that sucks ass you lost your tweeter, i had a similar problem happen to one of my mid to late 70's pioneer tower speaker. I had a signal generator plugged up to my stereo receiver and i was messing with my little brother across the hallway from me. He doesn't like high pitched sounds so i cranked up 18kHz, (which i can't hear since my hearing sucks) He told me to stop, i laughed, then he said "thank you" I didnt turn it off yet... I look over to my tower and there was thick white smoke pouring out of the 35+ year old tweeter.... yeah it wasn't funny
Don't get too down on the tweeter thing. Go to parts express and order 2 more. They are a lot cheaper than subwoofers! Disconnect the tweeter in the other speaker there, run wires from the old speaker's x-over and instal the new tweets to either side of the existing speakers. Angle them in a bit and the stereo image should improve. When things get damaged it's a free reason to upgrade them! ;)
What a downer, I've seen so many of your videos with those speakers being used and they even sound good to me, hearing them through your microphone. I hope you can find a match for them OR find a replacement.
Photographictime Ya, these are one of the very few sets of speakers I've had that sound perfect with just a simple series cap on the tweeter. I'm going to miss them if I can't find a matching replacement :-(
HayesHacker0NE They are early 80's vintage actually. The tweeter is a Philips AD-11600 T8 textile dome. From what I've read they are pretty nice. I also found the data sheet today.
sucks to have blown a tweeter for that.. And yeah thats a wierd issue. Never seen that before.. But then again, with electronics. ANYTHING is possible :D
Put a small light bulb in series with the tweeters or the speakers in general as protection for them... The light bulb will light up and increase in it's resistance if the input signal into the load is too high. I think EV did this on some of their speakers, and I know that MB Quart installed some lamps in the crossovers to protect the tweeters in some of their car stereo gear.
Yes, yet a nother Amp video :-) Love your videos, always realy good quality, lighting, sound. I realy like the way you explain your thought proces, and shows us the schematics, i am realy learning a lot from it. Just a shame your speaker had to die, while fixing that amp. Looking forward to more exelent videos. Thanks from Denmark.
That must suck that it took your tweeter out! If they are test speakers (and awfully nice for test speakers) I think you should use a hi-pass filter. Anyway, what I strange problem with those pots, what can you except from crap?! It did not sound that bad though!
There is a used Philips AD-11600 T8 on ebay here: www.ebay.com/itm/Assorted-Vintage-Philips-Tweeter-AD-0140-T8-0160-T4-11600-T15-/221399820749 but it's expensive and looks cruddy. There may be a replacement diaphragm for your tweeter. Try searching "Tweeter diaphragm" on eBay. There are 527 for sale. If you can't find the exact one, maybe a speaker rebuilder / repair shop would stock the diaphragm. Also, there are lots of other Philips and other brand tweeters (made by Philips) available on eBay. Good luck !
Hey maxx, I have an amp that has a little problem. When you select the main channel only, it works just fine. When you select the main channel and remote channel with nothing connected to the remote channel, nothing comes out of either. When you have speakers hooked up to both, both are just a lot quieter when you have both selected. What do you think the problem is? Thanks in advance. The amp is an MCS 3873 from the digital 5000 series, if that helps.
I have actually been surprised that you don't have a set of "sacrificial test speakers" sitting around. I'm sorry to hear about the tweeter going, I have always been amazed with how they sound.
Sorry to hear about the blown tweeter on the workbench. That's the reason why I haven't trusted any amplifier with my perfectly good iLive speaker. I usually refer all problems to the Polk Audio speakers I have, which is why I have so many problems with those speakers to this day. I'd take that speaker killer off the workbench after you get any of the good caps off of it. 2,000 watts of input power? How stupid is Gemini for saying that bullcrap? After the caps melt, maybe! :)
This another of those ones when I knew what the problem was right away because I had the same problems with an cheap Konig amplifier which always blew my years of quite a number of times because of bad pots, this actually doesn't look like a very bad amplifier but at least they should have used a bit better pots to say the least. Anyway, glad to see that you've got it working again. Cheers :)
Hey Max i have a Sony HCD-EC909ip bookshelf system i had it at full volume and my subwoffer's wires touched and sent it into protection mode now when i plug it in it just flashes Protection if you have any idea what this did to the boards or how to fix it it would be very appreciated i havent been able to use the system for almost a year.
