I have an Alpine/Luxman LE-109 phono stage. It seems to be making noise! It is second hand, and, I am not sure if maybe this is normal for phono stages?
It was giving a hum if I turned the volume above normal level on the amp. This amp (audiolab 8000s) gives no noise at all turned right up with the CD player, so this is definitely coming from the phono stage.
I now try it without the turntable attached. On the phono stage there are 2 phono inputs, one for MC and one for MM/MC.
At normal volume I don't notice any noise (though my room is not exactly silent anyway). With the volume turned up, MC/MM setting gives a smooth white noise kind of sound. MC straight setting gives the same but with a kind of buzz in addition.
Also there are buttons on the front, for MM/0 dB, 22dB, 32dB, and for 3ohms 40, and 100. They are anyway not used in MC straight mode. But just to let you know, they make noise too when switching them (only while in MC/MC mode though). Also the noise increases in MC/MM setting when the setting is changed from 0 to 22 and then more to 32.
I opened it up and could see nothing obviously wrong. No burned parts or anything obviously loose.
Any ideas? I can post a picture if that will help
Thank you!
Justin
It was giving a hum if I turned the volume above normal level on the amp. This amp (audiolab 8000s) gives no noise at all turned right up with the CD player, so this is definitely coming from the phono stage.
I now try it without the turntable attached. On the phono stage there are 2 phono inputs, one for MC and one for MM/MC.
At normal volume I don't notice any noise (though my room is not exactly silent anyway). With the volume turned up, MC/MM setting gives a smooth white noise kind of sound. MC straight setting gives the same but with a kind of buzz in addition.
Also there are buttons on the front, for MM/0 dB, 22dB, 32dB, and for 3ohms 40, and 100. They are anyway not used in MC straight mode. But just to let you know, they make noise too when switching them (only while in MC/MC mode though). Also the noise increases in MC/MM setting when the setting is changed from 0 to 22 and then more to 32.
I opened it up and could see nothing obviously wrong. No burned parts or anything obviously loose.
Any ideas? I can post a picture if that will help
Thank you!
Justin
Attachments
It all seems absolutely normal. Do you know what are the published noise/sensitivity specs? What is your cart?
analog_sa said:
Specs for the phono stage:
Rated output 150mV
Harmonic distortion factor 0.005% (at the time of 1kHz and 1V output)
Input sensitivity PHONO 1160 μV
PHONO2 2.5mV (0dB), 220μV (20dB), 80μV (32dB)
Input impedance PHONO 1100 ##
PHONO 247 kΩ (MM)
3Ω, 40Ω and 100Ω (MC)
SN ratio PHONO MM 95dB (MM, 1V output)
PHONO MC 80dB (MC STRAIGHT, 1V output)
Frequency characteristic 20Hz~20kHz
Crosstalk 85dB
Power source 100V 50/60Hz
Electric power consumption 25W
External size 438W×63H×310Dmm
Weight 4.5kg
And the cart is DL 103, with a Pro-ject Perspective deck. But this noise comes even when the deck is not plugged in at all to the phono stage. So I am figuring it is the stage.
Justin
Hi,
All sounds normal - you should get less noise with the cartridge plugged in.
Hum (not noise) is usually bad earthing practise in the turntable.
🙂/sreten.
All sounds normal - you should get less noise with the cartridge plugged in.
Hum (not noise) is usually bad earthing practise in the turntable.
🙂/sreten.
Phonostage is hissing
Hi
How is your phonostage powered - ac or batteries?
I have a few phonostages, including 2 old Lenteks - one of these acquired about a week ago. They are battery powered with a 9V battery. The one I had originally started hissing on the right channel. The second one does exactly the same on the same channel.
I now use them in a tandem fashion. the phonoleads from the arm go into each one's silent left channel.
The batteries I use in them are rechargeable. Someone suggested to change to ordinary 9V batteries. I haven't tried it yet.
bulgin
Hi
How is your phonostage powered - ac or batteries?
I have a few phonostages, including 2 old Lenteks - one of these acquired about a week ago. They are battery powered with a 9V battery. The one I had originally started hissing on the right channel. The second one does exactly the same on the same channel.
I now use them in a tandem fashion. the phonoleads from the arm go into each one's silent left channel.
