[mikeg]

Lets please avoid insults.

....you're just being silly....QUOTE]

 

[tyrion]

Quote:

Originally Posted by Wodgy Your logic doesn't make any sense. Your argument is that we can never trust experts. Hence, we cannot trust Mikhail. Why then do you say we should take his word on safety? It's illogical. As for your last statement, you're just being silly. If a UL lab says something isn't safe, you know such a product raises red lights and would likely make a juicy target for a liability suit. No, there isn't a 100% chance that the product isn't safe (this is a common line of lawyer argument by the way; you're not being clever), because nothing in life can be said with 100% certainty, but that's not what I said. Rational human beings would tend to believe that if a UL lab says something isn't safe, there is a significantly higher likelihood that it isn't safe. Safety standards usually exist for a rational reason.

Sometimes we need to introduce some silliness, otherwise these discussions get out of control. Actually, everything I said is perfectly logical if you followed the point I was making. I said earlier we all have to make judgements on who and what to believe. I was using extreme examples to point out the problem with what you said about the tenured professor, etc. mentioned by chumley. That was the whole point of my post. I said that I know Mikhail. I don't get the impression that he would knowingly sell products that he thought were not safe. My impression my be wrong but it is a choice I have made for the moment. Everything else I said was an attempt to illustrate that point.

 

[Wodgy]

Quote:

Originally Posted by mikeg Since I don't have any understanding of wiring and circuits, I can't evaluate your reference to Dr. Gilmore's statement. But the rest of the narrative by Strohmie, at least to my mind, confirms that there is lots of room for reasonable people to disagree with your statements that Mikhail misleads people. Therefore, I choose to give Mikhail the benefit of the doubt.

You're running out of gas.

You don't need any understanding of circuits to calculate the output impedance of a standard cathode follower (Gilmore's circuit #1). The formula is very simple: the plate resistance divided by the amplification factor (rp / mu). Here's a reference for the formula . The plate resistance of a 6SN7 tube is in the neighborhood of 7000 ohms and mu is 20. Here's a reference for that. What's the output impedance? Around 350 ohms. You can play with this a bit, a little higher, a little lower, but you can't push it down to 20 ohms, what Mikhael claims. Thus, this cannot be the Singlepower OTL circuit. (Dr. Gilmore is welcome to correct me if this analysis is wrong.)

That leaves both of Gilmore's other circuits. Both are push-pull.

 

[GlowWorm]

Quote:

Originally Posted by tyrion I know Mikhail. I don't get the impression that he would knowingly sell products that he thought were not safe. My impression my be wrong but it is a choice I have made for the moment.

Your personal "impressions" of the manufacturer's integrity are purely speculative, and quite frankly irrelevant. I don't think anyone here has ever implied that Mikhail has knowingly, and willingly sold amps that were dangerous, so your point is strictly an academic one. However, what is relevant, regardless of the manufacturer's intent, is that his amps are quite possibly unsafe due to shoddy workmanship.

 

[chumley]

Quote:

Originally Posted by mikeg I sincerely appreciate your methodical approach to resolving this matter. Perhaps such pictures could be provided by chumley who, in post #42 on this thread, described expert testimony to the hazards of his SinglePower amps; although he did not identify these experts. Since chumley expressed concern for himself and others, if exposed to these amps (i.e., he explained that he would neither use them, nor sell them), perhaps he would at least photograph their circuitry, and post these complete pictures. IMO, this especially makes sense in view of the fact that he has already opened the cases of these amps in order to have them examined by his experts.

Not as long as I have the implied threat of a lawsuit from Singlepower for posting just the kinds of pics you suggest. And even if Singlepower gave me express permission to post extensive pics (yeah, right), I'm an extremely busy forty-something father of two who works as a computer and networking consultant, to fairly high remuneration, in exchange for almost every darn bit of my time.

I offered what I have repeatedly identified as OPINION, both my own, and the aggregated informal opinions, subsequent to a cursory hands-on examination, of several knowledgeable friends. Nothing more. Want more? Either talk Mikhail into doing what, IMO, is the 'right thing' (see below), or do a less formal version of 'safety verification' yourself, with your own amp, people, time, and money. I do not offer these services.

And, no, I'm not shipping anything anywhere. Period.

Verifiable, comprehensive facts? It's up to either Singlepower to supply a sample amp of each type that they offer for sale to UL, et al for independent testing, and/or each owner to have their own 'trusted 3rd party' examine/test their amp to ascertain its safety. Or not.

The rest, as they say, is up to you.

