This morning while looking for something else in a local 'pound shop', I saw some circular rubber discs. They are sort that you connect to a shaft and then to your electric drill for sanding purposes.
Anyway, the are just the right size to go over or under most torroidal transformers and, as Peter says, there would probably be some benefit in losing those metal plates!
Anyway, the are just the right size to go over or under most torroidal transformers and, as Peter says, there would probably be some benefit in losing those metal plates!
I read this recently from an article found here: http://www.soundstage.com/maxdb/maxdb111998.htm
The faulty four: rubber, plastic, nylon, steel
Several years ago, Michael Green told me "When you are trying to make a good-sounding audio component, the more rubber, plastic, nylon and steel you can get out of it, the better it will sound." I immediately went home and removed the rubber pads that were on both sides of the toroidal transformer in my amplifier. Unbelievable. The amp sounded unquestionably better without those pads. Leaving the transformer resting on the chassis is very dangerous, however. A later experiment raised the transformer on a sand-filled baggie, and the sound improved again. A little later I found a very small inner tube and used it as an air cushion under the transformer -- another improvement over the sand bag. In my moded CD player, I replaced the nylon circuit-board standoffs with brass screws -- a significant sonic upgrade. In fact, Michael Green recommended brass as the replacement material for the rubber, plastic, nylon and steel if possible. The resonance characteristics of brass are the most musical of any metal -- which is why musical instruments with metal in them usually employ brass. Aluminum is the second choice if using brass is not possible.
The faulty four: rubber, plastic, nylon, steel
Several years ago, Michael Green told me "When you are trying to make a good-sounding audio component, the more rubber, plastic, nylon and steel you can get out of it, the better it will sound." I immediately went home and removed the rubber pads that were on both sides of the toroidal transformer in my amplifier. Unbelievable. The amp sounded unquestionably better without those pads. Leaving the transformer resting on the chassis is very dangerous, however. A later experiment raised the transformer on a sand-filled baggie, and the sound improved again. A little later I found a very small inner tube and used it as an air cushion under the transformer -- another improvement over the sand bag. In my moded CD player, I replaced the nylon circuit-board standoffs with brass screws -- a significant sonic upgrade. In fact, Michael Green recommended brass as the replacement material for the rubber, plastic, nylon and steel if possible. The resonance characteristics of brass are the most musical of any metal -- which is why musical instruments with metal in them usually employ brass. Aluminum is the second choice if using brass is not possible.
randytsuch said:
Randy,
What are going to build? I wish I had held off, I ordered a pair from Pltron on Thursday. But these here would be perfect for an Aleph X. At least perfect for my current thinking of how to build an X.
The pair I ordered are 160 VA, 15 volt. These are for a GainClone. The 4-5 week wait for Plitron is seems to be a good thing, it gives time to build the box and decide on initial details.
George
A very good article and a subject most often overlooked in building decent hi-fi. Don't know if I totally agree with everything that is written there though. My GC's use plastic in their construction and sound wonderful. Perhaps the argument against plastic was more to do with mounting components than case materials.
Peter, like you, I have noticed how much transformer mounting affects the sound of the GC's. In fact, I would now say to anyone serious about building hi-fi to build some GC's even it is just to have a test-bed that so clearly demonstates what affects the sound quality.
As regards the comments on monoblocks, you could just as easily get the same problems in a stereo amp unless you used a torque wrench to tighten down the screws holding the PCB's or chips etc. However, I would agree that replicating everything for each monoblock is very good practice.
Peter Daniel said:
You know, I was going to mention an old audio amatuer article that dealt with de ringing transformers with brass, but decided to opt for the easy way out and just answer the question so shame on me. If the transformer is potted it would be a simple thing to mount on a chunk of brass. Some of them have a big hole in the middle and care must be used as you could not place metal directly on the windings. The stuff I used was a sort of pourous foam that was from a standing mat. This then had an aluminum top and bottom plate. I mounted this on a brass threaded rod bolted to the chassis bottom, then slid my transformer sandwich over the rod and finished off the stack with another washer and bolt. So the whole thing was really suspended on brass. Thanks for the kick, I really must start driving through to the end with my answers.
Thank you for the pointers...
I will go ahead and use plastic tie then...
Right now, my box is made out of Plywood. I looked into 1/8'' brass enclosures - quite expensive (over $200 for the box) considering other parts. Is the extra expense for the box worth it sonically? (14x10x3)
For those who are interested in the toroids, my email address is:
hoxuanduc@yahoo.com
Thanks,
Duc
I will go ahead and use plastic tie then...
