#1
I have a blackstar ht1 which I have had for a few years, it has been working perfectly up until the last week or so, when I turn it on there is a slight hum and the bulb will light up so I know there is power there but no sound will come out of the speaker. I have had a look inside and cannot see anything wrong, but because their is no sound coming out I want to say it's the tubes that are playing up/broken.

Could someone give me their opinion on the issue and suggest what tubes I get as a replacement, I don't want to spend a lot on tubes especially as I am not sure that's the problem.
Legend.
#2
You need an ECC83 (12AX7) and an ECC82 (12AU7). JJ brand is fine and cheap. Having spare tubes on hand is always smart.

Typically when you have mains power (amp is on, bit of normal hum, tubes lit) but no sound, that suggests that the HT fuse is blown, which is usually an internal fuse. Take another gander at it and see if you can locate that fuse and see if the internal filament is physically broken. Or better yet, check it for continuity.

There are lethal voltages in amps even when off and unplugged so please be careful.
Last edited by Will Lane at Jan 5, 2017,
#3
Quote by Will Lane
You need an ECC83 (12AX7) and an ECC82 (12AU7). JJ brand is fine and cheap. Having spare tubes on hand is always smart.

Typically when you have mains power (amp is on, bit of normal hum, tubes lit) but no sound, that suggests that the HT fuse is blown, which is usually an internal fuse. Take another gander at it and see if you can locate that fuse and see if the internal filament is physically broken. Or better yet, check it for continuity.

There are lethal voltages in amps even when off and unplugged so please be careful.


I will have a look tomorrow thank you for the suggestion.
Legend.