Nice vid, i really like how you were able to explain what is going on with each step of what you're doing in a manner that makes it relatively easy to follow along and understand as you go.
I just love looking at you repairing stuff, it's easing the mind for some odd reason, even though I do not see myself doing it. Thanks so much for the content!
You may have to check the dead time on the PSU driver, you may need to increase it, looks like crossover conduction. Leaving that ringing on the PSU is not a good idea. Are there snubber circuits on each bank of the PSU in the amp? Increasing the resistors to drive the MOSFETs will decrease the rise time and attenuate the ringing, but you will have greater switching losses. What is the frequency of the ringing? You could try using some ferrite attenuation beads on the gate of each MOSFET.
@@barevids By lowering the frequency you have limited the power capability of the transformer. Depending on the magnetic saturation of the transformer core, at high power you could reach saturation in the core at lower switching frequency and blow the MOSFETs. If there is enough magnetic flux head room in the core, you may get away with it. One other problem with lowering the frequency to 17KHz, you are in the high end of the audio spectrum, those mono blocks do not have filtering I believe , so you will be introducing this switching frequency to the rest of the system. This is why PSU should be above the audio frequency spectrum to minimize interference.
@@h1nicolas alright, check out the video which I'm currently uploading and let me know what you would suggest. These amplifiers are only supposed to play up to like 500hz anyway so introducing 17khz doesn't worry me much. If there's a way to make the thing work properly at 24khz let me know what to try.
@@barevids Could you show the switching waveforms from the PSU ic, need to see the two outputs on the scope and see the dead time between them. You could try increasing the dead time. Its a TL494 IC? If yes, pin 4 controls the dead time, applying a voltage from 0 to 3.3V changes the dead time from 3% to 100%, see data sheet. I think 5% increase to the dead time should help (make it 5%). The 17KHz switching will pass through the power cables to the battery, any electronics close to the cables or connected to this cable will pick it up, if a full range amp, it will amplify this interference signal.
@@h1nicolas right okay. Well pin 4 is always at 0v in almost all car amps. It starts high and falls slowly to give the power supply a soft start style feature. So I don't think there's anything I can do in that regard.
Bad design on the power supply you say? That proli goes hand and hand with a dual input 8.5k board lol. Tisk tisk zenon. S&I for the win. Now back to the video. 😍
Good day bro, I have a question - If all of the power supply FETs are removed is the amplifier will still powers up with the power indicator light turns on? I really will like to know.
I have across a few amps doing that well. I modified the drive circuitry to reduce ringing, current draw and improve pulse current output. I don't know if you modify amps as well though. I rebuild and mod them and its so much fun!!!
@barevids I recently picked up a Fusion 4 channel amp that has blown power supply mosfets, only the fets on one side of the power supply have been blown (I assume it's due to the previous owner having the gain all the way up) but it still outputs on at least 2 channels as demonstrated by the guy I bought it off (I've never powered it on, as soon as I opened it and saw blown mosfets I put it aside for repair), so my question is this: Is it likely to have damaged anything else in the power supply?
Get yourself a desolder gun, its so easy, Time is money and less lifted tracks, Mind you I use a pump and wick but I only fix things for hobby but yeah I have a rework station too ahd the scopes, psu, and more lol
barevids any links to see what parts affect the signal path in these amps? I would like to learn more 😀 In the studio world of class a discrete transformer based designs companies are excited to say what parts they use and what does and doesn’t affect the audio signal/ path .. thanks barevids
How is your scope input grounded? I can't see anything at all.. You can't really point and laugh at ringing etc if your scope's signal ground return is through something like the mains plug...?
The noise on the screen is due to the awful piece of rubbish Chinese switching power supply that was being used. Not properly filtering output at all. The scope is hard grounded to the supply negative round the back with a nice thick wire.
Hey bud is there any way I could get ahold of you? By email or something? I have been watching your vids for weeks straight trying to figure out what is wrong with my own amp. It is an MTX 92001. I have checked the power supply and it seems to be fine as I have connected my volt/ohm meter to the power and grounds inputs on diode beep setting and I can see that it is charging the caps. I have pulled it apart and checked every fet on the board and they all check out. I have powered it up with a pc power supply and checked the rails and I’m getting +100 volts or so of DC on one and -100 volts or so on the other so that seems good too. The issue is that when it’s powered up and I check the voltage at the speaker output I’m getting +18 volts DC. I would greatly appreciate a little help in diagnosing my problem. And thanks for the great vids.
I wouldn't want a 8.5k board with dual inputs to begin with lol. I have a 3k with dual inputs and a 5k with tripples. Duals on a 8.5k is just bad to me. It seems zenon had alot of bad designs. Smh
@@150db8 dual is fine on 8.5k. See how tiny the traces are after the inputs lol. The multi inputs just allows for more wire going in, if your runs are long. If you have short runs less than half a meter, single input for the 10k is often fine if the traces are thick enough and split correctly. If the runs coming from the front however, you'd want to use dual input blocks on this to turn dual into quad.
@@barevids true that. Its just an ease of thought I guess. I like overkill. I'll like to see the back of the B2 raven. Heard it has bus bars on the back of the PCB to go along with the 4 1/0 inputs. 😮
Genesis, Alpine, JL Audio, Rockford, JBL... basically anyone who has actually designed their own board layouts and amplifiers from scratch, I hold respect for.
Hahaha naaahhh it's all good but I'm gonna have a look at it cos i realised lower transformer frequency means less power output so I need to try and get it happy at 24k some other way buy playing with snubber or some other stuff
You really need a good mechanical our vacuum solder sucker. As many to Toyo about modifying them using a vacuum chamber I still annoyed and a pulse width modulator to speed up the pump motor to become a super vacuum solder sucker. Extremely fast and efficient 10 times faster then doing it by hand if I ran a business using a handheld vacuum solder sucker I go bankrupt
