Hello sir, you have the bulbs connected directly to the output of the speaker amplifier, or there is some in between, some resistive load, this is somehow I did not understand.
Awesome! Brave man, sticking your fingers in there. Hahaha . LOVE IT!. Ive got something similar and its crazy 1000W/ch, runs 150V rails. FREAKY! - Problem is, cant use it for anything other then fun science! (don't have PA speakers in my living-room) - Keep up the awesome vid's. Great to see technical stuff on RUclips.
I have anewer lightweight Ross amp that has a nasty humm, i'm guessing they still use cheap capacitors. I'm yet to open it up but guessing it needs new smoothing caps.
Connectors always are my first concern when distortion happens in this kind of commercial amps. These units get abused all the time, so bad connections and broken solder joints happen.
Which sound track? The opening theme or music that was played during the test? The stuff that was played during the test was from some youtube timelapse demo videos by timestorm films I believe. I have a bunch of videos I downloaded and put on a bluray disk for testing video gear, and just had the audio out from the blurray player plugged into the input of the amp.
Ha ha ha. I meant (sarcastically) the long, continuous tone. By the way, I fixed my first electronic gadget. 5 disk carousel. The player couldn't tell whether there was a disk in a slot. I found the optical components (ir emitter plus photo transistor). I shined a remote control through the holes in the carouse which made it work! I tested for voltage across the led. It was there. So I replaced the led with one from one of these useless remotes. It worked. You inspired this guy.
I dont know but it scared the shit out of me!! I hate it when problems suddenly fix themselves and you cant find a problem or have a explanation for the customer!
+Jay Walt The problem was the connectors. I was able to duplicate the fault, but didn't have the camera running as memory card was full, and I hadn't noticed that it had stopped recording. As you saw when I was taping it, it did the same when I wiggled the connector right where I was tapping when it came to life.
That amp is not made for home use. It is made for commercial use. That amp is made for use by public address systems, bands, performing arts theaters, schools, universities, concert halls, auditoriums, and studios, gymnasiums, sports arenas, and similar applications.
So, I have a stupid question, I have one of these but don't know what its used for. Can I hook it up to a surround sound, or is it mainly used for band equipment? I want to utilize this piece correctly
You certainly can use it in a surround system, but you need a preamp to control it. If your receiver has main out, you can connect it for your main left and right speakers.
Though probably a decent enough design, the construction of the PCB shows absolutely no care or pride in the quality of workmanship in actually building the thing. Leads cut to different lengths, transistors up in the air, wires all over the place. It’s a mess, and I have little respect for companies that show no care.
The cap wasn't leaking. Someone spilled something on the top, it ran down the capacitors and came out the bottom. I pulled them and they were fine, not leaking.
In my opinion,one bias resistor is the problem,,because the amp works with +- 63vcc,and only the positive sine wave has a distortion,,i had an amplifier that had the same problem,,y changed tre resistor,,,and with a higjh ohm preset in parallell with the resistor,,,tha sine wave become,,,and the distortion was simmetrical,in my case until 170 watts.This ross amplifier,,i have one exactly like this,,,and works very well,,,not bridged,,and gives 150w/8ohms,,,,but the caps ara a little small,i replace with two 20000,f/80vdc,,and the power increased 10watt more,,,and less distortion. the transformers ara very huge...and each drives the power supply.(one,,the + and the other the - of course,,,eith the diodes rectifier bridge.
I've one of these on my workbench right now with a similar failure; dodgy soldering on channel B signal connector. I'm also observing that the power transformers are a bit on the noisy side to the point the desk is shaking a little. Do you recall if the unit in this video did that? Normally when transformers do this, I'm inclined to think there's a short somewhere, but nothing is dissipating excessively and I've honestly never dealt with so many VA's worth of transformers in a single appliance, so this might as well be normal, ha.
It's normal for transformer to hum and vibrate to some degree. There is something called "magnetostriction" in which the core of the transformer actually changes shape ever so slightly due to the magnetic field. Now, a loose transformer core lamination can actually rattle and cause some noise. You might try tightening the bolts that compress the transformer core, if it has them. P.S. Look up videos of electrical substation transformers being switched on. You can literally hear the inrush, LOL.
Dude,you have no ideea how to fix amplifiers....you never hit the mainboard with the amp on...one single broken/open circuit in bias area can blow all the output devices in a second,first time you male sure all connections are good,and al the circuits are fine and all the solderings are proper.
The caps were obviously bulging. Should have checked those first. You also might think about upgrading some of your test equipment. Audio oscillators aren't very expensive!
Should I remove the plastic caps to prove that they are not bulging ? This type of cap won't even bulge because the overpressure vent is on the other end. My vintage test equipment is just fine for what I use it for. I'm not in the business so I don't need new stuff and certainly can't justify buying any new stuff
Love these pieces of gear! I've got a Ross 800 that hasn't skipped a beat since 1996
Hello sir, you have the bulbs connected directly to the output of the speaker amplifier, or there is some in between, some resistive load, this is somehow I did not understand.
Awesome! Brave man, sticking your fingers in there. Hahaha . LOVE IT!. Ive got something similar and its crazy 1000W/ch, runs 150V rails. FREAKY! - Problem is, cant use it for anything other then fun science! (don't have PA speakers in my living-room) - Keep up the awesome vid's. Great to see technical stuff on RUclips.
that picture tube funeral freaked the hell out me for a second :P
I have anewer lightweight Ross amp that has a nasty humm, i'm guessing they still use cheap capacitors. I'm yet to open it up but guessing it needs new smoothing caps.
Sometimes it can be so easy ;o)
I am from Germany and I love your videos, every single one.
And what was the problem???a contact failed,,,one power cap,,,,or a resistor value wrong????
