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My Singlepower Supra Experience - Why mine almost blew up like a Hand Grenade (and yours might too) - Page 3

post #31 of 314
7/30/09 at 11:22pm
The fact that an amp has a design flaw that makes it dangerous does not mean it can't sound good. I fail to see how those issues are necessarily related.

Nor do all safe amps sound good

What will eat at those of us who own SP amps is what to do with them. Using them may be dangerous, and if so, selling them is out of the question.
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post #32 of 314
7/30/09 at 11:23pm
Quote:
Originally Posted by greggf View Post
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?
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.
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post #33 of 314
7/30/09 at 11:24pm
Aside from using underated components and lower quality parts (XICON polarized electrolytic capacitors used as output coupling) what worries me the most about the pictures is running the wires to and from the power transformer with NO additional insulation.



Most assemblers would use something like rubber grommets to line the hole in the chassis. Running the hot AC lines through the rubber. As this photo shows, there is nothing to protect the user if the insulation around the wires gets rubbed away. This can happen with movement of the wires due to shipping or any kind of transportation.

Quote:
Is there a means to have all the designs reviewed by competent members to know what extent our members may be in ownership of a serious hazard?
If you can take good quality photos of your unit, I believe Dr. Gilmore would be able to help you with an evaluation of your gear. He initially helped Tyson out in this thread
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post #34 of 314
7/30/09 at 11:25pm
Thread Starter 
IMO, if you cannot find a very good local tech, any singlepower owner should contact Wayne at Store for The Bolder Cable Company and ask him to take a quick look at it to see if there are any problems.

In my case, I decided to go ahead and have him do some custom work for me (change it from OTL to parafeed transformer output), but that's not necessary on all amps. Mainly, just getting a new input transformer with correct voltage, and changing the parts to ones that are correctly spec'd will get you a safe amp. There's nothing wrong with the circuit used, per se, but there is something very wrong with how Mikhail implemented it.

My advice, do not use your amps till you get them checked out. They are repairable, if you find someone willing to work on them. Most people won't, but luckily I found someone who will, and he's willing to work on others, too.
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post #35 of 314
7/30/09 at 11:29pm
Tyson, when did you buy your amp?
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post #36 of 314
7/30/09 at 11:34pm
Thread Starter 
I bought it second hand from a member here on head-fi (mulveling), and he got it several years ago. In fact, I believe it was one ofthe very first Supras ever made.
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post #37 of 314
7/30/09 at 11:40pm
Quote:
Originally Posted by PhilS View Post
I have a SP Supra that I have been using for the last 5 years without issue. Is there really a danger associated with continuing to use these amps?
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.
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post #38 of 314
7/30/09 at 11:43pm
Quote:
Originally Posted by tkam View Post
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.
That's a good idea. I'll try that.
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post #39 of 314
7/30/09 at 11:44pm
Just a warning to add in addition to tkam's post, be careful if you do decide to open up the chassis on any amp. There are often lethal voltages present inside or at least the potential for lethal voltages. At a minimum I'd recommend having someone around to assist who knows their way around electricity and can keep you safe.
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post #40 of 314
7/30/09 at 11:49pm
Quote:
Originally Posted by n_maher View Post
Just a warning to add in addition to tkam's post, be careful if you do decide to open up the chassis on any amp. There are often lethal voltages present inside or at least the potential for lethal voltages. At a minimum I'd recommend having someone around to assist who knows their way around electricity and can keep you safe.
Is the problem resolved if you leave the amp unplugged for awhile and allow the caps to fully discharge? I thought I read that somewhere on one of the earlier SP threads.
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post #41 of 314
7/30/09 at 11:50pm
Thread Starter 
Do not poke around inside SP amps - THEY WILL KILL YOU. Even unplugging them will not discharge those monster caps.
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post #42 of 314
7/30/09 at 11:54pm
Quote:
Originally Posted by PhilS View Post
Is the problem resolved if you leave the amp unplugged for awhile and allow the caps to fully discharge? I thought I read that somewhere on one of the earlier SP threads.
Not necessarily, no. Most builders/designers will put a bleeder resistor in so that if the unit needs work or inspection it is a much safer proposition. I have not seen enough of Mikhail's work to be able to guarantee that so proceed with caution. As Kevin said, some of those big caps (and even the seemingly little guys) can pack way more than enough voltage and current to stop your heart. If there is not a bleeder resistor it won't matter if the amp has been unplugged for days or weeks. Some of these caps can store energy for a long time.
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post #43 of 314
7/30/09 at 11:59pm
Quote:
Originally Posted by n_maher View Post
Not necessarily, no. Most builders/designers will put a bleeder resistor in so that if the unit needs work or inspection it is a much safer proposition. I have not seen enough of Mikhail's work to be able to guarantee that so proceed with caution. As Kevin said, some of those big caps (and even the seemingly little guys) can pack way more than enough voltage and current to stop your heart. If there is not a bleeder resistor it won't matter if the amp has been unplugged for days or weeks. Some of these caps can store energy for a long time.
Ok,but it is fair to say that if I just remove the outside case and don't touch anything inside, I should be fine right? Since it's been working fine for 5 years, I'd prefer not to have to send it to someone who can look at it, or throw it in the trash as the other option.
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post #44 of 314
7/31/09 at 12:02am
This thing looks not only dangerous, but clearly amateurish in design and assembly.
Any regular amateur building a first-time amp would do it better than this.

How anyone could ever pay hard money for this is totally unbelievable.
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post #45 of 314
7/31/09 at 12:17am
Thread Starter 
I would only recommend taking the cover off, snapping some hi-rez pics, reading the values of the parts, and closing it back up. DO NOT TOUCH ANYTHING. Post the pics here in the DIY section, or send them to Wayne to get some help.
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