Antique Sound Lab Hurricane Problem

==That's a great question. The older units fail after 3 months and the new units fail after 6.==

Ha-ha-ha !!! But seriously, folks, I am about to drop 2.5K on these monsters. Should I do it ? Is there something else there that sounds like it ? Large VTL stuff ? Anything ? This is a lot of money on an amp with a drifting bias and blowing resistors.

Thanks. I am taking the amp back to the hifi shop where it was on consignment to hopefully fix the blown resistors, if that's all it is. The other amp is fine, and I am falling in love with the sound. This pair has caps modified to Multicaps with silver wiring. It does indeed sound fabulous. I offered $2.5K for them, which seems like a good price for healthy units. I will mention the "cold solder" issue to them.

Regards,

Apparently, the preferred version has eight .22uf white circular multicap capacitors and the other version has rectangular gray boxy caps labeled "illusion". "My" amp is a mongrel, which started its life with the "illusion" caps and the previous owner had them changed to the top of the line multicaps with silver wiring, blowing over a grand in upgrade costs. I hope that the fix is an easy one.

What kind of failures are common ? My apparently had a blown resistor and tube. That's not too problematic. Serious failures requireing trips to the dealer are. How do people who own them cope with them ?

Well, it was the burnt-out 10 ohm resistor. Clearly a regular occurance in the life of this amp as other sockets had these resistors changed as well. The amps are running fine now...I think. One more question for the fellow sufferers - what bias do you run them at? I don't think I hear a difference between 440 mV and 490 mV. What has been your experience with tube life in these units ? Should one expect longer life at 400 mV than 490 mV ?

Thanks for your comments !

==In that case you have a flawed design. Burned out resistors==

Probably. I don't know if it is unusual for high power tube amplifiers to use sacrificial resistors to protect itself against failed tubes, but I certanily never had it happened in other tube amps I owned.

On the other hand it is a simple fix and the rest of the amplifier is intact.

If this doesn't happen too often, than this is not so bad. I suspect the wide bias range allowed owners to set the bias too high, resulting in a tube smoking. In my case, I suspect that I replaced the tubes in the wrong sockets, resulting in inadvertant high bias at that socket.

==You might consider having someone add those to your amps.==

Sounds like a good idea. Since I am spending considerable amount of time inside the amps, I can probably add them myself soon.

I have found that I had a blown resistor in another socket, mascarading as a healthy one, because the meter wire was broken on that socket ! Without a signal, ASL meter just drifts down slowly from the previous value !

OK, so now all is working and they sound devine. Do other Hurricane owners have the same amount of trouble? Or do these guys stay stable after being fixed and carefully biased?

Any feedback from other owners is greatly appreciated. I am trying to decide if these amps are worth 2.5K. These are definitely the best amps I had ever heard and by a considerable margin. On the other hand I never had to do this much work, not even on my old Citation.

I would respectfully disagree. The hurricane's sound is anything but dry and sterile. It has replaced a single ended amp in my system and delivers a very palpable, warm and liquid sound through Magnepans 1.6s. It has a tremendous presence and a spooky reality on voice, especially. I don't know why it sounds they way it does, as it seems a very straightforward design, but I would love someone to measure it well. I suspect, for example, that it may not have a straight frequency response - the differency between it and the previous amp were dramatic - like a 1-2 db drop in the irritation part of the spectrum - upper midrange, I guess. Usually that means less presence, but in this case it sounds like a lot more. Weird.

It sounds like an old argument over here that I had inadvertantly re-started. Sorry.

==I certainly wouldn't judge any amplifier based on the sonics of Magnepan 1.6.==

That makes sense, as you probably don't own these speakers. I do and that's the only speaker sound that matters to me when evaluating amplifiers. In my small experience, these panels have been rather easy to live with, and reveal upstream differences readily.

===They break by themselves; changing tubes only prolongs the inevitable===

That's what I am trying to ascertain - the frequency of the breakdowns in these amps. Your experience with them has been negative then ? How often was your pair out of commission ?

So far, after fixing the two burnt resistors and carefully adjusting the bias (on the low side - 450 mv) on a matched set of 4 quads of KT88EHs, so far they have been stable. But they do run hot and perhaps my fun is all in the future...