ADA Depot - A Forum To Support Users of ADA Amplification Gear
ADA Preamps => Original MP-1 => Topic started by: darralld on January 15, 2014, 04:27:15 PM
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When I get OD 1 above 5.0 OD 2 starts to clip. What's the cause? I tried turning down the trim pots. But it didn't change anything on either OD sound wise. Even turned down almost all the way. It still clipped.
Darrall
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normally lowering trimpot T2 should help.Could also be a busted T2 or C33.
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Lowering the trimpots did nothing. What exactly do they do anyhow? Doesn't seem to change anything when they are adjusted. Also MJMP we have had some emails back and forth in the past about my chorus sounding strange. Never really have got that figured out. But one thing I do notice is that when I adjust the depth I hear static while the numbers are scrolling on the display. Is that normal?
Thanks,
Darrall
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the trimpot T2 lowers or raises the gain in the OD1 circuit.
Yes you can hear a tikking noise sometimes.
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I'll try the trimpot again and see if it does anything.
Thanks
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I turned the trimpot all the way down then lowered my pickups until the light no longer flickered. Did the trick. Maybe the MP-1 is picky about the pickups being close to the strings?
Darrall
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Hey Darrall, what PUs are you using ? You shouldn't have to lower them. When the clip light "clips" can your hear it distorting badly ? Do you have anything else in front of the MP1 that's adding gain ?
Cheers Richard
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Pickup doesn't matter. All my guitars do it. Only thing I have between the guitar & MP-1 is a rack tuner.
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Does it make any difference plugging straight in and not go through the tuner (not that it should be adding gain, but to be sure)
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No it doesn't. I'm actually fine the way it sounds, other then the chorus sucking. I did order some new tubes. Maybe when I get them installed it will help.
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It's normal for the MP1 clip LEDs to flash a bit:
From the MP1 manual (which wont let me copy text, I had to type it):
The MP1 is monitored at fout points along the signal path for clipping via the front panel CLIP LEDS. If these LEDS flash on and off while you play there is no need for concern. The CLIP LEDS are there to help you pinpoint overload distortion in the event you are having trouble obtaining a clean guitar tone. If you hear unwanted clipping and the LEDS flash while you play, you should lower the level of the parameter whicvh is clipping as indicated by the CLIP LEDS.
When you turn the OD past 5 and the LED flashes, is there unwanted overload distortion ? if not it's normal and you can put your PUs back where they should be (as close to the strings as possible without the strings hitting the PUs when you play)
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my ada mp-1 original has always had much more distortion than i will ever use
should i turn the trimpots back to get more versatility inside a smaller range or will that not help?
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I know what you mean, they have LOTs of gain, more than I ever needed also but depends what style you play.
The trim pots should be set to get the best signal to noise ratio without overloading the OD circuits (basically as high as possible without causing "unwanted" clipping). Also OD 1 feeds OD2. I've never played around with the trims, maybe MJMP can provide some guidance on the optimal trim settings ?
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There is a guide on how to set the trimpots.See attachment.But you need a scoope to do it.
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on the trimpot issue
i typically run od1 and od2 near the same level. but from what i read about the differences it seems like i should max od2 first
and then add input color with od1 to get the best sound.
any opinions ?
either way it seems like i am not using the last 25% of od1 and if the top of od1 was lowered say to a 7
then i could have more options that would actually get used.
so my theory is that if i dial back my od1 trimpots, i could get more range because my 1-10 settings are working inside a smaller range.
am i understanding how the circuitry works?
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I turned the OD 1 trimpot down all the way. Raised OD 1 to 10 then lowered my pickups until the clip light stopped coming on. I think it sounds so much better this way. Can also get a pretty nice brown sound out of it now. Before I did this the clip light would come on around level 6. That left a bunch not getting used. I haven't messed with the trimpot for OD 2. I wonder if raising the level to 10 then lowering the trimpot would get rid of some unwanted noise that I get out of the unit? Buying these things used gives you no idea of what a previous owner may have done to it.
Darrall
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Where did you have OD2 set when you started raising OD1?
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The tubes will have an impact on the settings. But I have OD 1 at 5.0 & OD 2 at 2.4.
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Tubes will have no impact on the OD2 led.
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Sorry, I wasn't talking about the led. I was talking about my settings. As far as adjusting the trimpot, I had OD 2 down to zero. OD 1 up to 10 & the trimpot all the way down. Then adjusted my pickup until the led stopped coming on. Maybe it doesn't matter if the light is on or not. But it sounds better to me.
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Aah sorry my bad.Now it's normal that the od2 led blinks at a setting of 6.0.