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Post by Johnkenn on Jun 27, 2024 17:07:02 GMT -6
Was using my Stam 660 today for about two hours. Turned if off for about 20 then came back and turned back on and noticed a smell. Then noticed a little bit of white smoke so I immediately turned it off. Tried again - same thing and I’ve determined it was coming from a resistor or three. Three look pretty toast-ish. This was in my rack with one space above it open. It’s at the top, so I just moved it down a little to have a little more than one space. It’s plugged into a standard Furman power conditioner and that is plugged into the wall.
As you probably know, I blew the left side of my power amp about two weeks ago and a tweeter. That was on a different outlet - one I thought when we built the house was a more powerful 20 W or something…but I really have no idea. I have a a nicer Furman conditioner with voltage regulation supposedly. I also have two other power conditioners plugged into that for various duties. My power amp was plugged directly into the bigger Furman, so if it was a spike or something, the Furman didn’t stop it.
So - my question. Do you think this is just a run of bad luck or could I have some dirty power or whatever coming in? We built the house in 2007 and I’ve never had any issues.
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Post by Johnkenn on Jun 27, 2024 17:10:37 GMT -6
Meant to tag the smarties with EE knowledge. svart, ragan |
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ericn
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Post by ericn on Jun 27, 2024 17:22:34 GMT -6
I’m going to bet it’s not power related, there are so many other things in the house that are going to be more susceptible to spikes.
The thing is though if it is power related it’s probably related to your HVAC system and it’s demands.
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Post by svart on Jun 27, 2024 17:31:55 GMT -6
Meant to tag the smarties with EE knowledge. svart, raganHonestly it's hard to say. Could be an issue with the power, but it'd probably be more widespread around the house. It could be something with the outlet in that room, but only specific testing might be able to tell, and even then if it's a transient problem, it might be hard to see. How do you turn everything on and off? |
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Post by Johnkenn on Jun 27, 2024 17:33:38 GMT -6
I’m going to bet it’s not power related, there are so many other things in the house that are going to be more susceptible to spikes. The thing is though if it is power related it’s probably related to your HVAC system and it’s demands. Oh so you’re saying the HVAC is causing a brown out or whatever? I thought that’s what the voltage regulators protect against…that being said, I didn’t have this plugged into one with a voltage reg. Whomp. Probably gonna have to ship it somewhere (thank god it’s only the mono version)…because I want to make sure the burnt resistors aren’t the symptom of a power supply issue. |
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Post by Johnkenn on Jun 27, 2024 17:38:10 GMT -6
Meant to tag the smarties with EE knowledge. svart, raganHonestly it's hard to say. Could be an issue with the power, but it'd probably be more widespread around the house. It could be something with the outlet in that room, but only specific testing might be able to tell, and even then if it's a transient problem, it might be hard to see. How do you turn everything on and off? I usually leave the power conditioners on all the time. And turn off the actual units. My guess is the two issues are probably coincidental…but it’s weird a power issue would happen twice in a month or so. Is there any type of care I need to be doing when powering something like this up? Could it be it just didn’t have enough air flow? Like I said it’s in a floor rack and was only 1-2U spaces from the top. I’d say around - w inch gap from the top of the shelf to the top of the unit. |
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Post by jmoose on Jun 27, 2024 17:47:42 GMT -6
Well... your HVAC & everyone else's at this time of year creates what we'd generally call "dirty power" and yes having everything plugged into a furman or similar is at least the first line of defense.
IMO probably just bad luck.
Usually power 'issues' manifest in extremely obvious ways...
There's a shit ton of noise & ground loops. Terrible buzzes & whatnot that just won't go away...
Really bad power has not one or two pieces letting out magic smoke, but everything's gonna let out magic smoke and/or - be really unhappy in the obvious ways. Like, there's no headroom & everything is distorted... digital gear might start rebooting on its own... "Gremlins"
So yeah probably just time for you to pay up with the repair gods. They gotta eat too!
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Post by sean on Jun 27, 2024 17:48:07 GMT -6
Resistors burning and causing smoke is something happening inside the unit and I can’t imagine related to ventilation. Most likely those are current limiting resistors and are there for protection to the rest of the circuit…but they can smoke before failing. I would think that the Stam would be able to work with +/- 10% of 115v or 120V, but being a tube unit that likely runs hot in ideal situations if you had 130V going to it might cause issues.
