Audio Discussion > DIY

Flame Linear 400

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OldiesButGoodies:
Woke up this morning,  went to my shop to work on a CD player that is not responding to the skip button.  Turned on NPR radio on the Toshiba tuner going through the Phase Linear 2000/400 combo and got to work.  At one point I moved the PL400 a bit to get to the back of the pre and connect the CD and *poof*  smoke billowed from the right Genesis speaker!  Luckily the left one was disconnected as I had a small cheap sony tester speaker hooked up. Both the Sony and the one Genesis are toast (well,  I can sell the recently re-foamed passive radiator from the Genesis for parts I guess).   The cause:  80V of pure DC power to both channels.  One of the two 2N1304 bias transistors came disconnected from the driver board and caused a cascade of damage that included 4 PL909 output transistors spread across both channels.  Luckily the Oak Audio driver board did not suffer any damage (that thing is a  battle tank - recommended upgrade!), and after replacing the 1304 and the 4 PL909s,  the Flame Linear 400 is biased and singing again (that speaker destroying SOB).  Before I hook any more speakers in a permanent fashion, I will wire up this speaker protection relay that I ignored installing for so long...

The flame linear reputation lives on!

Oouch by Jose Sifontes, on Flickr

Untitled by Jose Sifontes, on Flickr

When the Phase Linear works it sounds REALLY good.  When it goes nuts,  it goes really nuts.  Respect those two bias transistors!

OBG

geoffr:
Is that amp that great as to risk damage to other equipment, or possibly cause a fire?

Sir Thrift-a-Lot:
80V.   That'll do it.   That relay is like the tooth that is cracked but you don't go to the dentist until it actually starts hurting.

OldiesButGoodies:
Well George Geoff,  on behalf of my recently diceased Genesis 20 speaker,  I would have to say no.... (anyone Have a pair of Genesis and is looking for a center channel? or maybe a pair of Genesis 10s that would want to upgrade to the version with passive radiators?   :P I digresss...). 

IMO the 70V (or 80V in my case) failure mode is rare - it happened to me because I flipped that driver board down so many  times  that the leads to Q6 were understandably ready to come disconnected [Edit: and the nuts that attach it to the chassis were loose - that did not help either].  Not everyone will have that problem. And if you add the relay protection you should be fine (which Scott [BMW75] did early on in his PL700, I ignored his advice,  my bad). 

So I will just fix the original design flaw by adding the safety circuit and continue using it in the shop. 

OBG

PS - No plans to connect it to my B&W 803s any time in the near future...  the above notwithstanding  :(|)

ataudio:
You're taking this much better than I would have. A had on old power amp to the same to a pair of KLH Model 6 speakers. I avoid old power amps now. Just gun shy I guess. But on a happier note im glad you were able to fix the PL400. 

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