Stand out phono stages


This topic has been started before by others and myself as well, maybe too many times, but it is worth revisiting since the source is so very important!
So far I have had the pleasure to enjoy two worthy phono stages: the EAR 834p and the JLTI.
I have to admit they are spectacular. Obviously the record and all the equipment downstream play a role in the sound heard. In some cases I prefer the JLTI and in other cases the EAR. But neither out do the other dramatically.
What phono preamps outshine others by a big margin, those that can be considered the last phono preamp ever needed.
pedrillo

Showing 5 responses by jcarr

Lew, Pat: In my view (and experience), the issue of cartridge loading primarily concerns what the phono stage can tolerate, and then as a lower priority what the cartridge would be most happy with. Put another way, what is commonly talked about as "cartridge loading" should probably more usefully thought of as "phono stage input termination."

To cut to the chase, the Connoisseur has been designed so that it is quite tolerant of loading across a broad range of cartridges - but the same is not necessarily true for other phono stages. With the Connoisseur, I happily run any of my own cartridge designs at 10kohm (used to be 47kohm) without feeling the slightest desire for heavier loading, but with most other phono stages, I find that something between 330~120ohms sounds better.

For a technical writeup as to why this can be so, please see Jim Hagerman's article at www.hagtech.com/loading.html. Some time back I wrote a much more detailed post on this same topic on Audiogon, and I wish that I could simply link to that, but I don't know how to find my own post! (^o^;)

cheers and hth, jonathan carr
Hi Lohanimal: I have used various models of the SP10 family, and in stock form they grab my respect but not my heart. Taking the controller boards out of the chassis can help (although shielding the cables may be required, along with implementing measures to ensure stability), and a redesigned motor controller will help matters more. My own preferences for modern reincarnation would be turntables with motors of the slotless or coreless pursuasion, such as the JVC TT-101, Lo-D TU-1000, Onkyo PX-100M, Pioneer P3a, Sony TT-8000, Yamaha GT-2000 (among others).

Given the small size of today's analog market compared to what it was in the 1980s, production volumes of such a modern DD turntable would be small enough that tooling such as stamping, casting, molding, forging etc. may or may not justify the capital investments (which would be high). And if projected production volumes didn't justify tooling, every component would need to be made individually via machining, optical etching, laser-cutting, water-cutting and so on. This wouldn't be cheap. Coming up with an elegant design is one challenge, but engineering it for efficient production is a completely different challenge nearly as difficult as coming up with the design in the first place.

>I genuinely believe that when big companies really 'went for it' some astonishing products that whilst not cheap, were still good value for money.

If Toshiba or Hitachi were to assign the guys designing their air-conditioning or washing machine motors to engineer a DD turntable motor, most likely the results would be very, very good. There is an interesting Japanese webpage by a retired JVC engineer, in which he talks about his involvement in designing the motor drive and controller circuits for the slotless DD motor of Yamaha's GT-2000.

http://37282.diarynote.jp/200708032337340000/
http://37282.diarynote.jp/200708041621320000/
http://37282.diarynote.jp/200708102338400000/
http://37282.diarynote.jp/200708111505150000/

Little chance that a billion-dollar company with a dedicated motor engineering division would assign its ace engineers to design a turntable motor today, however. Panasonic's cessation of SL-1200 production is more or less proof that the turntable market is too small for a big, mass-production oriented company to be interested in.

There are some German companies (Brinkmann etc.) however, that have motors that can be used in DD turntables (I know not whether these motors were designed from the outset for DD use), and at least one of those companies offers such a motor as part of a DD turntable kit.

>BTW why oh why won't can't you get the Connoisseur made again?

Several different reasons. First is that ever-tightening ROHS regulations and increasingly severe business conditions for component manufacturers have forced all of the high-performance transistors used in the Connoisseur 4 & 5 out of production, and in most cases the production lines themselves are gone, sometimes the companies themselves. FWIW, the sound of most transistors available today is generally less than impressive, and any new design would be at a severe handicap unless modern transistors can be found which are comparable in performance and sound to the devices used inside the Connoisseur 4 & 5.

