I would just return it. You've confused input and output impedance with sensitivity, btw.
Audible Illusions Modulus 3A troubles
Just purchased a used Audible Illusions Modulus 3A preamp for my system but only getting very very faint sound when turned all the way up. Plus the very very faint sound is very fuzzy as well.
I popped off the top & re-seated the 4 tubes but that was no help.
My 2 amps are both rated at 50k ohms input sensitivity, so this is the right preamp for them at around 1.2k ohms output sensitivity, running a biamp configuration. AI documentations confirms this.
I've tried each amp on its own, using both output RCAs on the preamp, to no avail.
How to tell what is wrong...looking into the return policy, but at least the shipment was insured.
Any ideas?
Thanks-Kevin
+1, I also would return it. The unit is not working. A common problem is with the tubes; they may need to be replaced with a new, high-quality set. Additionally, excessive noise or distortion might indicate a malfunction within the preamp itself. Further investigation into the preamp’s internal components may be necessary. I Suggest you return the unit. ASAP!
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yes, i've been through each setting, each input (they all come through in the same very very quiet manner), even to the point of adjusting the jumper switches behind the tubes - they also had no effect. Is there a way to prove that it is the tube? Is it ok to swap them around? I've heard one should keep the tubes in the same place. |
@hiend2 , more like 6 years! |
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Tubes in this AI unit may need to be replaced. AI designs push the biasing of these 4x6922 tubes to their limit. So potential lifetime of tubes is much shorter compared to those from preamp circuit designs from other manufacturers such as Audio Research, VTL, etc. You can buy 4 JJ 6299 tubes for $29/each from Amazon. You can get this to work without breaking the bank. |
@pwerahera +1 Good suggestion! Buy and try a new set of 6922's before returning the preamp. The joys of tube gear ownership! |
The tube filaments are powered continuously even when the power switch is in the off position. Even though the amount of electricity to the filaments is at a lower level, the tubes don’t last as long. I bought a used Audible Illusions L3 linestage. When I replaced the tubes with new ones I was amazed at how much better it sounded. It had much more gain since the setting on the volume knob was at a lower point for the same loudness. Try new tubes before you return it. Good luck. |
in the manual there is a good description of how to test tubes by rotating the two for the line stages, so will try that. I haven't tested phone input yet, they have their own set of tubes. Four 6922s in total - I've found the least expensive JJ brand for around $22 each. Will do this today during the Bears game, as I don't expect to be happy about their performance against Packers. Anyway, will try this to see if anything stands out. |
Two things: Is your cartridge a moving magnet or at least a high output moving coil?
Secondly, are you aware of the mute switch which is pushed in while the unit is not playing, but must be out when playing music? I've owned both an Audible Illusions 2D and 3A for many years. It's also been about 10 years since I've owned one. What I just wrote about the mute switch maybe just the opposite. The AI's are very long lasting units if you use the AI tubes. It is also a very good sounding unit with phono built in. Bob |
@kevinshunt, you should ask for a full credit refund on your Audible Illusions Modulus 3A preamp. The preamp was preowned, and you have no clue else might go wrong. Sometimes you repair one thing and something else breaks. Others on this Forum may have a different opinion but THIS is my opinion. I have heard that common issues with the Audible Illusions Modulus 3A preamp include problems with the tubes, which may need replacing with high-quality ones to prevent excessive noise or distortion.
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