------------------------------
 
From: omen!omen.com!caf@uunet.uu.net (Chuck Forsberg WA7KGX)
Date: Mon, 25 Jul 94 19:01:48 PDT

Newsgroups: rec.audio.high-end
Path: caf
From: caf@omen.UUCP (Chuck Forsberg WA7KGX)
Subject: Re: Exploding Amps III
Organization: Omen Technology INC, Portland Rain Forest
Date: Tue, 26 Jul 1994 02:01:44 GMT
Message-ID: <1994Jul26.020144.646@omen.UUCP>
References: <3112q6$jm6@tolstoy.lerc.nasa.gov>

In article <3112q6$jm6@tolstoy.lerc.nasa.gov> tarr@CS.YALE.EDU (michael tarr) writes:
>Now that the dust has settled here is some more on my exploding Belles
>150:
>
>5. My Thiel CS-2 has at least a blown midrange, probably a bad woofer,
>and the crossover has several completely melted capacitors. The cost for
>fixing this all will be well over $200 (first estimate -- things may
>keep getting higher).

I'd suspect the amp broke into an (possibly ultrasonic) osciallation.

This happened to a friend ca.  1959 when an Eico amp cut loose
and self destructed over the lunch hour.  The whole barracks
stank, and transformer tar was everywhere.  About half the parts
were shot, and the glass envelope on one of the tubes was
visibly distorted.  The tweeters on my AR-2 were fried, and only
a high frequency oscillation could have done that.

-- 
  Chuck Forsberg WA7KGX       caf@omen.COM      503-621-3406
Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, GSZ and DSZ
   Omen Technology Inc      "The High Reliability Software"
TeleGodzilla BBS: 503-621-3746     FAX:-3735    CIS:70007,2304

------------------------------
 
From: breivog@ornews.intel.com (Bob Breivogel)
Subject: Re: Exploding Amps III
Date: 26 Jul 1994 14:36:24 -0700

tarr@CS.YALE.EDU (michael tarr) writes:

(...)

>4. The amp was no UL listed or anything else (no stickers or mentions in
>the manual).

This raises a question. UL listing is *expensive* and small, low volume
manufacturers may choose not to do it. Is there any government regulation
requiring some sort of testing of a consumer product such as this? One
thing that UL looks for is that failures of components do not result in a
fire external to the equipment. There are specific requirements as to the
materials used in construction (e.g. "self extinguishing" ). 

I would be very concerned if the manufacturer showed little interest in
the amp after this incident. They should give you either a complete refund
or a new unit (your choice) and repair any damage to associated components.
Failing this, they should be blacklisted.

Bob Breivogel
Intel Corp - Aloha, OR
breivogel@ptd.intel.com