Threshold SA/12e tune up questions

[Eric M]

I've pick up a pair of Threshold SA/12e mono blocks which will arrive next week. My plan was to listen to them for a while and then decide if they could us any sort of tune up / rebuild as they are all original from 1992. After contemplating their weight and where they will rest (not on dollies, but on shelves), I'm wondering if there are some basics I should consider before getting a friend or 2 to get them where I want them?

-Power supply caps?
-Caps on FEB?
-I remember years ago when I was tinkering with Sansui equipment, they had issues with what everyone called "Black Caps" that were prone to failures. Anything like that on these amps I'd want to address sooner rather than later?
-Any advice would be appreciated ... and might save me a trip to the Chiropractor down the line!

Happy Holidays.

Eric M.

 

[Zen Mod]

all caps , generally

recheck of every bolt and screw , maybe even cleaning and renew of thermal grease on outputs

anyway , best to leave harder contemplating ......... and think when you actually get them

 

[Eric M]

Thanks. I got them the other day and took the tops off to give them a good blow with compressed air to rid them of dust. I also took lots of pictures and decided to put them to use before fooling with them. I nice little bonus that came with them was 2 copies of the Service Manuals for the S/350e all the way to S/1600e and SA/3.9e to SA/12e. It lists values for all parts as well. I've been going over the schematics.

If the SA/12e is a Parallel amp design, would the S/1600 be a bridged design using the same internals as the 12e but with 2 FEBs?

Thanks,

Eric

 

[Zen Mod]

make scans of all papers you have and either post them on DiyA for Greedy Boyz benefit, or send them to me and I'll post them both here and on my blog

last question - Pa is da Man for best answer.... hope he will chime in

 

[Eric M]

I know Threshold has been pretty secretive about their schematics and such. Is Nelson going to mind me posting the service manual? I know he parted ways with them in the early 90's, but, still, I don't want to step on any feet ....

 

[Eric M]

Who are da Greedy Boyz??

 

[Zen Mod]

fell free to do that ..... Treshold schmtcs are routinelly posted here , same as on my blog treshold | Search Results | Zen Mod Blog

I always think that there is something missing , when schematics are in question

🙂

 

[Zen Mod]

Greedy Boyz are occupants of this very space 🙂

 

[Eric M]

Ohhh, I'm a Greedy Boy!
Here you go, all 30 pages. The Output Board Layout was 11 x 17 and couldn't go through the scanner. I took a picture and converted it to PDF. It didn't size quite right. Give me your e-mail address and I can e-mail this to you also. What is your Blog address? I'd like to check out your other Threshold schematics.


Thanks,

Eric

OK, that didn't work. It's a PDF 14,500 KB and the limit here is 976 KB. Any suggestions?

 

[Zen Mod]

just send it to >zenmodiyaudio@gmail.com<

my blog - just click on link I gave you up , or see in my sig

 

[Eric M]

Shrunk PDF and converted to JPG and am posting 10 pages at a time .....

 

[Eric M]

11 to 20

 

[Eric M]

21 - 30. There's got to be an easier way.
Zen Mod, I'll e-mail the original, full size to you.

 

[Zen Mod]

ok,will take care of,when I'm back home

 

[mpmarino]

Thanks for the contribution

 

[tosh586]

Dear forum members, first of all thanks to the mods for reopening this thread. i studied the contributed schematics of the SA12/e, i'm dreaming about this amps since years. now to my question, its about the wiring connection of the FEB to the output stage. Drive and rail is marked on both schematics, but what's about "to stasis collector", i can't find the counterpart on the output stage. may be someone can help. sorry for my english, it's not my mother tongue. A few words about myself, i'm a hifi enthusiast since many years, now retired and living in Thailand, other interrest aside of music and hifi, vintage cars and electronic selfmade projects. Kind regards Peter

 

[Zen Mod]

plenty of Treshold related threads, where you can pick complete info

for starters, see here: https://www.diyaudio.com/community/threads/new-stasis-front-end.363701/

 

[tosh586]

Hi Zen
thanks for your reply, i've read the whiole trhead you mentioned but could not find an answer, just found out that others had the same question. using the search function i found the same question in a very old thread too, unfortunately no asnswer. seems to be a mysterium

https://www.diyaudio.com/community/threads/new-stasis-front-end.363701/post-6920141
https://www.diyaudio.com/community/...ld-schematics-once-online.123536/post-1521399

maybe someone else can help?

Kind regards Peter

 

[gary s]

If you look at the OS drawing S1905-C1 in post #11 - the two stasis transistors are Q1 and Q2 on the OS, you will see a point on each collector of these 2 transistors - I believe this is the point you are referring to.

 

[tosh586]

that would be the same point as the drive of output stage 1 and 2 are connected as seen in the attached drawings i found on the net. differing to the drawing 1905-C1 there are 4 stasis transistors.