[Icarium]

Quote:

Originally Posted by TreAdidas /img/forum/go_quote.gif Ok so let's quell some of the speculation here. I understand the concerns of possible safety issues. These concerns are apparently warranted due to the people in the know posting up here. Unfortunately, I have seen no comments about this having actually happened. Now assuming this happened to someone and they were still alive to tell the tale, we'd have heard about it. I think we're teetering on mass hysteria with little more than horrendously bad wiring jobs and mismatched parts. I understand that mismatched parts and crap wiring jobs can cause very very serious safety problems, but as of right now I have not read that anyone actually experienced this. So I ask..... [size=large]HAS ANYONE ACTUALLY HAD ANY PART OF ANY MODEL OF SINGLEPOWER AMP, BE IT A "STOCK" OR CUSTOM CONFIGURATION, ACTUALLY BLOW UP AND/OR SHOCK THEM?[/size] And just so we're clear - By blow up I mean the amplifier or some component thereof has produced some sort of violent hand grenade like blast (similar to this: YouTube - Exploding Capacitor). If the amp turned into a canon I want to hear about it! By electrical shock I mean the failure caused the user to experience an electrical shock, minor or otherwise. Either of these instances would have had to occurred without having opened the amplifier case. If someone opens the case and are all yeah I got shocked while I was toying around inside the amp, I would not necessarily fault Singlepower for that because it could have been caused by the person toying around in the amp. We've established here in this thread that only qualified technicians should be playing around with the amp's innards. If someone was listening to their amp and heard it fry and then went to touch the volume knob and was shocked, yeah total problem, totally Singlepower's fault, and I want to hear about it. Anyone?????????

I don't think people are focusing on the physical danger of these amps. I think it's mostly the fact that they were very poorly built and are failing at a very alarming rate. Moreover that they seem built/designed to fail by running things over voltage. It is worthwhile to point this out in amps that have the problem because perhaps with a little bit of a fix they will not fail.

I think the physical danger element is only mentioned as a precaution so that people who are curious what they have inside their black box do not hurt themselves opening it up and poking around. There's probably a risk even with a well built high voltage amp, but with the mess that is in these boxes that risk is multiplied many times. Of course, overall the risk is still low if you take some safety measures... but then again what's better? Making the risk known or having even 1 person get seriously hurt trying to mess with their amp?

If there's any hysteria it is over the fact that Singlepower amps are essentially built to fail and will fail. I speak from experience... my amp which I paid 7k for second hand is now nothing but a gutted chassis. It was essentially a bunch of burnt circuit boards... you know how much I got back from having parts sold? Like 20 bucks for some black gates + a fancy chassis. And I'm not even an isolated or extreme case.... sorry but this is hysteria-worthy buddy.

If you want to live in denial go ahead, but keep it to yourself because anything else is just insulting to the MANY people who have been burnt and are in the process of getting burnt.

 

[purk]

Quote:

Originally Posted by PhilS /img/forum/go_quote.gif Did we ever come up with a list of people that could service these amps? I remember we started a Singlepower owners registry, with a view towards finding out how many people owned the amps and identifying people to service them, but the registry basically just lists some of the owners. I wonder if we should start a new thread with a list of people that could check out and service these amps? Maybe we could settle on one or two folks with experience who would agree to service them, which might be more efficient for all of us, given economies of scale, and the one or two repair places might make a little money from repeat business. Does this make sense or not?

I think this is a good idea. I know a tech in Atlanta area that did a good work on my amp. Basically all necessary bleeder resistors were added to curcuit to help with voltage surge on my amp.

 

[Tyson]

Yes, the main thing is to have someone measure the voltage generated onto the circuit, and check that voltage against the parts rating and circuit implementation inside the amp. If the voltage is higher than the parts are built or configured to handle, you will need to get it fixed by a)reducing the voltage, and/or b) swapping parts to something built to handle the voltage. If you run parts outside of their spec, they will fail, it's just a matter of time. To deny this fact is akin to saying "Well, that shoddy wiring in my house hasn't caused a fire yet!" No, not yet, but you're taking a risk. Best thing to do is call an electrician to fix your wiring, no?

[size=large]Help is available[/size]

I know of 2 people on this board that will help you with this - Wayne (user name "Bolder"), and Kevin Gilmore. Kevin probably won't accept the amp from you to measure it, but Wayne will. What Kevin has done in the past, is analyze the circuit and implementation based on hi-rez pics, and developed a correct schematic and pointed out where the problem areas are. With that info, you can get a local tech to fix it, or you can contact Wayne to see if he is willing to fix it for you.