Right now, my box is made out of Plywood. I looked into 1/8'' brass enclosures - quite expensive (over $200 for the box) considering other parts. Is the extra expense for the box worth it sonically? (14x10x3)
For those who are interested in the toroids, my email address is:
hoxuanduc@yahoo.com
Thanks,
Duc
Now why would you want a brass case? That article promoted the use of brass over most other metals on the grounds that as many musical instruments are made from brass, it is the most musical of metals. What about violins!
But the amplifier case is not the transducer of the sound in a hi-fi system. If there is a church with a bell near you, go and stick your head inside the bell and ask yourself if that is the sort of environment to put delicate electronic components that are microphonic.
The inside of an amplifier case needs to be as quiet and vibration free as possible so that as little as possible is added to the signal. From that point of view timber is one of the best materials and, despite what others say, plastic (if used properly) is also effective. Many constructors who build a quick prototype on a piece of timber know this!
Brass may indeed be a better material for standoffs and other fixings in an amplifier as it is a non-magnetic material but I wouldn't go near it for a case, especially at the price. I doubt it would sound as good as your plywood case!
BTW two plastic ties would be more secure.
Ah!
You may all laugh again, because I did put an old mouse pad (cut in a circle) under my toroid. 
Very effective.
Or not?
Anyway, you can see my Gainclone on my new thread here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=15647
Please don't laugh to much...
JOE DIRT® said:
You may all laugh again, because I did put an old mouse pad (cut in a circle) under my toroid.
Very effective.
Or not?
Anyway, you can see my Gainclone on my new thread here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=15647
Please don't laugh to much...
I'm not laughing Carlos. I don't think that there is a set rule for this sort of situation. My philosophy is that if you are sitting there thinking about how a change will sound, then you are not able to fully enjoy the music. So make that change, if it works great, if it doesn't then change back.
In my experience, a lot of changes of this type make either no difference or they just make a slight change, ie not better and not worse. At least you have tried the mouse mat and that won't be on your mind in future.
Nice amp by the way. Good symetrical layout and plenty of space for any mods.
Nuuk said:
I'm not laughing Carlos. I don't think that there is a set rule for this sort of situation. My philosophy is that if you are sitting there thinking about how a change will sound, then you are not able to fully enjoy the music. So make that change, if it works great, if it doesn't then change back.
In my experience, a lot of changes of this type make either no difference or they just make a slight change, ie not better and not worse. At least you have tried the mouse mat and that won't be on your mind in future.
Nice amp by the way. Good symetrical layout and plenty of space for any mods.
Thankx Nuuk.
Actually, the mouse pad was not a mod.
When mounting the transformer on the box it was the first thing I did.
That old mouse pad was sitting on a box looking at me and I thought: what the hell, it seams a good thing to absorb transformer vibrations.
So I cuted it and mounted it under the toroid.
It doesn't really matter if it makes an audible difference.
But that material seams good to me, and it gives me some peace of mind.
It's not too soft, not too rigid.
It seams right on the mark.
I don't throw old things away, and sometimes they prove useful.
But sometimes I fill the trash can with useless things I keep.
Only the trash can! The whole of the top floor of my house is filled with stuff that 'may come in useful for hi-fi'.
I agree with you about the computer mats. And over here we can buy very cheap place mats (you put them under plates on a dining table) which also make good gaskets for transformers etc.
I think some of the best fun in DIY hi-fi is hunting out 'useful' stuff from non-hi-fi sources. The girls in our local toy shop got hours of fun watching me carefully select small bouncy balls to go under my speakers!
And it is even better if you can get things for free. From skips I have obtained lengths of aluminium section for heatsinks, some great plastic/fibreglass materials for rear panels/circuit boards, and (as you have seen) the pipe for my GC monoblocks!
Panelhead said:
Hi George,
I am going to build a gainclone. I talked to Stan a couple of weeks ago, and Stan said he built one just to try it out, and was amazed at how good is sounds, said it should be better than the Adcom he modded for me, and it's pretty cheap to try.
I actually already have a pair of 225VA 18 volt plitrons I picked up on ebay a while ago, but if I can find a couple more cheap, I want to try biamping, so I need four.
Everyone else,
On the subject of metals, I have seen recommendations to use brass screws to hold down transformers instead of stainless or other metals, claim was brass did not mess up the magnetic field around the transformer. Never tried it myself.
Randy
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