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In Reply to: Joule Electra tube noise w/ Merlins (long question) posted by rottenclam on May 18, 2006 at 16:43:01
I wish I had found this thread a long time ago. I have a Joule Electra VZN80 MKV amplifier and Merlin VSM-MX speakers, both of which I purchased over two years ago. I have experienced the buzzing/humming problem for the entire time. The sound has been so good that I have been willing to put up with the noise. Well, ... I just tried the toothpick tweak. It works as advertised!
I also tried a different version of the tweak. I was concerned that the toothpick might break and fall into the amplifier, so I tried something else. I put a 100 gram cylinder-shaped weight on top of one of the bias buttons instead of a toothpick. That works just as well. The goal is to keep the button depressed at all times, so anything that is heavy enough or provides the proper leverage (like the toothpick) will do.
Some other tweaks that I tried before the toothpick trick that helped to reduce, but not completely eliminate, the noise:
1. Provide good isolation for the variac. The variac used to hum quite loudly. I use an Equarack isolation system, which utilizes a combination of viscoelastic and ball bearings. This tweak reduced the noise level to a barely audible level. Also effective for isolation were a 4 inch maple block (good) and a Grand Prix Monaco amp stand (better, but expensive).
2. Place a Walker resonance control disc on top of the knob of the variac. Not quite sure why, but this tweak also reduced the noise quite a bit. There is a steel shaft under the knob. Perhaps the Walker disc helps to prevent the shaft from disturbing the big coil shaped transformer that is inside the case of the variac. I am just speculating. Anyways, the Walker disc fits perfectly on top of the knob. This tweek is very effective.
3. Use a good power conditioner. I use an Audience aR1p (relatively cheap to buy) with the variac. If I unplug it and go directly into the wall, the noise increases.
4. Use a power regenerator. After using the Audience aR1p alone, I ttied it in combination with an Exactpower Ultrapure power regenerator. This combo further decreases the noise and makes the music sound more detailed with even better imaging (in my opinion). Bobby recommended the Equitech 2Q power regenerator, which I might try in the future. The Ultrapure is pretty darn nice, though, at half the price (used).
5. Place Dynamat on the underside of the variac. This was the first tweak that I tried. It provided a moderate degree of noise reduction.
Other comments:
The Joule OTL amp and/or Merlin speakers/SBAM seem more sensitive to picking up noise compared to other amps/speakers that I have owned. Make sure that interconnects, power cables, and speaker cables do not touch each other, and if any of them they do, make sure it is as close to a 90 degree angle as possible. My speaker cables (Virtual Dynamics Master) cause a buzzing noise if they are in contact with the interconnects or if they are touching metal (my rack is made of metal).
Also, the VZN 80's binding posts are somewhat close together, so care must be made in placing spades onto the posts. If the spades are too close to each other, they can create a buzzing noise. This happened to me even though the spades were not touching.
Finally, power cords from JPS Labs (AC Analog and Digital) were effective in reducing noise. I have them with my preamp and sources. I'm not sure how they contribute to noise reduction, but they do.
I currently have Virtual Dynamics Revelation power cords for my amp/variac and for my BPT power conditioner that I use for my preamp and sources. I've tried to remove the VD cords but found that I missed the very good soundstage and the "you are there" sound that they impart. They don't add noise, nor do they seem to make a noisy background better (in my experience). I also have VD Master LE interconnects between my preamp and SBAM and between my SBAM and amp. I tried changing those, too, but could not talk myself into getting rid of them for the same reason I did not change the power cords. I previously had Cardas Golden Reference throughout - very nice, but a bit warm and compressed, with less detail, compared to the VD cables. When funds permit, I will eventually try the JPS Aluminata cords for comparison purposes.
Anyways, I thought I'd post my experiences for others to view. In my opinion, the Joule/Merlin combination is well worth the time and patience to get it right. I now have a very quiet background; my system sounds dialed in.
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