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Orientation to preamp controls

 

New member
Username: Rebeccah

Post Number: 1
Registered: Oct-08
Please forgive my ignorance. When my old Pioneer SX-780 receiver finally died after several decades of moderate use, the newer stereo receivers (in my price range) didn't have phono input jacks; but as luck would have it, I found a Nikko Preamplifier Beta 1 at a rummage sale for $5.00. It does seem to work when I plug the turntable into it, and connect the the preamp output to the tape input on the receiver.

But now, I'm trying to sort out what the various controls on the preamp acually mean.

For example, there is a switch labeled "Tone" at the up position, and "Defeat" at the down position. What is that?

The volume control is labeled in -dB, which seems odd to me. Do I correctly infer that it is measuring relative to the maximum output of the pre-amp, rather than relative to the input?

For Phono Impedence, I have options of 22, 47, or 100 Ohms. Nothing in my Dual CS 1242 turntable manual indicates what the impedence is. What should I set it to?

Next, I have two separate dials for selecting inputs and outputs: There is one labeled "Tape," which has options for "Source," "Play 1," "Dub 1 -> 2," "Play 2," and "Dub 2 -> 1." There is another labeled "Selector," which has options for Aux, Tuner, Phono 1, and Phono 2. I presume that if and only if you set the first selector to "Source," then the choice on the second selector determines the input source?

Finally, there is a knob labeled "Phono 1 Level" and one labeled "Phono 2 Level." What is the relationship between the Phono Level setting and the Volume setting? Do I do coarse volume adjustment for the turntable with one, and fine tuning with the other?

Thanks very much for any insight.

Rebeccah
 

Gold Member
Username: Stu_pitt

Irvington, New York USA

Post Number: 3053
Registered: May-05
Rebeccah,

I don't know your gear, but I'll try to help out a little...

The "Tone" knob alters the sound - boosts treble, bass, or something else along those lines. The "Defeat" setting means it is switched off or bypassed.

The volume control numbers are probably doing what you're saying. The numbers used are pretty much irrevelant.

The phono impedence has nothing to do with the turntable itself. It depends on the cartridge. If you don't know the proper load of your cartridge, use the setting that sounds best to you.

I've never used the "Tape" options. I think it has to do with recording. If you're not hooking up a tape recorder, leave it on "Source." "Source" bypasses the tape loop.

Yes, if you leave the first knob on "Source" the source knob controls which source is playing.

Phono level 1 and 2 probably have to do with MM (moving magnet) or MC (moving coil) type cartridges. MM cartidges need less gain that MC cartridges. If this is a gain selector, be careful. Connect your turntable with level 1. Turn the volume down somewhat low. If its loud, then use the other one. If you have to turn the volume up pretty high, use the other one. Its not a coarse/fine volume adjustment thing. MM cartridges have a higher voltage output than MC cartridges.

I'm not sure about the Phono Level switch, but the others are pretty standard. Good luck.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 13050
Registered: May-04
.

What "pre amp" are we talking about? The Nikko? So you are running the Nikko into the Pioneer? If so, are you taking the Nikko's output from the "tape out" on its back panel or are you using the "pre amp outputs" of the Nikko? You should be using the former ("tape out") to run to the Pioneer's tape input. This would make many of the front and back panel controls of the Nikko inconsequential to everyday operation. It would primarily take the Nikko's volume and tone controls out of the signal path and give you only one place to set volume - the Pioneer.


As mentioned, "defeat" means the tone controls are inoperable with the switch in that position. It's meant to give a slightly cleaner signal path though you probably can't hear any difference between "defeat" and just having the tone controls set to their center position. That switch is a marketing tool more than anything else.

Measuring in "dB" means nothing. It is relative to the input level of the source and that level varies from source player to source player. Your CD player is a different output level than your turntable which is different than your tuner so the pre amp always sees a different input level as you switch between sources. Use the numbers only as a reference for how you like to listen just as if the numbers where from 0-10, A-Z or the names of your pets listed by age. If you listen to "Fluffy" for CD's then you might listen to "Lilbit" for your turntable.


"For Phono Impedence, I have options of 22, 47, or 100 Ohms. Nothing in my Dual CS 1242 turntable manual indicates what the impedence is. What should I set it to?"


Your Dual has a 99.99999% chance of having a moving magnet cartridge or a high output moving coil installed. These cartridge types expect to see a load impedance of 47kiloOhms. Check for a "47k" marking on your pre amp. If you don't see it, then the input of the phono section is most likely set to that impedance internally and you won't use this switch. Look for another switch labeled "mm/mc" or "moving coil". This would indicate one of the phono inputs can be used with a moving coil cartridge - which you don't need. Either place the switch, if you find one, in the "mm" position or use the other phono input. In either case, if you don't see the "47k" or the "mm/mc" anywhere on the pre amp, you can use either phono 1 or phono 2 and simply ignore the switch for impedance.


"There is one labeled "Tape," which has options for "Source," "Play 1," "Dub 1 -> 2," "Play 2," and "Dub 2 -> 1."

Tape monitor overrides all other input controls. "Source" would mean the tape monitor is out of the loop and you are listening to whatever the "Selector" is set to; phono, tuner, aux, etc. Setting the tape monitor to "Play 1" or "Play 2" would select those specific inputs and would override the "Selector" switch. "Dub" allows tape copying fron one player to the other. Usually this can be achieved without overriding the "Selector" position though not all manufacturers agreed on this arrangement.


"Finally, there is a knob labeled "Phono 1 Level" and one labeled "Phono 2 Level." What is the relationship between the Phono Level setting and the Volume setting? Do I do coarse volume adjustment for the turntable with one, and fine tuning with the other?"

The "Phono level" control is used to balance the input levels between two turntables/tonearms using different cartridges. You should ignore this control unless you find the phono is playing considerably louder than your other sources, which is unlikely. Set the control to the highest setting and use only the main volume control to set your playback levels for all sources.

Just because a control is on the pre amplifier you don't have to use it. This pre amp was designed to provide flexibility and not all users will have the opportunity to employ the features this unit affords.

Go on line and there's a possibility you can find an owner's manual for this pre amp.



.
 

New member
Username: Rebeccah

Post Number: 2
Registered: Oct-08
Thanks for your replies, guys. I've also done some more looking around, both at my electronics documentation and online.

Just to be clear, the Dual TT is connected to the phono input on the Nikko preamp; the preamp output is connected to the tape input on an Onkyo TX-SR506 AVR (which replaces a Sony, which replaced the no-name HD special that replaced the original Pioneer receiver). The specific models of my current components are in my profile.

Nothing else goes through the pre-amp. I only got it because none of my post-Pioneer receivers had phono input, hence no RIAA decoding.

My cartridge is a Shure VST III, and its paperwork says it requires 47 kOhms, so I'm set there (I misread the units on the pre-amp, it's kOhms, not Ohms). Everything seems to work OK, as long as I turn up the gain (Phono 1 Level) and the volume on the pre-amp to about the 5:00 position. That gives me about the same perceived loudness as my CDs and the radio, which all go straight into the receiver. I see that you recommend turning up the phono level to its highest setting, which it almost is, so it seems like I'm on the right track, there, as well.

Thanks again. And thanks for clarifying the "Defeat" setting just nullifies the treble and bass settings.

Rebeccah
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