ADA Power Amps (Teach Me About Rack Power Amps)

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MrShake
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ADA Power Amps (Teach Me About Rack Power Amps)

Post by MrShake » Thu Jul 20, 2017 2:20 pm

Hey, all.

Recently posted about the ADA MP-1 I bought. I had to put in a new battery and might want to upgrade the tubes, but I really like the sounds in it for what they are. It's a nice change of pace from my routine, cool to play with the Marhsall side of the world, and love the instantly-'80s (in a good way) chorused sounds. I often find myself liking the misuse of high-tech '80s shredder gear in the service of post-punk music ("Disintegration", shoegaze, etc). My decade-long setup has been a Jazzmaster into a big ol' pedalboard (Rats, gnarly fuzzes, late '80s reverbs) into a nice big tubey silverface Fender 4x10 combo set to super-clean. This rack stuff cool 'cause it's all new to me. But it's perfect for that part of me that loves shoegaze, '90s punk (that Marshall-ish sound), and textural ambient stuff. And it's been great for recording.

I'd painted myself into a corner as far as power amps when I realized I needed a power conditioner for my little rack. I hadn't taken that into account when I drew out my "dream rack" on paper". It don't want to have to upgrade to anything bigger than 6U and the conditioner took one of the slots I'd reserved for power rampage.

This left me with limited options. 1U power amps seem few and far between, with guitar-oriented ones even fewer (as opposed to just straight up PA-style ones). Ideally, I'd like a tube power amp, but realize that it's out of my budget, especially if I'm locked into the 1U stipulation. I needed something 1U, not as harsh and cheap as a bottom-shelf off-the-rack current SS power amp (i.e. Behringer, et al), and hopefully without spending too much. Yeah, yeah, I know. The golden triangle. But I'm not a good enough player to really invest a fortune in what will realistically be my "second" rig, even if it's unique.

So, I bit on an ADA Microtube 100 (MT-100). I would have preferred the 200W version, but this was considerably cheaper, and there isn't one of those 200W to be found anywhere I've looked. This was a good deal, and I can't imagine I need too much power. This is for home practice, assorted recording, and small club/bar gigs. I hear the MT-100 pairs well with the MP-1, and whether or not it's "real" tube (it's not), the "warm it up" technology gave it a big edge in my book. Plus, I recently saw a gig where the guitarist was playing a (stock, I think) MP-1 into a Quadraverb into an ADA MIcrotube power amp (the MT-200) and it sounded like the end of the goddamn world, so I'm game to give it a try.

But, I'm new to heads/cabs/preamps/poweramps. So I need some advice. Please steer my garage-rockin' gorilla brain into the high-tech world beyond loud combos and fuzz pedals.

1) I have a 2x12 cab I recently re-wired to 4ohm (down from 16). It was wired in series, I converted to parallel to go with the super-powered SS bass amp I've been slaving the power section from, with perfectly acceptable results, other than a little SS sterility from the cheap power amp. Looking at these connections on the MT-100, however:
Image

... what's the best way for me to hook up my 4ohm cab to these outputs? I don't care about running in stereo until I upgrade speaker cabs next fall/winter, I just don't want to blow anything up by not having enough ohms giving resistance to the output.

Should I run it mono down the whole rack line to just one side of the stereo output, and only use one channel (i.e., 1 side of the stereo output)?

Or can I run stereo into it and have it "sum" the signal and only run on one side of the output at 4ohm?

Should I RE-re-wire my cab back to series and give it a 16ohm speaker load?


2) I know these things have a quirk where sometimes it goes into "safety" mode, and/or takes a while to start up. Still waiting on it to arrive, but as I understand it, this is a surmountable problem. Seems like there's some info out there on ADA Depot. But, are there any other significant issues with these things I should know about before I commence to rocking?


3) I've read a handful of comments online about the potential differences between MOSFET and the more "typical" BJT solid state amps. Can anyone elaborate in an exceptionally simplistic way for me as to how the two may differ in practical usage? Or is this all a bunch of hooey by armchair rockstars?


4) I've applied over at the ADA Depot forums, but never got the registration email it said it was sending me. Does anyone know if that's still active? I can't even see when the posts are from.

