space. And remember, if you have Alan build his phono stage separately, it would probably cost several times the price of the Lancelot.

Second, the massed strings on orchestrals have the faintest twinge of steeliness, but no where near as much as with the best CD’s. As I only got to use the unit for about 100 hours, it is possible that as it breaks in this minor problem will disappear.

Remember, I’m comparing this unit to ones costing several times as much. If I didn’t have the Wright unit, I would buy this one on the spot, as it is the second or third best phono stage that I’ve heard. And for someone just getting into analog, or presently using a receiver or preamp with a cheap built in phono stage, this unit will get you very close to the best. And remember, the CharmII is also the power supply for the Arthur v 3.0 D/A converter. Again, at this price the unit is a STEAL.

Next month, I’ll be reviewing the above three mentioned cartridges. Boy, I wish I hadn’t gotten into this one. Do you know what it’s like, trying to set up and alternate between three cartridges, even with an arm that is fairly easy to work with. It is probably the most difficult review to do, definitely worse than testing interconnects.. Maybe after this one, I’ll go back to just writing up tweaks, like I’m supposed to. Oh well, what we’ll do and sacrifice for our hobby. Till next time, Adios.