Check for red plating of a tube. Indicates a bad tube, or bad bias. Many people think that "lots of watts" is what it takes for good music, NOT so. My hand built tube amp of about 5 watts, can make your ears bleed in a bedroom, and is heard very well throughout the house.
Wow I am in so much need of information. I own a Monoprice 50 watt, and a 25 watt integrated amps. Over a couple years they both have stopped putting out any audio on the speaker outputs. Lights work, preamp stage has the VU meters moving, but no sound of any kind form both amps. There is very little information on troubleshooting these things online.
I have the same amp, and it has the same problem on the right channel. It is very loud, though. When I tap on the top of the amp with my finger near the tubes, the hum goes away. I think this sounds more like a cold solder joint to me. The amp is only 4 months old, so I'll call Prime Cables where I got it and see what they will do for me. It has a 1 year warranty. I would like to upgrade the tubes, eventually, once it's repaired or replaced. Maybe Russian or Tung Sol tubes?
Hi, Thank you so much for this video! I am wandering if you can tell or suggest what replacement tubes I can use for Rockville BluTube WD 70w AMP. TNX again.
Same exacting amp. Swapped pairs of tubes from right to left no change. Still a tiny hum in the left channel and no audio output. Right side still sounded great. So not tubes. Now what? Bad cap somewhere? Hope you respond, Thanks
I have a persistent crackle out of just the left speaker. Swapped tubes L/R, both sets one at a time and no change. Almost sounds like digital interference from a phone. Adjusting volume on the amp does not change volume of the crackle. While the amp is attempting to pair I get screeching and electronic noises from both speakers. Any ideas?
Similar technique in automotive repair to find out which ignition coil is bad by switch the coil from one cylinder to another, if the misfiring follows from one cylinder to the other than you know that coil is bad.
Thanks for posting! I've had this little amp for a few weeks and the 2 middle tubes have become misty/dull - is this any concern? I have not noticed any humming or change in audio quality. T The 2 smaller tubes are crystal clear. Thx
There's a local offer up offering for 65. I am worried they're old and the tubes may be going bad so I was thinking about offering 40 What do you think?
There are nice mods for this amp. Thee is also a problem with this amp. There is over voltage on the tubes. So the tubes don't last long. Greetings from the Netherlands.
My 90's 5.1 surround sound is clicking from all the speakers. Clicking like a clock. everything works and cant really hear it but at night with the volume low it's like Hell with that Dam Clicking! .....Any Ideas?😕
There is a relay that clicks off, and it does it immediately as you power off button. If there is a delay for this click to occur then I don't know. Now I had another problem, my speakers pop when I turn it off, that's fixed by replacing the capacitor at the power switch.
Ours was in the local Walgreens. You walk up to it, insert the tube into the right socket on the panel of many sockets (took a bit at times to find the right socket on the panel), push a button and the tube would get tested. A gauge would let you know if good or bad. Replacement tubes would be behind little doors under the testing panel. Awweee...the good old days. 👍👍👍
@@missternae262 it can't be. The right channel does not hum. The problem is something else. It does not matter anymore. I post this question a year a go! LOL
@@ele4853 Same exacting issue. Low level hum in the left channel and zero audio. Would love to know how to fix this. Swapped right to left pairs of tubes also. Not the tubes. Pre-amp issue I think but where on the board? There are some serious cheap china caps in these things. May start there.
Excuse me. So the conclusion is: This is a really "tube amplifier (hybrid with tube as preamp)". Others models with similar desing like nobosund only have the tubes as decoration.
Wait a minute. Aren't the tubes the final power audio amp drivers? If so, you will not get hum from solid state section until final power amp warms up anyway. Ergo your troubleshooting test tip is invalid. Just an FYI. Cool amp. Great tech tips otherwise.
Then, what is the correct explanation of that hum? If the "amp" has the tubes like preamp, i think the result of hum will be the same. If the tubes were in the power amp section i think will be even more bad the hum.
Myth. Transference of any oils from the outside of the glass to the inside would take over a decade, though it is a good idea to wipe them down so nothing burns on the outside of the tube. Touching the glass of a common audio tube (that is cool of course) will not harm the tube in any way.
Monoprice Hybrid tube amp- amzn.to/2VrT5RR vivatubes- www.vivatubes.com monoprice tube amplifier service manual - downloads.monoprice.com/files... Thanks for Watching Subscribe for more Tech Videos :)
Check for red plating of a tube. Indicates a bad tube, or bad bias. Many people think that "lots of watts" is what it takes for good music, NOT so. My hand built tube amp of about 5 watts, can make your ears bleed in a bedroom, and is heard very well throughout the house.
depends on the efficiency of the speakers, I run a carver M500t and wont run past 10 watts on my home grown four ways
Super helpful video - thanks! I have a video on this amp as well, but it's not as useful as yours :D
Oh man you are a life saver thank you so much!!!
Wow I am in so much need of information. I own a Monoprice 50 watt, and a 25 watt integrated amps. Over a couple years they both have stopped putting out any audio on the speaker outputs. Lights work, preamp stage has the VU meters moving, but no sound of any kind form both amps. There is very little information on troubleshooting these things online.