The cause of the problem makes sense. The input signal is dragged from the back to the front, and back again likely without shielded cables and its circuit tracks will pickup trash through mutual coupling given the high impedance of the circuit. A couple of new pots (pins up) routed with shielded cables, and cutting the original PCB tracks at the back end will likely permanently fix it. .
OH NOooooo... Bummer. Who made the speakers. I'd like to get a pair if they're still available. Hate to see a good egg fry... it died trying though. A product name on the next set in exchange for endorsement works too.
alladin sane They are actually Frazier S830A cinema speakers. Eminence woofers and Philips AD-11600 T8 textile dome tweeters. I think I used a 3.3uf capacitor in series with the tweeters, nothing more really needed. They have a nice flat, smooth response.
Hi Maxx, sorry about the tweet, but we learn by our mistakes they say so next time use the scope to check the speaker output DC offset, you can see if there is any oscillations happening and save a new tweeter. James
I would consider building a protection circuit for your beloved speakers. Your system sounds great through my NAD amplifier and Bose system that I configured to work with my quad core computer.
I always put an unknown amp on a scope before connecting speakers for just this reason. Amplifier oscillation is surprisingly common--especially in cheap poorly designed products. early high power solid state amps, and somewhat oddly in some high-end esoteric products (which, despite their designers intention, are also often poorly designed). It sometimes is intermittent and goes undiagnosed because you usually can't hear it. In my experience power amps with op-amps in the main feedback loop are especially prone to oscillation as common op-amps have extremely high gain and are not designed to be stable with several more stages following them. Their phase response in a circuit such as the Gemini's is difficult to quantify. Proper design of the phase response of a power amplifier and the resulting "phase margin" is something many designers either skip over and/or don't understand. It requires some rather complex math and engineering to calculate and high-end designers often "design by ear" more so than proper engineering. So some amps end up with very little phase margin and barely manage to avoid oscillation even when new. What that means is at higher frequencies the negative feedback is close to becoming positive feedback and sending the amp into wild (and often destructive) oscillation. With a marginal design many things can push the amp "over the edge" into oscillation including things like component tolerances/values changing, replacing transistors with newer versions, long speaker cables, exotic speaker cables with high capacitance, speakers that represent a highly reactive load, various kinds of ground loops between the inputs and outputs (i.e. when an amp is on the bench and your scope and signal generator share a common line ground) and more. Some amps will oscillate continuously and others will only oscillate under certain conditions like clipping, or when hitting certain power levels into difficult loads, etc. Either can quickly destroy tweeters if not worse. Gemini products are basically throw away junk with high profit margins even at their low prices. I honestly wouldn't trust this amp to not destroy more speakers in the future. It may, for example, still be prone to intermittent oscillation under certain conditions that don't show up in typical bench testing.
I've had many of these Gemini power amps come in for repair over the years, but the defective pots are not uncommon. I've had numerous models with defective pots where you could shake it after removal and hear a piece of the wiper jingling inside the metal case. The circuit design on this amp is extremely poor, and I don't particularly like where the pots are in the circuit. I've also had many of them cook output transistors while testing the amp with a dummy load. It's output power isn't even close to the company's advertised rating...talk about deception! Yet, newbie DJ's think these are great amps until they fry a few sets of speakers. The new models are even worse! I won't even repair them for people anymore...they're a module swap now. Not worth going down to a component level with them. I'll stay with my old and heavy BGW 750B's :) Frank Ferraro--Audio Craft Electronics
Frank Ferraro OMG, the 750B is one of the amps I've always wanted to mess with. Any of the old school BGW stuff really. I'm going to do a power test on this amp soon just for fun.
