Dante,

I could tell a couple were photos of your rig(s). I wasn't too sure about the others though.

Still, really nice work man

Quote from: MarshallJMP on Today at 01:17:36 PMDid that to Dante's MT100, but it's hard to find those 4700µF/80V caps in an axial housing. Good thing ADA also have the holes to put in a snapin cap (even 2 in parallel). I got these from mouser, if you want I can get you the part number. Found a 4700µF/80V snapin that fits so no need to put in 2 2200µF caps  like it was intended.

Yes please, if you would get me the part numbers, I'll order them.

I am understandably nervous since I've never done this before, but I think I have all the right tools for it and they aren't going to fix themselves.

Richard,

I know, that's why I'm thinking of it. All my ADA power amps are original, and I'm sure the caps are in need of attention.

Did that to Dante's MT100, but it's hard to find those 4700µF/80V caps in an axial housing. Good thing ADA also have the holes to put in a snapin cap (even 2 in parallel). I got these from mouser, if you want I can get you the part number. Found a 4700µF/80V snapin that fits so no need to put in 2 2200µF caps  like it was intended.

@Harley: I used two photos; one of the Flying Vee I gave my nephew for xmas and one of my two ADA rigs, the rest of the photos are from the web, which was nice

I kinda needed to lay this out for my own brain to comprehend where I was going to add the delay pedal in the chain and still achieve the 4cable method (probably ought to do a thread about the 4CM). I need to add a pic of the back of the ADA rigs.....someday

I'm also thinking since I'm going to have the amp open and replacing the power transistors, maybe I should also replace caps at the same time? 

Hey Harley, sounds prudent, the caps are old

Hey Robertkoa, so since that quote (2014) I bought a couple of MP-1s.  While trying to sort them out with my tech I swapped out the EVs in one MP-1 and put in a pair of Mullard long plates, it instantly sounded way better.  While theoretically short plate tubes should be less micro phonic, it's never been an issue for me, i.e. using the long plates.  As Harley says, try a few different combinations and your ears will tell you.

Sovtechs work well in Marshall circuits, as I discovered at a tube rolling night/workshop, originally IIRC Marshall used Winged Cs made in St Petersburg, but available no more .

From what you said in the other tube post, what I saw last weekend is closer to what you are chasing?  So a friend played me a youtube clip going through the development of the Paul Reid Smith Hendrix Marshall clone, where they got to check out his Marshall in a museum and then try to replicate it.  The results are pretty spectacular, albeit quite expensive heads (20w, 50w and 100w).

Hey Robertkoa, there is a mod some MP-1 users did that lowers the bottom end centre frequency, but like Harley said, when I was using a MP-1 it had plenty for me.  These days I use a MP-2 which has great cleans (and everything else).  All the voices in the MP-2 (10 of them) are tube, so no SS like the MP-1, and voices 1 (crystal clean) through 5 (Warm Vintage) only use one gain drive OD1 (i.e. no OD2 which is available for the higher gain settings 6 through 10).

For phase inverters, their job is basically to split the signal into +ve and -ve half of the signal to drive the push pull output tubes, which are typically 1 tube for +ve and 1 for -ve in a 50w head and 2 tubes each +ve/-ve for 100w heads (e.g. 6L6 or EL34s).  While PIs are often 12AX7s, PIs don't need that much gain so often it's better to use a 12AU7 or 12AT7 which are lower gain but higher current and push the output tubes harder (if you like a bit of output tube distortion).  I'd not thought about using a PI post preamp as by then I'm running stereo (well pseudo stereo) as channel A and B in either MP-1 or MP-2 are 180 deg out of phase (which happens at the stereo chorus).  To do what you are thinking, you could put a tube in the MP-1 FX loop which is after the gain and EQ but before the chorus and still mono.  So maybe a tube screamer but use a 12AT7 in it?

I've been using the Mullard long plates in my MP-2s.  I find them a bit more 3D and a bit more depth and nice smooth distortion.  My friend uses a Mullard short plate in V1 and a long plate in V2 in his MP-1.  Experimenting with V1 and V2 combinations (as Harley was saying) may get you closer to what you want?

For recording, I use the MP-2 cab sim outs.  Not quite as versatile as the dedicated ADA cab simulators e.g. my friend puts a ADA GCS-3 in his MP-1 FX loop.  The MP-2 cab sim outs gives you 2 x 12 or 4 x 12 selections but not mike placement options like the GCS.  However, it works great for me .

Hey Robertkoa,

   The MP-1 should have all the bottom end you'll ever need already. My stock MP-1 does and so does my MP-2. The only one that didn't have enough low-end warmth was the MP-1 Classic. It's more like the modern Marshall kind of preamp for lack of a better comparison, meaning it doesn't have that low-end like a Fender Twin. I did warm that up with a pair of long plate Mullards and it helped without cutting out any of the mids and highs.

  I have a pair of JJ 803s in it now, but I'll be experimenting with some different tubes and maybe trying some combination of long and short plate in it. I definitely has a lot of bottom in it now, but the mids and highs are not as articulate as they were before, so I may try a short plate in V2 that's not as hot. It squeals with very high gain settings.

  True there is not PI in these preamps. but with the Microtube power amps, I think it simulates that since those also use 12AX7 tubes for the "Presence" control. I always dial that back to around 9:00-10:00 to keep it warmer.

Hey Robertkoa,

 I have 803s in my MP-1 Classic right now, and TBH, I'm not that thrilled with them there. The classic doesn't have as much low-end response as the original MP-1, and I thought it might help, but it seems to lack the desirable midrange frequencies that I'd like to keep. So far, the Classic sounded it's best with long plate Mullards.

 You might want to go with a shorter plate in the MP-1 to keep the microphonic squeals down to a minimum, or mix it up and use a long plate in V1, and a short plate in V2.

Your ears will tell you what you like and what you don't.