 

[tyrion]

Quote:

Originally Posted by GlowWorm Your personal "impressions" of the manufacturer's integrity are purely speculative, and quite frankly irrelevant. I don't think anyone here has ever implied that Mikhail has knowingly, and willingly sold amps that were dangerous, so your point is strictly an academic one. However, what is relevant, regardless of the manufacturer's intent, is that his amps are quite possibly unsafe due to shoddy workmanship.

You missed my point. I never said that my opinion of what I believe was anyhting other than my impression from dealing with Mikhail. I have not characterized them in any other way. I never said that everyone should believe Mikhail. I only said what I have chosen to accept for the moment. I do not care whether you consider my comments to irrelevant or not. I was not speaking to you when I made my comments. They were addressed to two other participants in this thread. My point, again, concerned the statements that were made in posts about what unkown experts said, nothing else. I don't know how many times I have to explain this. I read these posts differently than you do. What you consider irrelevant, I consider relevant based upon what I have read. I have to say that whether there is shoddy workmanship is an open question. It is one that I am not qualified to address and haven't addressed.

 

[tuatara]

leaving aside the question of which mode the Singlepower amps operate in(alot of owners are probably like me, dont care as long as it sounds good) the issue of safety and long term reliabilty really should be addressed by Singlepower .
Probably the only way to end this matter is for them to have a recognised certification/safety lab test the amps to make sure they meet whatever standards are applicable and have the certifier publish the results.

As a slight side issue but related, I would guess that most of the amps sold to this point would be to Headfi members or friend of. However this source is finite and a business that wants to keep going and possible export regularly will have to source a larger client base which may mean getting into the shark pool, ie reviews in magazines like Stereophile and HiFi News.

Now HiFi News shows internal shots of the product tested in about 90% of their reviews plus conduct many lab tests. If the photos shown on HeadFi are indeed from a Singlepower amp(has that been refuted by the manufacturer?) then what do you think the reaction will be from possible purchasers who expect a different standard of presentation.
To me, and I may be wrong so bash away, Singlepower looks like a hobby that has blossomed into a business, but which hasn't quite grasped that there must be a difference, what isn't seen is often more important than that which is .

Headphone amps, and especially valve amps, are always going to be a very small niche market and any manufacturer that arrives and turns out a product that seems to work as well as Singlepower has to be encouraged but there are still basic standards that must be maintained and if there are doubts about safety then it is in that builders best interest to clearly and with best speed allay them.

While I applaud Singlepower owners for the vigorous deffence of their amps, I hope they remain open to reasoned arguments from the 'other side'.
I happen to own a SXH1 which comes in for plenty of flack on various issues and why not, if there're problems they should be sorted no matter who the manufacturer is.

 

[elnero]

Quote:

Originally Posted by Wodgy Then we have people like elnero who suggest that even if we get SMPTE engineers to evaluate one of these units on videotape, that might not be enough and that we should do it three times! At some point this all becomes ludicrous. How many times do people have to reconfirm what your gut instinct tells you?

You missed my point, I'm trying to say that for the sake of satisfying all partys involved we should not rely on only one persons opinion but try to confirm these results by getting the opinions of a few verifiable "experts" that have knowledge of tube circuits and point to point wiring. I have no idea what experience a SMPTE engineer would have with this type of amplifier, maybe it's perfectly valid, maybe not but I definately wouldn't be the one to decide such a thing.

One thing I do know, at this point I wouldn't be trusting Chumley's experts until he states who they are and what credentials they have in order to verify their credibility. These are serious allegations people, with serious consequenses for the manufacturer, the situation should not be made light of just because you think you know the outcome.

 

[mikeg]

I'm being quite honest in saying that I have absolutely no understanding of the subject that you are describing. I'm a lover of music, and have absolutely not interest or understanding of the innards of electronic gear. Although, in my younger days I did do lots of soldering when building Eico, Dynaco, and Heathkit kits. So, I feel that I do know a little about soldering wires, resistors, etc. Needless to say, the clusters of wires that I put together never looked anywhere as neat at the ones pictures in the kit instructions. But, the final products of my efforts worked, and I was never electrocuted. I guess that that's one reason that I'm not at all concerned with the "cosmetics" of the innards of my new SinglePower amp.