Let me check my schematic drives tomorrow. If I have the service manual, I'll send it to you. I used to be an authorized warranty station for them back in the late 80's through the 90's :)
Wow man, you sounded really down in the dumps on this fault finding sesh, but for me it was good to see you face a challenge even on such a crap piece of equipment, Btw sorry about your tweeter man.
Chewbacca651 The speakers are all fixed now. But yes, I do have depression problems more than I'd like. Times are getting pretty difficult, and it's hard to stay motivated.
Max, let me tell you, from my perspective you are one of the most motivated people I have come across. I love watching your repair vids and downloaded the Mixx software I saw you using on your vids about building your own sound system. Have to ask though "what job you do?" cos a lot of that stuff you build is not cheap, and even though I checked out the speaker designs for your subs I have no real space to get into such a project. Keep up the good work it's fascinating. Btw I subscribed :-)
Chewbacca651 I fix arcade stuff. I uploaded a couple videos recently, about various things I've been doing at work. Although I have a lot of stuff, most of it was trash picked or bought non-working for cheap. I barely make enough to break even on bills, even though I'm still living at home.
Not as bad as the RCA "250-watt" home theater system I did a video about that had 20 volts on its speaker terminals!
vwestlife i remember that xD
vwestlife Yeah, I remember that cheap piece of junk... 250 watts my butt...
+MilenniumEdition 56 you have 250 watts in your butt!!!????
+Steven King No. But there is no way in hell that 250 watts would be in my butt. But 250 watts might damage that chip...
Sorry to see your speaker damage.
that sucks ass you lost your tweeter, i had a similar problem happen to one of my mid to late 70's pioneer tower speaker.
I had a signal generator plugged up to my stereo receiver and i was messing with my little brother across the hallway from me. He doesn't like high pitched sounds so i cranked up 18kHz, (which i can't hear since my hearing sucks) He told me to stop, i laughed, then he said "thank you"
I didnt turn it off yet...
I look over to my tower and there was thick white smoke pouring out of the 35+ year old tweeter.... yeah it wasn't funny
Don't get too down on the tweeter thing. Go to parts express and order 2 more. They are a lot cheaper than subwoofers!
Disconnect the tweeter in the other speaker there, run wires from the old speaker's x-over and instal the new tweets to either side of the existing speakers. Angle them in a bit and the stereo image should improve.
When things get damaged it's a free reason to upgrade them! ;)
sonicfuker I actually got replacements of the same type. I hope to install them tomorrow.
RIP tweeter.
Thank you for sacrificing your tweeter for our education :)
I probably would've stripped that thing for useful parts and junked the rest. That amp really does seem pathetically cheap.
What a downer, I've seen so many of your videos with those speakers being used and they even sound good to me, hearing them through your microphone. I hope you can find a match for them OR find a replacement.
Photographictime Ya, these are one of the very few sets of speakers I've had that sound perfect with just a simple series cap on the tweeter. I'm going to miss them if I can't find a matching replacement :-(
Maxxarcade Yeah, think they still sell that model?
HayesHacker0NE They are early 80's vintage actually. The tweeter is a Philips AD-11600 T8 textile dome. From what I've read they are pretty nice. I also found the data sheet today.
sucks to have blown a tweeter for that.. And yeah thats a wierd issue. Never seen that before.. But then again, with electronics. ANYTHING is possible :D
6800 uf for a 200wpc amp? I've had 1970's 30wpc stereos with 8000uf+ caps. Pathetic. Makes Pioneer receivers look like Mark Levinson in comparison.
These days that is a High Output Amp .......Could fuses be put on the speakers for
protection ?
Why didn't the amp's protect circuit protect the speakers?