As far as your speakers go, DC offset can burn up tweeters.
At a studio outside of Nashville we had to get a balanced Furman power supply because in the summer when everyone is running their AC the voltage in the studio would drop below 110V and would cause the consoles power supply to fault and shut off the positive power rail, which does not make a fun sound through the speakers.
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Post by ericn on Jun 27, 2024 18:28:14 GMT -6
I’m going to bet it’s not power related, there are so many other things in the house that are going to be more susceptible to spikes. The thing is though if it is power related it’s probably related to your HVAC system and it’s demands. Oh so you’re saying the HVAC is causing a brown out or whatever? I thought that’s what the voltage regulators protect against…that being said, I didn’t have this plugged into one with a voltage reg. Whomp. Probably gonna have to ship it somewhere (thank god it’s only the mono version)…because I want to make sure the burnt resistors aren’t the symptom of a power supply issue. What moose said below, I’ll add the one stupid cheap piece of crap that I have noticed are most susceptible are cheap generic IPhone chargers, my new way of knowing if I’m having spikes. |
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Post by Johnkenn on Jun 27, 2024 19:01:24 GMT -6
I might look into getting a better conditioner for my rack too.
Dumb question, but no issues with plugging other conditioners into a main one?
I didn’t try it after it started smoking but my guess is it might have worked…
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Post by ericn on Jun 27, 2024 19:37:23 GMT -6
I might look into getting a better conditioner for my rack too. Dumb question, but no issues with plugging other conditioners into a main one? I didn’t try it after it started smoking but my guess is it might have worked… The problem is what is “ better “? Unless you have a known issue and find a unit that is designed and I really mean designed to solve that issue it’s useless. The most common issue is surge protection and Furman is the only one I know of that is designed to actually still protect after a surge, the rest all melt the MOV and become a $5 IKEA strip after a surge and of course don’t tell you “ hey I did my job now replace me”. |
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Post by ragan on Jun 28, 2024 6:04:07 GMT -6
I’d be interested to know which resistors burned up, and what that block of the schematic looks like. That would help inform whether AC mains issues is a good candidate for root cause.
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Post by keymod on Jun 28, 2024 6:34:41 GMT -6
As an electrical contractor, I always recommend a whole-house surge protector installed, not only in the main panel, but in all down stream sub-panels.
They are actually required now by the NEC for all new installations and/or service changes/upgrades
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Post by svart on Jun 28, 2024 6:53:59 GMT -6
There's a bunch of possible issues:
1) "Dirty" power: Has noise/glitches on the AC. Some of those transient glitches can be much higher voltage peaks than normal.
2) Surge: the actual AC voltage increases by some amount. Can be fast or slow.
3) Brown-out: the AC voltage drops to below normal. Can be fast or slow.
Any of these can be combined with each other too.
And I have to remind everyone once again, a "power conditioner" does NOT usually control the voltage. It's usually JUST a filter to try to remove some high frequency trash combined with some MOV devices to attempt to catch transient spikes. These are glorified power strips.
Higher quality "conditioners" might have a large 1:1 toroid transformer that is used as a large resonant filter (only allows a small amount of frequencies through).
There may even be some "conditioners" out there that might have AC inverters inside, but expect those to be $$$$.
I personally don't run any "conditioners" at all. My power strips have MOV devices inside, but nothing else. I shut off my whole studio at once with the breaker and in the 18 years I've been at this location, I haven't had a single failure in any gear.
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Post by Dan on Jun 28, 2024 7:37:23 GMT -6
Your amp was probably just old and in need of service. As for the Stam 660. New tube gear man. So many things can go wrong. The originals were point to point and 3 ru. The Stam is 1 ru. Heat leads to premature component failure.
