Zulkr9
100+ Head-Fier
- Joined
- Mar 13, 2012
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I ordered a used acopia A28MT300 from ebay. I heard these work well, can anyone chime in ?
Yes, my intention was to color the sound, preferably with an octal and to add an analogue EQ. I don't usually use EQ, but I've been playing around adding a bass boost from 55 to 220 hertz. It's been pretty satisfying alongside the strong mids of a Raytheon I've rolled in, I got the idea that an octal based sourced might play very well before my CTH then.The inputs are connected directly to a 20 kohm pot. Should not require a preamp unless you want to switch sources or color the sound more.
Definitely a burned component or a loose solder, it may be visible.Just looking to see if anyone has any suggestions for me in terms of what to try/troubleshoot for my CTH amp which would not turn on yesterday morning.
Swapped out the tube, no dice.
Checked the voltage on the AC adapter, it's fine, 27.9V measured with my meter vs. 28V, figure that's close enough.
But when I plug in the adapter, see a spark at the back of the unit. I opened it up to see if the power is making it to the board, and I can't seem to find 28V across any of the pins on the power inlet. (checked all combos of the 3 pins on the bottom of the board, unless there's some sort of coating on the solder that would stop this approach?)
Checked for continuity between the two metal pieces inside that same component (where power cord plugs in) and got 27 ohms. That was with no tube in it, and power switch off. No clue what's normal there.
Also no sign of any failures on the board. Nothing looks burned. No bulging caps etc.
When I try to power on, power light does not come on, tube does not glow.
(Posted on /r/headphones as well but not much there in terms of suggestions)
Cheers!
Update: confirmed that the pins outs have continuity to the inputs on the power jack.
And tried another power adapter. It was 24V with a display on it. It sparked also when connecting, and the display dropped to 2.5V when connected, meaning some sort of short in the amp somewhere?
Figured as much at this point. Thanks for the input HTSkywalker...Definitely a burned component or a loose solder, it may be visible.
Best check with the tech support docb@bottlehead.com or create a thread on their technical forum.Figured as much at this point. Thanks for the input HTSkywalker...
I do hate letting things break and not being able to fix them. Also hate the current throw away culture that's prevalent with electronics.
On the other hand, I did try pretty hard to diagnose, and can be less guilty upgrading now. Cheers!
That's great to hear! I have had mostly the same experienced. Mostly, because yes the contact cleaner did wonders. But what I never managed is to get the volume knob off. Believe me, I applied so much force and still it would not come off. I'd prefer to change the volume pot to reduce the slight channel imbalance at low levels, but that's not in the stars for me.