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hagtech wrote:

Iwas going to ask you about that funny looking damping material.  Then you explained it at bottom of post.  Very clever to use mouse pads!  Lately I've been using cork & buna rubber sheets from McMaster-Carr.  Seems to work much better on chassis then the regular spongey rubber.  I suppose it all depends on application.  For feet I still use sorbothane.

The magnetics themselves are quite quiet. The transformers are by Electro Print and they are fine. The chokes are by Hammond as Electro Print does horrible input chokes – they just do not handle high ripples and buzz like hell. Ironically the Hammonds, even though they nether specially warnished their chokes nor bake them, but they are completely silent in input choke application (30H and 40H). Also I’m attracted to Hammonds because the Hammonds choke had high DCR. I have no idea why but I experimented with few “better quality” chokes with lower DCR and detected that the reasonably higher DCR of the input choke produce better sound (with the same output impedances of the entire PS chain). The big choke of the B+ is a different type or problems as whatever I tried created some minor buzz when I use high plate current on the 6C33C. I end up ordering from Hammond a custom version of the choke that they call “Ripley”. The Ripley chokes are ~25% more expansive and take a month or two to make but they are completely silent, regardless of current they care. The Ripley are made by submerging the chokes in a bath of epoxy twice: first time then the coils is made and the second time when the entire choke is built. The Ripley looks ugly, it look like someone vomited on your choke, but they very silent in operation while high ripples applied to them.

Anyhow, returning to the subject: I find that it is not only the providing the elastic or vibration-dumpling material between the magnetics and chassis but it also about lifting of magnetics from chassis. Since I used steel chassis the deferent peaces of magnetics, working against the same steel chassis induce in the chassis some vibrations. The easier way is not to use steel chassis bit it has own merit in case of a single Melq. I fought with the stray fields in Super Melquiades’s power supply as the Super Melq has much more transformers/chokes and they are all run at higher current (I foolishly used a steel chassis in the Super Melq’s PS). Anyhow, I was not able to resolve the problem in there and was forced to use stupid “brutal force anti-dumping”. In case of a regular Melquiades just the simple lifting the magnetics from the chassis do the very necessary things. Sure, if to make it “properly” then it would be nice to encapsulated the magnetics in the cans where the magnetics would be suspended in patting and would not have any mechanical contact with chassis. It is not difficult to do but the way in which I have designed the chassis did not make this provision. Since I had a pair of made chassis I decided to do it as the original first amps was made and do not change anything.

hagtech wrote:

Question, do you put anything on the inside of the chassis?  I find it sort of works like tube dampers.  Strips of adhesive backed rubber (or the cork stuff) along the inside rims help to remove any ping.  Like a loudspeaker or turntable, it's a compromise between too much liveliness and overdamped and dead.

Nope, I do not use any explicit dumping inside of the chassis but I have plenty of “accidental” dumping.  It will be a few large parts inside, like large capacitors (250V/15.000uF, 450V/4.700uF and so on). Before I mounted them to chassis via their bolted harnesses. Then I begin to use the “lazy-man mounting”. I got in Home Depot a black silicon sealant and created a silicon bathes for the large parts if it applicable.  When silicon solidifies it holds very nice but still has some elasticity that works as a magnificent dumping for the entire chassis. It might look quite ugly and has no “manufactured feel” but it VERY functional and purposeful as besides the damping it also isolates the temperature of the cap from the temperature of the chassis. I like the silicon mounting…

hagtech wrote:

One more thing, try remove the shit steel screws from the power transformers and replace them with stainless steel or brass

Good idea, I did not think about it but it perfectly makes sense.  This is exactly why I publicized the Melq’s progress: because someone might point out some educational advise how to make the things better. I appreciate it…

Rgs,
Romy the Cat.

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