Rosie C

Happy NBD! I'm loving the colour

I placed an order for mandolin strings with Strings Direct on Saturday evening. They arrived this morning which I think is pretty good service over the holiday break - so a 👍 for them from me!

I've no advice to give, but congratulations on getting a JT Dingwall, and on starting on lessons! John Taylor inspired me to take up bass, though I've never really been able to play his lines

Thanks for that - it's definitely worth trying, and would fit with the suspicions that the foot pedal switches need cleaning - if they do, maybe other jacks and switches do

That's a shame! I'll probably still give it a go. It wouldn't be a problem on stage, but I only need the main volume knob at '1' for home practice and it's a little annoying.

I know! For bonus fun there's that little capacitor beside them, just asking to be damaged

Already done and dusted!

Fretless jazz with flatwounds. Fingerstyle. 100% neck pickup, 0% bridge. Tone knob set right round to the most mellow. GEB7 pedal with the lowest band set very low and the rest in the middle position. A clean amp with the EQ set level across the bands.

None taken! Nice work! I did look on ebay earlier for new capacitors, but immediately realised that I don't know what sort of pins they have soldered to the PCB - some of the new ones have wires, while some of the larger values have flat blades - so I can't progress until we open the amp again and this time look at the underside of the PCB.

My friend is a knowledgeable amp tech She explained it to me (though I've since been to Google to make sure I get it right here)... The 50Hz AC mains is rectified, converting it into a series of positive DC pulses, and the capacitors smooth the pulses into a steady DC voltage. If the capacitor isn't working properly, the ripples aren't fully smoothed and you can hear a ripple frequency in the speakers. But because it's between the peaks of the rectified wave the frequency has been doubled to 100Hz. I found this drawing which sort of shows the frequency doubling...

Thanks for all the responses. To answer the various questions: I don't know if it's the right foot switch for the amp - it came with the amp, but it was an estate sale so there's room for error The problem seems limited to the foot switches, it works fine when I just use the front panel switches None of the switches seem to be latching, they are just momentary Our best guess is that as @Sparky Mark says, the foot switches need some switch cleaner and a bit of use In other news, I had a friend stay over Christmas and she's an electronics engineer, so we took the amp apart to look at the front panel illumination. Inside the amp: Confirmation of the age: It turns out it didn't need great electronics skill. The front panel is connected to this board, and there is a 2-pin connector on the board (yellow ellipses) which comes directly from the mains transformer (yellow arrow). So the panel AND its drive circuit have been disconnected all this time! I had worried that maybe the panel was disconnected but the driver had still been live and was possibly damaged. I re-plugged the connector, and voila! Mmmm! While we had the case open, I took a photo of the power supply capacitors. There's a bit of 100Hz hum on the speakers and we're suspecting dried out capacitors. There's a bit of work to do to remove them though.

Before. It seems to power up OK. The pre-shape lamp is the only one lit and that's on both sets if lights. I was thinking of doing some testing today, see whether it's the panel switches or foot switches that cause the problem, and whether all five switches have problems.

I've finally got to play with my AH300 today. It's awesome, but there's some strange behaviour. The front panel has lamps for pre-shape, valve, compressor, effects loop, etc. and the pedal board has the same set of lamps. I'm assuming the same lights should be lit on both panel and pedal board. But when pressing various panel switches or foot switches it's easy to get them out of step - e.g. valve lamp is lit on the panel, but out on pedal board. I press either switch and it swaps over. Is this anyone has experienced before? Google AI seems to think it's a common problem, but I can't find any real website with information.

lovely!

We collected it in November but today I'm finally allowed to play the [1990s] Trace Elliot stack my partner bought me. AH300, 1x15 and 2x10. 😁 Edit: and on Boxing Day we took it apart and fixed the light-up front panel!