Blackstar HT5M- Volume going very low and cutting in and out.

conanthewarrior

conanthewarrior

New member
Hello everyone, I have a blackstar HT5 Metal amp head that has been great for years.

However, recently as I was practicing I noticed the volume was low so turned it up. However, the sound as I was playing then slowly faded down to nothing, back up again and then returned to nothing.

I had the volume higher than I usually would and switched the amp off. I let it rest for 60 seconds then it came back on, very loud as I had not turned the volume knob down.

It seems after around 5-10 minutes of use once the amp has warmed up the volume will slowly fade out to nothing, even if I turn up the volume much higher than I usually would need too.

I have noticed the clean channel works for longer than the overdrive/distortion channel- clean is still a fair bit quieter but works, but as soon as I switch to overdrive with gain the volume reduces almost instantly.

Another forum recommended changing the preamp valve/tube, luckily I had a spare Sovtek 12AX7 but the problem still persists. They recommended changing the power tube next, a 12BH7. I don't have one of these spare so will need to buy one, however I don't want too if it could be something apart from the valves.

What can cause the sound to fade in and out like this? Do I need new valves/tubes, or could something be going wrong with the amp and will need fixing?

Thank you for your help.
 
Sounds like it does this on it's own, but can you induce it ? By say, fiddling with the volume knob or tapping gently on a tube with the eraser end of a pencil ?
 
Tube issues are almost always the underlying cause of problems with tube amps. Do yourself a favor and pick up a spare or two for situations like this. It's like if a light in your house goes out: you're going to swap in a new bulb to see if that's the problem, you're not going to first check the switch and the wiring, or even the breaker (unless it's more than one light that's affected).

I can't remember if it's a certain type of capacitor or resistor, but if I remember correctly, there's a specific component that can be fine at first but start to flake out once the amp has been on a bit. One of the other guys on here will have an idea. Good luck!
 
Try cleaning the FX loop send and return jacks. My Egnater does the same thing and a little deoxit fixes it. If that doesn't work try telling it you love it.
 
Floyd Eye said:
Sounds like it does this on it's own, but can you induce it ? By say, fiddling with the volume knob or tapping gently on a tube with the eraser end of a pencil ?
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I haven't tried to induce it- is tapping the tube with a pencil safe as I will have to have the back of the amp open while it is on to do this?


MusicIsLife said:
Tube issues are almost always the underlying cause of problems with tube amps. Do yourself a favor and pick up a spare or two for situations like this. It's like if a light in your house goes out: you're going to swap in a new bulb to see if that's the problem, you're not going to first check the switch and the wiring, or even the breaker (unless it's more than one light that's affected).

I can't remember if it's a certain type of capacitor or resistor, but if I remember correctly, there's a specific component that can be fine at first but start to flake out once the amp has been on a bit. One of the other guys on here will have an idea. Good luck!
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I see, I hope it is just a tube issue. I will buy the 12BH7 power tube then to give that a try. Your analogy makes sense not checking the wiring if it could just be a bulb.
I hope it isn't a capacitor or resistor as I do not have the knowledge to repair this myself and money is tight. This would need a visit to an amp tech if it is the case yes?


IHateRap said:
Try cleaning the FX loop send and return jacks. My Egnater does the same thing and a little deoxit fixes it. If that doesn't work try telling it you love it.
Click to expand...
I have never used the FX loop so is this still worth a try? I don't have deoxit but do have electrical contact cleaner so its worth a try, thank you!
 
conanthewarrior said:
I haven't tried to induce it- is tapping the tube with a pencil safe as I will have to have the back of the amp open while it is on to do this?



I see, I hope it is just a tube issue. I will buy the 12BH7 power tube then to give that a try. Your analogy makes sense not checking the wiring if it could just be a bulb.
I hope it isn't a capacitor or resistor as I do not have the knowledge to repair this myself and money is tight. This would need a visit to an amp tech if it is the case yes?



I have never used the FX loop so is this still worth a try? I don't have deoxit but do have electrical contact cleaner so its worth a try, thank you!
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Yes, tap very lightly on the tubes with the eraser end of a pencil and see if any of them make noise.

Very recently I had a similar thing happen with my SVT II. I suspected a tube, but it turns out the volume knob is sketchy.
 
Floyd Eye said:
Yes, tap very lightly on the tubes with the eraser end of a pencil and see if any of them make noise.

