Hi-Lo Phono Selection?

[LarryC]

I offer for example the Pat-5 Bi-FET , phono input " High -- Low switch " please elaborate on what it's function must be ?

Phono Input Acceptance:

LO: Greater than 115 millivolts at 1 KHz.
HI: Greater 45 millivolts at 1 KHz

Impedances:

Magnetic Phono: 47,000 ohms in parallel with 220 pF.
High level: 50,000 ohms http://home.indy.net/~gregdunn/dynaco/components/PAT5/index.html

I go by db of gain rather than get confused by impedances and input voltage "acceptances." The above website includes a table (below) that plainly says what the inputs are about. The High phono is for MM carts with output voltages of, say, 10 mv. The Low phono is for carts with 2-4 mv or so out. I think line outputs were rated at much higher, 1.0 volt!

There are two BIG differences between the phono and line inputs:

• the phono inputs both apply the RIAA eq curve, which greatly increases the bass and reduces the treble by the prescribed amount; these changes are incompatible with non-phono sources!
• The linestage gain is only 20 db, which is WAY below the phono gains of 57 and 63 db.

Gain:

Magnetic Phono (LO) to Audio Out:

57 dB

at 1 KHz.

Magnetic Phono (HI) to Audio Out:

63 dB

at 1 KHz.

Magnetic Phono (LO) to Tape Out/E.P.L. Out: 37 dB at 1 KHz.

Magnetic Phono (HI) to Tape Out/E.P.L. Out: 43 dB at 1 KHz.

High Level to Audio Out:

20 dB

.

High Level to Tape Out/E.P.L. Out: unity.

[LarryC]

dp

[CallMeJoe]

>They must have been equalized
in the preamps, since the equalization was to correct for the spectral
character of the microgroove albums. As you surmise, there were vastly
different qualities of RIAA curve implementation.

I
disagree. I have a considerable number of early microgroove records
and they do not exhibit "vastly different" curves. For one thing, the
curves were based on a number of physical issues that yielded pretty
much the same curve no matter who calculated it. The curve was set in
stone in 1955, but previous LP's were already close enough for the
playback to be correct already. In fact, as I go back through recorded
history it is only in the 30's that significant variants begin to be
heard.

Dave

Mea Culpa; I stated that poorly. Recording companies were relatively consistent in implementation of the recording curve. It was the playback curve that was poorly implemented by some hardware manufacturers.

[johnyholiday]

I also offer for example the Voice of Music 1428 all tube amp, function switch ---phono ---- magnetic or ceramic, please elaborate on what it's function must be ? can't be boosting the opamp 6dB like the Pat-5 Bi-FET.........could i have added voltage to the statment johnyholiday:

Low compliance or High compliance voltage for properly implementing the "RIAA curve" for phonograph input, Impedance matching (Z)

[LarryC]

I believe your questions were answered by the information given earlier in the thread, including the complete irrelevancy of compliance and (IMO) impedance matching.

The ceramic vs. ceramic are two very different inputs, with around 40 db difference in gain, not 6 db. I don't believe the RIAA curve was used in the ceramic input, unlike the in magnetic (phono does not always have to mean "RIAA"). Hope this helps.

[johnyholiday]

I believe your questions were answered by the information given earlier in the thread, including the complete irrelevancy of compliance and (IMO) impedance matching.

The ceramic vs. ceramic are two very different inputs, with around 40 db difference in gain, not 6 db. I don't believe the RIAA curve was used in the ceramic input, unlike the in magnetic (phono does not always have to mean "RIAA"). Hope this helps.

