Regarding transformer mechanical vibrations

[AnotherJohnson]

Some observations that may help someone else.

Earlier this year we acquired a house in the neighborhood where our first and only grandchild lives. It has a pretty decent second floor “bonus room” and I thought I could turn it into a dedicated audio space.

I decided to move the LP275Ms to this space, along with my best other components. We spend about half our time in that house to facilitate assisting with child care.

The room is on the central heat and air system, but because of the locations of the supply and return lines, the amps are not in a directly cooled air stream.

I noticed that this system sounded pretty decent, room and all, for about an hour of listening, after which I would start to notice faint transformer vibration noise.

I called CJ and we talked about it. Jeff always gives good advice, and we discussed some options. One was to replace the offending transformer with a new one that would be available later in the year. But he also mentioned cooling issues and floor vibrations.

I had never had this issue in the other house where the room is larger, the floor is oak laminate over concrete, and the HVAC system is on a dedicated zone for that room.

The problem continued ... the room at the new house was always good for about an hour. The transformers would get hot, and the mechanical vibration would start, and it would amplified by the 2nd story “flexible” floor.

I got tired of this, and about two or three months ago I took the amps back to the old dedicated room at the other house. They run cooler there, and, if they did vibrate, the laminated oak on concrete floor would not give it away. Problem solved. Not a hint of transformer vibration, even after several hours of listening.

So ... the point of this story is that sometimes problems are associated with the location rather than with the gear.

It was a cheap fix. The light and sassy Marantz PM-Ruby integrated amp is reigning in the new room, along with other second tier components. It has no cooling issues, and it sits on the top of the console instead of on the floor. All of my best gear is back in its original location as a system, and everything sounds great!

[admin]

It just shows you how important the floor is when it comes to equipment performance. My listening room is above a two-car garage and I put in a reinforced cross beam in the garage below with a metal post to dampen the vibration of the listening room.... what audiophiles do for their love of music.

In the DIY section of CJO I have a post about making coasters for vibration control. You may want to try them out. Cheap and easy to make and may solve your issue.

[AnotherJohnson]

Thanks, Admin! I should have looked for the other thread.

This room is over a two car garage too. It is a very nice room, similar in size to Roberto’s and Bear’s...12’x18’x9’. I had the movers lug the F208s up there, and until I sell those, they’ll stay there. They actually sound quite good, and don’t seem to be very amp sensitive.

I had to get one of my sons help to move the LP275Ms, but he was happy to assist. It is more blessed to give than to receive .

It was a good overall experiment. Now I know that my dedicated room in the outbuilding at the other house is even more special than I’d realized.

I’ve postulated a new rule this year. Two of my three systems are on second stories. The new rule is that nothing goes into these systems that weighs over 50 pounds. If it weighs over 50 pounds, it either goes to the dedicated room built on a slab in the outbuilding, or I will have to begin a new system in a first floor great room, which would no longer be dedicated space.

If I did not like the F228Bes so well, a pair CLX arts would be on their way to the LP275Ms in the main system already.

[Big Dog RJ]

This is an important aspect when installing large monoblocks in a system. Not the first time this has happened, have experienced this myself when using the big Premier 8A's, Manley Ref350's, and Melos triode monoblocks. The mighty SS 800w Thresholds Statis series didn't have this particular issue but had other power up issues.

There was another member here on our forum using the ART300's that had transformer hum. I believe the amplifiers were sent back to JF, figured out the cause and is working fine now, although I didn't hear from him recently. The larger the monoblocks, the bigger the trannys which have a higher hum & noise rating compared to slightly lower powered amplifiers.

I also very clearly remember one chap back in hometown had massive Melos monoblocks powering his big Avant-Garde Trio's. There was a constant hum, which was very annoying due to the Trio's efficiency higher than 110dB, used to amplify those singing trannys! It was just a bad match. Later on he sold off the Melos and went for Cary Audio CADse anniversary series SET monoblocks using pairs of the 300B tubes. That was a far better match.