Very recently I had a similar thing happen with my SVT II. I suspected a tube, but it turns out the volume knob is sketchy.
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I am going to attempt this in about 10 minutes, sorry to sound silly but what noises am I looking out for when I tap the tubes? And if I hear any noises what does it mean, that the tube making noise needs replacing?

Sorry to hear you had a similar thing happen to your amp. I highly doubt it is the volume knob as it happens on both the clean channel as well as the overdrive/distortion channel and they have individual volume knobs for each channel.
 
conanthewarrior said:
I am going to attempt this in about 10 minutes, sorry to sound silly but what noises am I looking out for when I tap the tubes? And if I hear any noises what does it mean, that the tube making noise needs replacing?

Sorry to hear you had a similar thing happen to your amp. I highly doubt it is the volume knob as it happens on both the clean channel as well as the overdrive/distortion channel and they have individual volume knobs for each channel.
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High ping ping sound or like someone is knocking on a pipe in your basement
 
japetus said:
High ping ping sound or like someone is knocking on a pipe in your basement
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Ok I see, I will try this now. Do I need to be on the overdrive channel or the clean channel or does it not matter? Also where the amp is open I obviously avoid touching anything yes?
 
conanthewarrior said:
Ok I see, I will try this now. Do I need to be on the overdrive channel or the clean channel or does it not matter? Also where the amp is open I obviously avoid touching anything yes?
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Yes just turn your amp on turn the volume up a bit and gently tap each tube with something light, like a chopstick or pencil tip.
 
japetus said:
Yes just turn your amp on turn the volume up a bit and gently tap each tube with something light, like a chopstick or pencil tip.
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Ok, I tried tapping the valves with a pencil whilst the amp was on with the back off, and the valves/tubes aren't making any noise when I tap them.

Is this a good or a bad sign?
 
Sorry to bump the thread, but I attempted tapping the tubes gently with a pencil whilst it was on, and there was no high ping sound or anything like knocking on a pipe soundwise.

Does this eliminate the tubes as the issue, or is it still worth trying the power valve?
 
Change the tube, yes. They can do all kinds of weird things when they're going. Volume jumping or cutting in and out is pretty common for a bad power tube. And not using the loop is even more cause to clean jacks. Not using it lets dust/dirt collect.
 
napalmdeath said:
Change the tube, yes. They can do all kinds of weird things when they're going. Volume jumping or cutting in and out is pretty common for a bad power tube. And not using the loop is even more cause to clean jacks. Not using it lets dust/dirt collect.
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OK, thank you for your reply :).

I will order a power tube/valve and keep my fingers crossed it is this.

Also its strange you mention rust- everything in my studio is showing layers of rust, such as the tommy bar on my Mic stands, my guitar strings if I leave them too long, and even the screws to remove the back cover of my amp head were rusty. I have no idea what is going on with the humidity/climate to make everything rust as this is only a recent thing.

EDIT: Sorry you said dust, not rust.

I didn't realise the effects loop could also cause problems, can this cause volume to fade in and out if the inputs were slightly rusted, or would this cause different issues? And when I use the electrical contact cleaner, how should I clean the insides of the inputs, like is there anything that is a good idea or would plugging in and unplugging a jack a few times suffice?

Thanks again for your help.
 
conanthewarrior said:
OK, thank you for your reply :).

I will order a power tube/valve and keep my fingers crossed it is this.

Also its strange you mention rust- everything in my studio is showing layers of rust, such as the tommy bar on my Mic stands, my guitar strings if I leave them too long, and even the screws to remove the back cover of my amp head were rusty. I have no idea what is going on with the humidity/climate to make everything rust as this is only a recent thing.

EDIT: Sorry you said dust, not rust.

I didn't realise the effects loop could also cause problems, can this cause volume to fade in and out if the inputs were slightly rusted, or would this cause different issues? And when I use the electrical contact cleaner, how should I clean the insides of the inputs, like is there anything that is a good idea or would plugging in and unplugging a jack a few times suffice?

Thanks again for your help.
Click to expand...
Dirty FX loop jacks can cause issues. They're real common in the old Peavey 5150's, JSX, & Triple XXX's. If had a few that acted up like that and spraying inside the jacks with Deoxit, and spraying a plug and popping it in and out a few times, spray, pop in and out, spray pop in and out a good 2-3 times fixes it, (if that's in fact the issue). Just dirt and dust collecting in there can do weird things too, especially if you don't even use the loop. I used to have an old original HT5R head. That little thing rocked through a 4x12! I put a Tungsol 12AX7 in the preamp, and it really woke it up. It was a fun little amp. Had the 1x12 combo too, put a V30 in it.
 
