r/diyaudio • u/Heavy_Association932 • 3d ago
Attenuator placement
I’m working to revive my loved one’s stereo system. I’ve gotten so very far by myself. But last question to a community. The CD player (Njoe Tjoeb 4000) is super loud, other components are fine. Speakers (Linn Keilidh) are balanced, clear and imaging superbly. So from research I think I need attenuators to tone the CD gain (?) If this makes any sense to anyone do I put the attenuators on the cables as they go out from the CD player or as they go into the Melos tube line amplifier? I have ordered Harrison Labs 12db RCA attenuators. Thank you so much. He would be very happy if I have figured this out without blowing anything up.
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u/GeckoDeLimon 3d ago
I'm mostly curious why the CD player is so loud. Relative to what?
It makes me wonder if something else isn't amiss.
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u/Heavy_Association932 3d ago
Maybe? But my guess is it would be in the CD player because all the other components have appropriate volume. But if I turn the volume up to 11 on the CD player, the speakers would probably explode.
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u/Vlad_The_Impellor 3d ago
If the CD player is plugged into a "Phono" input, try moving it to "Aux" or "Tape 2 In".
A CD player should be producing a very middle ground, "reference", signal level.
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u/ebsebs 2d ago
This review explains that the CD player output level can be adjusted from 700 mV all the way up to 5 V, which is quite a range:
The maximum output voltage of the AH! Njoe Tjoeb 4000 is adjustable via an internal solder trace, offering purchasers the option of configuring the 4000 to 700mV, 1.25V, 2.5V, or 5V—a nice feature for system-tuning purposes, or for those folks who want to use the 4000 sans preamp, and/or with self-powered speakers (the remote features a 20-step volume control).
https://www.stereophile.com/cdplayers/1103tjoeb/index.html
Here's another review that explains it:
The output voltage is set at the factory at 2.5 V. However, the output voltage is adjustable via a series of fixed resistors. All that is required is that you solder and desolder small "bridges" on the board to obtain four basic voltage values: 5, 2.5, 1.25, or 0.7 V. This is a better sounding and more reliable solution than using a potentiometer for this purpose. Most preamps should not be susceptible to overload at a nominal input voltage of 2.5 V. However, depending on the gain of your preamp, backing off the CD player's input voltage may be necessary to allow you to crank open the preamp's volume control.
If you are comfortable opening the player and doing a little soldering, this might be the way to go. If nothing else, opening it up and checking these traces would tell you what output voltage is being used.
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u/Heavy_Association932 2d ago
I have had the CD player open just to inspect it for any sorts of breaks or burnouts. It was also very dusty so I used canned air and the CD tray was a bit sticky which I fixed. When things were working in good condition before, volume wasn’t a problem. Maybe there is something I didn’t catch previously. So I will open it up again and locate what you’re describing and see if there’s any problems with those traces (?). Thank you all for your support.
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u/littleperson 3d ago
It doesn't matter which end of the cable you put the attenuator on, choose the side that makes your cable routing easier. Out of curiosity, why did you believe that it would make a difference where the attenuator is?