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Joule Electra tube noise w/ Merlins (long question)

71.139.8.246
Posted on May 18, 2006 at 16:43:01
rottenclam
Audiophile

Posts: 105
Location: San Francisco
Joined: May 31, 2002
 Hey Rich,

I appreciate this part of the asylum. Your comments are always helpful. Anyways, onto the conundrum that currently plagues my system:

My system consists of the current edition of Joule Electra VZN-100 monoblocks in musicwood, a Joule Electra LA-150 pre, and the latest Merlin VSM-MX speakers. Before I took delivery of my Merlins, the Joules were hooked up to a pair of Alon Exoticas (NOT the Grand Reference, but the babies), which are 88db sensitive with a very OTL friendly impedence curve. At that time, the slight hum coming from the speakers (when no source or preamp was even hooked up) was fairly minor. Audible, but minor. Once the Merlins arrived (arrggghhh, after a 9 month wait), I hooked 'em up and the tube noise/hum increased. I'm pretty sure this has everything to do with the Merlins being 89db sensitive.

As I mentioned earlier, the tube noise/hum is the same WITHOUT any preamp or sources even plugged into the wall. Also, I have put a cheater plug on the outlet to the cord that connects to the variac, floating the ground, in order to see if it was a ground loop, with everything else unplugged from the system. The noise was still there. BTW, all of this is being done on a dedicated 15a circuit.

Of course the noise lessens or increases, depending on the listening distance, but because I sit between 9 1/2 to 10 feet from the Merlin drivers, this noise is quite audible, not during rock and roll or MOST other music, but during the delicate and soft classical passages. This minor thing is now really starting to irk me.

With all this said, the sound is absolutely beautiful. Really, I wonder just how much better it can get? Music never sounded closer. The Joule/Merlin combo is a winner in my book, but during the soft classical passages, this tube noise/hum really irks me.

So my questions are; how common is this complaint? Has there been various editions of the Joules in the past that were more quiet but sacrificed some musicality? Is it a regional issue (having to do with the power company)? Are there different tubes (other than the stock EI or GE in the driver stage) that might be less noisy? Are less sensitive speakers the only solution in sight?

Thanks for your attention,
Jake

Re: Joule Electra tube noise w/ Merlins (long question), posted on March 30, 2009 at 23:50:26
The Groovy Guru
Audiophile

Posts: 50
Location: So Cal
Joined: September 16, 2004
 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.

RE: Re: Joule Electra tube noise w/ Merlins (long question), posted on April 2, 2009 at 08:16:21
Rich Brkich
Dealer

Posts: 611
Location: Near Syracuse, New York
Joined: April 3, 2000
Contributor
  Since: July 1, 1999
 Thanks for your post! Some good tips there. Here are some thoughts on your comments:

"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."

Ahh, the variac.... its benefits allow the OTL's to be operated at the sweet spot of filament voltage and bias, independent of local line voltage, but yes, they can be noisy. The noise here is MECHANICAL... i.e vibration which is why all the things above can make a difference. This vibration is caused by the nature of the variac's design and also by power line noise (DC offset, power line asymmetry). Mechanical damping devices (like a walker puck) just simply act to damp vibration and can be very effective. Because the variac is a type of toroidal transformer, things like DC noise on the power line or asymmetry can get the coils in the the variac vibrating in which case a good power line conditioner can help if this is the issue. The variac will generally always make some degree of noise if you ear is close to it though. I'm pretty sure Jud Barber started putting the Variacs into wooden cases (like the amps main chassis) in later verions of the OTLs becuase the larger wooden enclosure helps cut down on variac noise (sound) a bunch.

A note about power regenerators.. I have tried a few over the years. Some like the PS audio are very good, but there are others which use DC/AC switching (power converters) ... these latter types will do the job in making up for power losses at current peaks, BUT they are often significant noise generators. I have found them to often make a good sounding system sound worse than bypassing them and going directly into the wall. In general, we (I) like the balanced transformer power conditioner units on the OTLs (made by Equitech, BPT and there may be a few others out there) which have worked very well for us and other Joule OTL customers.

Having set-up many systems with Merlin VSM's with Joule OTLs, I have not run into any issues cable runs being a cause for noise. I'm guessing, you must live in a very heavy RF environment. I am not familiar with the VD cables though and some cables designs are more prone than others to picking up noise.

As to the JPS Analog AC and Digital AC power cords, they reduce noise because the cables are made with filter networks and a cable whose dielectric material absorbs EMI/RFI. This help prevent external noise form getting in or out of the power cord.