do you mean magnetic vs. ceramic ?,........this has indeed become a pile of
scabby grey pants, johny has read and will study,such statements across the World Wide
Web as "Ceramic cartridges are high impedance signal sources.","Ceramic
cartridges don't require RIAA equalisation as they have a
largely flat(-ish!) response. They do, however, need an input impedance
of 1MOhm or thereabouts generally, and so the 47KOhm of the average
line input may give some odd frequency response results", "Although
RIAA has nothing to do with the manufacturing of the cartridge, it is
needed when playing back a record.","the old Decca Deram cartridge,
which behaved like an MM cartridge if
you plugged it into an MM input, but like a ceramic cartridge if you
plugged it into a ceramic input - all down to the load impedance it received","Some very old (typically TUBE) equipments had phono input
designed for
high impedance and high output level CERAMIC cartridge.","the ceramic cartridge, a piezoelectric device that used newer, and better, materials, were more sensitive, and offered greater compliance,
that is, lack of resistance to movement and so increased signal voltage ability" etc. yes of course this helps like all Klipsch threads.....as far as the original question is he cutting or adding ~XdB

[Audio Flynn]

>They must have been equalized
in the preamps, since the equalization was to correct for the spectral
character of the microgroove albums. As you surmise, there were vastly
different qualities of RIAA curve implementation.

I
disagree. I have a considerable number of early microgroove records
and they do not exhibit "vastly different" curves. For one thing, the
curves were based on a number of physical issues that yielded pretty
much the same curve no matter who calculated it. The curve was set in
stone in 1955, but previous LP's were already close enough for the
playback to be correct already. In fact, as I go back through recorded
history it is only in the 30's that significant variants begin to be
heard.

Dave

Mea Culpa; I stated that poorly. Recording companies were relatively consistent in implementation of the recording curve. It was the playback curve that was poorly implemented by some hardware manufacturers.

The Scott vintage tube phono sections were the best vintage for my taste. As good as AMPEX was for open reel tape machines they could not implment a phono stage as good as any lowly Scott integrated let alone a dedicated preamp like the 130.

My pursuit of a satisfying phono section is like the script to "The Holy Grail".

[Mallette]

Dang, Mr. Holiday, it's hard to pick out what you are saying there, but let's be clear on one thing:

>Ceramic cartridges don't require RIAA equalisation as they have a largely flat(-ish!) response

Fine and dandy, but the DISCS are RIAA equalized and don't have a "flatish" response. Playback RIAA deemphasis is required for any RIAA standard disc, or any disc cut with a magnetic head, to achieve anything like accurate playback. I'll repeat that RIAA is simply a standard and that before it was set there were lots of standards calculated and applied to achieve a flat response from a magnetic cutting head, and that all were close enough to RIAA to work reasonably well as they were all based on the same principles.

Magnetic cartridges generate a signal that is proportional to the velocity of the stylus. It's the INVERSE of the magnetic cutting head, which is made to "wiggle" by applying the amplitude modulated signal. As the frequency increases, the "wiggle" increases generating a higher voltage. Therefore, the output signal is not flat at all. Since the cutting head is the inverse of the playback head, you have to apply and inverse curve to get something like flat.

Ceramic cartridges are constant amplitude. The voltage doesn't change with the frequency. Further, they are inherently low fi. Due to these to issues no RIAA deamphasis is required and, if applied, it sounds really icky.

Ceramic cartridges without RIAA just sound garden variety icky.

Dave

[johnyholiday]

johny " ( Z ) = Tone "

Low compliance or High compliance for properly implementing the "RIAA curve" for phonograph input, Impedance matching (Z)

................this statement is in regards to (Z) as a measure of compliance reactivity,measured in magnitude and phase, johny never said anything about low compliance of a cartridge, to low mass tonearm,or a high compliance of a cartridge,as mated with a moderate mass tone arm.......example 1 the Pat-5 Bi-FET is to show some preamps have a switch to boost signal,but this doesn't cover the whole gambit (but answers original question),example 2,the Voice of Music 1428 all tube amp, both the impedance and signal level have to be compatible,if
devices are to work properly together,to match existing standards for
similar devices.....Frequency response of cartridges can be effected by output to input impedance interaction with preamps,see better example below. Hope this helps with any input to output (Z) device having " tone suck out " one might experience...

[mike stehr]

Stanton/Pickering 380 stereo fluxvalve.

[johnyholiday]

Stanton/Pickering 380 stereo fluxvalve.

nice http://forums.klipsch.com/forums/p/103909/1051745.aspx http://www.audioasylum.com/audio/vinyl/messages/81/814164.html