Connectors always are my first concern when distortion happens in this kind of commercial amps. These units get abused all the time, so bad connections and broken solder joints happen.
What you didn't do a photonicinduction and put a sledgehammer though that picture tube?
I would like to purchase the soundtrack for this episode.
Which sound track? The opening theme or music that was played during the test? The stuff that was played during the test was from some youtube timelapse demo videos by timestorm films I believe. I have a bunch of videos I downloaded and put on a bluray disk for testing video gear, and just had the audio out from the blurray player plugged into the input of the amp.
Ha ha ha. I meant (sarcastically) the long, continuous tone. By the way, I fixed my first electronic gadget. 5 disk carousel. The player couldn't tell whether there was a disk in a slot. I found the optical components (ir emitter plus photo transistor). I shined a remote control through the holes in the carouse which made it work! I tested for voltage across the led. It was there. So I replaced the led with one from one of these useless remotes. It worked. You inspired this guy.
@@Texas3246 hhahahahahahaa , me too , great for dance all night .. hahahahahaha
Thanks for this video. This amplifier interests me. Do you know the values of the 2 large capacitors in Uf? thank you very much in advance
10 000 uF , 63V
5:37 What happened there?
I dont know but it scared the shit out of me!! I hate it when problems suddenly fix themselves and you cant find a problem or have a explanation for the customer!
+Jay Walt It was a picture tube funeral!
+Jay Walt The problem was the connectors. I was able to duplicate the fault, but didn't have the camera running as memory card was full, and I hadn't noticed that it had stopped recording. As you saw when I was taping it, it did the same when I wiggled the connector right where I was tapping when it came to life.
I almost died...
I don't remember if I ask you this before, This a full time job for you?
Cheers.
What a brutal main filter caps. :)
That amp is not made for home use. It is made for commercial use. That amp is made for use by public address systems, bands, performing arts theaters, schools, universities, concert halls, auditoriums, and studios, gymnasiums, sports arenas, and similar applications.
Yes we all know this is a commercial brute.
So, I have a stupid question, I have one of these but don't know what its used for. Can I hook it up to a surround sound, or is it mainly used for band equipment? I want to utilize this piece correctly
You certainly can use it in a surround system, but you need a preamp to control it. If your receiver has main out, you can connect it for your main left and right speakers.
What's with the picture tube?
Though probably a decent enough design, the construction of the PCB shows absolutely no care or pride in the quality of workmanship in actually building the thing. Leads cut to different lengths, transistors up in the air, wires all over the place. It’s a mess, and I have little respect for companies that show no care.
Did you replace the leaky cap ?
The cap wasn't leaking. Someone spilled something on the top, it ran down the capacitors and came out the bottom. I pulled them and they were fine, not leaking.
In my opinion,one bias resistor is the problem,,because the amp works with +- 63vcc,and only the positive sine wave has a distortion,,i had an amplifier that had the same problem,,y changed tre resistor,,,and with a higjh ohm preset in parallell with the resistor,,,tha sine wave become,,,and the distortion was simmetrical,in my case until 170 watts.This ross amplifier,,i have one exactly like this,,,and works very well,,,not bridged,,and gives 150w/8ohms,,,,but the caps ara a little small,i replace with two 20000,f/80vdc,,and the power increased 10watt more,,,and less distortion. the transformers ara very huge...and each drives the power supply.(one,,the + and the other the - of course,,,eith the diodes rectifier bridge.
Nice when no heat.
I've one of these on my workbench right now with a similar failure; dodgy soldering on channel B signal connector. I'm also observing that the power transformers are a bit on the noisy side to the point the desk is shaking a little.
Do you recall if the unit in this video did that? Normally when transformers do this, I'm inclined to think there's a short somewhere, but nothing is dissipating excessively and I've honestly never dealt with so many VA's worth of transformers in a single appliance, so this might as well be normal, ha.
It's normal for transformer to hum and vibrate to some degree. There is something called "magnetostriction" in which the core of the transformer actually changes shape ever so slightly due to the magnetic field.
Now, a loose transformer core lamination can actually rattle and cause some noise. You might try tightening the bolts that compress the transformer core, if it has them.
P.S. Look up videos of electrical substation transformers being switched on. You can literally hear the inrush, LOL.
Wien bridge oscillators aren't supposed to be noisy.
Hello sir
I need your help
Please give me Panasonic TH-37PA20 service manual
Sir
I can not download this manual
Please give me a manual
I want this amp. to blow up so -fuckin- badly. 2:57 in so far, nothing.
That is pretty much like the amp I have which will pop a 100W speaker.
WOW! 50km? For a capacitor? Don't you just HATE wasted trips?
i guess he doesnt have a phone :)
An iwatsu scope, i got a 4 channel one of those
Bought that one in 84. It blew up last year. Have a tektronix now.
Luvved that jump scare HAHAHHA
Dude,you have no ideea how to fix amplifiers....you never hit the mainboard with the amp on...one single broken/open circuit in bias area can blow all the output devices in a second,first time you male sure all connections are good,and al the circuits are fine and all the solderings are proper.
Lol.. I learned along time ago never do anything like that with a high powered amp plugged in. You could get the shock of you life
He does it for 35 years and is certified .
sounds like crap compared to that tube preamp you had the other day
The caps were obviously bulging. Should have checked those first. You also might think about upgrading some of your test equipment. Audio oscillators aren't very expensive!
Should I remove the plastic caps to prove that they are not bulging ? This type of cap won't even bulge because the overpressure vent is on the other end. My vintage test equipment is just fine for what I use it for. I'm not in the business so I don't need new stuff and certainly can't justify buying any new stuff
Beefy amp