Hi Bill

"But once I put a little pressure between the screw head, the board, the cork & the chassis, things started to ‘tighten’ up."

This is the part that has my interest over everything.

A lot of folks would think that just setting something there will do the trick and sure there is a difference, but when you make the tention happen, just like Costin with his speaker drivers you with your boards and what we do as a daily part of what we do, that's when the lights turned on for me. So you said you did this open chassis? I'd like to see how the transfer happen to make a comment there, but looking at these pics was great and a place where we could get a sense. very nice

looking foward to some music reports

michael green
MGA/RoomTune

That's priceless lol!

Now you know why I had to have a factory.

There should be some type of supplemental pay for audio wives.

michael green
MGA/RoomTune

Speaker crossovers are excellent candidates for mu metal, you know, what with the inductors and all.

Geoff Kait
Machina Dynamica

You've gotta have a good story about the wine glass, smokes, mints and cheese. You've got all the bases covered for the long haul project, there (except for crackers.)

Are you thinking of leaving it this way or just for current trials?

That baby would look great on a nice tunable wood platform ;)

Good luck in the hunt.

wkhanna wrote:

Got home tonight & noticed a buzzing sound from the Schiit Gungnir DAC.

Upon closer examination, I discovered the 60 hertz magnetic field from the two transformers where causing the Mu Metal to vibrate vigorously.

I concluded the best approach in this experiment was to isolate each transformer.
I also left the chassis cover off (again) to test the effect.

No perceptible change in the sonic signature after a short listen, but not having hum & vibrating Mu Metal allows the mind to rest easier.
But do not fret, Michael.
Dan will be over soon & we will conduct a detailed evaluation of free chassis, mounting tension & other variations.

Bill - on the Hill
Practicing Curmudgeon & Audio Snob
- just an “ON” switch, Please –

This is why it's a good idea to place the transformer on cork or viscoelastic material AND to completely enclose the transformer in mu metal. And why the transformer should be *completely encased* with mu metal. With the top open the lines of flux will escape out the top and could cause the mu metal to flutter on the way out. The lines of flux will escape out the bottom if the bottom isn't mu metaled. Recall mu metal is slightly magnetic. Covering the tops of transformers with mu metal will also reduce the magnetic field. It also helps to unscrew the bolts or screws holding down the transformer a bit. Another trick is to use a strip of electrical tape to connect the mu metal sheets; that in itself might stop the mu metal from moving. The vibrating transformer being coupled to the chassis would be most unwelcome to all the circuit boards. One last note. That HiFi tuning fuse sitting there all alone there right next to those big transformers. I don't like that one bit. What to do, what to do?

Hope this helps.

Geoff Kait
Machina Dynamica

wkhanna wrote:

Thanks for the feedback, Geoff.

It was late, did not have much time to play.
All of your points were on my mind.

First, the field strength from these transformers is quite strong.
I have worked with Mu Metal previously in my professional duties, & yes, it does have ferrous characteristics making it susceptible to the magnetic field.

It is unfortunate that the transformers are soldered directly to the board.
I am planing on applying a piece of MM on the bottom side of the board directly under the Xformers.

I also realize fully enclosing is the best method due to the large field flux.
But I have also noticed the amount of heat generated by the Xformers is significant.
I am a bit hesitant to totally enclose the top due to possible thermal issues.
I am considering putting a series of 'vent' holes in the top piece of MM over the Xformers.

One last issue is how the board is supported in the area of the heavy Xformers.
Only one stand-off near the center of them which allows plenty flex on the ends of the baord
I am going to use some cork between the board & chassis to reinforce the area around them.

Bill - on the Hill
Practicing Curmudgeon & Audio Snob
- just an “ON” switch, Please –

I haven't done a complete thermal analysis but I am pretty sure the metal alloy transfers heat very well and acts as a heat sink. Or you could attach actual heat sinks to the mu metal. I also am fond of outboard battery powered fans like the O2Cool fans.

Cheers,

Geoff Kait
Machina Dynamica

Sorry for the late response.

Seems like everyone and their brother was tuning yesterday, so this little boy was busy.

Really good to see the pictoral, it says a lot. I won't jump in much unless you ask. I'm a believer in exploring and letting people explore on their own. I can usually see what's going on, but prefer to be a guardrail on the side of the road instead of a backseat driver.

The descriptions help a lot.

this statement

"No perceptible change in the sonic signature after a short listen, but not having hum & vibrating Mu Metal allows the mind to rest easier."

I'm sure has Toledo looking as well myself. Looking forward to seeing the next few steps. One thing though if you don't already do. With making this big of a change, you might want to do the keep on repeat thing going if your able to.

