Amplifier problem..

Louddog

Member
I have a new amp, Blackstar HT-40.I have had it for a few months, no problems. I turned it on last night and have no volume. I can hear the guitar thru the speaker, but cannot get any volume at all. No cracking or buzzing, just the usual sound of a humming working tube amp.

Any ideas??
Thanks
Doug
 

Louddog

Member
No, it is in the exact place it has been since I got it. I know it's not much to go by, but it is just strange that it seems like the volume knob would just not work. Thanks. The normal tube amp hum does not get any louder when I crank it either.
 

ocnor

Lord Of The Thighs
First check to see if all of the tubes are glowing normally. If the tubes seem ok then plug your guitar into the effects return and test for sound. That will help to determine if the power section is working. You can test the preamp setion by plugging your guitar into the input and running a cable from the effects send into the effects return of another amp or into a mixer/interface.
 

ranjam

New member
Well, you can now learn to troubleshoot. Start with the obvious; the cable, then the guitar. If that's OK, move onto the speaker. Grab the speaker lead, and put a 9-volt battery on it, thusly;

speaker_test_zps8d02bd91.jpg

Just touch the battery to the 1/4" plug quickly, and you should hear a 'pop' from the speaker, and depending on which way you have the battery, the cone either pushes out or pulls in. If this seems OK, then it's not the speaker. Move on.
Try other tubes. It won't likely be an EL34, since two going down simultaneously is just too weird. Probably a 12AX7/ECC83. If that seems OK, then it's time for a real tech. There may be a break on the PC board around the input jack (very common with all amps that have PC board mounted jacks), which is something anyone can do.
Start with all this, and you should have a working amp in no time flat.
 

miroslav

Cosmic Cowboy
Yeah...I would start with the tubes. If you can gently rock them in the sockets with the amp on and you or someone playing...and see if at any point per/tube if the power kicks in/out (I would maybe set the volume on mid-point so you don't take your head off if it kicks in).

I recently had a similar issue with an amp...and at the end of it, it turned out to be some oxidation and loose pin sockets.
After cleaning and tightening each pin sleeve inside the sockets (a PITA)...the tubes were back to a snug clean fit and no more issues.
Then again it could be just a blown tube.
Then again....it could be the output transformer. Had an amp working fine, put it on Standby and went to grab bite to eat for about 30 minutes, came back and flipped the Standby to ON......and nothing. The tranny was gone.
 

Bill L

Massivdonian
This may sound stupid obvious, but have you tried another instrument cable? Almost sounds like a bad/weak solder connection. After that, check tubes, speakers, other electrical issues. My years as a computer guy taught me to never overlook the obvious.

Oh, the stories I have from troubleshooting with novice computer users.

Good luck.

Bill L
 

Louddog

Member
Thanks to all. I figured it out. I unplugged my cords to my effects loop in back and it works fine. I was reconnecting and noticed there is a switch next to the loop inputs marked -10db or +48db, I must have pushed the -10, killing the effect loop which must cancel the input signal.
Any negative press towards Blackstar amps was not intended as I freaking love this amp!:)
Thanks again
Doug
 

ecc83

Well-known member
If all the valves are alight switch off, unplug from mains and take out the HT fuse. If it has blown replace it (500mA T 20mm).

If the amp now runs, fine, one of the EL34's must have flashed over, will probably never do it again. If the fuse is ok or it blows again, see your retailer.

I see you are now rocking again! No matter, the above still stands.
Dave.
 

Greg_L

Banned
Thanks to all. I figured it out. I unplugged my cords to my effects loop in back and it works fine. I was reconnecting and noticed there is a switch next to the loop inputs marked -10db or +48db, I must have pushed the -10, killing the effect loop which must cancel the input signal.
Any negative press towards Blackstar amps was not intended as I freaking love this amp!:)
Thanks again
Doug
What do you have in the loop? Engaging the -10 switch shouldn't "kill the loop" unless you have like pro level rack gear in the loop. If it's just standard pedals, then -10 is what you should always use.
 

Lt. Bob

Spread the Daf!
What do you have in the loop? Engaging the -10 switch shouldn't "kill the loop" unless you have like pro level rack gear in the loop. If it's just standard pedals, then -10 is what you should always use.
correct ....

But if it's a serial loop and you had cords going to the loop but NOT to any devices OR if you had those devices turned off that would do it.
 
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