Hi-Lo Phono Selection?

[Tarheel]

I have two different Harmon Kardon units from the early 60s....one receiver and one integrated amp. Each has a Hi-Lo phono connection. Using the "Hi" I get very little volume while the "Lo" is much louder. I am using a moving magnet Clearaudio virtuoso wood cartridge. Is "Lo" the proper setting or do I need a step up gizmo? If I need to step it up to use the "Hi" setting should I expect better sound?

[tigerwoodKhorns]

Sounds like Hi is for high outpt and low is for low output cartridges.

[artto]

Without the model number(s) it's hard to tell for sure, but since low output moving coil pickups were not widely used yet in the 60's, and because you mention that using a moving magnet pickup with the "LO" produces louder volume, I suspect the "HI" phono connection is for use with a high impedance pickup such as a ceramic or crystal type which were much more prevalent in the 50's and 60's. These were usually of lower quality and required higher tracking forces and were typically installed in portable record players, entry level record changers and the large console (furniture) type stereos such as those made by Zenith, GE, and Magnavox. The "LO & HI" nomenclature is sort of a misnomer ~ "LO" is higher output for lower output pickups, and "HI" is lower output for higher output pickups, but remember, its really decribing the HI or LO impedance property of the type of pickup.

http://archives.telex.com/archives/EV/Miscellaneous%20Electronics/EDS/PC1%20EDS.pdf

[Tarheel]

Thanks for the reply guys. I was hoping that would be the reply artto and that there is not something wrong with both amps. Makes sense. One unit is the HK A500 and the other is a HK FA 3 Award Series (still available in kit form). I don't have manuals for either.

[Groomlakearea51]

As arrto said; one is for moving magnet and one's for moving coil. Some older high end ss amps have three settings, 30, 50 and 100 k'ohms. "Lo" generally is about 30-50 and high is generally for 100.

[artto]

As arrto said; one is for moving magnet and one's for moving coil. Some older high end ss amps have three settings, 30, 50 and 100 k'ohms. "Lo" generally is about 30-50 and high is generally for 100.

Umm, actually I didn't say that ~ I believe I said just the opposite. Moving coil pickups were not very common back then, but cheap crystal and ceramic pickups were. []

FWIW, from Wikipedia (not my source of info - my memory is - this is just some documentation)

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

[LarryC]

I am using a moving magnet Clearaudio virtuoso wood cartridge. Is "Lo" the proper setting or do I need a step up gizmo? If I need to step it up to use the "Hi" setting should I expect better sound?

My rule: whatever sounds best is the right way. As I recall, some MM carts had amazingly high output voltages back then, and had to be plugged into the "hi" input to keep gain within bounds. To me, the "lo" input is the logical one. Hopefully it's a good match.

As said by Artto and others, phono inputs of that vintage would have been only for MM carts. MC carts of that era (ESL, Fairchild, Ortofon) were usually boosted by transformers first, [edit] which were then plugged into regular MM phono inputs. Only more recent preamps (BAT, Joule among others), have had MC phono inputs.

Ceramic carts are a different kettle of fish. They have VERY high [edit] outputs, too much for mag phono inputs as I recall, and they have an entirely different response curve, so I'm pretty sure that the usual RIAA phono compensation is completely inappropriate. Ceramics have much more bass output and reduced highs compared with magnetic, so that they could serve as LINE inputs in cheap players, bypassing the need for preamp phono stages. The "hi" phono input on your receiver/amp would probably not work out with a ceramic cart. Ceramics are not in the audiophile league IMO.

[Tarheel]

Thanks Larry. You and Artto are correct I think and your rule of thumb works for me. Just now ordered a new quad of 12ax7s for the front end. Gold pin Electro Harmonix. Phono section had a Peavey in place which I switched out for a Telefunken.

[DoubleJ]

Thanks Larry. You and Artto are correct I think and your rule of thumb works for me. Just now ordered a new quad of 12ax7s for the front end. Gold pin Electro Harmonix. Phono section had a Peavey in place which I switched out for a Telefunken.

Tarheel:

Where did you buy the 12ax7's?

Thanks

JJ

[Tarheel]

JJ....ordered then from tubedepot.com. I have also been pleased with dougstubes.com and thetubestore.com. $16.95 for the 12ax7s per tube plus $2.00 for matching.

[Mallette]

Sounds like Hi is for high outpt and low is for low output cartridges.

Essentially correct, but specifically MM or ceramic/piezo. Ceramic/piezo were the dominant carts of the day as they were cheap to make and put out high much higher voltages than mm. Most are easy to recognize due to the flipover lever for 78 that was almost ubiquitous. Astatics and Ronettes were the better ones, but none of them would satisfy any of us.