I'm curious if you have tried grounding your metal rack? If cables make more noise when touching the metal parts of the rack, it could be that the RFI that the rack is picking up has no place to go (ground). Just a thought! :-)

Again, thanks for your post.. glad you are enjoying your Joule OTLs and Merlin speakers!

Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison

RE: Re: Joule Electra tube noise w/ Merlins (long question), posted on April 3, 2009 at 17:02:25
The Groovy Guru
Audiophile

Posts: 50
Location: So Cal
Joined: September 16, 2004
 Thank you Rich for the feedback and insight! I will look into the Equitech and BPT power conditioners, and I will also look into grounding my rack. I am also going to try more JPS cables, as they seem to really work as advertised. As it is, I am enjoying my system immensely!

RE: Re: Joule Electra tube noise w/ Merlins (long question), posted on November 5, 2009 at 12:31:47
jbelt2@tampabay.rr.com
Audiophile

Posts: 7
Location: Florida
Joined: November 15, 2006
 Rich, have the Joule VZN-80, LA-150 MKII and Merlin VSM-M speakers. Considering picking up a balanced power conditioner for my system, but only want to invest the money if it will make a real difference in sound and protection.

I have dedicated 20 amp circuits to both the amp and the pre-amp (plus source components). Power fluctuates at both outlets between 118-124 volts. I live in a high lightning area, so lightning and surge protection are a must. Through your experience, would you recommend the Equi=tech or BPT for my situation? If so, which ones have you had the best experiences with? Thanks in advance.

RE: Re: Joule Electra tube noise w/ Merlins (long question), posted on November 5, 2009 at 14:26:39
Rich Brkich
Dealer

Posts: 611
Location: Near Syracuse, New York
Joined: April 3, 2000
Contributor
  Since: July 1, 1999
 Is the voltage fluctuation long term (i.e. as the day goes by the line voltage drifts up or down over the period of hours) or is the line voltage change short term (jumping up and down over the period of minutes)?

I have heard clear improvements in sound when using these units, especially when we use them in various hotel rooms at trades shows. These transformers based units use their transformers to provide common mode noise rejection... so the quality of performance is dependent to a significant degree on the quality of the transformer.

For example, the entry level Equitech units use nice but cost effective transformers made outside the USA. Their better Q series units use transformers from Plitron (made in Canada IIRC) which are built to better tolerances/winding techniques (possibly also better wire) which cost more.

FWIW - I do not sell Equitech or BPT at this time. I am less familiar with the BPT products, but from their web-site I see they use Plitron transformers... they also look like they have more sophisticated filtering (i.e. more filters in addition to the transformer and the spike/surge protection looks for sophisticated than the Equitech- In general my experience with the "filtered" outlets on the Equitech is that they do not very good sounding). Some of the BPT products use the ERS material... though the few inside pics I see of their units that use it show it is used allot... my experience is that using too much of this stuff can tend to make things start sounding too dry.

Since you are in FLA... I would make sure the spike/surge protection is very good in whatever you get given the amount of lightning Florida gets. From experience with Equitech units in several customer hands, I know they do a good job in spike/surge protection... from their website - it looks like BPT would do a good job too.

What am I using these days???... on more budget gear, I have on of the cheaper Equitech Son of Q units around. For the big rig (Joule, Audio Aero etc) I am using Running Springs PLCs.. mainly on front end (CD/Pre use). On mY OTL's I generally use a JPS Aluminata Power cord (a bit of a power conditioner in its own right) going direct into a 20A JPS In wall Wired circuit.

Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison
RE: Re: Joule Electra tube noise w/ Merlins (long question), posted on November 6, 2009 at 04:25:17
jbelt2@tampabay.rr.com
Audiophile

Posts: 7
Location: Florida
Joined: November 15, 2006
 Rich, thanks so very much for the great response. You're the best. Jim

RE: Re: Joule Electra tube noise w/ Merlins (long question), posted on November 14, 2009 at 20:01:17
jmimac351
Audiophile

Posts: 852
Location: Central FL
Joined: April 7, 2000
 Jim, I have a nearly identical system as yours and am using the Equitech Model 1.5Q. I have the VZN-80, LAP 150mkII, CD player, etc plugged into it and it works great. I have VSM-MM speakers. I've forgotten what it sounds like without it. I live in Orlando and had the same concerns.

