upgrading a threshold 4000 : PLEASE need a courtesy

[inertial]

HI,

Unfortunately my 4000 amp is 100% dead ,so I have to recicle cabinet and PSU.
I have +/- 75 volt B+ ()MONO).

I like the Series, so I have asked in france ( see treshold lovers website) to a lab that restore Threshold amps, but they have responded that the amp is not compatible with more modern type.!!

So I ask if some kind good guy here,
can make physycally two plates of alluminim of 6 mm thick ( to screwing to my heatskins that are 340 per 145 mm) with attached the entires channel of SOMETHING good ( if threshold or Pass better of course because I am alovers of the brand of mister Pass) of about 200 watt / 8 ohms.

My power transformer is 1000 VA ,SQUARED - not toroidal - and the capacitors are 4 Cornell Dubiler 15000 microfarad /80 volt still working!

I hope To have some good news from someone here...
Obviouslly I0' ll pay money bank or paypall the value of the work plus materials.

P.S. I love AB class with little % of clas A operation because thae amp is only for bass zone ( 20 - 350 Hz) and I would save heat.

Thanks for reading!

Cheers

Paolo Pontello - Phaseless High end Speakers

 

[Andersonix]

I like the Series, so I have asked in france ( see treshold lovers website) to a lab that restore Threshold amps, but they have responded that the amp is not compatible with more modern type.!!

The way I interpret this: The amp uses TO-3 case transistors, but the modern case is TO-247 (aka TO-3P), so you want to make an adapter so a new amplifier can fit your heat sink?
More info, please?

 

[inertial]

Yes, you are right.
I have two heatsinks 340x345mm with a lot of holes, so I have to attach over it a plate of 6mm of alluminium, where to fix the new plastic transistors and all the components & circuits, PSU excluded.
I think it's possible, because 99% of amplifiers class AB works with a dual B+ of, in my case, 75 + or - Volts. So I don't see any difficults.
In facts, I have asked to AussieAmplifiers and they have suggested me their modules NX300 that it's beautiful modern amp but I'am nostalgic and would like to put a Threshold amp in a Threshold cabinet!

Thanks for reading.

 

[Nelson Pass]

You can still get TO-3's through distribution. Digikey and Mouser have parts
like STMicro BUX48, BUX 98 and 2ST2121 in stock.

Also, when you say 100% dead, what do you mean. Have you tested the devices?

 

[inertial]

Dear Mr. Pass,

I have taken my 4000 in laboratory, and they have said that all transistors (power and signal) are destroyed.
In addition, they can't guarantee a repair, even at about 600 Euro cost.
At this point, my interest is in more musical and modern, IMHO, S350 or S450.
Do you think it's possible?
Do you know some kind guy, maybe in Europe, that can do the work?

Thank you very much!

 

[Zen Mod]

pictures can't do any harm

 

[Triodethom]

Pictures please. To loose all the transistors and not have a lot of magic smoke let out and a blown transformer is very unique .

 

[inertial]

Hi all!
I can send the pictures, but I don't understand the reason. I have specified as the technician of the lab that repair amps have said that all 24 power transistors for channell are dead. And also all the signal transistors.
From the photo nothing useful can be seen - the transistors appears normal.
There's no sign of fire, or melted components, etc.

Thanks for reading.

 

[Nelson Pass]

You said they said "all transistors (power and signal) are destroyed".

I doubt that this statement is true.

Now it is possible that all power devices are destroyed, but I have never seen
such a case. I have met technicians who would say such a thing without doing
the amount of work necessary to confirm that.

Since you would have to take every transistor out anyway, I suggest you
do so carefully and test each one.

