Sweet jibbly though, what a con of an amp. It looks like a Blackstar HT5 inside it, with added on unnecessarium.
The vendor has done some fault-finding, and came to the sensible conclusion that the headshell and chassis can be saved. Turns out the PT and OT are good to go too.
The valves were still fitted, and they work fine in my little Trainwreck-a-like mini amp. As far as I'm concerned, I got my money in the headshell, which is quite nice, the transformers and the valves. The chassis can be repurposed too.
A general overview.
Yebbut no.
So far, I've confirmed the transformers, switches and fuses are working. The switch only switches live. Nasty. One that switches live and neutral would only cost a penny or two more. All the fuses are intact. A basic wazz round the non-surface mount transistors/regs shows they're all good to go.
I plugged the transformers back onto the board, used an 8 Ohm power resistor rather than plug the OT back to the output board, and powered up.
We have heaters!
We have HT!
We have a stupid standby switch! - It does what it is supposed to do, insofar as it switches correctly. HT is applied where HT should be at the valves.
If I apply a signal to it while I have an 8 Ohm load resistor attached, the 'Infinium' lights comes on.
If I switch off, back on again, it's repeatable.
Switching out the 12BH7 for another one makes no difference. Swapping in an ECC99 makes no difference. I knew the valve was OK anyway.
I sat back to allow my eyes to recover.
I tried putting the signal into effects return. The 'Infinium' light comes on. There is a brief moment where there is an output. There's still HT.
I'd expect a voltage to show at the bias test points. It looks like the 'Infinium' circuit has issues, and that's where I stop. The IC controlling it is not user replaceable.
Why fit such a system to an amp that really doesn't need it. It'd have been simpler, more reliable and cheaper to cathode bias it and be done. I've done a lot more squitting about with it, and it keeps pointing back to the 'Infinium' being the culprit.
Still, I now have, as above, two transformers, a headshell, two valves and possibly a chassis, for less than £30.
I don't mind PCB amps. I really don't. I like op-amps. I have no problems with hybrids. This is e-waste though.
A couple of things to note. The schematic and PCB call the 12AX7 V2 and the 12BH7 V1. I can't keep it in my enfeebled head that the pre-amp valve is V2. No. It's V1, and always will be. If you're playing along with the schematic at home, I'm aware I'm using my designation as it keeps things unjumbled.
I knew it was dead, I only really wanted the shell. The transformers and valves are a bonus.
The headshell is really nice
The vendor has done some fault-finding, and came to the sensible conclusion that the headshell and chassis can be saved. Turns out the PT and OT are good to go too.
The valves were still fitted, and they work fine in my little Trainwreck-a-like mini amp. As far as I'm concerned, I got my money in the headshell, which is quite nice, the transformers and the valves. The chassis can be repurposed too.
A general overview.
Yebbut no.
So far, I've confirmed the transformers, switches and fuses are working. The switch only switches live. Nasty. One that switches live and neutral would only cost a penny or two more. All the fuses are intact. A basic wazz round the non-surface mount transistors/regs shows they're all good to go.
I plugged the transformers back onto the board, used an 8 Ohm power resistor rather than plug the OT back to the output board, and powered up.
We have heaters!
We have HT!
We have a stupid standby switch! - It does what it is supposed to do, insofar as it switches correctly. HT is applied where HT should be at the valves.
If I apply a signal to it while I have an 8 Ohm load resistor attached, the 'Infinium' lights comes on.
If I switch off, back on again, it's repeatable.
Switching out the 12BH7 for another one makes no difference. Swapping in an ECC99 makes no difference. I knew the valve was OK anyway.
I sat back to allow my eyes to recover.
I tried putting the signal into effects return. The 'Infinium' light comes on. There is a brief moment where there is an output. There's still HT.
I'd expect a voltage to show at the bias test points. It looks like the 'Infinium' circuit has issues, and that's where I stop. The IC controlling it is not user replaceable.
Why fit such a system to an amp that really doesn't need it. It'd have been simpler, more reliable and cheaper to cathode bias it and be done. I've done a lot more squitting about with it, and it keeps pointing back to the 'Infinium' being the culprit.
Still, I now have, as above, two transformers, a headshell, two valves and possibly a chassis, for less than £30.
I don't mind PCB amps. I really don't. I like op-amps. I have no problems with hybrids. This is e-waste though.
A couple of things to note. The schematic and PCB call the 12AX7 V2 and the 12BH7 V1. I can't keep it in my enfeebled head that the pre-amp valve is V2. No. It's V1, and always will be. If you're playing along with the schematic at home, I'm aware I'm using my designation as it keeps things unjumbled.
I knew it was dead, I only really wanted the shell. The transformers and valves are a bonus.
The headshell is really nice