:)

michael green
MGA/RoomTune

Hi bill,

"
I am currently seriously considering making a polycabonate enclosure.
Maybe a maple base to replace the aluminum OEM piece.
"

Are you considering any other wood for the base? I know maple is big in audio, but, there are other alternatives that you may want to try that have better tone. What type of footers are you considering, if any? How the chassis sits on the shelving could be looked into, also.

I am sure Michael has a few thoughts on this and and would give you more info if you wanted.

I dunno what you guys are using for mu metal but hopefully it's the annealed type. Annealed mu metal is light years ahead of the stuff that was around a few years ago. Just saying.

Geoff Kait
Machina Dynamica

Yup, that's the one.

Geoff Kait
Machina Dynamica

People question tweaking as if it's a bad thing or possibly a road to distortion. For myself viewing recordings from my angle, stereo and listening to it, has to take that chance. The chances of something in the stock realm being able to plug & play and actually fitting into the environment perfectly is a shot in the dark. Tuning a system, and eventually learning how to tune a recording needs to keep heading closer to the norm of what is done in this industry. Listeners for years have done the plug and play, thinking "this is it, the sound of the component" but in that mind set everything listened to has to live with that one particular setting, a setting that was made with completely different ears and conditions. When someone starts down this path it opens many doors, one of the most important is the door of the mind.

michael green
MGA/RoomTune

michael green wrote:

People question tweaking as if it's a bad thing or possibly a road to distortion. For myself viewing recordings from my angle, stereo and listening to it, has to take that chance. The chances of something in the stock realm being able to plug & play and actually fitting into the environment perfectly is a shot in the dark. Tuning a system, and eventually learning how to tune a recording needs to keep heading closer to the norm of what is done in this industry. Listeners for years have done the plug and play, thinking "this is it, the sound of the component" but in that mind set everything listened to has to live with that one particular setting, a setting that was made with completely different ears and conditions. When someone starts down this path it opens many doors, one of the most important is the door of the mind.

michael green
MGA/RoomTune

Nobody is suggesting Plug and Play. Hel-loo! Of course there are many people who have no interest, zero, in tweaking, tuning, treating CDs, treating the room, any of it. Your whole argument against Plug and Play is nothing more than a Strawman Argument. As for me I am quite sure that the norm of what is done in the industry is NOT where I want to go. When someone starts down that path, judging from what I read here, it CLOSES many doors.

If tuning is required for every recording then it must be the road to distortion for the majority of recordings. Tweaking on the other hand is the path to enlightenment, grasshopper.

Cheers,

Geoff Kait
Machina Dynamica

A friend of mine is not only a listener but also a DIY-er, so he designed and built a nice-sounding power amp. He went through countless hours of measurements and voicing, and yesterday we gave it a final listening in my system, then called it a "finished" product. The final step was to put the top panel on, and then came the horror: the sound went downhill, the THD (measured at the output posts) skyrocketed and nothing was the same, so we decided to take the "lid" off ant see what happens. As you expect, all the goodies were restored. We scratched our heads, looked at each other and even tried to put the cover on without tightening the screws so much: no way, the bad and ugly reared its head again.
OK now, to make a long story short, we found out that the holes in the cover (and the corresponding holes in the side panels) were drilled after the plates were treated (black), so there was a conductive path once even a single screw was put in place. We changed all screws with nylon ones (good I have a bag of various trinkets available) and here you have it: a nice sounding, airy amplifier (somewhat overdamped, if you ask me, but this is just personal taste).

Hi Costin

Thanks for the report! Remarkable isn't it, and once the thinking begins the lights don't turn off.

michael green
MGA/RoomTune

I had to look up the strawman stuff again cause I had forgotten the meaning. Pretty funny stuff! I don't really care that much about the art of debate. What I do care about is the sound and how to get there in a way that makes sense, basically capturing and preserving the signal, and reintroducing it into another evironment as faithfully as possible. We have all seen that the tuning way for Geoff Kait doesn't make sense. Even though he offers tweak products he doesn't believe this is a part of tuning in any way, not according to him "I admit I don't understand tuning" Geoff says. But this is strange to me that a person in this industry who makes products that he claims makes a difference in sound can't understand tuning, tuning after all being a variable tweak.

Geoff also says "If tuning is required for every recording". Doesn't Machina Dynamica being in the tweak business have an understanding of how recordings are different from each other? If Geoff is not familar with tuning, and if Geoff Kait doesn't have an in-room system, or care to (according to Geoff himself), how exactly would he or could he know or even care to make a comment about something he is not even doing or understanding what it is?