The batteries I use in them are rechargeable. Someone suggested to change to ordinary 9V batteries. I haven't tried it yet.
bulgin
sreten said:
Really?? With the cartridge plugged in, I should get less noise than with no turntable at all connected to the phono stage??
Re: Phonostage is hissing
With a power cord that goes to the mains.
Also in Japan there are only 2 pins in the plugs. I come from England where we have 3, the 3rd being earth. So I don't quite get how it works with only 2, but I have been told that somehow it does work and there is an earth.
Justin
bulgin said:
With a power cord that goes to the mains.
Also in Japan there are only 2 pins in the plugs. I come from England where we have 3, the 3rd being earth. So I don't quite get how it works with only 2, but I have been told that somehow it does work and there is an earth.
Justin
You might find only two pins on the plug, but is there a metal strap on the plug ? That is the earth connection . I've seen plugs like that but can't remember if it was in Japan.
ashok said:
Metal strap? It is just a cord with a plug with 2 pins. I guess it is the same across continental Europe too. The guy in the shop said the earth is the negative, or something. Anyway, it's all like that here so it must be right I guess.
Ah.... now I have looked it up on wikipedia.
"Type A (North American/Japanese 2-pin)
An American ungrounded polarized plug and a Japanese ungrounded socket. This plug can only be inserted into the socket in one manner, with the wider pin — the neutral contact — being inserted on the left.
An American ungrounded polarized plug and a Japanese ungrounded socket. This plug can only be inserted into the socket in one manner, with the wider pin — the neutral contact — being inserted on the left.
NEMA 1-15 (North American 15 A/125 V ungrounded)
Standardized by the U.S. National Electrical Manufacturers Association [5] and adopted by 38 other countries, this simple plug with two flat parallel pins, or blades, is used in most of North America and on the west coast of South America on devices not requiring a ground connection, such as lamps and "double-insulated" small appliances."
So, maybe has no earth then!?!? That is the standard in the US right? And the Europlug (most standard in Europe) also is an unearthed 2 pin plug. So what do you guys in the US and Europe do when you stick a knife in your toaster? Do you just get fried? And, more to this point in question, how are your phono stages earthed?!
Thanks!
Justin
Justinasia said:
Why so surprised? The effective noise source at the input dependes on the source impedance and with a cart connected is always less than without.
input bipolar transistors that have been "sufficiently" stressed (by things like static electricity) but not stressed to the point of hard failure can become noisy.
is the preamp making more noise than it "should"?
mlloyd1
is the preamp making more noise than it "should"?
mlloyd1
yesJustinasia said:
Having an earth pin or even adding one correctly will not protect the user from this kind of stupidity.
If you genuinely believe that you need to be protected from these kinds of abuse then consult an electrician.
I am only aware of two devices that MAY work in your situation, ELV and RCCB. But, I WILL NOT BE TESTING them in any similar manner.
mlloyd1 said:
Well, as I have never had a phono stage before, I do not know how much noise it "should" be making. That's the trouble really. I was actually expecting it to make NO noise! Like my CD player (just a portable one) makes no noise when a CD is not playing, even with the amp turned right up. And even the computer, with no audio playing, through the amp, is making less noise than this phono stage. How can I tell if it is more than it "should" be? One thing I could do is record it I suppose, and sent it here (can you attach audio files on the forum?)
If it is those bipolar transistors, are they cheap/easy to replace? And is that something I can do myself with a soldering iron or something?
AndrewT said:yes
Having an earth pin or even adding one correctly will not protect the user from this kind of stupidity.
If you genuinely believe that you need to be protected from these kinds of abuse then consult an electrician.
I am only aware of two devices that MAY work in your situation, ELV and RCCB. But, I WILL NOT BE TESTING them in any similar manner.
Well, yes you've got to be kind of stupid to be putting a knife in a toaster right! But hey, I was a kid! Had to get some toast out of the toaster that was stuck. Then I thought to myself, "Oh, I wonder what happens if I touch those pretty red glowing strips of metal?" So I did (with the knife). Suddenly all the lights turned off and gave me a big shock!! But, shock from the lights going off! Absolutely no electric shock.
I didn't do it since.
That was in England, where we have 3 pin plugs. Seems to work well right!
Ah but to get back to the point, could this noise be due to not having an earth?? What do you guys do in the US and Europe? Do you have simple 2 pin plugs running from your phono stages??
