I got this amp in last week and knew as soon as I hit the channel switch there was a problem.
I haven't plotted out the schematic yet, but it looks a fairly marshall-esque amp...and sounds it.
The noise is longer and louder from the first time switched and gets better with cycles, but it never goes away and builds back up when left on the clean channel for a bit.
The LED flickering as well must point towards the relay board. Is this DC leaking into the signal? An absent coupling cap? I have BTW never built or used those types relays.
Switching issue
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studiodunn
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Switching issue
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Stevem
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Re: Switching issue
There are solder jumpers on each of those 8 pin ICs in your photo, and one of them does not seem to be making a full connection.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
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Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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studiodunn
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Re: Switching issue
I finally dug into this amp a bit and came to the conclusion that one of the optical relays must have a fault. The issue was very inconsistent and all the reading in and out of the relay board were fine. i dig check all the connections and bridges on the board and found no problems.
That said i just installed a mojotone relay and switching is working like it should...almost.
The amp is pretty straight away marshall with a pair of gain/volume controls to allow for "channels". Gain 1 and 2 into relay - relay out to V1b - TS - volumes 1 and 2 feed the relay out to PI. My issue now is the shunting a channel to kill the bleed. I've used both side of the relay and need a clever way to ground out a channel on the relay.
That said i just installed a mojotone relay and switching is working like it should...almost.
The amp is pretty straight away marshall with a pair of gain/volume controls to allow for "channels". Gain 1 and 2 into relay - relay out to V1b - TS - volumes 1 and 2 feed the relay out to PI. My issue now is the shunting a channel to kill the bleed. I've used both side of the relay and need a clever way to ground out a channel on the relay.
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studiodunn
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Re: Switching issue
I'm not that clever so I just worked around the problem.
I spit the gain and volume pots up, used separate inputs from V1a to each gain then to the ralay. I used the other side of the relay to ground out the unused channel.
I ended up just using the ch2 volume as the preamp MV for both channels and the ch1 volume as a variable dropper for that channel. That way I can keep ch1 cleaner as the volume goes up.
It is definitely more fickle to balance volumes but can be done at all volumes and gain settings.
I spit the gain and volume pots up, used separate inputs from V1a to each gain then to the ralay. I used the other side of the relay to ground out the unused channel.
I ended up just using the ch2 volume as the preamp MV for both channels and the ch1 volume as a variable dropper for that channel. That way I can keep ch1 cleaner as the volume goes up.
It is definitely more fickle to balance volumes but can be done at all volumes and gain settings.
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