Jump to content

The ultimate DIY? A Stax SRM-T2!


spritzer

Recommended Posts

Just measured my output voltage, and it was slightly out of balance:

(which corresponds to R-channel having a very small weight)

L+ 100%

L- 110%

R+105%

R- 110%

(Switching input channels produces same result, so it wasnt the signal source)

What primarily controls the gain? EL34? K216?, ecc88?

Link to comment
Share on other sites

  • 2 weeks later...

I lost at least a hundred dollars to counterfeit parts. Also, 2SC3675 is 6.97 per piece at bdent for 30 pieces right now. That's over 200 dollars for just that part, and more if you want spares to do repairs. It's getting harder and harder for people to build this thing nowadays.

Link to comment
Share on other sites

IIRC the J79 (or K216) was the most expensive part when this thread was started a few years ago. Ironically it has not changed in price much.

We should have cleared out Sanyo's entire stock of 3675 when they were $.50 each instead of being 'practical' and only taking 50-100 each per person tongue.png

Link to comment
Share on other sites

A little update on the futurlec C3675 devices.

They were sent from bangkok, delivered by Deutsche Post, and invoiced from Australia. That's interesting.

http://i.imgur.com/AbRHB.jpg

okay... bent legs, like the ones I saw in my local hobby shop. Fair enough. Anyways, from left to right: utsource, futurlec, and bdent

http://i.imgur.com/PLmj1h.jpg

straighten out the leads. All of them look similar. The futurlec devices have similar letterings to the utsource devices.

Measured the Vbr and hFe using the handy measurement tool recommended by KG:

voltage breakdown:

utsource 1057V

futurlec 1252V

bdent 1117V

hFe:

utsource 46 @ 10uA(Ib)

futurlec 23 @ 10uA(Ib)

bdent 41 @ 10uA(Ib)

Hmm... So the hFe of the futurlec devices is a bit low. However, I am not testing at database conditions, so that might be the cause. Will have a curve tracer in 2 months time, I'll learn how to use it, and report back again.

Link to comment
Share on other sites

Yes, interesting. Fake parts are real nuisance and trouble causer.

Have a look at this video clip

For those of us who don't have full facilities to check the parts including myself, can only hope that, even if all effort is put in to make sure that the build is good, can only pray that when the switch is flipped everything works. Also hopefully, it continues to work properly for a long time to come. I only have the vbr tester which is insufficient to check other important perimeters.

Edited by Victor Chew
Link to comment
Share on other sites

  • 2 weeks later...

So I was blowing these 4A rat shack fuses (had no problem with a higher quality 4A fuse that I pulled from the BA) on a T2 (blubliss DIY), and decided to hook up the wattage meter just to see what was going on. The logger can only take data once every second, so I assume the "Max Amps" and "Max Wattage" mean the max recording during that one second interval. Hopefully this will be some use.

LL.gif

LL.gif

Edited by purrin
Link to comment
Share on other sites

  • 1 month later...
  • 1 month later...

I was lucky enough to get a set of boards from lil knight. I have been trying to get all the orders ready for the hard to get parts for this amp. Right now bdent.com has all but the 2sk246gr. I found some on ebay but after reading through the thread am not sure whether they are real or fake.

A lot of the parts have gone way up in price and I understand that since most of these things are now obsolete. The current pricing from bdent is

2sa1486 $3.52

2sk216 $5.69

2sc3675 $7.12eek.png

2sc3381 $17.75eek.pngeek.png

2sj79 $8.82

Are there better prices out there? If this is what I have to pay, okay. But if there are more reasonable prices out there I'm having a hard time finding them and knowing that the parts are real.

Thanks for any help guys.

Link to comment
Share on other sites

I was lucky enough to get a set of boards from lil knight. I have been trying to get all the orders ready for the hard to get parts for this amp. Right now bdent.com has all but the 2sk246gr. I found some on ebay but after reading through the thread am not sure whether they are real or fake.

A lot of the parts have gone way up in price and I understand that since most of these things are now obsolete. The current pricing from bdent is

2sa1486 $3.52

2sk216 $5.69

2sc3675 $7.12eek.png

2sc3381 $17.75eek.pngeek.png

2sj79 $8.82

Are there better prices out there? If this is what I have to pay, okay. But if there are more reasonable prices out there I'm having a hard time finding them and knowing that the parts are real.

Thanks for any help guys.

i can get way better pricing (at least, a year ago when i last ordered) on 2sk216/2sj79 but i'd be looking at ordering about 1,000 of each

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.