Jim

Thanks for addtional info Jim! - NT, posted on November 15, 2009 at 08:16:34
Rich Brkich
Dealer

Posts: 611
Location: Near Syracuse, New York
Joined: April 3, 2000
Contributor
  Since: July 1, 1999
 NT
Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison
An update!, posted on June 6, 2006 at 11:32:16
rottenclam
Audiophile

Posts: 105
Location: San Francisco
Joined: May 31, 2002
 Rich,

After speaking with another Joule customer that shares this same problem, he shared with me a technique for substantially lowering the noise floor:

1. Once the amps have warmed up, with no music playing, put your ear up to the speaker. Now, reach down and press the DC offset button (or any of the output tube bias buttons). Has a significant part of the noise/hum stopped? When you release the button does the noise return? If so, move on to step #2. If you hear no difference than this tweak is not for you.

2. Insert a toothpick between the button and the edge of the hole in which the button sticks through, with the button depressed, so it can be held down.

3. DO NOT, I repeat, DO NOT forget that you cannot have two buttons simultaneously pressed on one of the monoblocks. Jud Barber makes this very clear in the manual. Only put the toothpicks in when you're just about to sit down for critical listening. Take them out when not doing so. When the toothpicks are in, you cannot accurately adjust voltage, and you definately cannot bias any of the tubes.

Checking the DC offset does not have any effect on what you are hearing musically, other than dramatically reducing the noise/hum of the amp that ensues during basic operation. From what I understand, the communication between the display and the point in which you press the button are not in the musical signal path.

With that said, I have talked to Jud, and he has told me that he has shipped numerous versions of the Mark V iteration of the VZN-100, and he has not heard the kind of deep concerns that myself and this other customer have expressed. Maybe this noise/hum issue is relegated to mine and the other customer's OTLs only. Maybe we're just the ones that are most sensitive to it, and nobody else seems to be concerned. Either way, the "toothpick tweak" is an aural lifesaver for me. It may put the user at a disadvantage when trying to interface with bias checks, voltage checks, etc; but sonically, this, in my opinion, is the only way that I can listen to the amps now.

-Jake

Re: An update!, posted on June 6, 2006 at 13:00:25
Rich Brkich
Dealer

Posts: 611
Location: Near Syracuse, New York
Joined: April 3, 2000
Contributor
  Since: July 1, 1999
 Very intertesting (and clever!)!

This suggests to me that there must be something going on in the wireing to the bias controls that is injecting noise into the amps... something that I will have to talk with Jud about.... It can well be that RFI is sneaking in via the system that connects the amp to the built in LCD meter... loading it by pushing one of the bias buttons down may give the noise somewhere to go or prevents it from making its way in.
Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison

Re: An update!, posted on August 29, 2006 at 18:23:34
tms0425
Audiophile

Posts: 7
Location: Indiana
Joined: September 16, 2005
 Just wondered if this was ever solved besides this little fix?

I have the EXACT same behavior with my VZN100 MK V's and assumed they are all that way. I noticed it reduced the noise when the driver test buttons are pushed, but never even thought about operating it that way full time. The risk of screwing up and pushing a bias button simultaneously seems too great to me.

I previously had Reimer Teton GS's which were 95db sensitivity and it was really intrusive with them on quiet passages. I didn't worry about it too much since I had VSM-MX's on order and after talking with Jud a couple of times I decided it was normal and I'd just have to live with it. With both my TSM-MX's and the VSM-MX's, the reduced sensitivity helped, but the noise/hum is definitely still there.

These amps otherwise sound so terrific. Do I need to just get over it and enjoy them?

Tom

OK... lets see..., posted on May 18, 2006 at 17:04:52
Rich Brkich
Dealer

Posts: 611
Location: Near Syracuse, New York
Joined: April 3, 2000
Contributor
  Since: July 1, 1999
 Are you VZN-100s MKIV or MKV... just want to be sure what you have. If you have one of the newer version of the 100's they should have a mute switch on the input. Does the noise occur when the input of each amp is muted? Is the noise level the same in each channel?

Are you using any special power conditioning or power cords on the amps?
Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison

Re: OK... lets see..., posted on May 18, 2006 at 19:00:07
rottenclam
Audiophile

Posts: 105
Location: San Francisco
Joined: May 31, 2002
 Rich, thank you for your attention.

My power cords have remained stock (the standard Chinese "Well Shin" cords that Joule provides), and I have experimented with a few different configurations of giving them power. For a while I was using a Shunyata Hydra, but later sent that piece packing. Currently I have the system on a Cablepro bar (the latest one endorsed by Naim) which is made by Wavelength (the company out of Texas, not to be mistaken with Gordon Rankin's company). This Cablepro bar goes directly into the wall. For a while, in another room (with another system), I did have the Joule/Merlin system plugged into the Hydra, and later the Cablepro, which then fed into a PS Audio wall outlet.