Quote:

Originally Posted by Wodgy You're running out of gas. You don't need any understanding of circuits to calculate the output impedance of a standard cathode follower (Gilmore's circuit #1). The formula is very simple: the plate resistance divided by the amplification factor (rp / mu). Here's a reference for the formula . The plate resistance of a 6SN7 tube is in the neighborhood of 7000 ohms and mu is 20. Here's a reference for that. What's the output impedance? Around 350 ohms. You can play with this a bit, a little higher, a little lower, but you can't push it down to 20 ohms, what Mikhael claims. Thus, this cannot be the Singlepower OTL circuit. (Dr. Gilmore is welcome to correct me if this analysis is wrong.) That leaves both of Gilmore's other circuits. Both are push-pull.

 

[mikeg]

IMO, conclusions regarding safety of an amp, that are based solely on a few partial pictures of the amp., are also purely speculative. In fact, this entire discussion regarding safety, and it's disparaging implications regarding Mikhail, are founded on nothing but speculation. Can anyone point to any incident of actual or perceived harm that's attributable to the 200 or more SinglePower amps that are supposedly owned by Head-Fi members?

Quote:

Originally Posted by GlowWorm Your personal "impressions" of the manufacturer's integrity are purely speculative, and quite frankly irrelevant. I don't think anyone here has ever implied that Mikhail has knowingly, and willingly sold amps that were dangerous, so your point is strictly an academic one. However, what is relevant, regardless of the manufacturer's intent, is that his amps are quite possibly unsafe due to shoddy workmanship.

 

[mikeg]

Since you mentioned that you consulted numerous experts, I'm surprised that you don't have sufficient time to arrange for a few photographs of your already opened amps. Are you saying that SinglePower implied a lawsuit against you, were you to provide pictures for Dr. Gilmore's consideration? I was under the impression that your sense of public responsibility (e.g., not wanting to endanger others by selling your amps) may weigh on you sufficiently to have the photos furnished, or at least forwarding your amps for examination, and photography by others.


Quote:

Originally Posted by chumley Not as long as I have the implied threat of a lawsuit from Singlepower for posting just the kinds of pics you suggest. And even if Singlepower gave me express permission to post extensive pics (yeah, right), I'm an extremely busy forty-something father of two who works as a computer and networking consultant, to fairly high remuneration, in exchange for almost every darn bit of my time. I offered what I have repeatedly identified as OPINION, both my own, and the aggregated informal opinions, subsequent to a cursory hands-on examination, of several knowledgeable friends. Nothing more. Want more? Either talk Mikhail into doing what, IMO, is the 'right thing' (see below), or do a less formal version of 'safety verification' yourself, with your own amp, people, time, and money. I do not offer these services. And, no, I'm not shipping anything anywhere. Period. Verifiable, comprehensive facts? It's up to either Singlepower to supply a sample amp of each type that they offer for sale to UL, et al for independent testing, and/or each owner to have their own 'trusted 3rd party' examine/test their amp to ascertain its safety. Or not. The rest, as they say, is up to you.

 

[Wodgy]

Quote:

Originally Posted by mikeg IMO, conclusions regarding safety of an amp, that are based solely on a few partial pictures of the amp., are also purely speculative.

FYI, the pictures that Braillediver keeps posting are not the only Singlepower pictures that have been posted. TrevorNetwork also posted three pictures of the interior of his amp. They show a similar construction technique (or lack thereof). So it's fair to say that the style of construction depicted is not confined to a single, isolated amp.

 

[mikeg]

I defer to Dr. Gilmore's posing #105 on this thread, in which he says that "As soon as someone posts complete pictures of the insides we will
have more to discuss..." Short of satisfying this request by Dr. Gilmore, speculations regarding safety are just that, pure speculations. And, IMO anonymous people who promulgate and spread such speculations regarding matters of safety, and people's livelyhood, and their reputation, are contributing to what I view as a cruel and irresponsible activity.

Quote:

Originally Posted by Wodgy FYI, the pictures that Braillediver keeps posting are not the only Singlepower pictures that have been posted. TrevorNetwork also posted three pictures of the interior of his amp. They show a similar construction technique (or lack thereof). So it's fair to say that the style of construction depicted is not confined to a single, isolated amp.

 

[Wodgy]

Quote:

Originally Posted by elnero These are serious allegations people, with serious consequenses for the manufacturer, the situation should not be made light of just because you think you know the outcome.

