The ultimate DIY? A Stax SRM-T2!

[luvdunhill]

It´s alive!!!! I had a minor scare when I forgot to tighten one of the 485VAC wires (so the PSU made no sense at all) but it was quickly fixed. No noises and no smoke and the same goes for the + side as well. Now I just need to finalize the wiring and turn my attention to the amp chassis...

nice! you might want to put a few of the outputs under load. then again maybe not

[spritzer]

That's great Biggie! I hope you get another day off in the next 90 so you can finish it.

Right now I'm just not sleeping so I can solder in all the transistors on the amp. Well that and add XLR loopouts and RCA inputs/outputs.

[Kerry]

Here's my progress on the power supply. I'm waiting on a couple of caps, but I've got most of the other components in. I'm going to mount this onto the rails and start populating the sand tomorrow. I've left this full size so you can see the fixes (reverse diode on on the neg 12V supply) and the 30V zeners instead of the 1N4007's.

http://img864.imageshack.us/img864/9232/t2ps001.jpg

I've also left out the 2SC3675's so that I can use the emmitter lead to apply the patch to the bottom of the board.

Here's a shot of the cut trace and I've also removed the solder mask (I used a 1/8" end mill on my drill press for this) on the traces so that I can use it to mount the resistor and one end of the .1uF by-pass cap:

EDIT: I also replaced the rectifer diodes because they were no longer available with these: DSEP12-12B

also a number of caps were no longer available:

220uF 250V caps with these: ECO-S2EP221BX from digikey

100uF 450V caps with these: ECO-S2WP101BA

680uF 450V caps with these: EET-UQ2W681EA

Edited March 29, 2011 by Kerry

[livewire]

That sure looks "sharp". Great way to do it.

I just break out the xacto knife and "cut & gut".

[spritzer]

That is a very nice way to do it.

I'm struggling to fit 4 XLR connectors, a 4PDT switch and 4 RCA's to the back panel in the small space between the umbilical sockets. About 1mm of space to spare and then there is that little voice saying "better not fuck this up"...

[Pars]

Oh, you have that little voice too?

Good luck!

[luvdunhill]

Kerry, that's similar to what I did. I used a SMD resistor though.

[spritzer]

Oh, you have that little voice too?

Good luck!

Yup and it didn't fail me now. Who needs sleep anyway...

I need to do some cleanup and trim a faction of a millimeter off the XLR loopout socket on the right plus drill the mounting holes for those but it was indeed a very tight fit. Also, yeah those are silver WBT's, might as well use them for something...

[Kerry]

Beautiful job Birgir

I like the idea of using an SMD resistor for the PS fix, though I'll stick with the standard one for this build since it's already cut this way.

[nattonrice]

Had a chance to sit down today and I think I've found the problem in my -500v supply.

Does anyone know where to find the DSEP12-12B Ixys Rectifiers apart from mouser (export restrictions mean I can't get them)?

If it isn't the rectifiers or the two caps then I'm gonna take up religion and try prayer.

[n_maher]

Had a chance to sit down today and I think I've found the problem in my -500v supply.

Does anyone know where to find the DSEP12-12B Ixys Rectifiers apart from mouser (export restrictions mean I can't get them)?

If it isn't the rectifiers or the two caps then I'm gonna take up religion and try prayer.

If you need something from Mouser that you can't get elsewhere just post a request and I'm sure one of us will help you out.

[nattonrice]

Thanks Nate, I didn't think of that =)

I'll post something in the opps-I-didn't-order-it thread.

Edit: done!

Edited April 3, 2011 by nattonrice

[pedefede]

Does anyone know where to find the DSEP12-12B Ixys Rectifiers apart from mouser (export restrictions mean I can't get them)?

You can try Partsconnexion:

DIODES-64784 is similar: IXYS 12A 1000V Ultrafast, Soft Recovery (FRED) Epitaxial Diode (trr = 50 ns; TO-220AC package DSEI12-10A, 2.95$

I finally put together an order for screws at McMaster ... but even though i was able to make an acount, they are not willing to ship oversee

"Due to the complexity of U.S. Export regulations, McMaster-Carr has decided to only accept orders from a few, long-established customers of ours overseas"

Does any US/canadian etc. want to help me: buy the stuff and mail it to me, and get pay'd through paypal?

I have a excel-sheet (BOM) that can make the order in 2 sec.

Peter

[ujamerstand]

Us Canadians get the same shaft as you do.

[nattonrice]

That raises a good question pedefede, is the 15A rating critical or is it more the 1.2kv rating?

I have a truckload of Fairchild 8A 1200V Stealth diodes here... could these concievable be used instead of the IXY part?

I have a feeling 8A may be too low.

[spritzer]

I got my screws here with no export issues.

I also don't see any reason why 8A diodes shouldn't work but lets wait for Kevin to chime in.

[Pars]

Bolt Depot is another place to look for fasteners. Not sure what their export policy is.

[luvdunhill]

That raises a good question pedefede, is the 15A rating critical or is it more the 1.2kv rating?

I have a truckload of Fairchild 8A 1200V Stealth diodes here... could these concievable be used instead of the IXY part?

I have a feeling 8A may be too low.

The voltage rating. Those Fairchild parts are fine, most likely the same parts I'm using in fact.

[nattonrice]

Marc you've made my day =D

... and yeah fastener-express is where I get most of everything I order screw related.

They are the only place I've seen with a decent collection of metric anodized Al cap screws.

[kevin gilmore]

Any diodes you can get your hands on that are 1000 volts or better, and a couple

of amps or better and fit in the board will work fine. But if you are nuts, get

a few different kinds and pick the ones with the lowest noise. But be wary, because

actually measuring the noise differences between the diodes at the regulated output

requires all sorts of trickery to get valid answers.

[Linear]

But be wary, because actually measuring the noise differences between the diodes at the regulated output

requires all sorts of trickery to get valid answers.

I'm just about to undertake this exact task.

Could you share some of your trickery?

[kevin gilmore]

Plexiglass blast shield and rubber gloves...

Really good high voltage teflon caps to take

the DC out, so you can measure the AC, and

floating 3 wire 5.5 digit nanovoltmeters.

[Craig Sawyers]

I finally put together an order for screws at McMaster ... but even though i was able to make an acount, they are not willing to ship oversee

"Due to the complexity of U.S. Export regulations, McMaster-Carr has decided to only accept orders from a few, long-established customers of ours overseas"

Does any US/canadian etc. want to help me: buy the stuff and mail it to me, and get pay'd through paypal?

I have a excel-sheet (BOM) that can make the order in 2 sec.

Peter

Check back through the thread - I posted some UK suppliers that I used which would have no problems shipping to Denmark

[justin]

if anyone needs .1uF/1000V caps for electrostatic amp stuff..

[pedefede]

I finally put together an order for screws at McMaster ... but even though i was able to make an acount, they are not willing to ship oversee

"Due to the complexity of U.S. Export regulations, McMaster-Carr has decided to only accept orders from a few, long-established customers of ours overseas"

I found a nice way to get the stuff from McMaster, that i want to share. I made a US-address at www.nybox.com, where McMaster did want to ship. I also shipped order from future eletronics, and partsconnexion to the nybox-address. Nybox then put all 3 packages into 1, and shipped it to me B) So i only had to pay 1 oversee-shipment+toll!!!

So building process starts tomorrow. I will wait with the last small order from Banzaieffects, - since there will probably turn some little forgotten/broken part up, during the proces.

Peter