The ultimate DIY? A Stax SRM-T2!

[chiguy]

I understood that it's PCBs only.  I was asking if these PCBs used old (out of production) or new (current production) sand. 

Edited August 31, 2015 by chiguy

[blubliss]

If anyone is interested, I'm thinking about selling my T2, but I would like to do that locally (Los Angeles) and preferably to someone who is a DIYer. I will consider shipping it if the right person comes forward...

[Earspeakers]

I understood that it's PCBs only.  I was asking if these PCBs used old (out of production) or new (current production) sand. 

I thought you might have meant that but didn't parse. Current production silicon T2? Didn't know there was such a thing. This one is using out of production (original T2 design) silicon, or the original T2 design at least (2SK216, 2SJ79, 2SC3381, 2SA1486, 2SC3575 etc). Any links appreciated. 

Edited September 1, 2015 by Earspeakers

[chiguy]

I was referring to what JoaMat has been doing with his T2.

Posts starting here:

Still needs  2sk79 and 2sk216 though.

And this:

http://www.head-case.org/forums/topic/6837-the-ultimate-diy-a-stax-srm-t2/?do=findComment&comment=667947

 

 

 

[GeorgeP]

I understood that it's PCBs only.  I was asking if these PCBs used old (out of production) or new (current production) sand.

Pretty sure you can use the newer/cheaper sand on the old boards if you wanted (but it would not necessarily be plug and play). The 3381 replacement(s) might be tricky though. Can't avoid the j79 and k216.

 

[mortal_fiend]

Okay, so I've managed to track down all of the sand for the PSU, still working on the Amp section.  This means it's time to start casing the PSU up and testing things out.  I realize that traditionally we've all gone with pretty much the same chassis design.  Has anyone had any esoteric ideas that they think would work, but haven't had the will to try out?  I've always wanted to build something out of stone (especially after seeing the new Orpheus 2 from Sennheiser).  As long as the heatsinks are standard, can anyone see a problem with making the top and bottom this  way?

[nopants]

anyone got a BOM xls on their HDD? kevin's links seem to be down

Edited September 10, 2015 by nopants

[Kerry]

I do have a BOM for the original build.

PM me and I can email it to you.

In other news, I've been working on a shrunken version of the T2 inspired by Joamat.  The bigger challenge was the PS which I've just gotten some boards back from manufacturing.  Lot's of SMD parts especially on the bottom of the board.

I've also included some 3D CAD drawings of what I think the chassis will look like.  The PS board is 206mm (W) x 200mm (D).

The chassis will be 12"(W) x 14.25" (D) x 3.33"(H).  I'm using the new GR HV PS for all of the elements including the 60V supply.  12V supplies are still 7812/2912.  I've also included a 5V supply since I wanted to use the new Digital attenuator.  I should have parts next week and I'll show some more pics once I have the board built up.

This is going to be fun

[kevin gilmore]

i hate microsoft

remotely administered computer requires an ok to change the kernel...

(brilliant)

fixed now. does not seem to happen very often

[JoaMat]

That PS board is impressive small.

Edited November 11, 2015 by JoaMat

[nopants]

thanks Kerry, luckily Kevin got it back up. those umbilicals are a killer

excited to see the end result of your shrink. that board looks difficult enough just to solder, not to mention the heatsink drilling seems nightmarish. is size the main reason you don't opt for angle brackets?

[Kerry]

Yes.  I wanted to save some width.  In the end, I think it's less work not having to mill the angle brackets and just tap the heat sinks.  It's only a few more taps than mounting the angle brackets.  Also, my metal work got very good from building a couple of mills where precision is critical.  Definitely not for everyone.

I'm going to start milling the bottom plate and tapping the heat sinks this  weekend.

PS  I can't show the bottom of the PS since I saved the PS to the wrong format and ultimately lost it.

EDIT:  I have roughly the same space available as the original T2 Chassis for the transformers since the heat sinks don't go all the way to the back of the chassis.  They would not otherwise have fit.

Edited September 11, 2015 by Kerry

[GeorgeP]

Great work Kerry, as always.

I have been busy on the T2 front as well. After Tran/Lil Knight (the douche) ran off with my and others' money in the failed chassis group buy, I started reaching out to various shops. Managed to find one that had the patience to deal with a small custom order so organized a new group buy with a few folks here. Started in Jan/Feb and finally finished just this past week. Despite all the hours with the machinist and assisting on drawings, this was easier for me than redesigning the PCBs to fit a particular chassis or heatsink. These ones are the same as the ones KG had made a few years back, so no new design features like yours.

 

 

 

[luvdunhill]

Wow nice! Any left over extrusion material?

[Kerry]

Wow. That's fantastic. Where were you able to source the heat sinks?

great work!

[GeorgeP]

Custom die at around $3k to have those sinks made. Then each batch in 12ft lengths which can then be cut to any length.

Wow nice! Any left over extrusion material?

Were you meaning heatsink?

[luvdunhill]

Yeah, I could take some of the extra off your hands.

[nopants]

I'm also down for some heatsink if there's any left over

[GeorgeP]

Marc, I have a few pieces left but was going to try using them for a Carbon and maybe some other stuff. That said, I suspect there is enough interest that I could have another batch made (minimum order is 4 x 12 feet). Doing some rough math, a 16" piece (slightly smaller than what is needed for the T2) would be about $50 without any tapping. Drop me a pm on what you might need as I can have them cut to any size.

[JoaMat]

/

 

Edited November 11, 2015 by JoaMat

[spritzer]

I always do my tapping with a cordless drill.   

Those chassis do look awesome.  Great work. 

[Victor Chew]

Nice work George and Kerry. Looking forward to seeing the completed amps.

[Craig Sawyers]

Those chassis do look awesome.  Great work. 

^ This

[G600]

Kerry, brilliant work, cheers !

Dunno why, but SMD for high voltages (when possible) seems to be safer to me.

Less chance of badly bent things, and cold solder joints. But I'm uneducated.

[Pars]

I always do my tapping with a cordless drill.   

Those chassis do look awesome.  Great work. 

Never tried using either a cordless drill or my drill press to tap holes. Any links to how you do this? I always figured it was a quick route to broken taps...

I had a couple on my puter. One seems to be lil knights...