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Post by doubledog on Jun 28, 2024 7:41:06 GMT -6
I'm going to recommend this again (and I use the Walmart link only because it's easy to get and easy to take back if you don't like it): www.walmart.com/ip/APC-UPS-1500VA-900W-UPS-Battery-Backup-Surge-Protector-BX1500M-AVR-Dataline-Protection-Black/481285511it will regulate your power and keep a consistent voltage. It's not going to stop lightning - nothing will stop lightning - but it might help with daily fluctuations caused by appliances in your home, or by your power company (my power flickers in the summer with AC systems going on and off and its only a matter of time before the Texas power grid fails again). Anyway for < $200 I think it's a no-brainer. I have a smaller version of this (600VA) and if I lose power in the middle of a session, it keeps my computer monitor and interface up long enough that I can save (what's left) and shutdown safely. if the power only flickers, I might see that in the lights but everything else stays up (as long as I'm not actively recording). I do not have my preamps and outboard plugged in, but with one or more of these units you easily could (up to 900W per). It is a little strange to see the waveforms that get recorded when your preamps are drained of power during an outage though - no plugin in that world that could recreate that...  |
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Post by mcirish on Jun 28, 2024 7:51:21 GMT -6
I worked as a bench tech in my previous life. Smoke from a resistor indicates over current. Something is causing that. Hard to say eactly what it is but my guess would be a resistor in one of the tube stages. If the tube is starting to short out, it will draw extra current, which makes the resistor have to disapate that in heat.
If I was in Nashville, I'd have a look at it, but alas, I'm in Chicago.
I would be very glad to wrong, but I wouldn't hold my breath expecting Stam to come through with any schematics. I've already been down that road with one of their preamps. You'd have better luck getting the original schematics and then tracing things out if they don't use the same numbering.
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Post by svart on Jun 28, 2024 8:03:48 GMT -6
I'm going to recommend this again (and I use the Walmart link only because it's easy to get and easy to take back if you don't like it): www.walmart.com/ip/APC-UPS-1500VA-900W-UPS-Battery-Backup-Surge-Protector-BX1500M-AVR-Dataline-Protection-Black/481285511it will regulate your power and keep a consistent voltage. It's not going to stop lightning - nothing will stop lightning - but it might help with daily fluctuations caused by appliances in your home, or by your power company (my power flickers in the summer with AC systems going on and off and its only a matter of time before the Texas power grid fails again). Anyway for < $200 I think it's a no-brainer. I have a smaller version of this (600VA) and if I lose power in the middle of a session, it keeps my computer monitor and interface up long enough that I can save (what's left) and shutdown safely. if the power only flickers, I might see that in the lights but everything else stays up (as long as I'm not actively recording). I do not have my preamps and outboard plugged in, but with one or more of these units you easily could (up to 900W per). It is a little strange to see the waveforms that get recorded when your preamps are drained of power during an outage though - no plugin in that world that could recreate that... Those don't really work the way you think they do. They don't "regulate" in the sense of generating AC at a precise frequency. These are what they call "line-interactive" devices, which means they mostly allow the line voltage through untouched, but will switch in a device to increase or decrease voltage a few percent for a small amount of time. They might have a small transformer with taps that relays will switch in and out to boost or cut the AC, or they might have a low power inverter that is switched in and out. When you say "its a little strange to see the waveforms that get recorded when your preamps are drained of power during an outage", do you mean your preamps are also connected to the UPS? Because a UPS of this caliber will ONLY be square wave output and would have horrific implications on noise in things like preamps.. |
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Post by doubledog on Jun 28, 2024 8:20:41 GMT -6
I'm going to recommend this again (and I use the Walmart link only because it's easy to get and easy to take back if you don't like it): www.walmart.com/ip/APC-UPS-1500VA-900W-UPS-Battery-Backup-Surge-Protector-BX1500M-AVR-Dataline-Protection-Black/481285511it will regulate your power and keep a consistent voltage. It's not going to stop lightning - nothing will stop lightning - but it might help with daily fluctuations caused by appliances in your home, or by your power company (my power flickers in the summer with AC systems going on and off and its only a matter of time before the Texas power grid fails again). Anyway for < $200 I think it's a no-brainer. I have a smaller version of this (600VA) and if I lose power in the middle of a session, it keeps my computer monitor and interface up long enough that I can save (what's left) and shutdown safely. if the power only flickers, I might see that in the lights but everything else stays up (as long as I'm not actively recording). I do not have my preamps and outboard plugged in, but with one or more of these units you easily could (up to 900W per). It is a little strange to see the waveforms that get recorded when your preamps are drained of power during an outage though - no plugin in that world that could recreate that... Those don't really work the way you think they do. They