Feb 3rd, 2016
Q) I am running an old solid state receiver an older turntable have been playing much more acoustic music in the last year. A friend who is a real high-end tube nut says if I want to hear vinyl played back well, I need to consider at least running a tube pre-amp. He had a couple of recommendations of pre's that he believes are well designed for turntables. As I found, there is a 'pre-amp in' input pair on the back of the receiver, so it can be done. But can it make much difference if the pre-amp sends its signal into the same old solid state receiver? I am included to spend that money on turntable maintenance and more music.
A) This question has been asked and answered many times in 30 years. Although I've owned some fancy stuff (most of which seldom worked or did anything special as claimed) and I've owned just simply well designed, inexpensive things, ultimately for listeners out there it's a matter of faith in the name of product, how it's been marketed to you, and it’s style appeal. From a technical and scientific view much, but not all, of this super audio stuff is a joke and ironically truly better fidelity can be had from a $200 thing.
Quickly the reason is that most low level tube preamp designs are problematic (aside of guitar preamps etc.) is because the tube has too much thermonic noise and worse yet are the microphonics (self noise and mechanical resonances coming from the tube when used in a high gain preamp.) At line level (ie aux in, tape deck, cd level coming in) these noises are hidden because the tube is not being used at such high gain, heavily equalized circuit. The RIAA equalization, especially for phono, requires almost 16db of bass increase in the low frequency to correct the cartridge and recorded equalization already existing in the vinyl recording. So again such designs boost all the "tube" noise excessively. Many of these designs also do not provide the proper cartridge loading impedance and the audible results vary tremendously from manufacturers (who presently are for the most part importing cheap chinese made products and hyping them for big dollars).
In 35 years of experience the bottom line is that using a truly well designed turntable (again the expensive stuff is usually inferior to basic well made inexpensive designs), with the proper and correctly tracking cartridge (forget about most of the expensive ones they simply don't do the job any better than original designs and manufacturers done by Stanton, Audio Technica and a few others). The irony is that Audio Technica/Signet built or supplied the basic cartridge which retailed for $100 or so to other companies who "dress up" the cosmetics or coloring to "create" a special very pricy and profitable supposed audiophile product. Consumers are not aware of how much window dressing and marketing spin goes to convince audiophile to buy these products, some of which are an outright scam and others way overpriced for what you get.
The choice I can offer is information as to the best performing honest products for the money spent. Customers have to overcome their passion for names or clever marketing styling and then truly amazing products are available which do the correct job. This return letter will be posted to the web site, so I'll take this matter a little further. The best preamp designs are typically class A FET input designs with appropriate cartridge loading switches. IE, all cartridges must be correctly loaded with a certain resistance (usually 35,000 to 100,000 ohms resistance. They also need a capacitance loading of 50 to 300 picofarads to damp high frequency transient resonances of the cartridge as well to suppress radio frequency interferences (RFI). Also specialized grounding design is implemented at the input to reduce ground loops, hum and again RFI. Also important is the preamp equalization must replicate the required RIAA standard equalization to obtain the best fidelity signal output and frequency response of vinyl to cartridge to preamp. The simple irony is that basic designs which implement this criteria are inexpensive and with a careful listening test prove to be better on a wide range of vinyl. Records themselves have slight variations in the way the grooves have been cut (Newman Lathe, Microgroove, Dynagroove, etc.) Certain stylus types (Especially hyper eliptical or shibata tips) retrieve more information with lower noise (both vinyl noise as well as lessening the audibility of clicks and pops). Indeed many vinyl manufacturers would also digress from perfect RIAA record equalization, and oddly enough not even cut the record at the correct pitch! So that in general the record was made to sound OK for it's target audience in a different era! Be aware of this.
Modern preamp of records requires, in my opinion, an outboard equalizer to help correct tonal inbalances and and especially trick equalization done by the engineers to zing up the record. Usually this was audio engineer adding more midbass and forcing the vocals to be more “up front”. Todays speakers don’t need this extra emphasis and indeed most records need more extreme deep bottom end equalization (below 80hz) more brightness equalization (above 6khz) and typically to dip a little equalization in the midrange which will clean up a muddy or excessive “warm” recording. Now here is a case where usin a getter equalizer (with better parts, lower noise op amps etc.) will make significant audible improvements. So much improvement that the special “magical preamp” will be of little sonic value. Remember also, that all the recordings you get have been through hundreds of transistors, capacitors, connectors, wires, preamp, compressors, cutting lathes, etc. Adding another stage of equalization to correct the poor or good taste of an engineer from 30 years ago listening on archaic speakers is going to prove an asset to the true audiophile.
Thanks again for the inquiry,
I hope you find this helpful, give a call for more info on EQ etc (617)926-8020.
-Vince