Clean channel not working. Still doesn’t with tested good valves in, something else going on, but not too easy to investigate stuff with loads of surface mount and SS shenanigans.
Big heat sink with presumably voltage regulators on, heat right next to the filter caps seems a terrible idea. Strong theme of this amp, sent it off without a fix as it was nothing readily apparent.
Showed up set to bridge mode, had to open it and find the switch. Turns out not on the side with the diagram. Do spot a toasty looking resistor bottom left though. Still tested right, luckily as it was missing a stripe.
Right side this time, showing the classic K135 and J50 mosfets. Hand marked bridge/stereo switch on the pcb to the left.
Laney VH100R, made a bunch of noises and blew a fuse.
A shorted power valve, a miles out of spec (like, measured a couple of meg rather than open) grid resistor. Suspect someone tried a ‘fix’ by swapping positions before selling this as ‘working’. Couple of dud pres too.
Bought dead on ebay, to have a look at. Turned out it was just bunch of dead preamp valve, guy had reloaded it with JJs and they died after estimated 50 hours use.
Front of it, 5150 MKI style, but reverb option.
Random tested parts box valves I stuffed in, the Infinium sorts out the bias for them. Works fine by ear, not sure sticking a probe in won’t interfere with its function, so didn’t.
Inside, the infinium part is the board on the back of the chassis with bunch of push connectors. Small board with ribbon cable is the reverb. Modular inside, would guess lots of stuff in common with other models in the line.
Clsoer shot of the small modular boards, along with showing that the main circuit is pretty normal through hole pcb, not mystical magic that cannot be fixed like is often claimed about these amps. Ribbon cable is data from digital reverb.
Even the flightcase didn’t save this one from UPS. Chassis is loose, the bolts pulled right through the sleeve, and the rivnuts broken loose, meaning the bolts just spin but are retained. Had to push them all the way thorough the sleeve, then address the oversized holes later.
New transformer in there and the reverb connector is removed and replaced with an XLR on the back presumably for an external unit.
Another view of the guts, showing the wiring for new transformer. No HT fuse in these puts the PT at risk.
Other end of the chassis.
Detail of the reverb mod. Now I’m thinking maybe a DIN rather than XLR but I put it back in flightcase and put stuff on top waiting for a rivnut tool showing up.
Not my usual, but Ashdowns tend to be fairly easy fixes, stuff is accessible, and the tech support is good it it gets hard.
Buncha replaced knobs, it has had a life. Nasty loud buzz that doesn’t stop when you turn the output volume, but kinda cuts in and out when you wiggle it. Valve is an EHX, tests OK.
Power board pulls easy, few screws, resolder the power caps. EQ controls have their own board, just undoing the pots and taking the tips off the sliders gets that out on some wires. Replaced the master vol pot as had one in stock, that fixed the noise, but intermittent volume changes when prodding the board, so not the only issue. Everything else off the front and more screws to get the rest of the pre board out, balance pot is bust out the solder, solder that and everything else that is a getting loose risk. Back together, and it works fine, but the dial does light up any more. Arse.
think I’ve blogged a buncha these, but they remain kinda stealth Matamps. This is a 50w with the aluminium knobs I’ve not had before. The knobs are much fancier in person, look kinda tacky in photos, machined aluminium to touch.
Matamp turret track build.
Unpopulated valve bases. 100w PT topside too, so probably built mostly and finished as 50 or 100w to order.
Loaded with 6550, sounds great with bass, so I left it like that, bunch of the JJ pres were dead/microphonic. For sale, £400.