Gentlemen, I've just read the first 70 pages of this thread.

Beside the reading pleasure (yeah, I'm getting as crazy as you all, finding that reading technical things is enjoyable), I saw something extremely special...

This project is something I haven't seen before, and my English is too short to put proper words on it.

Dr Gilmore, you have been quite busy doing this between bottle washing.

Congrats to everyone that finished their T2.

Edited November 2, 201411 yr by G600

The on-semi announcement kind of throws a wrench in the works for the newer version of the T2 doesn't it? 

 

That being said, I have a few pieces of the mpsw06 left. Do we need to match the hfe, since it's a sub for the 3381?

We can use the Fairchild parts but I don't relish the thought of having to do the matching for a couple of T2's.  I might have a line on some 2SC3381's so there will probably be two layouts. 

mpsa06 is fine for those, very low power.

Fairchild version should be available for a long time.

good to hear, in that case I think the main hurdle will still be the power fets.

/

 

 

Edited November 11, 201510 yr by JoaMat

I like the stn substitute in that picture

Just curious. Did Stax use c3381 in T2 servo.

Edited November 11, 201510 yr by JoaMat

Stax used 2SC2291 but the schematic has it hand written on it "or 2SC3381". 

the one i had used the 2sc3381 parts

same silicon, one was a 5 pin, the other a 7 pin

How about HN4C51J  as replacement for 2sc3381? It's a Toshiba dual NPN common base in sot-25.

Edited November 29, 201411 yr by JoaMat

yep, that would work.

Not a whole lot of fun soldering those by hand though... 

my heart is being pulled so many ways I don't know what version to make 

my heart is being pulled so many ways I don't know what version to make 

 

All of them. 

Because d-_-b

Edited December 3, 201411 yr by nikongod

To add to your pleasure I will probably do a third version.  It will be tailored to the parts I can buy in bulk but leaning more towards the original design.  I've been stocking up on parts just in case I build some so a special version is in order. 

All of them. 

Because d-_-b

It's kind of an issue Ari, if I have boards lying around I somehow always end up populating them. It's part of the reason I have shied away from p2p work, aside from incompetence.

 

I started looking at the newer board files, do they have to have offboarded heatsinks? I got the impression that the original footprint was to match with aesthetics of the amplifier board.

I was looking for one-off deals and found this for fabbing the boards. There's enough area to do a run of the original, so that should encompass all of the current variations that currently exist. Plus black is free, which is of course priceless

 

Also some leftover space to add some boards if you were so inclined, was going to try to see if I could shove a dynalo in there

 

Does anyone see issues using 1oz copper for this? 

 

There are also some more recent options such as PCBway which has criminally low prices, but I can't justify using this without forming a group

would not do 1oz copper. too thin.

2 oz minimum, the original boards were 3oz

The original boards are badass and could cave in a skull. :dusty:

fair enough, china it is. I think PCBWay quoted me 5 boards for 350-ish for just the amplifier

If you want to split the cost I wouldn't mind taking an original board set (with the old sand like the 2sc3675's). Is that quote for the shrunk (400mm depth) boards?

No that was for the original board, http://www.pcbway.com/pcb-board-quote.html

Would cascaded CCS - be of any benefit in modified T2?

I am not sure it would. In the BH I can say it sounds much better to my ears* but didn't really measure any different.

Edit: compared to the CCS that the BHSE uses. I still prefer the original CCS.

Edited December 10, 201411 yr by luvdunhill