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In Reply to: RE: Any inexpensive stage for playing 78's? posted by bjh on January 29, 2015 at 12:15:08
I've tried several options for 78 playback, including the Re-Equalizer. That unit is convenient, but adds phase distortion and noise. The best inexpensive option is to build the JE-Labs mono preamp (see link). I get terrific results with this unit, fed by a series-wired Stanton 500 w/2.7 mil stylus. Just bump up load resistor to 100K to compensate for the rewiring. I find this gives better results than simple L-R summing. Turntable is a new Stanton ST-150 (using just one channel.)
Surface noise on clean records is almost non-existent; dynamics and frequency response are amazing!
Follow Ups:
nt
Sure - on the schematic there is a 47K resistor from the phono input to ground. Just replace it with a 100K resistor to compensate for the cartridge modification (assuming you are going to wire the coils in series as suggested.)
Is it due to the change in series resistance from parallel? I don't have enough electrical background to fully understand. Thanks.
You're doubling the output impedance of the cartridge by connecting the 2 coils in series, so you double the impedance of the load by adding another 47K resistor in series (thus 100K more or less). Just like matching the impedance of your speaker to the output transformer (only in reverse!) I think that is the correct explanation - someone please correct me if I'm mistaken.
nt
Hi, I have not noted added noise or distortion in my setup but I am curious about the noise and distortion you and David Pogue have found.
Why/how would it add phase distortion unless it were not designed and or built correctly?
I have not compared it to an all in one variable eq phono stage which would be preferable if it was as good or better than my current combination -- McCormack Micro Phono Drive Rev. A w/powersupply + Reequalizer. Perhaps going forward I will find an all in one unit I like.
One thing I find more important for vintage record playback is ease of use and -- I love the layout of the controls of the Re-equalizer and find it to be a great tool to play a wide variety of pre RIAA records.
The manual is available for free and is an excellent guide for anyone interested in pre riaa records whether you use the Re-equalizer or not.
Here is the mention in stereophile
I would respectfully submit that Art Dudley is not (by his own admission) an experienced hand at 78RPM playback. Now I'm not an EE - although I have scratch-built several excellent vacuum-tube preamps - but it seems to me that any circuit that "undoes" previously-applied equalization and then applies its own is going to add undesirable artifacts to the sound. Don't get me wrong - I lived happily with the re-equalizer for several years - but the improvements gained by moving up to the JE are substantial.
Is the JE unit you built an actual kit? Or did you roll your own with the schematic as shown on their page?
You'll have to roll your own following the schematic. Luckily it's a relatively simple circuit (and you only need to build one channel!) If I can help out in any way, don't hesitate to ask. Somewhere I found a schematic for flat equalization (not included on JE website) which is essential for acoustic and many European electric 78s.
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