Audible Illusions Modulus 3A problems

I just ran across this post and am curious if anyone else has come up with other solutions to the problem of stepped attenuators causing popping noises when turned.

I had exactly the same problem..changed out the tubes and the noise drastically was reduced...only problem is this Pre eats up tubes fairly quickly!

I am sure it is the stepped attenuator. I have switched tons of amps into the system just to have fun
and the preamp, right channel, is consistently the culprit. It is a very loud and destructive sounding pop! The cleaning worked temporarily as mentioned by others.

I do love this preamp and after five years I retain the
original tubes. I've bought others brands to play with but the microphonics were horrible and am going to have to bite
the bullet and spend $100+ at AI or Kevin Deals to retube this.

I am hesitant to do all of this because I pre-paid for the preamp factory direct via my employeement and it took AI a year to deliver and at times I wasn't sure if it would ever show up.

Jo, are you sure your amp is working properly? I found some of these 'pops' using the M3A on amps with some problems on the output stage. It could also be a stepped attenuator problem, but this is my experience. The problem was not the preamp but the amp.
Bye

Johnatmc99,
I have a 1995 AI L-1 and it is as quiet as a church mouse. Maybe just defective units or a very uncommon amount of dust in the environment. AS far as the original post i would just give Jerry a call.

The Preamp sounds FANTASTIC and I may just mute the signal when I change the volume for a while. The $850.00 and up is more than I want to consider but eventually I may go for the $250.00 fix. I appreciate the response from the factory, this is a great preamp! I am considering going to the stock phono section rather than the Gold board so if I do I'll need to fix it first.

I own a pair of AI L-1s. They both have a master volume control in addition to seperate volume controls for the left and right channels. One was manufactured in 1994 and the other in '95. Each pre-amp has a sound that I would describe as a static pop which comes from the loudspeaker. This fault only appears in the left channell volume attenuator of each unit and the '94 unit has the problem to a much greater degree than the '95. I get no such static pop from the right volume control or the master volume control,which may be coincidental. I posted this concern on this forum about a year ago and got a response which suggested rubbing alcohol applied to the volume attenuator with an eye dropper and it did in fact eliminate the problem,but only for a couple of weeks and the problem resumed...no better... no worse.. I also received a post from Jerry at AI asking that I call him as soon as possible as he might have a solution. This was very encouraging and I appreciated Jerry's concern, but when I phoned Jerry, I got Art. Art stated ,under no uncertain terms, that he had never heard of this problem before. The conversation did not go very well and I still have the problem. If the volume is not being adjusted then there is no noise... so I live with it as I thoroughly enjoy the sound of the pre-amp but wish there was an easy fix for the static pop.
This may not be of any help except to let you what to expect from AI and that there are others with the same frustration.

Regards & good luck!
John

I have a Modulus 3 that has been modified by the factory to a Modulus 3A with a similar problem. When changing the left volume you here a scratchy noise but once you leave it it plays okay. Please let me know how you solve this problem.

I think the first response is correct. The same thing is true with my M3A, vintage 1998. Dust and dirt get into the attenuators producing noise when changing them. It has no effect on the performance. AI offers two deals: upgrade depending on year costs up to 850. Trading yours for a new one with AI costs 1390. IMHO, a little noise when changing the attenuator isn't worth either price presuming that the preamp is functioning correctly.

It appears that the switches internal contacts are beginning to loosen/break-down. Suggest you contact me regarding replacing the sub-assembly. Cost is $250 and now takes apx. 7-10 days. Regards, Jerry/AI Service Tech

Hello,
It can be something to do with the tubes. Try changing them to a known good quality set and see it would help. There were other tube preamplifiers I used to have that had similar problems. It turned out to be bad tubes.

Goodluck.

Tora

I do not think this this will help, but I heard that AI3A's built prior to moving to the Swiss made attenuators had more of a problem with the noise you indicate. I heard in the beginning of the stepped attenuator introduction there were problems like you discribe. If you have the older attenuators you may be out of luck. This may be a blanket statement that may not apply to all AI3A's so don't take my word for it.

The spray you use helps, but it is only a temporary solution. I think to get new attenuators it's about $250. I read somewhere it is a easy change, but is only offered at Audible Illusions.

call AI and speak to Art... see if he can help.