I guess it all depends on the basic critical factors, such as proper grounding, dedicated wiring with separate CB's, floor composition and exact location on the floor. Definitely once these have been addressed and proper installation has been done, I guess the rest is upto the system to deliver.

Anyone else who has had similar encounters?
Cheers, RJ

[AnotherJohnson]

Yes. And don’t forget the HVAC.

I had not experienced this with any big amps before, but this size space (there’s about 2200 cubic feet here) is small enough that big amps can heat it up like space heaters. If it’s on its own zone, it’s ok. The HVAC just has to run more. But on a larger zone, like this one, it’s too far from the controller to affect a quick HVAC response.

If these had stayed cool, they might have worked here.

I can’t really tolerate any sort of extraneous background noise if I’m seriously listening. Any level of hum, even if it’s only during silences, is a show stopper for me.

[AnotherJohnson]

The best system is in a finished outbuilding space in a rural area. It has its own HVAC and humidity control.

If I plan to listen there, I turn it down to 68 F and 40% RH earlier in the day. I may even start the electronics cooking in advance.

When I go out there to listen, I shut the HVAC and humidity control off so as not to have to hear them cycle.

The room is well insulated, and there is no traffic at night. It is quiet as a rule.

My biggest aggravation is remembering when I get up to leave, to turn the HVAC and humidity control back on.

This afternoon I am in the room that precipitated this amp post. I am listening to Isaac Stern’s favorite violin encores.

It’s really perfect for that. The violin is reproduced beautifully and the accompanying instruments are not brash or heavily layered.

And there is the Stickley mission recliner. That’s my favorite audio system tweak.

The gear and the room are up to the program. I love when that happens.

[AnotherJohnson]

Another thing that had to be sorted for the big tube monoblocks when I first got them and installed them in that outbuilding dedicated room a few years ago was the power.

I had wired the circuits myself, so I knew exactly what was what, but I could not get rid of a ground loop.

I had the two big monoblocks on separate circuits as I had run the Krells. They were both grounded on the same bar in the service box.

By all that is right, a ground loop should not have been an issue. I reworked stuff and was baffled.

I talked to Jeff. He said “put the amps and preamp on the same duplex outlet.” I thought he was nuts. But I did what he said. AND IT WORKED!

I had been using two dedicated 20 amp circuits. It was making things worse, not better.

[Big Dog RJ]

Roger that AJ, that's another very crucial thing, the dedicated AC lines plus overdoing things...

I've posted this before but since you touched base, I'll reiterate.
Back in home town (cmb) our mains voltage was horrendous! Although rated at 220-240V it used to swing down to 160v and peak to 290! It was a nightmare for two reasons, other than a host of other issues: 1. This unstable swing was not good for tubes, especially large monoblocks. Biasing with the LEDs on the CJ's was as bad but biasing with a multimeter on the Manley amps... forget it!
And 2. It ruined tube life!

I was so annoyed with this, so I asked both LJ and Eve Anne their best advice. They recommended voltage stabilisers for each amp then followed by two separate lines not for each amp. Rather one line for the preamp and source gear, which was the ART preamp at the time, and the other line for both amplifiers on their own. They didn't recommend high current, anything between 10A to 15A with a 10AWG is more than effective for domestic audio applications.

Eve Anne also suggested using an isolator from Best Power, made in the USA and shipped all the way to Colombo. So I installed this config and all was well... until the isolator started its own hum. It was even louder than normal but it was the nature of the unit. I enquired again and it turned out that this particular commercial grade isolator has to be housed / located in a separate room, not close to the audio system. Ah! Did that and all was well.

At the end, the voltage stabs did a great job of maintaining stable voltage to each of the monoblocks and the mains isolator did a great job maintaining things over the rest of the system. However, when the Apogee Divas went down and then we ventured into Maggies, using various iterations ending with the MG20.1's, since panels are very revealing, I could actually still hear that isolator hum through the Maggies! So the isolator had to go but voltage remained ok, however things weren't as quiet as they ought to be.

