Warning About The Singlepower Extreme - Owners Please Read - Page 3

Ok, this is clearly the hammond 266n12 transformer used in exactly
the same WRONG way as monoboy's unit.

Telltale signs
Black and White winding (110v)
Orange and Brown winding (110v)
Red and Blue winding (6.3v)
Grey and Yellow winding (6.3v)

mrarroyo's transformer is clearly one of the hammond 300 series
likely the 378x.

Telltale signs
Red, Violet, Red/yellow, red high voltage winding
yellow, yellow/black, yellow winding (5V not used)
green, green/yellow, green (6.3 VAC)
Brown, Brown/yellow, Blue/yellow, Blue (one of the 2 primary windings)
White, White/black, Black/red, Black (other primary winding)

Sorry for the basic question, but is the potential 378X transformer in my MPX3 a good thing or a bad thing? Thanks.

I'm pretty sure that is a good thing. Knowing the exact model number
would make it much easier. Some of the 300 series are only 3 amps
on the filament (not enough) some are 6 amps which should run
most of the power hungry tubes (6bl7). Still temperature is the
key here. If its getting massively hot, then you are probably going
to want to do something about it.

more info
http://www.hammondmfg.com/300series.htm

Kevin, I can lay my hand on the transformer cover all day long. It is warm but not hot. BTW, Mikhail was paid to install the Supra transformer. I have never removed the transformer case but the original cables were cut when the Supra was installed. I sure hope he did it because otherwise I lost money (nothing new w/ Singlepower, I know). Thanks.

Now that all of us Extreme owners are wondering if our amps are going to explode at any minute. I was wondering if we are any better off with any other brand headhone amps. It doesn't appear that there is any regulating body connected with headphone amps, such as UL (underwriters laboratories) to assure anyone that these products are safe for consumers. Am I wrong about this ? maybe some of the big international companies comply. But what about all the smaller guys selling amps? Especially the ones made in China?

I hope this thread can be done effectively because this is a serious issue for the membership. This amp is of concern to a lot of people and help from our senior members with the experience is needed and appreciated. What we don't need is sensationalism of possible hazards. Lets find the problems and offer direction.

This is a hobby industry and the things being found with SP are probably more wide spread than them. If the effort to find this problem can be put to all products that haven't been submitted to the proper certifications, we would all be better for it. This is the nature of buying on the internet. There are no safeguards or assurances and a world wide economy has people from Bengal, India buying a product made in Denver. That this community has the responsibility to protect itself and keep an eye out for these things is a credit to Head Fi.

Thanks Nate for alerting everyone to this serious problem.

I agree with this:
And I agree with this:
One should not chastise anyone else for saying they like the sound of their Singlepower amp. Likewise no one should write off the safety concerns that have been brought up here. We all agree there is a problem and each of us is trying to figure out our best course of action. No one is trying to piss off other members who are suffering through the same thing. People directing their anger over raw deals with Singlepower to other members because they say they like something is futile.

Our frustration (and I know that is putting it politely) is with Singlepower, not each other. Let's keep that in mind and help each other out. So far that is what is happening here in this thread.

I was laid over in Denver on a flight to San Diego last week and I recalled that Singlepower's shop is or at least was right by the airport. The thought definitely crossed my mind.

[QUOTE=DavidMahler;5897595]
EDIT: My anger is not directed at you sorry....QUOTE]

No problem. I fully understand the point you are making.

I've only had my amp for three weeks and it looks like at the
very least I need to replace the transformer. Seems I spoke
to soon.

I was trying to make the best of a bad situation but could have
been more sensitive to others I'll agree.

Apologies if my comments offended anybody but obviously I am
supporting the owners and not Mikhail or SP.

Let's draw a line on this issue.

Withdrawn

Withdrawn. Thanks for all concern.

What's the worst that could happen if the transformer fails? Could it potentially damage my source or headphones?

2 seperate issues.

1) extremes with the hammond 266n12 transformer.

A primary to primary (which is the secondary) short (monoboys amp)
could put a significant percentage (depending on where the short is)
of the AC line onto the chassis. The fuse may or may not blow. And
current will flow from the chassis thru whatever low impedance it
finds to ground/neutral. Likely thru another component like your source.
At least on these units (all i've seen so far) the output capacitors are
rated to take the full power supply voltage, so a shorted output cap
is unlikely.

2) mpx/ppx things.
Almost all of these i have seen have output capacitor ratings between
33% and 66% of the B+ line. (160 to 250 volt caps) (300 to 530 volt B+)
Eventually these caps have to fail because the turn on thump when the
tube warms up typically goes way above B+/2. In fact the voltage on tyson's
amp is a steady state of 280 volts with 250 volt rated caps. Definitely
not a good thing. With high impedance heaphones, the headphones will
definitely fry. Best thing i can do for these things is series back to
back 5 watt zener diodes rated at 12 volts. And a 100ma fuse.

As you get into the supra/sds things it gets far more complicated
and the balanced units have additional problems. Voltron's amp for
example has a 1200 volt power rail with 900 volt rated caps to light
the gas tubes.