 

[Zen Mod]

.........but I don't understand the reason.......

last time when Witch Hunters were cohorting my little place , I was forced to hide my crystal ball

later , when they ( WH) goes away , I spotted that price for hiding my crystal ball in hurry was scratches all around

unfortunately - masters these days aren't so good in crystal polishing , as they are good in simple swapping of LCDs , so my (crystal) ball is waiting for some ole master , to make it useful , again

that's the reason why I need pictures to see posted - here - my remote device for remote observing of ooked remote devices is ooked

 

[Triodethom]

Pics Please

Hi all!
I can send the pictures, but I don't understand the reason. I have specified as the technician of the lab that repair amps have said that all 24 power transistors for channell are dead. And also all the signal transistors.
From the photo nothing useful can be seen - the transistors appears normal.
There's no sign of fire, or melted components, etc.

Thanks for reading.

That's so the designer (Nelson Pass) and some very bright other people (Zen Mod) can have a look at it . They want to help, as others of use wish to learn the pictures say a thousand words.

 

[inertial]

OK, I'll try to get some pictures and will post.

Thanks!

 

[inertial]

photos of my broken 4000.. :-(

her eare the photos. I havbe also contacted THRESHOLD LOVERS FORUM AND THE LAB IN fRANCE HAS RESPONDED THAT THE AMP IS NOT REPARAIBLE WITH SECURITY, NO GUARANTEE AS LIKE HERE IN ITALY FOR 500 EURO (!!)

aND i HAVE ALSO ASKED IF COURTESLY , FROM THE MOMENT i LOVE MUTCH MORE S/350 AND S/450 MODELS, IF WAS POSSIBLE AND "UPGRADATED" AND AT WICH COST...
tHEY ARE RESPONDED ,THAT THE AMPS ARE NOT COMPATIBLE (!!!) WITH MY REQUEST ( i THINK THIS IS FALSE, BECAUSE THE PSU, PLUS OR MINUS 75 VOLT IS ok, SO i DO NOT SEE THE ISSUE.
MAH!?

ANYONE CAN SUGGEST ME ONE VALID ALTERNATIVE ?


/media/share/scansioni/threshold3.jpg

/media/share/scansioni/foto_threshold.txt


THANKS,

PAOLO - PHASELESS SPEAKERS

 

[Zen Mod]

pic links no habla

WHY YOU ARE SHOUTING ?

 

[Andersonix]

Press the "Manage Attachments" button.

 

[Antoinel]

What is status of fuses; in line with power rails, the loudspeaker, and the transformer's primary? They are lightbulbs in cognito!

 

[Antoinel]

Dear Mr. Pass,

I have taken my 4000 in laboratory, and they have said that all transistors (power and signal) are destroyed.
In addition, they can't guarantee a repair, even at about 600 Euro cost.
At this point, my interest is in more musical and modern, IMHO, S350 or S450.
Do you think it's possible?
Do you know some kind guy, maybe in Europe, that can do the work?

Thank you very much!

Fortunately any working Threshold amp, is always state of the art/science, musical and modern.

 

[Antoinel]

You said they said "all transistors (power and signal) are destroyed".

I doubt that this statement is true.

Now it is possible that all power devices are destroyed, but I have never seen
such a case. I have met technicians who would say such a thing without doing
the amount of work necessary to confirm that.

Since you would have to take every transistor out anyway, I suggest you
do so carefully and test each one.

Your advice is valuable. I prefer to leave the transistors alone on the heatsink, and instead cut the traces on the PCB to isolate base and collector of each for individualized testing.

 

[inertial]

hi alls,
finally here is the pics
No doubt all the 48 transistor are broken, the thinghs make me hungry is that that responsable of french labs of repairs threshold have said to me that my amp is not upgradable TO A MORE MODERN s/350 OR S/$%= O OTHERS....tHIS IS VERY, SUSPECT.imho. wHAT DO YOU THINK ABOUT, very expert guys?



http://i.imgur.com/I9i1ezV.jpg
http://i.imgur.com/VfZbwUX.jpg
http://i.imgur.com/FswLtld.jpg

 

[Zen Mod]

you need first thing first - competent and honest technician ,to find what's broken and what's still operational ;

then you can be given with estimation what's needed for intended change , then decide is money involved adequate for that conversion

frankly - we can't go despite your obvious language difficulties , combined with your lack of electronic knowledge .

you need someone local , to help you in vivo