I believe, and I could be wrong, but what Geoff Kait seems to be doing himself is creating Strawman Arguments. He seems to even be using the term Strawman Arguments within his. If he could give examples from doing and showing people what and how he tweaks as I do on http://tuneland.techno-zone.net/ (shameless self promotion) as Costin just did, and Toledo does, and we are seeing Bill & Dan do, than he could be looked upon as being a listener with an active system giving an opinion, let alone talk of photons, and a many step CD tweak that he says cures all and if your not doing, your systems is all wrong, or your hearing is.

Again and I might be wrong, maybe others could help me with my learning dissabilities, but isn't what Geoff does according to wiki, making strawman arguments to accuse others of making them who disagree with his opinion, maybe not even opinion but sales pushing? I mean doesn't he have to be doing to back up his statements? It would seem to me so. I don't know the audiophile world is an odd one to me and sometimes I feel miles away from the listening world.

michael green
MGA/RoomTune

First of all, convince my friend to use wood side and top plates for his amp (the front and back cannot be changed since they house binding posts, the ON/OFF switch and other stuff).

Second, to remove the top panel of my own amp, replace thw screws with nylon ones and insert small elastic dampers (will those be springs or rubber?) between the top panel and the case. And then, insert the (nylon) screws and only tighten them as needed, thus achieving a "floating" top panel. Maybe I even won't put back all screws and once (if?) I hear that one of the screws left is more important I'll replace it with a "butterfly head" screw that I'll be able to adjust on the fly.

michael green wrote:

I had to look up the strawman stuff again cause I had forgotten the meaning. Pretty funny stuff! I don't really care that much about the art of debate. What I do care about is the sound and how to get there in a way that makes sense, basically capturing and preserving the signal, and reintroducing it into another evironment as faithfully as possible. We have all seen that the tuning way for Geoff Kait doesn't make sense. Even though he offers tweak products he doesn't believe this is a part of tuning in any way, not according to him "I admit I don't understand tuning" Geoff says. But this is strange to me that a person in this industry who makes products that he claims makes a difference in sound can't understand tuning, tuning after all being a variable tweak.

Geoff also says "If tuning is required for every recording". Doesn't Machina Dynamica being in the tweak business have an understanding of how recordings are different from each other? If Geoff is not familar with tuning, and if Geoff Kait doesn't have an in-room system, or care to (according to Geoff himself), how exactly would he or could he know or even care to make a comment about something he is not even doing or understanding what it is?

I believe, and I could be wrong, but what Geoff Kait seems to be doing himself is creating Strawman Arguments. He seems to even be using the term Strawman Arguments within his. If he could give examples from doing and showing people what and how he tweaks as I do on http://tuneland.techno-zone.net/ (shameless self promotion) as Costin just did, and Toledo does, and we are seeing Bill & Dan do, than he could be looked upon as being a listener with an active system giving an opinion, let alone talk of photons, and a many step CD tweak that he says cures all and if your not doing, your systems is all wrong, or your hearing is.

Again and I might be wrong, maybe others could help me with my learning dissabilities, but isn't what Geoff does according to wiki, making strawman arguments to accuse others of making them who disagree with his opinion, maybe not even opinion but sales pushing? I mean doesn't he have to be doing to back up his statements? It would seem to me so. I don't know the audiophile world is an odd one to me and sometimes I feel miles away from the listening world.

michael green
MGA/RoomTune

A Strawman argument about a Strawman argument! I wouldn't have believed it if I hadn't seen it with my own eyes! Absolutely priceless.

Cheers, Geoff Kait
Machina Dynamica

Hi Costin

If I can be of help in any way let me know, you can find my email on TuneLand. Toledo is a really cool guy too who I'm sure will be a cheering section and fan of the project. If you guys would like you could even start your own threads on tuneland. The guys would love to welcome you. I know most of the fun is creating your own specialized baby so I won't push, but if you do have any questions I would be thrilled to explore them with you.

this is exciting stuff :) I mean really exciting stuff :)

Oh, almost forgot, I know folks like to call it isolation so I hope no one minds that I call it transfer, but nylon has a pretty cool sound to it. I use it with some of my Tuning Canopies & Tuning Rods and a lot of my guys like the flavor. Like your saying have to be careful of too much but I think you guys are going to have a blast.

michael green
MGA/RoomTune

Costin,

The forum is hoping today. Hard to keep up.

Costin, you have been busy and doing in quiet fashion. You like Bill and Dan get your hands dirty and start playing and getting to where you want to go. That's what it's all about.

None of the endless talk .. Try it and see where it takes you, right.

