[Muamp]

It would appear I have to write 5 or more TEXT posts as a new member before Head-Fi will allow me to post pictures of my ESHS.
I want to get involved with this tread, but because, I guess rules to stop spammers and advertisers etc, I am forced to wait until I have written more text posts.
 
David.

 

[Muamp]

At last, I am allowed to add my photos:
 
This is just a small selection from the last years work in my spare time. I can bore you silly with many more.
I have put them in a sort of chronological order.
 

My very first attempt with mild steel stators and transformer energiser.
 

I attempted to make my own audio transformers on torroidal cores.
This is a core from a 9 volt power transformer. It wasn't very successful.
The winding was by hand with a half metre bobbin.
 

This is my transformer energiser and a home made 18w+18w amp.
 

Small on-ear panels with mild steel stators, I later used wire mesh.
 

Still with 0.7mm thick steel perforated with 2mm holes at a pitch of 5mm.
Neoprene spacers and "clingfilm" diaphragm, which sounded brilliant!
 

 

And this is how it looked when tested.
 

 

Testing the panel with a condensor measurement mic' and Audacity as a signal generator.
 
CONTINUED IN NEXT POST......

 

[Muamp]

MORE....
 

My first attempt at a valve energiser. It is the TubeCAD of November 1999.
 

Modification based on the same circuit.
 

Some more mods' and a PSU on PCBs cut on my home CNC.
SMPS's now used for valve heaters, much better.
PCB mount Triads for the power rails.
 

Heater SMPS and Vdc bias with a 48v transformer and x8 multiplier,.. more detail as to why I prefer this method later....
 

Close up of the Triads, PCB mounted.
 

This is the PCB I have just CNCed for the valve energiser. I will build it later this week, when I have time.
I use CadSoft Eagle FreeWare and PCG-GCode ULP, also free.
 

These are my CNC panels. Various on 0.5mm FR4 and 1mm FR4.
Some here are the standard 2mm holes with pitch of 5mm, others are 1.5mm holes, with I think 4mm pitch,.. I can check....
Also some plastic spacers on 0.5mm sheet plastic cut with a compas cutter.
I will also try Neoprene spacers and both Mylar 2um and clingfilm diaphragms.
Later, another day I can show my home made diaphragm stretcher, it is a copy of one I saw on Google a while back.
 
I have many questions for you guys, hope I haven't bored you too much.
One day I hope to be at the same level as Wachara C.
 
Cheers,
 
David (Muamp).

 

[davidsh]

Bore me silly
Nice work

 

[chinsettawong]

Hi Muamp,
 
Thanks for sharing the pictures.  How do you like headphones?  How big is the active diaphragm area?

 

[Muamp]

The CNC panels are outer dia. 90mm, inner dia. 70mm.
The steel panel is inner dia. 80mm, outer hexagonal.
The on-ear panels are 1" inner dia. cut with a hole punch. I only have a 1" punch, so it had to be 1".
 
 
Muamp.

 

[GvTT]

Hello,
 
I have been asked what coating to use, regarding availability in Europe.
 
Here are a few things I already read in this thread or at other locations:
 
- graphite powder (rubbed in, buffed) => [ risk of dust, crackling, reports of not too long lived...]
- soap => [ sensitive to humidity, reports of short live]
- elvamide => [apparently a mess to work with, never read a detailed report about problems, just things like "ït's troublesome"]
- nylon (dissolved) => any comments?
- antistatic cleaning gel => recommended by many in this thread, seams to be working fine
- (antistatic?) floor cleaner => seems to me like something between the cleaning gel and soap
 
- antistatic vinyl record cleane => read about this somwhere else, long ago, but sounds intriguing.
      should be quite wear resistant. I am just a little worried, it might be conductive. Any comments on this?
 
The reason for this post is the antistatic vinyl cleaner. I am really interested if anyone has used this and can report here.
 
Kind regards
Georg

 

[chinsettawong]

Hi Georg,
 
If you already have the vinyl cleaner, please try it and let us know how well it performs.
 
A few years ago, when I want to test some coating materials to see if they can perform, here are what I do:
 
1.  I tension the Mylar on my inner tire stretcher.
 
2.  I rub on different coating materials on the Mylar surface at different location and use a permanent pen to write on the Mylar which type of coating material it is on each location.
 
3.  When the coatings are dry, I use a gigaohm meter to check the resistance and make a record.
 
4.  I recheck the resistance again on the next day for the next 3 weeks and make a record.
 
Most of the antistatic cleaners that I've tried measured the same or with similar results after 3 weeks.  There're a few that didn't measure well even on the very first day, and of course didn't improve after many days have past.
 
The floor cleaner that I recommended was tested with very good result and therefore I 've been using it for the past few years.  It's cheap and readily available here in my country.
 
Wachara C.

 

[davidsh]

If you are worried about low resistance of the anti static vinyl cleaning stuff, I guess you could check with a normal DMM whether the resistance is measurable.

 

[wppk]

hello
would anyone be intersted to know that I tested the uhu contact glue for the membrane as I was (very kindly) advised to try, and that it didn't work well for me, and then, I found another glue, which works ?
If yes, I will write about it.
for the question of the antistatic product, does anybodu know what to find easly in France ? I have tried something that worked but the antistatic effect faded away... I will try other products here and say if I find a good one, if it helps

 

[chinsettawong]

Hi Wppk,
 
Please do share with us your findings.
 
By the way, there are many kinds of contact glue on the market.  The ones that work well for me are those "yellow rubber glue".  It has bad smell and certainly is solvent base.

 

[wppk]

ok
thank you for the information
I just tested this and it works fine
http://www.simplyspeakers.com/speaker-repair-adhesive-mi-3035.html
there is a smell too, but not horrible, they advise to use the glue in an airy area, anyway.
it is efficient and faster than the others I tested.
I was talking to Georg, ( so nice man ! ) and he said that some people would be interested in knowing how I repair stax lambdas. Is it the case ? And is it the right place to do so, or must I use another post, or create one ?
thanks

 

[chinsettawong]

What problem do you have with your Stax Lambda?
 
There is nothing special about it.  I'm sure that you can shoot your questions here and some of us can help you.

 

[wppk]

I have to replace the membrane ( not the protective one, I did it, but the product I used for the antistatic doesn't last, so I am going to try others).
I don't have lots of questions, in fact, I have been repairng seven lambdas yet, ( protective membrane) and as stax lambdas a said not to be reparable, I thought that maybe it would interest some people to know how I repaired what I could repair.
but maybe other people already did it and wrote it on head fi ? I never found that, and when I didn't know how to repair them, I talked to someone who proposed to repair my first lambda, wich had static noises. He told me that as far as he knew, he was the only person who was repairing lambdas. But when I got the lambda back, the issue was still there. so as I had nothing to loose, I decided to try to mend them by myself, and I did. wat I was asking on this thread a few minutes ago was if some people would be interested to know how to do it, and then, try to repair their lambdas by themselves. knowing that I couldn't fix all problems of all my stax, and that today, I am searching ways of making a whole repair. It can work, because I changed the sound membrane, it worked perfectly well, but finally, the product ( antistatic) I was using lost it's effect, so I have to find another one, and also, the best glue for the mylar.
of course, I cannort guarantee to people who would try to mend their lambdas that it will be working, but it worked for me, until I had an imbalance problem, added to the static noises, and then, I have to repalce the sound membrane, as firstly said.

 

[chinsettawong]

Please do share with us your experience.