Justin
Double-insulated is beyond the abilities of most diyers. So three wire with anything metallic that the user could touch safety-grounded is the minimum acceptable. My phono stage has a separate raw supply; that box has a three-wire power cord. There is a stout wire that runs along the others in the cable connecting the raw supply to the preamp box. It electrically connects the two case grounds, thus the remote preamp box and metal parts are also returned to the safety ground.
It is sometimes hard to explain how much noise a noise is.
If you have to put your ear up to the speaker to hear it, it is possibly normal. If is distinctly audible with no music playing and gets louder as you turn up the volume, then it is noise and it is being generated in your preamp circuitry. If the power cord has not been modified, then it has a floating-ground power supply, and 2 pins is just fine. The transformer chassis is electrically grounded to the preamp case. It will not be the source of hum, much less hiss.
As previously stated, if it was coming from poor grounding, it would be a distinct hum, not a hiss.
The unit looks like is was made during the mid 1980s. My guess is that one or more of the electrolytic caps used to bypass the power supply near the active gain stage has started to break down. This will produce a hiss, usually quite consistent in tone, unlike static on a radio. Let's not forget that the overall gain in a low-level MC phono preamp is about 68db - that is a voltage gain of about 2600 times the original signal. It dosen't take much of a signal to make very audible noise (music or otherwise).
To fix it, get a schematic and start tracking down all of the electrolytics in or near rthe gain stages and replacing them with new, same-value parts. Test it after each substitution. When you get the bad one, the hiss will dissappear. Then, finish doing all the rest, cause they will not be far behind. 😉
Good Luck!
JesseG said:
It is sometimes hard to explain how much noise a noise is.
If the power cord has not been modified, then it has a floating-ground power supply, and 2 pins is just fine. The transformer chassis is electrically grounded to the preamp case. It will not be the source of hum, much less hiss.
As previously stated, if it was coming from poor grounding, it would be a distinct hum, not a hiss.
The unit looks like is was made during the mid 1980s. My guess is that one or more of the electrolytic caps used to bypass the power supply near the active gain stage has started to break down. This will produce a hiss, usually quite consistent in tone, unlike static on a radio. Let's not forget that the overall gain in a low-level MC phono preamp is about 68db - that is a voltage gain of about 2600 times the original signal. It dosen't take much of a signal to make very audible noise (music or otherwise).
To fix it, get a schematic and start tracking down all of the electrolytics in or near rthe gain stages and replacing them with new, same-value parts. Test it after each substitution. When you get the bad one, the hiss will dissappear. Then, finish doing all the rest, cause they will not be far behind. 😉
Good Luck!
I am trying to search for a schematic. So far all I can find is a website where you can pay to download the user manual or the servie manual. If no-one knows where I might find it for free, then, which manula shoudl I download? User or service? (Service is more expensive).
Also I found this info on another site, in case it gives you more info on my problem:
Low Noise, High Gain: circuitry
To handle delicate MC input signals with the tenderness they deserve [sic], the LE-109 has an "MC Straight" circuit configuration in which the audio signal goes directly to the phono EQ section. That way, no selection circuitry or other obstacles stand in the way of fidelity. This circuit uses two discrete dual differential, full complementary amplifiers. Low-noise high Gm FETs are used throughout. Powered by dual independent bipolar power supplies, these high-speed amplifiers set the ultimate standard in phono pre-amplifiers.
Independent L/R Power Supplies
The LE-109 has two power transformers that are completely independent. This approach prevents cross-channel interference and is far superior to the usual ripple prevention technique of simply employing a powerful regulator circuit.
[From a pop-up window link off this page:
http://www.thevintageknob.org/LUXMAN/LV109LE109/LV109LE109.html# ]
Definately the service manual - if you plan to keep this preamp long-term then you will need the service info. If you sell it, having the service manual will enhance the value. 😀
This is the input you should be using for your DL-103.
BTW: it just occurred to me: do you have the shorting plugs installed on the other pair of inputs when you are using the phono stage? These are very important. Most multi-input phono stages from this era were shipped with a pair of shorted RCA plugs that were intended to be inserted into the unused inputs (if any). This was to prevent noise pickup from the open jack.
If these are not in place, this could easily account for your noise 'problem'. 😉
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