Floating chassis top .. It will interesting to see what you come up with and the elastic dampening material you eventually settle on. Maybe even a combination there.

You are realy embracing the variable tension concept in very creative ways..first your speakers and now the amp.

Let's us know how things work out.

Good show!

Actually, I will be trying to achieve two goals:
1. Make my system as tunable as possible (that's to enjoy the endless variations of tuning).
2. Make the tuning process as fast and reliable as I can (that's because I honestly don't wand to spend 15 minutes tuning for each and every CD).

I have many ideas running through my mind, including "numbered" dials so I can add a little leaftlet to each CD, reading something like "TOP = 40, TREBLE = 25 etc.)

And now for some answers (in no particular order):
- the case of my friend's amp is stainles steel;
- I was thinking about keeping only three screws (two in the back and one front, just in the middle). The back screws would be on viscoelastic material (since they move less) and the front one on a spring (since this one will be used for on the fly adjustments);
- try a different approach to mu-metal shielding, i.e. a shorted coil around the transformer.

The problem is my time is very limited so between the 10-12 hours day at the office, the commute and around 6 hours of sleep I barely have time for food and (some) listening. I must admit that I devote my weekends mostly to socialization and listening sessions which does not leave me much time for playing "screwman".

All the best,
Costin

I still get goose bumps when someone starts to tune. There's a peaceful sense that happens getting closer to that music we love.

When Dan & Bill mentioned hearing more of the room recorded in, a big smile came to my face. That's one of my favorite parts of a recording. It's a new chapter of listening altogether when going from instruments to instruments in a room or several rooms depending on the type of recording and how done. And here's the thing, someone can mention this event but it only really makes sense when you hear it. I talk about recordings being like mansions with a bunch of rooms to float in and out of, and I hear people say "I don't want to tune", but after they experience this a few times it's hard to not want that with every recording. I don't even think about it anymore. It's like playing an instrument, once you get fair at it, it's a matter of picking it up and playing. You don't think about the pain of playing just the enjoyment of doing so. So when people start off with "I'm not going to tune every recording" I just smile, sure that's what you say now till you start doing it. I've seen some modest listeners turn into listening animals so I blow off the comments anymore. You never know what someone is going to do when they get the power to do it.

I'm like this, I will at least tune in a recording once to see how far it goes to a degree, and then may or may not tune it the next time. Completely up to the mood but knowing I can is what makes the difference. Like I've said even recordings that I thought were poor get surprisingly listenable when you set them free. If you look at what I listen to it's pretty clear that I don't spend all my time trying to tune the untunable like some here have tried to paint of me. Heck no this isn't meant to be work. I do this for a living and still have music as my hobby, so that should say how I feel about it.

As you guys start to tune more and see others finding different ways I think the tone around here will loosen up a little. Usually when it goes from jump to jump to slide is when the fun gets going, and it's when people stop worrying about the word distortion. Distortion belongs lockup in some room and the key thrown away. Tuning certainly frees you up from that dred.

michael green
MGA/RoomTune

My friend (the one with the DIY amp) has an additional problem: the toroidal transformer is affixed to the bottom of the chassis wit one large screw. Of course, that cannot be replaced with nylon since it would not hold the mass of the transformer. Now any toroid has a poloidal (polar) leakage that goes into the magnetic screw, diffuses in the whole case and (eventually) closes if the top is affixed with metal screws.
Any idea on how to secure the transformer to the case (without removing it an placing it in a different case)?

Costin

Hi Costin

Do you have the thread size and maybe even a picture?

I have meetings this week with a few custom shops where I could run over material shear testing with them. If I can see what is happening it will help.

michael green
MGA/RoomTune

As in convincing my friend to deliver a fully functional amp at parts cost and without a case.
I intend to split it threefold:
(1) transformer and rectifier bridge
(2) voltage stabilization, input buffer, pre-driver stage and drivers
(3) capacitor bank and power stage proper (who knows, maybe even a pair of it, making the thing dual-mono)

Section (1) and (2) will go into light acrylic boxes while section (3) (or 3L and 3R) will be bolted to custom-made heatsinks and covered with some removable protective grilles (talking about 80Vpp there).
Still have to think about umbilical cords...

The experiment will cost me around 1500 EUR (~$2000) but I hope the outcome will beat his classic "all in a box" approach.

Yes, I agree you should start a thread on the project!

I've totally enjoyed this thread and think it would be very cool to see more of them. Nothing like seeing a system than through the eyes of it's master.

michael green
MGA/RoomTune

Any pics on Dan's doings? If not maybe a description of placement?

thanks guys, fun stuff

michael green
MGA/RoomTune