hey guys...

there is an auction on ebay that is in my town, so if figured i would bid on it just to mess around with it. Its a phono pre-amp that is described as "equalized" does that mean that its a balanced in and out?? if so aren't all phono preamps that way???

heres the auction for thier wording and pics...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=004&item=140026318988&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

i wonder if its of good quality since its for the broadcast world...i think it will be fun to mess with anyway.....

thanks for your help!
Scott

Equalized means that it contains RIAA demephasis. The only phone preamps that don't have this EQ built-in are so called moving-coil "head amps" which are designed to preceed a phono stage with EQ like this one.

Regarding balanced I/O; the answer is NO, very, very few home phono preamps have this feature. Balanced I/O is used on very few pieces of home equipment, and it does not generally match-up particularly well with your typical unbalanced setups.

My advice would be to pass on this one...

While you mention it...what do you mean by "balanced I/O" and "unbalanced". I know they use different connections, but what's different about the signal?

Just curious.

Never mind. Looked it up on the net.

ah, good! you said "RIAA demephasis"! I have been wondering for a while...what in the flip does RIAA mean????? :)

Record Industry Association of America

http://www.riaa.com

While you mention it...what do you mean by "balanced I/O" and "unbalanced". I know they use different connections, but what's different about the signal?

Just curious.
This is a complex subject, and so my answer is going to be oversimplified. But here goes:

Ballanced ouputs send a voltage that swings equally and opposite out of both the plus and the minus connections. The ground on a ballanced line is just there to act as the shield, but it does not pass any current.

By contrast, A normal unblallanced connection (of the type that we all know) will only swing a voltage on the plus half. The Minus half is ground, and while its voltage does not swing at all, it does still pass current.

Ballanced I/O is done for reasons of noise immunity, and it is definitley quieter if you run really long cables.

http://en.wikipedia.org/wiki/Balanced_audio

I have been wondering for a while...what in the flip does RIAA mean????? :)
A lot of people use "RIAA" as a shortened term for "the RIAA equalization standard".

I'll bore you with a little history. Back in the days of acoustical recording, life was relatively simple. A disc of warmed wax was placed on a gravity powered turntable and sound waves travelled down a horn and vibrated a mica disc which moved a stylus that etched a squiggle in the wax. The process was completely mechanical.

Things got complicated when electronics were added in the path between the performer and the disc. The good news is that the sound could be captured far more accurately, the bad news is that physics made it hard to transfer that information to the disc.

What follows is a gross oversimplification, so forgive me. It takes far more energy to reproduce a low frequency note with the same apparent loudness as a high frequency note. On a record, that means the groove has to wiggle far more from side to side for a low note. This caused headaches for the early electrical recording engineers. Basically, two problems arose. If you try to accomodate the new bass information, the groove spacing had to be so wide that it significantly shortened the recording time. A far bigger problem was that common record players couldn't track the groove. The engineers found that if they de-emphasized the lower frequencies, they could solve the problem. Older acoutical record players couldn't reproduce the low frequency anyway and they found they could design new electrical record players in a way to re-emphasize the bass to the appropriate level.

The problem was each record company came up with their own scheme. Some companies set their "turnover" frequency as low as 150-200 hz while others set it as high as 500 hz. This difference didn't much matter with the record players of the time.

When RCA and Columbia developed microgroove high fidelity records in the late 1940's-early 1050's, the difference in turnover frequency became noticeable. In the meantime, engineers found that if they pre-emphasized the higher frequencies, they could raise the signal further above the noise floor and get a better signal to noise ratio. On playback, you just correspondingly cut the high frequencies. It became apparent that if a standard could be developed at the start of the hi-fi era, both manufacturers and consumers would benefit. The record companies got together with their industry organization, the Record Industry Association of America and hammered out the equalization curve now commonly referred to as the "RIAA curve".

RIAA was not the only standard, though. The British Decca company has "ffrr" (full frequency range recording), which is close to the same curve.

For those of us who are interested in 78's the standard phono pre-amp poses a dilema. If we play a 78 through the RIAA curve, the bass is unnaturally emphasized and the treble is cut. A lot of people tolerate this because original recordings were bass thin and the treble de-emphasis helps with the inherent 78 surface noise. It's not accurate, though and does not present the wonderful music capured on these old records with the best possible sound.

Fortunately, there are pre-amps available which output a flat signal. This signal can then be fed into a computer where, with the use of charts, the correct turnover point can be applied. Various filters, including continous noise and low pass, can be applied to remove the high frequency hiss. The result is a transcription that sounds far better than the music on the record ever sounded.

Doug

It became apparent that if a standard could be developed at the start of the hi-fi era, both manufacturers and consumers would benefit.

Wouldn't it be nice if this were still the norm? Especially if/when the new standards were backwards-compatible with the old (e.g., MPX stereo FM, "RCA" color TV system)?!

Blu-Ray vs. HD-DVD, anyone?

Wouldn't it be nice if this were still the norm? "RCA" color TV system)?!


I was thinking the other day about DLP projectors and their color wheels. The first color TV to be sanctioned by the FCC used a field sequential method that used a color wheel. It was developed by CBS. They had to increase the frame rate to avoid flicker and the only way to fit the additional frames in the designated bandwidth was to lower the resolution. This rendered the new system incompatable with current black and white TVs. The FCC considered that the lesser of two evils in the competing technologies and since there were relatively few TVs anyway, the adopted the system. RCA was the main backer of the competing technology, which although compatible with current sets, suffered from poor color fidelity, interfering dot and line crawl patterns, poor registration, and high studio and receiver costs. RCA sued the FCC and although they eventually lost, the delayed the introducion of the CBS system long enough that too many black and white sets had been sold to go forward with an incompatible system.

My other thought is mhardy's signature quote. It reminds me of a verse from the original version of "Shake, Rattle and Roll" performed by Big Joe Turner. The lyric is: "I'm like a one eyed cat, peeping in a seafood store".

Doug

Any ideas where one might find these " flat signal " preamps? Inexpensive, of course. I'm juggling 3 mortgages...