With the exception of power cords, which as I said before, remain stock, all cabling is Audience AU24. My Joules are the latest editions, having been delivered in October of 2005, and I have experimented with the mute switch both on and off. The noise remains. Both channels have it, although the right channel maybe has it a hair worse. Sorry, I dont have an SPL meter in order to confirm how much of a differance the sound is between channels, but from my ears, I can tell you it is very very slight.

The power conditioning seemed to have little to no effect, but as I said, the only "conditioner" I've used was a Shunyata Hydra 4. I am open to any suggestions, but in your experience, is there just some noise with the Merlin/Joule combo that comes with the territory, or are they supposed to be very quiet?

-Jake

Re: OK... lets see..., posted on May 19, 2006 at 13:44:32
Rich Brkich
Dealer

Posts: 611
Location: Near Syracuse, New York
Joined: April 3, 2000
Contributor
  Since: July 1, 1999
 ... thanks for the addtional info, it helpts allot. With the amps muted and nothing connected to thier inputs, that pretty much tells me the noise you are getting is from the amps..

I am not familiar with the cable pro, but I don't think it is helping or hurting the issue here as I am reasonably sure the issue you are dealing with is not power line related as it sounds like you are syaing that indpendant of whatver power cord or power line conditioning you have used, that the noise is still there in the same manner.

Lets move onto your amps... The MKVs are the quietest OTL Joule has made. Having said that, that does not mean these amps are dead quiet. Thier design (floating power supplies and the circletron design topology) mean that if things are not perfectly in balance, some noise is going to be generated and this is uusally the case. Also there can also be some variability between pairs... some being a little more quieter or noiser than others. I have knwon Jud to do some tweaking (probably fiddiling with grounds inside the amps) to some pairs of OTL to get them a quieter. I have heard a few pairs of MKV version Joule VZN-100 OTLs on VSMs and the noise level is pretty low on these amps... requiring you to be standing next to the speaker to be able to hear the noise - these amps though are never dead quiet though (no amp is actually and the all have varying amounts and types of noise) and the more effiecient the speaker, the greater the problem. Having said that, you may be able to get things a little more quieter by getting the balance between the two halfs of each amp better matched. I would like you to check the DC offset - that extra button near ther bias buttons (no music , inputs muted) of each amp and let me know what each amp is reading. Depending on what you are reading there I amy have you tweak bias settings to get things dialied in a little better which may help reduce the noise a bit.

I can imagine in a setting where the noise floor in the listening room is low enough, that even a fairly quiet pair of VZN-100s when hooked up to a efficent speaker like the VSMs will have a noise level that is audible from several feet away. What hurts here is that the noise tends to be buzzy in nature which is more apparent to the ear in nature than a hum.

Now, there are seom possible issues we have not considered here....

1) RFI.. probabaly not a issue here..
2) Power line issues (which convential power filter type products you have used cannot possibly correct).
3) There is something amiss with the common variac power supply unit that is causing both amps to be more noiser than they should be... never seen this before and I doubt this is the case.

Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison

Re: OK... lets see..., posted on May 19, 2006 at 22:37:33
rottenclam
Audiophile

Posts: 105
Location: San Francisco
Joined: May 31, 2002
 Rich,

Thank you for such a thorough and thoughtful response. As you said, my expectation should be tempered in accordance with the nature of tube amps, which tend to be more noisy than solid-state. And yes, I know that some tube amps are more noisy than others, my curiosity is just whether the reputable Joule/Merlin combo is as noisy as my setup has turned out to be.

Last night while listening to Stevie Ray Vaughn, Sigor Ros, and Miles Davis; I was again struck by how deeply I can hear into the recording, but it was only during the very delicate parts of the "Round About Midnight" Miles SACD that the hum bothered me. Unfortunately this is heard quite predominantly during classical music, of which there are so many delicate and quite parts, so that is a bummer.

My DC Offset seems to be reading normal. I usually check it every couple of days just to make sure that it is not at 0 or 1 (it seems to be anywhere from 5 to 40) and I wait until the amps have been on for at least an hour, before checking. I have experimented with the feedback controls, the variac settings, and the bias, all in order to fit my room and my musical tastes. I keep the amps between 64 and 65, the output tubes around 27, and the input/driver stages close to 120. My feedback is set to around 7 or 8 o'clock, depending on whether I am in a more musical or analytical mood.

I have been in contact with another Joule customer, with a similar system, who is experiencing the same thing, so I will update you with our collective findings. He took delivery of his Joules in December (mine came in October), so maybe it is a current tweak from Jud that is not working out as planned.....or not.

Updates to follow. Thanks again Rich.

-Jake

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