It would seem that Gemini may have subcontracted the X3 to "Bastards, Inc".
How about? If I send you amplify, I need to fix make me that sound to. Is a M-80 .
gemini is total crap. i only use numark ,HK,McIntosh and Bose.
Speakerkiller 9000
Put a small light bulb in series with the tweeters or the speakers in general as protection for them... The light bulb will light up and increase in it's resistance if the input signal into the load is too high. I think EV did this on some of their speakers, and I know that MB Quart installed some lamps in the crossovers to protect the tweeters in some of their car stereo gear.
I miss this kind of videos :)
You can always polish a turd but, well you know the rest. Sorry to hear about the tweeter, dude.
Yes, yet a nother Amp video :-)
Love your videos, always realy good quality, lighting, sound.
I realy like the way you explain your thought proces, and shows us the schematics, i am realy learning a lot from it.
Just a shame your speaker had to die, while fixing that amp.
Looking forward to more exelent videos.
Thanks from Denmark.
Similar thing happened to me once... since then, only used crappy speakers for testing.
Hi Maxxarcade, this video helped me isolate a faulty relay in a Gemini GXA amp. Thank you. =)
Wow sucks about the speakers. I was always a fan of those
Why was there LEDs inside of the thing on the board?
Por favor necesito el diagrama de ese amplificador
I have a peavey cs 800 with similar problems
That must suck that it took your tweeter out! If they are test speakers (and awfully nice for test speakers) I think you should use a hi-pass filter. Anyway, what I strange problem with those pots, what can you except from crap?! It did not sound that bad though!
There is a used Philips AD-11600 T8 on ebay here: www.ebay.com/itm/Assorted-Vintage-Philips-Tweeter-AD-0140-T8-0160-T4-11600-T15-/221399820749
but it's expensive and looks cruddy. There may be a replacement diaphragm for your tweeter. Try searching "Tweeter diaphragm" on eBay. There are 527 for sale. If you can't find the exact one, maybe a speaker rebuilder / repair shop would stock the diaphragm. Also, there are lots of other Philips and other brand tweeters (made by Philips) available on eBay. Good luck !
Glenn Watkins I already found a source for new tweeters, exact replacement. Hopefully they actually have some left.
Hey maxx, I have an amp that has a little problem. When you select the main channel only, it works just fine. When you select the main channel and remote channel with nothing connected to the remote channel, nothing comes out of either. When you have speakers hooked up to both, both are just a lot quieter when you have both selected. What do you think the problem is? Thanks in advance. The amp is an MCS 3873 from the digital 5000 series, if that helps.
***** Thank you. I was wondering what that was! I'll see what I can do about it.
I don't think the video is dumb because we all learn what to also check faulty trim pot, so this video is really important :3
Solved my cs800 issue with this video
I have actually been surprised that you don't have a set of "sacrificial test speakers" sitting around. I'm sorry to hear about the tweeter going, I have always been amazed with how they sound.
Poor eminence. :(
Crap amplifier but even crappier case
What switch did u used behind it?
Sorry to hear about the blown tweeter on the workbench. That's the reason why I haven't trusted any amplifier with my perfectly good iLive speaker. I usually refer all problems to the Polk Audio speakers I have, which is why I have so many problems with those speakers to this day.
I'd take that speaker killer off the workbench after you get any of the good caps off of it.
2,000 watts of input power? How stupid is Gemini for saying that bullcrap? After the caps melt, maybe! :)
Good amplifier not problem
Are you sure it actually blew the tweeter and not just the filter cap? I have never blown on of those 2 way speaker tweeters just gernaded the caps
Acc0919mc Definitely the tweeter. I tested it separately today. It's a Philips AD-11600 T8 textile dome.
I have had equipment I was working on kill or damage my test gear. Sometimes what I was working on got killed. It never fails to annoy you.