Sold the whole lot off, packed our bags and migrated down under... and now with just a very simple circuit- a dedicated 10A AC line with a separate CB on the mains board, wired with 10AWG on one line, fully dedicated to the system. Connected to the Nordost Qbase8 power board and then directly connected to the Nordost QX4 unit, and then onto preamp as primary earth, phonostage stage as secondary point on power board, followed by source gear, monoblocks to outer outlets, and last outlets used to power the CLX's, that's the recommended config for the Qbase8. So all 8 outlets are plugged in sequence, with primary earth dedicated for the preamp, followed by the rest equally balanced across, and not mixed up. One 10A primary AC line is all you need.

Now things are so quiet, it's spooky! I can hear the rain...
Cheers and thanks for pointing that out.
RJ

[roberto]

RJ and all,

I am going to give a little advice. When you have a lot of voltage variation, basically it is due to a poor or loose mechanical ground. The ground cable is loose at the entrance of the house/building or at the post, the pole. There you have to ask the help from the electrical company, the supplier. At the house/building, you can retaight again all the ground cables, the green color and usually the white/gray color (Neutral) are the ones. When a lighting storm is, the best thing is to unplug from the wall all the AC connectors.

On a rare occasions, the supplier might have a problem. Their variation is +- 10 Volts, in other words, at 240V, is normal to get up to 25OV. If this happens, the tabs at the post transformer should be adjusted to a lower gain. Also, you have to report this to the supplier company. It is wise to make a video with your cellular, and show it to the supplier. Also, if the variation is between the permitted limits, the retaighteen cables at the electrical panel box of the house is a must.

Here in Costa Rica, due to our all year earth wakes, the connectors get loose. So, it is wise to retaighteen every six months or so to all the electrical cables at the electrical panel box.

Happy listening!

[Big Dog RJ]

Yes Robbo mate agree.

However, that voltage issue and hum problems were back in my hometown, not here in Aus.
Infact over here, the supplier / power grid distributor has to by law supply the required voltage within its parameters, otherwise you can actually sue them big time!

So they're very careful they get it right, and most of the time about 98%, the voltage and current supply are very good. In newer residential estates, such as the ones we live in now, all AC mains are underground, therefore no power lines or visible poles... This is a big factor especially when those drunk drivers crash into poles!

Another thing I noticed, if I play the system during the day or in the arvo when there's light, it is very quiet thanks to our solar power. It makes a difference! Obviously at nights, things are much quieter but it's not a drastic change compared to our previous place which was virtually unbearable to listen during day times, it was far too noisy.

We're very lucky to have stable power in the majority of our states, with a few exceptions in remote regional areas. So this is a very good thing, plus great for hifi!

Cheers mate, hope you're keeping well and enjoying those tunes. RJ

[AnotherJohnson]

Our voltage and frequency are quite stable too. I’ve monitored it and there is very little variation with time unless the distribution grid is overloaded as it can become on days when much of the country is excessively hot. If the grid is taxed, you can see some weird stuff, but it’s not common like it once was.

If you read advertisements for filters and power supplies, you would think that “dirty” power was rampant. Note that the same guys invent and sell you filters as also sell you super expensive power cords.

Another level for Dante. Souls who in life made their fortunes by enticing the gullible to pay huge sums for worthless accessories are tormented for eternity by having to listen to Harry Pearson rant on and on about the ultimate reference - Live Music - and how much life was added when the $2000 power cord was plugged into the $3000 voltage clamp and filter.

YMMV as usual. Power availability and power quality are serious issues in much of the world.

[AnotherJohnson]

I got into another transformer mechanical vibration issue with a light SS amp (the CA150).

This surprised me. It is light, so I’d put it on top of the console. I could change it from audible to inaudible just by changing the support under it.

I’ve moved it to a different system, replacing it with the ET7 and MF2275. The ET7 is on the console and the MF2275 is quietly residing on the lowest shelf.

It’s funny how finicky some of these things are.