I agree with you, and I feel really bad for the manufacturer. Really bad. However, there are also serious potential consequences to his customers if these amps are unsafe (you in particular will be interested in my comments in the other thread about fire insurance in Canada) and it's only reasonable to try to get to the truth as well as we can. None of us will have perfect evidence unless some of us are willing to pony up money for a proper UL-style certification test (and even then some people, e.g. Tyrion, have said they won't believe safety tests conducted by a UL facility!). Since that is unlikely, even with the test money coming from Mikhail (I suspect even he doesn't seriously believe his amps, as currently assembled, would meet UL standards), we can only listen to opinions, however imperfect they are. I agree with you, it would be nicer if people giving opinions always provided their names and qualifications, but just because they don't doesn't mean the stated opinions are invalid, just that they need to be taken with a bigger grain of salt. Try to evaluate what arguments are they using. Do they appear valid? What about Braillediver's specific point-by-point questions in Strohmie's new thread? What does your gut tell you when looking at those pictures?

Ultimately, when the interior of these amps looks like such trash, the burden of proving their safety falls upon the manufacturer. He made the decision to assemble them that way, and it seems that he may have been ashamed of it enough to try to prevent pictures from getting out for two years. He also made the decision not to get UL certification as far as we know (he's not listed in the UL's database, though there is a chance that he chose an alternate standards organization). Not exactly the best set of judgments.

IMHO, it's still possible for Mikhail to salvage this thing and turn it into a win-win situation for everyone. However, he needs to stop the BS. He should tell us that he's submitting his amps to a lab for testing, or if he has already done so he should tell us. If the amps fail independent safety testing, he should be honest about why. He should promise to fix the problems in new amps, and offer to fix the problems in older amps if people want them fixed. He also needs to explain to us why he claimed the amps were single-ended when they weren't. It's fine if he made a mistake, but he should be honest about it! He can also be honest that the "pure class A" was more marketing than strict reality for low impedance cans. Fine. Just be truthful. People will respect that more than the carefully couched lawyer/marketing talk that he used in his last public statement. If he handles this right, I suspect he could easily emerge stronger and more respected than before. If he just sticks his head in the sand while True Believers defend him with increasingly tenuous arguments ("I won't even believe it if the UL says it's unsafe! They're just a bunch of know-nothing idiots! I have absolute faith in Mikhail!") things will just smolder forever.

 

[mikeg]

Are you volunteering to receive the donations, buy amps from Mikhail, arrange for their tests, and prepare the unbiased report of results?

Quote:

Originally Posted by Wodgy I agree with you, and I feel really bad for the manufacturer. Really bad. However, there are also serious potential consequences to his customers if these amps are unsafe (you in particular will be interested in my comments in the other thread about fire insurance in Canada) and it's only reasonable to try to get to the truth as well as we can. None of us will have perfect evidence unless some of us are willing to pony up money for a proper UL-style certification test (and even then some people, e.g. Tyrion, have said they won't believe safety tests conducted by a UL facility!). Since that is unlikely, even with the test money coming from Mikhail (I suspect even he doesn't seriously believe his amps, as currently assembled, would meet UL standards), we can only listen to opinions, however imperfect they are. I agree with you, it would be nicer if people giving opinions always provided their names and qualifications, but just because they don't doesn't mean the stated opinions are invalid, just that they need to be taken with a bigger grain of salt. Try to evaluate what arguments are they using. Do they appear valid? What about Braillediver's specific point-by-point questions in Strohmie's new thread? What does your gut tell you when looking at those pictures? Ultimately, when the interior of these amps looks like such trash, the burden of proving their safety falls upon the manufacturer. He made the decision to assemble them that way, and it seems that he may have been ashamed of it enough to try to prevent pictures from getting out for two years. He also made the decision not to get UL certification as far as we know (he's not listed in the UL's database, though there is a chance that he chose an alternate standards organization). Not exactly the best set of judgments. IMHO, it's still possible for Mikhail to salvage this thing and turn it into a win-win situation for everyone. However, he needs to stop the BS. He should tell us that he's submitting his amps to a lab for testing, or if he has already done so he should tell us. If the amps fail independent safety testing, he should be honest about why. He should promise to fix the problems in new amps, and offer to fix the problems in older amps if people want them fixed. He also needs to explain to us why he claimed the amps were single-ended when they weren't. It's fine if he made a mistake, but he should be honest about it! He can also be honest that the "pure class A" was more marketing than strict reality for low impedance cans. Fine. Just be truthful. People will respect that more than the carefully couched lawyer/marketing talk that he used in his last public statement. If he handles this right, I suspect he could easily emerge stronger and more respected than before. If he just sticks his head in the sand while True Believers defend him with increasingly tenuous arguments ("I won't even believe it if the UL says it's unsafe! They're just a bunch of know-nothing idiots! I have absolute faith in Mikhail!") things will just smolder forever.