Hey Guilio, just to backtrack a little, we are guessing that the tubes (one or other) is the problem and why you don't have distortion patches working. Swapping out the tubes for known good ones is easy and won't hurt anything and may fix the issue. If it doesn't fix it then something else is wrong (possibly with the tube circuit board). Another approach is find a tech with a tube tester and test the 2 tubes. So take off the top of the unit, remove the tubes from their sockets, they may be a little tight but gently pull them out. Then you can take them to be tested. The tubes will have writing on them saying what they are, so scribble that down and tell us. Either way, swapping in new known good tubes or testing the current tubes rules them in or out of your current problem and is the easiest place to start trying to work out what's wrong, and would probably be the first thing a tech would do trying to fix it. Now again 5 months is nothing for a tube, even with constant use they should last a couple of years but they can and do fail. It may be just one tube is dead (so if you can, get them tested).
That said, at some point you will need to replace them so buying a new pair want go to waste. Selecting new tubes is a rabbit hole. They are only made in 3 countries (Slovakia (JJs), China (TAD and other brands), and Russia (lots of good brands but harder to source since the war and Vlad decided to block tube exports to the west which has also pushed up the price
).
All 12AX7 tubes brands are electrically equivalent, i.e. they will all work in your MP-1 Classic. However, they all sound a little (sometimes allot) different. Also some seem to suit the ADA circuit better than others (tone/sound wise). ADA had tubes made for them in China. The closest to the original ADA tubes are probably TADs. Have a good read through the tube posts
http://adadepot.com/index.php?board=38.0 So our advice so far is to 1. rule tubes in/out as the issue (easy to do and is the most likely cause of your problem (but it may no be
) 2. what you can easily do yourself and not have to pay a tech to do it. I buy my tubes from Tube Audio in Melbourne (Australia)
https://tubeaudio.com.au/mullard-12ax7-ecc83/. I use Mullard Long plates in all my MP-2s. They have gone from $25 AUD each to $40 AUD (because of the war). These are the Mullards Harley referred to and they will work quite well in your Classic. Wherever you buy tubes from, make sure they are a reputable site that test the tubes before they sell them and have a good returns policy in case they are duds (they shouldn't be duds but it can happen).
Now I'm hoping that your issue is just a bad tube (unlikely it's both of them). Swapping in some known good tubes will answer that question, but as I said, you can get them tested, you need to find someone with a tube tester, a device that most tube amp techs will have and only takes a few minutes.
EDIT: Check if both tubes a glowing, so take off the lid, power the unit up (careful not to touch anything while the power is on) and check that both tubes are glowing and look them same. If one tube is glowing and the other isn't, then you've located the bad tube (if this is the problem).
The next step below is still worth trying even if one tube isn't glowing as it "may" fix it and it's free and easy to do.
The very first thing you could try (make sure the power is OFF!) is just pulling out the current tubes and putting them back in a couple of times. It is possible that the connection in the tube socket has a little bit of dust or whatever. If the guy you bought it from replaced the tubes, he may have sprayed some contact cleaner into the tube sockets to clean them. While this seems a good idea it's NOT. There's a post MJMP did ages ago which explains why you shouldn't do that (basically makes any dust in the socket worse). So pulling them in and out a few times may just fix it? And doing that will give you a little confidence changing tubes, it is very easy, take your time, be gentle(ish), don't force anything, line up the pins, there's a gap you need to line up and it takes a little pressure to push them all the way in.
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Topic: ADA mp1 - Solid States works only (Read 1944 times)