don't "regulate" in the sense of generating AC at a precise frequency. These are what they call "line-interactive" devices, which means they mostly allow the line voltage through untouched, but will switch in a device to increase or decrease voltage a few percent for a small amount of time. They might have a small transformer with taps that relays will switch in and out to boost or cut the AC, or they might have a low power inverter that is switched in and out. When you say "its a little strange to see the waveforms that get recorded when your preamps are drained of power during an outage", do you mean your preamps are also connected to the UPS? Because a UPS of this caliber will ONLY be square wave output and would have horrific implications on noise in things like preamps.. as I said in my original post (that you quoted above)... I do not have my preamps or outboard connected to the UPS. The UPS I have is not large enough to support it, so when the power drops, only my computer, monitor, and interface stay up - which is fine. And as the power drains out of the caps in the preamps, the audio gets pretty gnarly for a second or two. When the UPS dies (the batteries go after time and in smaller units the battery costs as much as the whole thing) then I'll be getting one of these 1500VA units. As for how the UPS works, I will defer to APC's own documentation here -- www.apc.com/us/en/faqs/FA158913/I've been using small UPS's in my studio for 15 years. They've worked for me. YMMV of course. |
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Post by Johnkenn on Jun 28, 2024 9:15:01 GMT -6
I worked as a bench tech in my previous life. Smoke from a resistor indicates over current. Something is causing that. Hard to say eactly what it is but my guess would be a resistor in one of the tube stages. If the tube is starting to short out, it will draw extra current, which makes the resistor have to disapate that in heat. If I was in Nashville, I'd have a look at it, but alas, I'm in Chicago. I would be very glad to wrong, but I wouldn't hold my breath expecting Stam to come through with any schematics. I've already been down that road with one of their preamps. You'd have better luck getting the original schematics and then tracing things out if they don't use the same numbering. Oh...he will make good. |
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Post by Johnkenn on Jun 28, 2024 10:43:46 GMT -6
I worked as a bench tech in my previous life. Smoke from a resistor indicates over current. Something is causing that. Hard to say eactly what it is but my guess would be a resistor in one of the tube stages. If the tube is starting to short out, it will draw extra current, which makes the resistor have to disapate that in heat. If I was in Nashville, I'd have a look at it, but alas, I'm in Chicago. I would be very glad to wrong, but I wouldn't hold my breath expecting Stam to come through with any schematics. I've already been down that road with one of their preamps. You'd have better luck getting the original schematics and then tracing things out if they don't use the same numbering. There’s a tech here that had worked on one before and said there had been an issue with the power transformer. But suggested I send it to his (Stam's) tech. |
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Post by the other mark williams on Jun 28, 2024 22:33:06 GMT -6
I worked as a bench tech in my previous life. Smoke from a resistor indicates over current. Something is causing that. Hard to say eactly what it is but my guess would be a resistor in one of the tube stages. If the tube is starting to short out, it will draw extra current, which makes the resistor have to disapate that in heat. If I was in Nashville, I'd have a look at it, but alas, I'm in Chicago. I would be very glad to wrong, but I wouldn't hold my breath expecting Stam to come through with any schematics. I've already been down that road with one of their preamps. You'd have better luck getting the original schematics and then tracing things out if they don't use the same numbering. There’s a tech here that had worked on one before and said there had been an issue with the power transformer. But suggested I send it to his (Stam's) tech. John, have you reached out directly to Josh stam ? I imagine he would get the unit sorted for you one way or another pretty quickly. It's a fairly new piece, isn't it? I know that doesn't address the bigger question re: the power in your space... |
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Post by Johnkenn on Jun 28, 2024 22:57:31 GMT -6
There’s a tech here that had worked on one before and said there had been an issue with the power transformer. But suggested I send it to his (Stam's) tech. John, have you reached out directly to Josh stam ? I imagine he would get the unit sorted for you one way or another pretty quickly. It's a fairly new piece, isn't it? I know that doesn't address the bigger question re: the power in your space... Yeah - I’m talking to him now and we’re figuring it out. 🤞🏻 |
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Post by prene1 on Jun 29, 2024 9:39:11 GMT -6
I run a server grade cyberpower UPS with all the Sinewave crap and all that to my power conditioners.
I have a few and they’re networked around the home and studio for my gear and server. Never had issues.
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Post by damoongo on Jun 29, 2024 11:21:06 GMT -6
John, have you reached out directly to Josh stam ? I imagine he would get the unit sorted for you one way or another pretty quickly. It's a fairly new piece, isn't it? I know that doesn't address the bigger question re: the power in your space... Yeah - I’m talking to him now and we’re figuring it out. 🤞🏻 Curious what he says... |
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