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by marqueemoon » Thu Jul 20, 2017 7:41 pm

Most power amps are going to want to see a load connected. I know digital amps are one exception.

ADA is still around, so if you can't hunt down a manual for the answer just ask them.

If that's a no-go then yes rewiring your cab to 16 and using the bridged output would be the next step.

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by sears » Sun Jul 23, 2017 8:12 am

I betcha if you were willing to go 2ru and hEaVy you could have a slammin' sound. Like say the Crest CA2. Get a tube compressor and/or a tube preamp in front of it, like the Retrospec Squeezebox. You would have something as saggy as you want, clean, loud, reliable and really good sounding.
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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by MrShake » Wed Jul 26, 2017 3:52 pm

sears wrote:I betcha if you were willing to go 2ru and hEaVy you could have a slammin' sound. Like say the Crest CA2. Get a tube compressor and/or a tube preamp in front of it, like the Retrospec Squeezebox. You would have something as saggy as you want, clean, loud, reliable and really good sounding.
Oh, I couldn’t agree more. Unfortunately, 1U is a pretty important decision-maker, thanks to me not considering the power conditioner and apartment stuff, etc (we live in a tiny apartment downtown). Plus, I’m not quite enough of a guitarist to really shell out for that level of gear on my “secondary” rig. Something like a Crest and Retrospec are way, way out of my budget. At $1300 for the pair of them, I’ll have to file that under "maybe one day". But I agree, I bet a rig like that would sound earthquaking.

(also)

There's an update on my purchase. Things got a little goofy.

Upon review the next day, I realized that I had not, in fact, purchased the “Microtube 100”, as was stated in the wording of the listing. It was actually the 100-watt “MicroFET” series, which, to my understanding, mostly just lacks that “warming tube” on the input stage. That warmth was a somewhat significant reason the Microtube initially appealed to me, but i figured it wouldn’t be the end of the world to use the MF100 for a good-but-cheap 1U power amp (still cheaper than most on the new market), and it would get me by until I could upgrade eventually. The photos in the listing were pretty clear, but due to the aesthetic similarity between the Microtube and Microfet 100s, I guess I missed it in my eagerness for an ADA power amp, which don’t seem as available as I’d expected them to be. Plus, uh, it SAID "Microtube" in the title of the listing. Caveat emptor, but I was still mildly irritated. It has still not arrived, but I expect it tomorrow.

However, two days after I paid for that one, I found a Microtube 200 (MT200) for a great deal, based on what listings I’ve found. That's the one I've been wanting all along. I was keeping my eye out and priceshopping for a while, but the only one I’ve even found available anywhere online is sitting at $300 in someone's rack rig on Reverb, which was out of my immediate budget. This one had popped up for half that (and free shipping!), so I bit on it, with the plan to sell the Microfet to offset the cost, maybe earn some back and still come in just under market price on the big boy.

The MT200 arrived today, and... it’s pretty sweet. My one concern is that on first startup, there was a tiny bit of a soft, discharge-like pop, and the tube in Channel B lit up much more than the one in A. Everything sounds pretty OK, and I’ve tested each channel independently, but I think I’m going to replace the tubes maybe tomorrow if I can make it to a shop. At least one of the ones in there is a JJ from what I can see through the grate. I’ve only put in apartment volume levels so far, and can’t tell if it’s the preamp or the power amp that seems like it might be adding a touch of grit to my clean tones. [Edit: maybe it's just my attempt at "clean tube" on the MP-1, because I don't think I'm getting it as much on solid state settings). Maybe it’s my imagination, but I can’t tell. Maybe it’s just “warmer” than the 450W Behringer bass head I was slaving as a temporary power amp until I got this. I re-re-wired the old cab I have back to 16ohms for safety (approved in the manual for this model). Maybe that has something to do with it. Replacement cabs are in my future. More than I’m letting on, in fact... but that’s for another post for (hopefully) early next week.

Regardless, I like it. A lot. I need to make sure everything checks out in a maintenance sense, but first impressions are really positive so far. Mostly clean, quite warm, and the presence knob lets me turn it all the way down and roll it up to add clarity in until it’s just crisp enough for me. And I figure with a cab (or cabs) at the proper impedance, or perhaps in stereo, it’s going to roar.

Here’s my new sickness. What the hell is wrong with me?