Second reason is that I am responsible for all of Lyra's engineering developments (schematics, simulations, circuit board layouts, mechanical designs, prototyping, testing), I come up with most of the strategic product planning, I do the box designs, I write most of the user's manual, and I keep an eye on production to make sure that any issues are either nipped before they happen or are taken care of promptly and thoroughly. Since I am not that good at juggling multiple projects at once, I always need to think carefully about where to most sensibly allocate my development efforts. More cartridge development means less time available to spend on the electronics, and focusing efforts on the electronic projects can mean no new cartridge designs for a time. Hard choices that can have long-lasting repercussions.

Third reason is that regarding the Connoisseur 4 and 5, I have already been there, done that, and wouldn't derive any personal satisfaction from a new project unless I could be reasonably confident that it could surpass my previous efforts. Transistors permitting, certainly a bit more performance could be squeezed out of the Connoisseur 4 & 5 formula, which is what the 4-2, 4-2SE and 4-3 have been about. But where is the challenge and personal satisfaction in merely refining an old formula?

OTOH, it takes serious mental effort to come up with a valid new engineering approach, and requires even more meticulous work and soul-searching to build up the confidence that the new approach will be able to surpass the old designs.

For a designer to be truly quality-oriented requires that he be his own worst enemy, and only release designs which surpass the performance of his previous efforts, preferably in as many ways as possible.

I have a few different design approaches for line preamp and phono stage in development, but whether anything will eventually be put into production or not depends on how happy my ears will be with those designs.

BTW, entering US patent number 4,512,008 into a search engine should allow you to download a pdf of the patent for Yamaha's MC phono stage.

kind regards, jonathan
Ralph (Atmasphere) wrote:

>All preamps are class A.

For discrete circuits, this is true. OTOH, the vast majority of opamps only have a very small output range in which they run in class A. If the signal amplitude exceeds that range, the opamp's output circuits will shift to class AB operation. This is because opamp manufacturers place great emphasis on energy efficiency, and therefore internally bias their output stages in a manner that keeps the standing currents quite small.

That said, it is possible to keep many opamps in Class A operation over a larger range by connecting a current source (or even a well-chosen resistor) from the opamp output to one of the power rails (which rail works better depends on the design of the individual opamp). However, this "forced" Class A operation needs to be implemented by the preamp designer. I have seen many opamp-based preamp designs (and DACs) where Class A operation was not implemented.

kind regards, jonathan
Hi Lohanimal: The old Yamaha HA-2 (1979) and HA-3 (1982) were also of this type.

http://jp.yamaha.com/products/audio-visual/special/hifi-history/other/

The HA-2 shipped with a dedicated headshell with two embedded JFETs, thereby bringing the front end of the phono stage forward so that it was less than an inch away from the cartridge. No modifications to the tonearm were required; the tonearm wiring could be used as-is.

http://audio-heritage.jp/YAMAHA/etc/ha-3.html

The HA-3 exchanged the dedicated headshell for a compact encapsulated block that contained two JFETs, had 4 short leads coming in and four short leads going out, and was secured with double-sided adhesive tape. The user could thereby install the JFET block into his favorite tonearm or headshell. Again, no tonearm modifications were necessary.

http://www7.ocn.ne.jp/~mai-k/analogue/transe1/yamaha.html

In more recent years, the prolific Japanese DIY amplifier designer Akihito Kaneta (Kaneda) has published at least one phono amplifier design which installs a JFET headamp inside the tonearm headshell.

kind regards, jonathan
Hi Lohanimal:

The HA-2 in particular was highly sought-after by Japanese audiophiles, and widely praised for its sonic immediacy, as well as for its innovative approach. I never owned the HA-2 (couldn't afford it as a student), therefore I can neither confirm nor deny those views. I did own the HA-3, and once I corrected the RIAA equalization network, it sounded quite good.

I later exchanged the HA-3 together with an Audio-Technica AT-37 MC cartridge and Kenwood turntable (probably the KP-880D) in return for a studio-grade Denon open-reel deck, but a small part of me wishes that I had kept that HA-3. The circuitry knowledge that I have now would let me modify it into a much higher level than I could back in the mid-early 1980s.

Clearaudio's Absolute Phono page states that theirs is "the world's first active headshell moving coil phostage". If you forget about Yamaha and ignore the entire Japanese audio scene, they may be right (grin).

http://clearaudio.de/en/products/electronics-absolute_phono.php

kind regards, jonathan carr