 

[penger]

Here's the link to the Owners registry thread. http://www.head-fi.org/forums/f5/sin...gistry-415152/

 

[Hirsch]

Quote:

Originally Posted by Tyson /img/forum/go_quote.gif As can be seen, those are not premium quality parts, far from it. But here's the rub - those 2 big @ss soup can sized capacitors? They are rated for 450v. Not bad, except the voltage from the transformer is [size=large]530 Volts![/size] Now, even though they are connected in series, there is not a leveling resistor(s) in place between them. That means there is a high degree of danger that they will blow up, [size=xx-large]Yes, BLOW UP LIKE HAND GRENADES!!!![/size].

Uh, no. While I can't defend Mikhail's builds, which vary from worse than awful to actually very good, this danger is wrong. The key is that they are indeed connected in series. That has several effects. Capacitance and storage capacity are reduced, but voltage is increased. By putting them in series, you've turned two 450 volt caps into one 900 volt cap, which is more than capable of handling the voltages the transformer is putting out. There are plenty of reasons to distrust Mikhail's builds, but this one isn't going to blow for the reason stated. See below for brief primer:

Capacitance

or

Capacitors in Series

For convenience:

Quote:

Does it ever make sense to put capacitors in series? You get less capacitance and less charge storage than with either alone. It is sometimes done in electronics practice because capacitors have maximum working voltages, and with two "600 volt maximum" capacitors in series, you can increase the working voltage to 1200 volts.

I'm actually somewhat surprised that people who are far more technically adept than I didn't point this out earlier in the thread. There are plenty of real issues with the amps, but this isn't one of them. Best to stay focused on the real problems, not phantoms.

 

[arrowmark]

I have a MPX3 with upgrades that has worked with no problems for 4 years.

 

[kevin gilmore]

Capacitors - Multiple Capacitors
(resistor networks for capacitors in series)

big electrolytics like used in tyson's amp have capacitance values that are +/-10%
or more, and leakage that varies 50% or more. Without balancing resistors
across both of the caps, The result can in fact be dangerous.
If you want to continue to run a unit with these caps, a pair of 100k 1 watt resistors
across each of the two caps will increase the safety margin a significant amount.

For tyson's amp, 530 volts for a WCF is absolutely the wrong direction for a low
impedance headphones. Half that voltage and twice the idle current decreases
the output impedance of that amp by about a factor of 3.

Not the least of which is that the 530 volts puts the top tube's cathode about
100 volts out of spec. A trick that is in absolutely every single ES1 and ES2.

There are lots of ways to make these things safe without having to change the
sound signature.

 

[Tyson]

More bad news - here's an update from Wayne regarding the High/Low voltage switch on the back of my amp:

"The amplifier that you gave me to repair/rebuild has a switch on the back panel to change between "High" voltage and "Low" voltage. The HV is actually 530 V and the low is 260 V.

After careful examination of the other parts used in this amp, I was curious about the ratings of this switch. The numbers were covered by a blue decal. I peeled the decal off and cleaned up the switch.

This is what I found

It is an Electroswitch C4D0206N sold by Digi-Key for $16.00.

Here is the pdf of the spec sheet for the switch.

It is rated for use to 0.5 amp at 25 volts DC. The switch is only being fed 21 times what it is rated for.

I would be very careful if I owned one of these amps with this switch."

 

[TreAdidas]

Quote:

Originally Posted by Icarium /img/forum/go_quote.gif And I'm not even an isolated or extreme case.... sorry but this is hysteria-worthy buddy. If you want to live in denial go ahead, but keep it to yourself because anything else is just insulting to the MANY people who have been burnt and are in the process of getting burnt.

Haha an "Extreme" case... given that a model of SP's amps are named extreme that made me laugh. And then my laughter stopped.

I am a Singlepower owner and trying to get into the nuts and bolts of this and figure out what the hell I should do. I spent my hard earned cash on one of these amps and I'm not ready to shelve the thing just yet. I am looking for indisputable proof that danger exists and so far all I have seen is some very convincing speculation. I appreciate all of the talk going on here.

 

[thathertz]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Ugh...should I have the same worry about my MPX3?

Same here Skylab.

Quote:

Originally Posted by TreAdidas /img/forum/go_quote.gif The is starting to sound like mass hysteria... :: puts headphones back on and turns up the MPX3 :: Meh... I'll deal with it.

Have to agree with you right now. I mean right now I'm listening
to my MPX3 and it's just seductive, engaging, compelling, exciting....

I think, unfortunately, this is going to be a lottery. Mikhail created
some truly classic amps during certain periods in time. My guess is he
got snowed under due to demand, got sloppy and never managed to
get full control over his business.

Do I think my MPX3 is going to blow? NO.
Would I ever let a member of my family listen to it? NO.


Quote:

Originally Posted by greggf /img/forum/go_quote.gif I'm with vcoheda on this one: how can we trust opinions on gear, when people said that the various Singlepowers sound so wonderful? What else are folks terribly wrong about?

Gregg, people speak as they find.

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif Some are definitely known to have issues. All I will say for right now (I have a rather lengthy post I've been working on for literally weeks) is that I would never, ever, under any circumstance leave a Singlepower amp on and unattended.