Hi. Is there maybe a ground loop going on causes the oscillation
? a ground loop, between earth or zero, and /or -Ve from signal shortcut?
This another of those ones when I knew what the problem was right away because I had the same problems with an cheap Konig amplifier which always blew my years of quite a number of times because of bad pots, this actually doesn't look like a very bad amplifier but at least they should have used a bit better pots to say the least. Anyway, glad to see that you've got it working again. Cheers :)
Hey Max i have a Sony HCD-EC909ip bookshelf system i had it at full volume and my subwoffer's wires touched and sent it into protection mode now when i plug it in it just flashes Protection if you have any idea what this did to the boards or how to fix it it would be very appreciated i havent been able to use the system for almost a year.
RIP tweeter, you've served a long and fruitful life
thank you for this video i found it very helpful, i'm wondering how can i get the circuit diagram for gemini XG-3001
The cause of the problem makes sense.
The input signal is dragged from the back to the front, and back again likely without shielded cables and its circuit tracks will pickup trash through mutual coupling given the high impedance of the circuit.
A couple of new pots (pins up) routed with shielded cables, and cutting the original PCB tracks at the back end will likely permanently fix it. .
Tienes el gemini x1
OH NOooooo... Bummer. Who made the speakers. I'd like to get a pair if they're still available. Hate to see a good egg fry... it died trying though. A product name on the next set in exchange for endorsement works too.
alladin sane
eminence delta pro 8A
alladin sane They are actually Frazier S830A cinema speakers. Eminence woofers and Philips AD-11600 T8 textile dome tweeters. I think I used a 3.3uf capacitor in series with the tweeters, nothing more really needed. They have a nice flat, smooth response.
Hi Maxx, sorry about the tweet, but we learn by our mistakes they say so next time use the scope to check the speaker output DC offset, you can see if there is any oscillations happening and save a new tweeter. James
Bad circuit engineering ,small GND shield on first amp.. and maybe a dry caps ?.
I would consider building a protection circuit for your beloved speakers. Your system sounds great through my NAD amplifier and Bose system that I configured to work with my quad core computer.
Where are you getting all these amps??? I can't find anything broke like this locally
Wow. I knew some products could be cheap, but that does seem like a hugely lazy design.
Sorry about the tweeter buddy.
they have a whole bunch of those speakers ranging from 225 watt all the way to 1000 so you should beable to find a great replacement
I always put an unknown amp on a scope before connecting speakers for just this reason. Amplifier oscillation is surprisingly common--especially in cheap poorly designed products. early high power solid state amps, and somewhat oddly in some high-end esoteric products (which, despite their designers intention, are also often poorly designed). It sometimes is intermittent and goes undiagnosed because you usually can't hear it.
In my experience power amps with op-amps in the main feedback loop are especially prone to oscillation as common op-amps have extremely high gain and are not designed to be stable with several more stages following them. Their phase response in a circuit such as the Gemini's is difficult to quantify.
Proper design of the phase response of a power amplifier and the resulting "phase margin" is something many designers either skip over and/or don't understand. It requires some rather complex math and engineering to calculate and high-end designers often "design by ear" more so than proper engineering. So some amps end up with very little phase margin and barely manage to avoid oscillation even when new. What that means is at higher frequencies the negative feedback is close to becoming positive feedback and sending the amp into wild (and often destructive) oscillation.
With a marginal design many things can push the amp "over the edge" into oscillation including things like component tolerances/values changing, replacing transistors with newer versions, long speaker cables, exotic speaker cables with high capacitance, speakers that represent a highly reactive load, various kinds of ground loops between the inputs and outputs (i.e. when an amp is on the bench and your scope and signal generator share a common line ground) and more.
Some amps will oscillate continuously and others will only oscillate under certain conditions like clipping, or when hitting certain power levels into difficult loads, etc. Either can quickly destroy tweeters if not worse.