Here's one with the typical flip.

Dave

[johnyholiday]

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

[WMcD]

Just to add to the mix.

As others have said, there were no MC cartridges in the '60s or even early '70's.

My recall on the ceramic and pizo is vague; I was young at the time. One reason for the flip over was that the 78 rpm records required a larger stylus than the microgroove 45 and 33rpms.

Certainly the 78's did not have an RIAA equalization.

There are several issues I don't have the answer to:

1) Were there stereo ceramic pickups? Maybe.

2) When a preamp had an input for ceramic, did the preamp use RIAA equalization? That might change with the sophistication of the preamp.

Wm McD

[CallMeJoe]

1) Were there stereo ceramic pickups? Maybe.

Yes, there were.

2) When a preamp had an input for ceramic, did the preamp use RIAA
equalization? That might change with the sophistication of the preamp.

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.

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

Compliance is a mechanical characteristic of the cartridge's stylus and cantilever. It has nothing to do with RIAA curve or electrical impedance.

[Mallette]

Just to add to the mix.

As others have said, there were no MC cartridges in the '60s or even early '70's.

My recall on the ceramic and pizo is vague; I was young at the time. One reason for the flip over was that the 78 rpm records required a larger stylus than the microgroove 45 and 33rpms.

But of course. You didn't replace a stylus but the entire cartridge. It was unified. There were some that had replaceable needles, but many simply replaced the entire assembly with a pop out, pop in capsule.

Certainly the 78's did not have an RIAA equalization.

Not entirely true, and not true at all from 1954 on...which wasn't long. I have a number of RIAA 78's. Curves at or near RIAA get more frequent in the late 30's up to that date when it was formalized. Most curves weren't far off as they were based on the physics of the same materials. Edison Diamond Discs were an exception. The EQ for them was so far off RIAA or flat that they sound really bad played today without highly specialized circuits. However, they were really quite "audiophile" played back per Edison specs.

There are several issues I don't have the answer to:

1) Were there stereo ceramic pickups? Maybe.

Of course there were...and are.

2) When a preamp had an input for ceramic, did the preamp use RIAA equalization? That might change with the sophistication of the preamp.

Indeed. There were plenty of ceramic pickups in use and sold probably into the 70's or better. I haven't researched, but they were predominant in your basic record players and consoles most of my early life and all were RIAA after 1954.

Wm McD

[LarryC]

My recollection, admittedly dim for that far back, is that the amplitude of the signal from magnetic carts was/is based on the velocity or acceleration of the stylus, while the amplitude of the signal from ceramic carts was based on a different principle, such as the pressure on, or amount of displacement of, the stylus; the velocity/acceleration in a mag cart produced much more treble and much less bass -- a kind of reverse RIAA curve perhaps. Certainly mag carts didn't have little EQ circuits inside of them.

I still think that ceramics put out a signal strength much closer to standard line inputs, and that, because they had much stronger bass and weaker highs than mag carts, they didn't need RIAA or some other equalization in cheap, inaccurate amp stages. For those reasons, mag carts could not substitute for ceramics in a given circuitry.

I'll bet those 78 RIAA curves were made for mag carts.

As I recall, stylus radii for LP "microgrooves" was only about 1 mil, whereas 78s required 3 mils. I suppose "mils" were 1/1000th of an inch.

[Mallette]

Larry, your thoughts parallel mine. The ceramics are basically strain gauges and current is generated proportionally to the strain. Also, I believe the EQ curve is part of this strain. That is, there was no separate circuit to provide an "RIAA" response. The MM cart didn't have a "natural" curve so a standard was set. The standard is based on the response of the medium, the disc. In a way, it's a bit like Dolby in that you emphasize in one direction and deemphasize in the other to produce an optimum signal with minimum noise and distortion.

I could be wrong, but I am pretty sure it is something like that.

Dave

[johnyholiday]

1) Were there stereo ceramic pickups? Maybe.

Yes, there were.

2) When a preamp had an input for ceramic, did the preamp use RIAA
equalization? That might change with the sophistication of the preamp.

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.

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

Compliance is a mechanical characteristic of the cartridge's stylus and cantilever. It has nothing to do with RIAA curve or electrical impedance.

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

[CallMeJoe]

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

That is a High/Low Gain switch, giving an additional 6 dB of amplification in the "High" position. It has nothing to do with cartridge compliance. The impedances noted are for two different sets of inputs, the Phono (Low level) and Aux, Tuner, etc. (High Level); also not compliance related.

You can find a passable primer on phono cartridge compliance here at Galen Carol Audio (the first link I found through Google)http://www.gcaudio.com/resources/howtos/tonearmcartridge.html' title="here">.

[Mallette]

>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