Haha, I didn't expect a lightning fast response! Thanks for sharing the specifics of what you changed. You're talking about "10.Upgraded 4 opamps to socketed Burr Brown OPA2604APs. These will yield better S/N performance and increase overall gain and warmth." Well that good to know. I'll update the doc. Regardless - will making the modification being mentioned reduce noise? Will it affect the sound at all? And finally just out of curiosity, which components surrounding the op-amps affect the gain? I'm not looking to increase gain, but I'm happy to learn :) Thanks a lot! Tom On Sat, Oct 20, 2018, 20:28 Kaz Kylheku wrote: > It's hard to say without some A/B comparison, with another unit, if that > is more noisy than normal, but the MP-1's are not known for being quiet. > That's why there are these "noise mods" out there. > > I basically changed every op-amp that passes audio to NE5532. For the quad > in the EQ section, I used a MC33079. Just desolder the old, solder in the > new; repeat bunch of times. It's good to do just one or two at a time and > confirm the work after each one. Don't play the "which of these 11 op-amp > chips I changed at the same time is bad/mis-soldered" game. > > BTW in that doc you linked to, step (10) claims falsely that fancy op-amps > will give the unit more gain; that is not true. The gain is determined by > the other components in the op-amp circuit! It will be the same. We're > definitely not looking for more gain by swapping op-amps, and it would be > wacky if that happened. > > On 2018-10-12 08:27, Pilau Tigered wrote: > > Hey Kaz, good to hear from you. > > So are you saying that level of noise is just how this device is? > > Modding/upgrading the MP-1 is definitely worth it! In that note, do you > think you could maybe share what exactly you changed with the opamps? > > On Fri, Oct 12, 2018, 18:23 Kaz Kylheku wrote: > >> Stock ADA MP-1's are noisy. In your Youtube video, nothing strikes me as >> odd, other than the buzz when the audio interface is used. (I concur that >> it is probably a ground loop.) >> >> I haven't done anything to my MP-1 in a bunch of years now; just enjoying >> it daily! >> >> When I ripped out all the audio-passing op-amps and replaced them with >> better ones, it really cleaned up. I couldn't believe I could just put down >> the guitar on a stand, mute the strings and walk away. >> >> Those ADA people created a lot of future work for hobbyists by creating a >> great design, and then stuffing it with some crappy components. But for >> some of us it is worth it. >> >> On 2018-10-10 06:03, Pilau Tigered wrote: >> >> Hello Kaz and the ADA MP-1 mailing list! >> >> I have recently acquired a used ADA MP-1. The unit is rather noisy and it >> has a faulty front input plug. These issue led to hours of research and >> discovery, including finding out about this mailing list and Mr. Kylheku >> (among other leading figures in the mp1 technical community) >> >> ** I'd love it if someone could help me debug and locate the source of >> the issue ** >> >> I have also put together a list of information and >> mods/upgrades/refurbishing instructions and other technical resources for >> the ADA MP-1: https://tinyurl.com/ada-mp1-refurbish-upgrades, feel free >> to check it out >> >> Pilau >> >> >> >> > > >