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Phono Preamps...?


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8 replies to this topic

#1 of 9 OFFLINE   John Besse

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Posted October 12 2005 - 09:50 PM

I have a Denon 3801 receiver and just purchased a Goldring GR1.2 turntable to play Opeth, Porcupine Tree and Metallica records. The turntable, if you are not familiar with it, has a Goldring Electra moving magnet cartridge. I'm extremely happy with the sound so far of my new setup, except the volume level is a bit quite. I read somewhere that phono preamps are designed to increase line level. But, I also read that the typical record player on a standard receiver will not give proper bass and treble levels without using a phono preamp. Is this true? I'm happy with how my system sounds sonically, minus a few pops here and there from dust or whatever on a record. But, I have never noticed a huge difference in bass and treble levels as a result of playing a record.

Anyways, I have a few questions as to whether or not I need a phono preamp and why... First, what is the main purpose of using a phono preamp, as well as does it make that much of a difference? If I do decide I need to add a phono preamp to my setup, what is the price range I should be looking at? There is a model on eBay, the TCC TC-750, which sells on eBay or at PhonoPreAmps.com for $43.50. I was also looking at two more expensive models. One was from Audio Advisor, Parasound Zphono, which is $150. The Zphono sounds almost identical to the TC-750. The other preamp I was looking at was on the Needle Doctor web site, which was the Bellari VP129. The Bellari preamp is a tube phono preamp which runs $200.

Ultimately what I am looking for, is with a record player, what is the necessity of using a phono preamp...? Also, if it is really recommended that I use one... How much should I be looking to spend? I'd really like to go the most cost effective at the moment. I'm really liking the price on the TC-750 as it is going to be under $50 shipped. But, like most products, I'm sure buying cheap has its disadvantages. The only thing is I don't know what it is I'm getting into! So, any information would be greatly appreciated. ...And thanks for your help!
"Empire had the better ending. Luke gets his hand cut off, finds out Vader's his father, Han gets frozen and taken away by Boba Fett. It ends on such a down note. That's what life is, a series of down endings. All Jedi had was a bunch of Muppets."

 


#2 of 9 OFFLINE   Philip Hamm

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Posted October 13 2005 - 12:48 AM

I'm not familiar with the 3801. Does it have a "PHONO" input? If so, you don't need a preamp, use the input on the receiver. If not, you do. Simple as that.
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#3 of 9 OFFLINE   Brian Fellmeth

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Posted October 13 2005 - 01:47 AM

Radio Shack (of all places) makes a small battery powered phono preamp that is dead quiet and highly regarded by some hardcore audiophiles, and its cheap. Even if your receiver does have a phono input, you might want to give this a try (but don't use it with a phono input or else you'll have 2 phono preamps in the chain).

When LP's are mastered, the frequency response is intentionally distorted. A phono preamp reversed this process besides boosting the level of the signal.

#4 of 9 OFFLINE   ChristopherDAC

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Posted October 13 2005 - 02:39 AM

The phonograph preamplifier serves two purposes: first, it raises the level of the extremely low-level signals from the electromagnetic pickup, which are in the microvolts, far below the usable sensitivity of amplifier line-level inputs. This improves the distortion and signal-to-noise charcteristics of the audio. Second, it reverses the effect of the "RIAA equalisation curve", a specially designed pre-emphasis filter inserted during recording to better match the frequency characteristics of the audio to the physical characteristics of the record. If the inverse filter is not inserted in the playback chain, the sound is distorted comapred to the original.
Some phonographs include a preamplifier, which generally may be switched on and off. Some amplifiers, particularly older ones and better new one, have an input with the proper preamplifier [and you should never connect anything else to this input, which should be clearly marked PHONO]. If neither one applies to you, you need to buy one, but they're not particularly expensive. If you absolutely must have a tube unit, you will spend much more than you would otherwise, but that makes little sense unless the rest of your setup is tubes: since this is a voltage amplifier and not a current amplifier, the usual low-noise FET circuit will do everything you need.


#5 of 9 OFFLINE   John Besse

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Posted October 13 2005 - 05:15 AM

The Denon 3801 does have a phono input on the receiver. As I said, I'm overall pretty satisfied with the sound. Other than the volume level is a bit low. At this point, would I not connect a phono preamp from my turntable to the receiver and still use the phono input on the Denon? As Brian Fellmeth stated, "don't use it with a phono input or else you'll have 2 phono preamps in the chain." I really doubt my receiver is acting as a preamp, but I'm not sure... I also doubt it would be reversing the effect of the "RIAA equalisation curve." as ChristopherDAC stated. I know my table does not have a preamp that is switchable either. So, I'm still kind of lost as to what I should be doing. Sorry if I sound like an idiot here, but I just kind of jumped into records without researching things out first!
"Empire had the better ending. Luke gets his hand cut off, finds out Vader's his father, Han gets frozen and taken away by Boba Fett. It ends on such a down note. That's what life is, a series of down endings. All Jedi had was a bunch of Muppets."

 


#6 of 9 OFFLINE   Allan Jayne

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Posted October 13 2005 - 06:12 AM

Using the phono input and finding the output level a bit low is not abnormal. With no phono preamp the level would be so much lower that you would hear hum and noise when you cranked the volume.

So I am sure the phono input of your receiver has a phono preamp stage in the audio signal path.

Second subtopic -- It is not absolutely guaranteed that the phono preamp in your receiver has a correct RIAA equalization curve. Adjusting the graphic equalizer should be enough to correct the frequency response if that is not correct.

If you do decide to go with a separate phono preamp, connect it to another receiver input besides the phono input.

A "microphone" input to an amp or receiver has an extra preamp stage without the RIAA equalization curve.

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#7 of 9 OFFLINE   Philip Hamm

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Posted October 13 2005 - 07:58 AM

Quote:
It is not absolutely guaranteed that the phono preamp in your receiver has a correct RIAA equalization curve.
I differ with this. I can't imagine that a DENON reciever with a phono input would not incorporate the RIAA curve. I think ever phono input made for the last 40 years probably incorporates it.

John,

If your receiver has an input that says "PHONO" you don't need to buy or do anything but plug the turntable in and listen. Make sure the needle is tracking correctly, but that should have been done for you. Did you install the cartridge into the table or did it come with it?
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#8 of 9 OFFLINE   chuckg

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Posted October 13 2005 - 10:26 AM

I'll toss my hat in here....I don't know about the 3801, but my receiver has an input that is selectable for line level or phono level. You may want to check that your input is configured correctly.
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#9 of 9 OFFLINE   PaulT

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Posted October 13 2005 - 11:30 PM

I checked the Goldring website and the Electra MM has a 5mV sensitivity. The Phono Input of the Denon 3801 (according to the manual) has a 2.5mV sensitivity, so if anything, the output of the cartridge should be overdriving the input of the Denon.

It seems the phono section of the Denon is a better match to a 'high output' Moving Coil cartridge, which will be around 2.5mV (standard MC are low output 0.5mV and unless you have a MC/MM switch on your preamp/receiver, you will need an external phono preamp/transformer to boost the signal for those cartidge types).

In your case I would leave things as is and enjoy your vinyl.
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