Hi, guys,
i have build a Crescendo millenium amp publishrd in Electors mag.But it dosent work. while teasting supply & out putis shorted & the pair of 2sj 201 /2sk1530.
now the set is dead. I have purchased 2 new pairs Can any budy
guide that from where to start re cheacking the cercuit.
neeraj
i have build a Crescendo millenium amp publishrd in Electors mag.But it dosent work. while teasting supply & out putis shorted & the pair of 2sj 201 /2sk1530.
now the set is dead. I have purchased 2 new pairs Can any budy
guide that from where to start re cheacking the cercuit.
neeraj
Crescendo ME can be a little tricky.
Hard to say what you should change.
There has been a number of topics about Crescendo ME before.
So there are several members here that have also built this amplifier.
goto search http://www.diyaudio.com/forums/search.php
and search for
Threads with 'Crescendo' in title only.
Hard to say what you should change.
There has been a number of topics about Crescendo ME before.
So there are several members here that have also built this amplifier.
goto search http://www.diyaudio.com/forums/search.php
and search for
Threads with 'Crescendo' in title only.
peranders said:Were the output transistors insulated properly? Did you have the bias turned down?
Are you aware of that you can test the amp _without_ the mosfet's soldered? Is driver OK? Just the mosfet's went
Hi PA
Transisters are properly insulated, Bias was turned down, But while checking out put voltage onput & out put get Shorted
Move the feedback resistor 22k or 33k (if I remember correctly) to the gates instead from the output. It doesn't matter which gate you take. By this you'll take the feedback from the VAS stage (BF470/471 or whatever you have there).neeraj said:Hi PA ,
Sorry for delay.no i am not aware of testing amp without power transister. Any link or idea?
Of course you have fuses on both rails
and you have also chosen low values when you test, like 315 mA or so.You don't have fuses
Yes, this amplifer has a name for either working, or giving lots of problems. I took a close look at the circuit, and the compensation really needs some work. This is another design where in the all out pursuit for low distortion, the designer has played it too close to the edge and ended up with something with very marginal stability. A pity, because it has all the ingredients that could have made it solid, classic design. You are not the first one to be burnt neeraj, and you will not be the last. If you are looking for a good design, try one of Apex's circuits, or an Ostripper bipolar output one.
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