Audiolab 8000A low volume from cd input than tuner input - diyAudio
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Old 23rd April 2013, 01:55 AM   #1
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Default Audiolab 8000A low volume from cd input than tuner input

Strange issue:

I tried to do a comparison between 2 different cd players on how they sound, so i connected them to the cd and the tuner inputs of the Audiolab 8000A (early version).
The player that is connected to the tuner input sounds louder than the other connected to the cd input.
I did the same with only one player, connected at a time in different inputs, same thing;i have to adjust a little higher the volume knob.
While the volume is louder when connected to tuner and tape 1&2 inputs,it's quiter when connected to the cd input.
Cd players are NAD521bee and Marantz CD63 SE KI.
According to the Audiolab's manual all inputs have the same sensitivity 100mV/20K and i guess they should sound of the same level.
Nad's output level at 0dB is 2.1V rms with output impedance 200Ω.

Is this normal behaviour or the CD input of the amp is faulty?
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Old 23rd April 2013, 05:41 AM   #2
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More likely the CD input is actually less sensitive by design and the manual is wrong. CD levels output are much higher than old analogue sources like tuners and cassette recorders
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Old 23rd April 2013, 08:42 AM   #3
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So you are saying not to worry?

Where is better to connect it?

The signal is not distorted, i just have to lower the volume when connect it to tuner/tape inputs
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Old 23rd April 2013, 09:27 AM   #4
AndrewT is offline AndrewT  Scotland
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The CD is possibly a direct connection from vol pot to power amplifier.
The other inputs possibly have a gain stage added in. It might be as little as +6dB (2times voltage gain). This stage may be before the vol pot. So be careful, an early located gain stage can be overloaded. Some testing of the various inputs should identify what is happening.
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Old 23rd April 2013, 01:16 PM   #5
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in an Audiolab 8000A "earlier model" you have about other 10 serious issues to trouble you than a gain mismatch...
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Old 23rd April 2013, 05:10 PM   #6
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I called IAG and told me that the cd input sensitivity is lower than 100mV in the first 8000a series.
They suggested to use either the tuner or tape 1&2 inputs, nothing to worry about.
Sakis, 10 other serious issues? Please explain (Για εξηγησε μου σε παρακαλω ρε πατριωτη!!!)
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Old 23rd April 2013, 05:28 PM   #7
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γεια σου πατριωτη

Hello!!
-- earlier versions had 220 volt primary windings now days most countries have 230V
( in such a bad design the few more volts might be critical )
--PSU capacitors right side of the amp placed horizontally some years ago, combine horizontally with excessive heat that tends to concentrate in the sealed box and your caps are toasted
--Manufacturer likes to run drivers hot that could actually destroy quiet a lot of pcb area and expect plenty of soldering to be done
--expect other smaller capacitors to be toasted favorite areas around the drivers and secondary power supply
--expect also toasted or grilled resistors that often have values that drifted from original value
--expect the all situation to be even worst of the amplifier has been working for long time in ambient temp above 22 degrees
--expect the bias to be already drifted to anything and vary from ch A to Ch B benefit of the all above situation
--Presuming that the above is fixed you need to find out how the hell you will be able to set the bias and that can be a rather painful story
--If you have the time to bother with this and decide how much bias and how it will be ever possible to set it , you may verify your setting at 22 degrees in your listening area and then you will be very surprised to realize that the presumed set bias will vary once if the amplifier is working with the cover on or not, and even if the temperature in your listening area goes higher than 22 degrees to something like 28 for example for any possible reason IE room thermostat failure or summer !!! ...variations though are quite high

Was that enough ?
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Last edited by east electronics; 23rd April 2013 at 05:35 PM.
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Old 23rd April 2013, 06:18 PM   #8
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since you are able to read Greek you may wana take a look at this

Audiolab 8000 ?????? ??? ??????????
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SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
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Old 24th April 2013, 01:04 AM   #9
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The only issue i noticed after some hours of listening at low volume,is that the front left side of the amp gets quite hot, measured it at 37C on the chassis,you cannot even touch the amp.
I took some measurements inside the amp and this area goes up to 50-52C.
Is this normal or maybe should i return the amp?It's the early version.
Thanx for your link, i'm still a member but the last years i have moved in the UK.

Please advise what to do
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Old 24th April 2013, 07:49 AM   #10
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well 37c ....52 c.... could you please state the room temperature ?
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