Absolutely.

Tyson, I must thank you for bringing this to our attention.
I'm getting my amp checked as soon as I can. God knows who will
have the requisite skills here in the UK but I would imagine there
are quite a few UK SP owners reading this now who are willing to
share information.

I wonder just how many SP owners there are out there?

Back to the music.

 

[thathertz]

Sorry guys I'm catching up...

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif There's nothing wrong with folks impressions, running parts out of spec does not necessarily equate with bad sound. The two are, at least in some cases, mutually exclusive. So don't go dismissing every word you've read, even Kevin will tell you that some of the amps sound good despite their engineering flaws.

My MPX3 sounds amazing. I've had Meier amps, 4 Graham Slee amps
and a Rudistor. The MPX3 beats them hands down.

Quote:

Originally Posted by tkam /img/forum/go_quote.gif This is unfortunately one of the largest problems, since in reality just about every SP amp was at least somewhat custom it's hard to say for sure one way or the other. It is however a good idea to open it up and take a look. Even if you don't have a clue what you are looking at, keep an eye out for overstressed parts (bulging caps, burnt resistors, etc). If your still not sure you can always post some hi-rez photos there's plenty of people around here who can take a quick look and point out anything bad.

I think that's a great idea. Bearing in mind these amps can kill under
certain conditions. DO NOT TOUCH ANYTHING INSIDE.

 

[TreAdidas]

Quote:

Originally Posted by moonboy403 /img/forum/go_quote.gif My Extreme didn't blow up, but the transformer gave out. Smoke came out of the chassis and took out one of my tube.

Here we go... this is more like it.

Ok did you ever figure out what caused this? Any more information? Did the amp ever work again? What did you do?

 

[thathertz]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Unless you know how to safely discharge caps, I wouldn't risk it. They can hold a charge for some time. Don't mess with them unless you know what you're doing. Also, everyone should not panic over point-to-point wiring with a star ground. A star ground uses individual wires to connect ground to a particular ground point. It results in extra wires, however, it is not inherently unsafe. I'm not excusing Mikhail's work, but do not equate wires running around with poor build quality. The opposite can be true with a carefully constructed amp. Personally, I think that star grounds are a great way to build an amp and can provide a measure of safety over using an exposed ground bus. I have radios and test gear built this way that have been operating safely since the 1940s. It's a good construction technique when used properly.

Erik, always the voice of calm and reason. Thank you.
We need you in this thread!

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Yes. Components should never "float" inside a chassis. Every component should be secured on both ends. Tie each end to a tube socket, tie point or terminal strip. Larger components, like big capacitors, should be further secured with a capacitor clamp bolted to the chassis. Bare leads are also a bad idea. While it may be overkill, I put spaghetti on every lead for every component. The "problem," however, is that building this way will result in a lot of wires running around. That can look like a bird's nest, but it will be safe and functional. What you really have to look for is that each component is secured. If you have that, then the construction can be sound. There's a lot more to this, but I don't want people to freak out just because they see wires. There are some exceptional amps built using point-to-point that, to an uneducated eye, might appear "dangerous" when the fact is that they're extremely well built. And no, I don't think this example is well built.

I think we need to get under the hood. Holy sh** I really don't
want to spoil the fun I'm having but it seems inevitable.

Quote:

Originally Posted by Happy Camper /img/forum/go_quote.gif I've ran mine hard (weeks at a stretch which won't happen again) with nary an issue. I have taken it apart and did a through inspection after a couple threads about trouble. I also took it apart at our last meet and had a couple DIY guys look it over. Nothing visually evident like discoloration or malformed components. Mine is a Platinum w/pc board PPX rev.A. As to the comments about the credibility of anyone saying a SP amp sounds good, that's just beyond comprehension. Hey Boom, you don't know what your talking about with that SP amp of yours.

Agreed. There seem to be way more people satisfied with SP amps
than those that have issues. Does that mean we shouldn't be concerned?
NO. But there's no reason to throw your amp in the trash just yet.

Quote:

Originally Posted by grawk /img/forum/go_quote.gif Please stop trolling. People who talk about how their amp sound don't contradict what has been done inside their amps. It's comments like these that muddy the waters and make these issues contentious.

X2

 

[thathertz]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Yup. I did exactly the same thing last night. Moved the CSP-2 to be my main headphone amp. MPX3 now sits next to the Extreme, disconnected and useless. I'm not confident that the local tech I use to fix stuff is up to the task on this, so I am still trying to decide whether to try to have these looked at/fixed up, or to dumpster them.

Sky, I'm sure there are many member here that would look at your amp
and advise you. You could then advise others.

 

[PhilS]

I tried to open mine this afternoon and can't get the hex screws undone. I have the right size hex key, but the size is so small that when I try to turn the screw, it doesn't budge, and it's torquing the key and it's going to break if I push it too far. I tried three screws and gave up.