Mylar for ES headphone project

j beede

Member
2007-12-24 5:04 am
NorCal
First time ESL project... I am going small for a first effort; headphones. I need some recommendations regarding easy to find (local) sources of small amounts of 1/2 mil mylar--novelty helium balloons? I would prefer clear material. What distance from the outer ear to the diaphram has been shown to work for full range and safe operation? Maybe a Stax owner might provide this dimension as a starting point?
...j
 

kayne

Member
2008-01-03 11:37 pm
Half thou mylar is commonly available in the form of a "rescue blanket" which is used for accident victims to protect them from temperature or rain and is available from camping shops (outdoor shops). It is typically silver being aluminium coated and may be coloured red or orange on one side and is about 5' x 3' in sixe for about $5 Aus. The conductive coating can be removed with caustic solutions such as oven cleaner or drain cleaner.
 

j beede

Member
2007-12-24 5:04 am
NorCal
I used 0.7mil plastic "drop cloth" from the local home improvement store. It tensioned easily with no wrinkles and I was able to produce a very consistent graphite coating that left behind a very slight gray shading. I am using a 550VDC bias and can see no drop in voltage when I connect or disconnect the "panel" so the leakage is not catastrophic. I ran the bias up to 1100V and the panel remained dead silent, my transformer began humming audibly however. My air gap is larger than intended, so efficiency and leakage are probably down as a result.
 

j beede

Member
2007-12-24 5:04 am
NorCal
el`Ol said:
There are cooking bags made of mylar.


These are thicker than what I was looking for. Good idea though. I also tried those metallic looking helium filled balloons--also far thicker than 0.0005". As I am using pre-tensioning rather than heat shrinking, I am willing to try a variety of thin membranes. It remians to be seen whether they lose too much tension over time. Compatibility with cyanoacrylate adhesive is another key issue. The drop cloth has worked well so far.
...j