Gemini products are basically throw away junk with high profit margins even at their low prices. I honestly wouldn't trust this amp to not destroy more speakers in the future. It may, for example, still be prone to intermittent oscillation under certain conditions that don't show up in typical bench testing.
Igracias
Cuantos wttios maneja este amplificador
Porque no recibo respuesta
I found one of these , protect lights up when its powered up , what should i do?
Wow, I have some very good headphones; I've heard that 42Hz signal XD Cheaper ones can't drop that deep as far as I know
step 1: buy a huge and powerful blender
step 2: blend that piece of crap
step 3: give the remainings to nasa and say them to send it to the moon
Why not just replace the gain thingy instead?
Looks like the speaker protect circuit needs a little more work.
I have no idea what you're talking about, but I still watch all of it.
Good job finding those bad pots. Sorry abt the tweet.
what are the model/brand of those test speakers you have. sorry to hear the one tweeter blew. They really are a nice setup for your test bench.
kwapedog Frazier S830A (Eminence) woofers with Philips AD-11600 T8 textile dome tweeters. Early 80's vintage.
wow. that is a damn shame.
Would love to see more amp fixing, when you've some time off course. Love those videos ;)
I've had many of these Gemini power amps come in for repair over the years, but the defective pots are not uncommon. I've had numerous models with defective pots where you could shake it after removal and hear a piece of the wiper jingling inside the metal case. The circuit design on this amp is extremely poor, and I don't particularly like where the pots are in the circuit. I've also had many of them cook output transistors while testing the amp with a dummy load. It's output power isn't even close to the company's advertised rating...talk about deception! Yet, newbie DJ's think these are great amps until they fry a few sets of speakers. The new models are even worse! I won't even repair them for people anymore...they're a module swap now. Not worth going down to a component level with them. I'll stay with my old and heavy BGW 750B's :) Frank Ferraro--Audio Craft Electronics
Frank Ferraro OMG, the 750B is one of the amps I've always wanted to mess with. Any of the old school BGW stuff really.
I'm going to do a power test on this amp soon just for fun.
That should be an interesting video...I've never seen a Gemini clip symmetrically...I'd be glad to send you some BGW schematics if you need them. :)
Frank Ferraro Do you know where I can find schematics for a BGW 6000 Proline? I've looked everywhere with no luck.
Let me check my schematic drives tomorrow. If I have the service manual, I'll send it to you. I used to be an authorized warranty station for them back in the late 80's through the 90's :)
put a cap in series with your speakers, keep the dc off the speaker..
link schematic please ..,,nice video
what is the signal generator you use...I want one
its better than skytec xD
RIP noble tweeter, you had a good run
Very interesting video.
Wow man, you sounded really down in the dumps on this fault finding sesh, but for me it was good to see you face a challenge even on such a crap piece of equipment, Btw sorry about your tweeter man.
Chewbacca651 The speakers are all fixed now. But yes, I do have depression problems more than I'd like. Times are getting pretty difficult, and it's hard to stay motivated.
Max, let me tell you, from my perspective you are one of the most motivated people I have come across. I love watching your repair vids and downloaded the Mixx software I saw you using on your vids about building your own sound system. Have to ask though "what job you do?" cos a lot of that stuff you build is not cheap, and even though I checked out the speaker designs for your subs I have no real space to get into such a project. Keep up the good work it's fascinating. Btw I subscribed :-)
Chewbacca651 I fix arcade stuff. I uploaded a couple videos recently, about various things I've been doing at work.
Although I have a lot of stuff, most of it was trash picked or bought non-working for cheap. I barely make enough to break even on bills, even though I'm still living at home.
Arcade stuff, you mean slot machines, 1 arm bandits that sort of thing?
Chewbacca651 No, just old school arcade games, pinball machines, jukeboxes etc.
Did you find the tweeter?
+Rajesh Rengarajan Yes, there is a video about it too. ruclips.net/video/i9Xv_T1HDRg/видео.html