upgrading a threshold 4000 : PLEASE need a courtesy

[ds23man]

Your first tech is a bloody idiot! How can he tell all transistors are broken without desoldering them????????????? The only thing he did was take the lid off!

 

[Antoinel]

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

I fully agree with Zen Mod. Some questions.

• Was this amp accidentaly flooded with water? I see signs of rust and sediment [dirt] on the components.
• Did you buy it new or you bought it as is from somebody else?
• Are you saying that you were using it and suddenly it went dead?
• Does it have the correct fuses? I counted four on the back plate.
• Did you personally check the PSU and observed +/-75V?
• Do you have its schematic?

 

[Antoinel]

inertial. Did you know that the power output transistors in every Threshold amp were highly matched for performance, and hand-selected; maybe by Mr. Pass?. If they are not broken, then they [48 transistors] are worth today more than $1000. I suggest that you or lab technicians must prove first by testing that each transistor is broken or not.

 

[inertial]

Thanks, you are right, but local her the situation is a real disaster!!
yOU are telling me that those technician have said me false argumentation?

Because all power and signal ( both channel) are DEAD? 😕

I KNOW THESE PERSONS : THEY ARE ALWAYS BE HONEST, WITH ME AND HAVE REPAIRED ALL MATERIAL I HAVE GOT THEY, EXCLUDED THIS 4000, UNFORTUNATELY.....

btw, i HAVE AN ARTICLE , MAJBE i CAN BETTER OPEN A NEW THREAD , WHERE AN ITALIAN ENGINEER GIACOMO PRUZZO of COSTRUIRE HI - FI , italiazn diy magazine ) HAVE SHOWED COMPLETRE SCHEMATIC OF an S / 300 THRESHOLD.

He have rebuild, all excluded the final output stage ,where, at the post of the stasis, he has closed a global "ring" of feedback from input and output and have soubstituited the power transistors with complementary mosfet IRFP 530/9530 (3 pairs for channel) , obtained, clear 100 watt/ 8 ohm .

I'll open a new thread with modded schematic, because a friend of mine has jet build the two complete vetronite's circuites - plates , with all signal transistors: ALL done ,less than the final output stage.

Seems it work well, but i want to see prototype in function into mine 4000 chassis .
I think , with more mosfets pairs, or 3-4 pairs of IRFP 140/9140 , wich I suppose are sufficent to make 200watt / 8 ohms.

Stay tuned.... photos of 2 vetronites "schedas- circuits " are in arrival soon,
with complete schematic also. 🙂

cheders and thanks for reading

 

[Andrew Eckhardt]

How do you breach output transistor safe area in an amp like that anyway? Put it in a fire, crank it up, and load it at 1 ohm?

 

[inertial]

No, I simply listen with my DIY - 6,5 ohms near resistive load , 90 db efficency -and the amp has worked perfectly for 17 years .
Unfortunately, 2 months ago, one bad day , no signal at the output....got it at the lab and understand the "problem".

I have wondered for the broken 100%.

For pure luck,I suppose , no damage had occours at the speakers.....

But now , I am indecise: or I install this "Clone-Threshold" modded by Engineer Giacomo pruzzo of "Costruire hi-Fi" - italian DIY magazine - of 15 years ago, or I'll must put into the chassis a module by AKSA or Aussieamplifier, or other.....😕

Mj personal preferences was obviously for a more modern amp but always a THRESHOLD SCHEMATIC, this is important for me, because <I 'm a fan of Mrf. Pass!!😉

Cheers

Paolo venezia - italy

 

[Zen Mod]

Italy is big country ; find someone to repair it

 

[Antoinel]

Italy is big country ; find someone to repair it

inertial. Zen Mod is a qualified, renowned [famous] and a skilled DIYer who will fix it for you. Send him a private message regarding $$ details. I am curious to know the cost to ship [ground] your Threshold heavyweight from Italy to Serbia?

 

[Zen Mod]

naah

Serbia is still outa Funny Union , so customs are preventing operations as that

.........I'm having only Cart Blanche for OPLDF

so - that's what I'm most qualified, renowned [famous] for .........

 

[inertial]

HOW TO contact ,in private , ZEN MOD - GURU?

inertial. Zen Mod is a qualified, renowned [famous] and a skilled DIYer who will fix it for you. Send him a private message regarding $$ details. I am curious to know the cost to ship [ground] your Threshold heavyweight from Italy to Serbia?

I have trouble with contact , in private , ZEN MOD, the GURU ( I KNOW HIS HIGH value!!😎

can you kindley indicate to me ( very inexpert of forums ,sorry!) which buttons I must push/selectionated, to contact directly , in private, he?

THANKS , 🙂

Paolo Pontello,
C.E.O. PHASELESS - HIGH END , LOW COST ( also in kit) SPEAKERS, handcrafted in italy.

 

[Zen Mod]

to send private message to any member hare :

-click on member's name (left upper corner of member's post , above his avatar) , click on third line from top - send a private message to - new window for PM will open

ZM , Guru of Dumbness