Smash said:
Yes. Slowly put it in. Then slowly pull out.. start going a bit faster tempo, and then BAM! It will all shoot out at once
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I don't know if that was meant to come across as dirty, but it sure made me actually lol! I will give this a try, thank you

EDIT: Also with the rust problem I mentioned (everything in my studio is getting rusty for some reason, tommy bars on mic stands, the feet of my chair, and even guitar strings if left on for a long time, plus when I opened the amp the screws were even rusted!) I am going to try removing and reseating the valves/tubes a few times and see if this helps, as I imagine if the screws can rust maybe the contact area where the tubes go could have potentially rusted and is causing issues?
Removing and reseating them a few times might remove it if there is any inside?
 
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napalmdeath said:
Dirty FX loop jacks can cause issues. They're real common in the old Peavey 5150's, JSX, & Triple XXX's. If had a few that acted up like that and spraying inside the jacks with Deoxit, and spraying a plug and popping it in and out a few times, spray, pop in and out, spray pop in and out a good 2-3 times fixes it, (if that's in fact the issue). Just dirt and dust collecting in there can do weird things too, especially if you don't even use the loop. I used to have an old original HT5R head. That little thing rocked through a 4x12! I put a Tungsol 12AX7 in the preamp, and it really woke it up. It was a fun little amp. Had the 1x12 combo too, put a V30 in it.
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Ok thank you, I will try this with the electrical contact cleaner I have and put a jack in the way you describe to clean it.

Nice on the HT5R, the preamp valve I removed to test the other valve was actually a Tung-sol I purchased to improve the sound too! Now I know it isn't the preamp I can put the Tung-sol back in place of the stock Sovtek. I know there have been videos saying valves/tubes don't matter, but I at least thought the Tung-sol was an improvement over the Sovtek.

Also nice on the cab choice, I haven't tried a V30 with it.
I am rocking mine through a blackstar 4X8 cab- I know thats a strange speaker size but I demo'ed the 1x12 Blackstar metal cab against the 4x8 Metal cab and found it sounded better. It cost a little more but I love the sound, and usually without this issue I need the volume very low for bedroom levels, and even under 1/4 on the overdrive channel is very, very loud!
 
conanthewarrior said:
I don't know if that was meant to come across as dirty, but it sure made me actually lol! I will give this a try, thank you

EDIT: Also with the rust problem I mentioned (everything in my studio is getting rusty for some reason, tommy bars on mic stands, the feet of my chair, and even guitar strings if left on for a long time, plus when I opened the amp the screws were even rusted!) I am going to try removing and reseating the valves/tubes a few times and see if this helps, as I imagine if the screws can rust maybe the contact area where the tubes go could have potentially rusted and is causing issues?
Removing and reseating them a few times might remove it if there is any inside?
Click to expand...
Oh shit. We were talking about amps?
 
I always keep a known 'good' set of power and pre-amp tubes on the shelf. That way, I can roll known good glass through all the pre and power positions to trouble shoot. Once a set of glass is shot, I replace with my known good set, and then get another set of fresh tubes for the shelf.

Definitely check the FX loop - they are notorious for being the culprit in noise and signal loss and frequently clear up with a shot of deoxit.

Don't overlook every cord and cable between the guitar and amp if you have stomps in front and for anything in the loop. I recently chased a low volume / low signal issue in one of my more valuable amps and I was convinced it needed to go to the shop. But I discovered that more than one of the patch cables on my pedal board were pure crap. They were the 'push fit' cables from Lava - which came with the board - but I never had a lot of confidence in. I was SO relieved when I found my signal loss was due to those the sh*tty cables. I then spent a decent amount of $$ on brand new custom length Mogami cables for all the connections on my board, and the rig has never sounded better.

Be sure to follow up and post whatever the problem was - simple or not so simple. Knowing what the culprit was in these trouble shooting threads helps make the threads more informative and valuable for members in the future using the search function to chase down a gremlin. It can be super frustrating / discouraging to find a thread that matches your symptoms to the 'T' only to get to the end of the thread and see that the OP never followed up with what the problem and the solution was!!! But good luck tracking this one down.
 
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