Image

Oh, and this setup has made me fall in love with a Supersonic Fuzz Gun and Fender Blender in whole new ways. The Blender is disgusting.

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by marqueemoon » Wed Jul 26, 2017 6:19 pm

So period correct!

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by MrShake » Thu Jul 27, 2017 5:07 am

marqueemoon wrote:So period correct!
Ha! True! I figure when it started with an SPX90, I was doomed to that. It was piece by piece, but I guess that's the stuff I like. And wait until the new cab situation gets resolved next week. ;)

You know, it's funny. I love reading old forum posts about whatever gear I'm currently digging on, and I see people spending THOUSANDS of dollars flipping boutique fuzz to get (for example) that "Siamese Dream" tone. I'm not generally aiming to replicate another sound I've heard, but some like to do that (no judgement on my part). I read threads about people trying this and that for YEARS and then finally being happy with some limited-run gizmo that nails it for them. That's totally great, and I wish them luck and I know the journey can be part of the fun. But a lot of times, I can't help but think, "Why don't you just buy an opamp Muff and a used JCM800 and be done with it for the same price, or maybe even less, saving the time and effort?"

Incidentally, the tubes in this MT200 are currently a JJ short plate in Channel A, and a Groove Tubes 12AX7M in Channel B. The GT tube "flares up" when I turn it on, much more than the JJ, then dims to match the other one. I'm going to zip out in an hour and pick up some Tung-Sols (the cleanest ones my local GC appears to sell) and see if that changes. I know virtually nothing about tubes beyond my crash course the past week. There's a place across town that has Mullard long plates that I'm considering picking up for the MP-1 whenever I eventually get over there, and the preamp works/sounds fine for the time being, so it's really just the MT200 I'm concerned about.

Anyone have any suggestions this morning before I head out the door?

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by sears » Thu Jul 27, 2017 6:05 am

No suggestions, that thing is gonna be great. I use a Markbass tube compressor for bass sometimes. I have played guitar into it, and it feels great. Big and clean.
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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by MrShake » Thu Jul 27, 2017 9:46 am

Walked all over the damn city when the GC I went to had zero 12AX7s in stock. Despite what the website said. Grrr.

So, I busted my butt to the other one, now under scheulde constraints. Sweaty and out of breath, a train and a walk later, I made it to the other store and picked up some of what they had left (not a wide selection). Luckily, they had Tung-Sols.

A 2-day crash course of internet research (and sifting through the people who don't know what they're talking about), and I seemed to put together that Tung-Sols might stay cleaner and not break up as early as some others. Perfect for my purposes in a power amp -- adding warmth for the SS output to crank, but not add too much color or any grit of their own. I don't know that I'd be able to I.D. it as a solid state amp immediately in a blind test, even if it doesn't quite have the richness of an all-tube setup. Or maybe it's close or way off and I can't tell at spare-room levels. But having seeing one in use live recently, being right in front of those cabs, it was really powerful without being harsh.

I have to do a little more testing, and try it out at practice space volume, but any perceived grit I thought I might have been getting from the power amp is now gone. Still nice and warm, and the presence control allows for a pretty wide range from thickness to brightness. While I don't have a lot of experience yet with rack power amps, the MP-1/MT200 combo is so far making for a bitchin' dip into the non-Fender amp world.

Does anyone else here use one? I'd love to hear your experiences and opinions...

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by MrShake » Mon Jul 31, 2017 3:16 pm

Update time.

I got the Microfet 100 in the mail. It's pretty much exactly what I expected. Nice, clear sound amplification. I honestly don't know what the tubes actually DO for sound in the Microtube, but it definitely sounds "warmer" than the Microfet, which I guess is just the same solid-state parts of the MT200, only without the tubes. I was going to sell it, but frankly, it would be perfect for driving studio monitors or acting as a backup in case the MT200 fails. And if I wanted to sell this, if I needed to go buy one of those later, it would probably run more than the MF100 cost me. Grr. That's going to bite into the deficit I was going to offset on the cabs. I've put it in the one blank spot in my rack case for the time being, just to keep it safe from getting banged up, but it's not even plugged in.