I have the same amp, and it has the same problem on the right channel. It is very loud, though. When I tap on the top of the amp with my finger near the tubes, the hum goes away. I think this sounds more like a cold solder joint to me. The amp is only 4 months old, so I'll call Prime Cables where I got it and see what they will do for me. It has a 1 year warranty.
I would like to upgrade the tubes, eventually, once it's repaired or replaced. Maybe Russian or Tung Sol tubes?
Thanks,what is tube role in amplifier?
Hi, Thank you so much for this video! I am wandering if you can tell or suggest what replacement tubes I can use for Rockville BluTube WD 70w AMP. TNX again.
Same exacting amp. Swapped pairs of tubes from right to left no change. Still a tiny hum in the left channel and no audio output. Right side still sounded great. So not tubes. Now what? Bad cap somewhere? Hope you respond, Thanks
I have a persistent crackle out of just the left speaker. Swapped tubes L/R, both sets one at a time and no change. Almost sounds like digital interference from a phone. Adjusting volume on the amp does not change volume of the crackle. While the amp is attempting to pair I get screeching and electronic noises from both speakers. Any ideas?
Hello I from japan!
Good video :-)
Similar technique in automotive repair to find out which ignition coil is bad by switch the coil from one cylinder to another, if the misfiring follows from one cylinder to the other than you know that coil is bad.
Thank you for tutorial :)
Nope. You CAN touch tubes with your fingers. It's not a halogen lamp. Also, this amp is NOT a hybrid, its a full tube amp and actually quite nice
Thanks for posting! I've had this little amp for a few weeks and the 2 middle tubes have become misty/dull - is this any concern? I have not noticed any humming or change in audio quality. T The 2 smaller tubes are crystal clear. Thx
I have this Amp and I hear the hum out of the right channel as soon as it is turned on. Any way to test the solid state component?
That's s good tub amp there's higher end tube amps - tubes have a cleaner sound
Jason JJ Cruz isn't there so much distortion from live to this thing that any difference between tube and chip is just romantic nonsense?
There's a local offer up offering for 65. I am worried they're old and the tubes may be going bad so I was thinking about offering 40 What do you think?
50 and under is a good deal.
There are nice mods for this amp.
Thee is also a problem with this amp. There is over voltage on the tubes. So the tubes don't last long.
Greetings from the Netherlands.
Great man
I've a brand new (Chinese Preamp:hifi M7 tube Preamp 6z5p + 12ax7b Marantz 7 circuit) lft chnnl low sound, rt chnnl good. Tubes appear to be ok. Suggested fixx, Tubes??
(2:20) The right speaker's hum sounds like a Star Wars light sabre.
nice bro :)
My 90's 5.1 surround sound is clicking from all the speakers. Clicking like a clock. everything works and cant really hear it but at night with the volume low it's like Hell with that Dam Clicking!
.....Any Ideas?😕
Is it normal to hear a "click" from the tubes when i turn off the amplifier?
I think is something about glass dilatation.
There is a relay that clicks off, and it does it immediately as you power off button. If there is a delay for this click to occur then I don't know. Now I had another problem, my speakers pop when I turn it off, that's fixed by replacing the capacitor at the power switch.
When I was young you could take your tubes to a tube test station .Ours was at the grocery store.
Ours was in the local Walgreens. You walk up to it, insert the tube into the right socket on the panel of many sockets (took a bit at times to find the right socket on the panel), push a button and the tube would get tested. A gauge would let you know if good or bad. Replacement tubes would be behind little doors under the testing panel. Awweee...the good old days. 👍👍👍
My left channel is humming. swaped the valves, nothing changes. Solid state troubleshoting?
Both tubes are bad
@@missternae262 it can't be. The right channel does not hum. The problem is something else. It does not matter anymore. I post this question a year a go! LOL
@@ele4853 Same exacting issue. Low level hum in the left channel and zero audio. Would love to know how to fix this. Swapped right to left pairs of tubes also. Not the tubes. Pre-amp issue I think but where on the board? There are some serious cheap china caps in these things. May start there.
Excuse me. So the conclusion is: This is a really "tube amplifier (hybrid with tube as preamp)". Others models with similar desing like nobosund only have the tubes as decoration.
Estas seguro martus es realmente un amplificador de bulbos o son solo decoración
They mix chips and tubes cause tubes look neet sticking out. And those little cages are prescious.
👍👍👍👏👏👏
Wait a minute. Aren't the tubes the final power audio amp drivers? If so, you will not get hum from solid state section until final power amp warms up anyway. Ergo your troubleshooting test tip is invalid. Just an FYI. Cool amp. Great tech tips otherwise.
Then, what is the correct explanation of that hum? If the "amp" has the tubes like preamp, i think the result of hum will be the same. If the tubes were in the power amp section i think will be even more bad the hum.
jp040759 the tubes are preamps to color the sound. You’re just wrong.
You don't handle tubes with your bare fingers
chinese want to be......still rockin with my Carver M500
You should not be sticking your greasy sweaty fingers all over the tubes.
Myth. Transference of any oils from the outside of the glass to the inside would take over a decade, though it is a good idea to wipe them down so nothing burns on the outside of the tube. Touching the glass of a common audio tube (that is cool of course) will not harm the tube in any way.
An audiophile I see?
man.... just upload the video starting at minute 4..... so much white noise until you actually deliver. like pulling teeth.
Free content with a good explanation of the issue, how about you shut the hell up.