Speaking of:

Image

I'm delighted to have upgraded my cab situation! OK, so, yes, I realize I drank the ADA Kool Aid (which would almost certainly be Blue Raspberry), but I found some ADA Split Stack cabinets online. I realized that they don't tend to pop up REAL often on the local Craigslist (I never see them), and that if I bought from GC, the shipping would be less than half what it would be from any other vendor anywhere but locally. So I had the pair shipped to my local store for $60 in moving fees, better than the $150-$200 I've seen elsewhere. They're nice, but not "pay double to ship them" nice. Got to the store, plugged them in to make sure they worked (this gets important later), and then took them home. They're the "standard" version, not the "vintage" model. I know what the difference is, but I'm unclear on how those were developed/released/marketed.

Got home, opened them up to see what was inside (making one of those crumbled corners a little worse in the process, oh well). Is it normal for these things to be lined with what seems like insulation? Big fluffy pads stuck to the back panel. Will post pics later. I don't think I've ever seen that, but I've only ever really bonded with a few amps, so my experience is limited. As long as it sounds good.

Then, of course, one of them wouldn't output any sound. At all. And this being a new setup for me, I was totally stymied. Turned out to be one that of the extension jacks (the serial one) had been all f'd up by the previous owner, and the contact point that says "this jack is not in use" wasn't making contact. I finally got it working with some pliers and bending (trickier than I thought). Oh well, likely won't use that anyway, and can replace later. But the hour of troubleshooting was irritating. (Is it the power amp? Is it Channel B? A bad patch cable? Bad speaker cable? Do I have everything routed right? What happened in the last half hour to cause it to fail?) I definitely see the appeal of guitar -> fuzz -> amp when it comes to troubleshooting.

This pair has clearly seen better days. Kinda dirty. Both of them have some decaying plywood on one corner of the back panel on both cabs, and in both cases, the corners are all cobbled back together with screws. Like they'd been kicked hard, or maybe the cheap plywood just started to crumble a bit. But no worries, I can have someone cut me some of those sometime, and it will hold up for now, as it's not going to be gigging every week. The speakers inside are still the stock Celestials (G12S-50), and sound very nice to my ear. Way more high end than the woofy, wooly 4x10 I've been playing through. Crisp and lively and electric. Code on the flange that starts with 05EC dates from March of '95 if I'm not mistaken? Anyway, with 200 watts going into them (and I know SS watts aren't as loud as tube watts, and that it's sort of ridiculous to measure loudness in watts, but whatever), it's pretty fucking loud at "2". Which is PERFECT *swoons*.

Why did I get these? Not because they're ADA, though again, I realize I've been the resident fanboy lately. The split 2x12 was probably THE reason I got these. The angled speaker was a plus, as was the stereo option from my power amp. Shoegaze heaven. I can also run one cab over by the drummer and boom -- instant monitor. I knew I wanted a "half-stack" of some kind for this rig (4x__), but the portability ("small gig? take half!") and versatility ("small gig? take half!") interested me. If I HAD to cut down on volume (small apartment, thin walls), I could deal with going mono to only one cab. And I know there are other 2x12s out there, but the vertical form factor with these had appeal, the way they were matched for the purpose rather than just being a pair of 2/12s. Finally, that they're theoretically designed to compliment my pre- and power amps (in both sound and ohms/configuration) was icing on the cake.

Anyway, I'm going to have to break them in, take them for a few test runs, but they seem pretty solid so far. I thought I'd post a pic, but the lighting in my office is all screwy. I had a blue spotlight within arm's reach, so there you go. It's functional, not pretentious. I can do that without any lighting help.

Image


I'll also stop posting enthusiastically every time I get new ADA gear, but I was considering starting an "ADA Appreciation Thread". ADA Depot's forum seems completely shuttered, despite the good info still available over there. OSG seems like a pretty good place for lovers of cool gear that's been unfairly orphaned or maligned. Might be a nice way for people to consolidate some information nowadays? And that way, you won't have to see so many of my threads popping up .

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Re: ADA Power Amps (Teach Me About Rack Power Amps)

Post by HT_Murgatroid » Sun Sep 23, 2018 2:42 pm

@MrShake, any chance you could post a picture of the back side of the jack plate? I have one of these cabs i just got but it has no wires. I'd like to see what it looks like correctly wired.

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