I am doing a bit of pre-planning for possibly scratch-building an SSTRAN AMT3000 clone. I have a full schematic and most of the parts, but am deciding what AC adapter to use. I know that the circuit has provision for either an AC or DC power input, but am wondering what the kit was supplied with. Can anyone here who has an AMT3000 look at the AC adapter, and tell me whether it supplies AC or DC to the transmitter, and at what voltage please? I am pretty sure it was a switching type supply, made by Triad, but cannot find a suitable DC switching supply manufactured by them. (I already have a linear one that supplies 16V AC, which will work, but I want to look into DC switching supply options too).
Thank you in advance!
This should answer your question
"The kit is supplied with a 120V AC to 18V AC power adaptor with an American 2-pin plug. This is of course useless in the UK, so I ordered a 15V AC UK adaptor from CPC for about £3. The unit will work from any adaptor providing 15V to 20V AC or 20V to 24V DC at 300mA or more, and fitted with a 2.1mm power plug"
https://www.vintage-radio.com/reviews/amt3000.html
Thanks @mark. Not sure how that bit of info evaded my Google search. Apologies for bothering you, and thank you for taking the time.
I had mine out a few months ago but its repacked and stowed away presently and not easy to get to, but I never had an original adapter but used an equivalent. I dont know, but I thought it was DC powered. But really dont know.
I guess that's no help.
I dont know, but I thought it was DC powered.
I think you're right @richpowers. I had an original AC adapter with my AMT3000. I remember it being fairly small and lightweight, which would point to it being of the DC switching type. I know that the brand was Triad. I was a bit confused, because the schematic indicates that it will operate from 20V DC, and I couldn't find a 20V DC adapter made by Triad. I was reluctant to go much higher in voltage, as the extra power will be dissipated in the 15V regulator. However, the info that @mark found makes me think that it's worth trying a 24V DC switching adapter. Triad makes one of those. It's probably the one that was supplied with the original kit.
@rugster I'm tempted to make it a point to dig mine out tomorrow and see what the wallwart says .. but really that shouldn't be neccessary, Carl is a diehard SSTran user, it's in operation right now. I'm surprised he hasn't piped in yet.
@richardpowers and @rugster I earlier decided I would chime in on this but I've been hung up in another thread trying to repair some links.
I have the Manual plus 2 AM3000s so I will switch over to this topic just after dinner... Have a seat in the waiting room.
@richardpowers What links are you referring to? The manual I have is for the AMT3000.
@rugster Here is a description of the power cube (wall wart) for my SSTran AMT3000:
Part # 218054 \ Class 2 Transformer
3081 | E175399
INPUT 129 VAC 60 Hz 25W
OUTPUT 18 VAC 500 mW
Made in China
It does not contain the TRIAD name, nor is it a switching supply.
Memory tells me that my second AMT3000 power cube is exactly the same, although at the moment it is missing from that transmitter which is in storage.
Thanks @carl-blare. After all the trouble you and Rich have gone to, I looked a bit more closely at the pictures I took of my AMT3000 kit when I had it, and realized that the box of the wall wart is in several of the photos. I think that if I enlarge the image enough, I might just be able to read the product number on the side. Mine was a Triad, but I think I am being a bit precious about this, as I imagine the AC adapter was changed throughout the life of the kit, depending on what was available at the time.
I just bought a linear wall wart that puts out 16V AC (it's big and bulky!) I am also about to order a 24V DC linear supply (not wall wart), and a lightweight 24V DC switching one. They should all work, but I'm interested to see if there's any difference in hum suppression between the linear and the switching supplies. It doesn't hurt to experiment.
I also realized that of the pictures I took of my AMT3000, there are some quite detailed close-ups of both sides of the board. Between the schematic and these pictures, I have more than enough info to design a close copy of the original board. However, it's easier to build it Manhattan-style, which is what I plan to do.
More to come on this, hopefully. If I never post about it again, it means that my attempts failed miserably, and I'm purposely avoiding the subject and trying to move on with my life! 😊
OK, this has been a lesson in why I need to not ask others to do my dirty work for me, and do it myself. After looking closely at the unboxing picture of my AMT300 kit, back in 2010, I see that the wall wart that came with my kit was a Triad WAU16-400 - a 16V AC 400mA wall-mounted transformer. I'm a bit annoyed with myself, as I just bought the slightly larger version of that - a 500mA version. Weirdly, it's cheaper than the 400mA one, which would have been why I plumped for it. It's good that I got the one with higher current handling, but I don't care much for big and heavy wall warts, as they tend to take over valuable spaces on power strips. Oh well.
Well, I finished my scratch-build of the SSTRAN AMT3000, and it's working! I'm glad that the manual and schematic were available online, so that I could source all the parts and build it. I have it all cased up, and the front and rear panels labeled with Dymo labels - nothing fancy, but it looks like a bona fide homebrew project. I'll post photos in due course, but it's going to take me a while, as I'm planning on writing it up as a full post on my blog.
In short, it's working well. From what I can remember, it's working as well as my old AMT3000 did. It doesn't sound as good as my SW200/Rangemaster combination, but that's to be expected. As some point, I hope to make up a cable, so I can feed my AMT3000 clone with audio from the SW200. I have only ever heard the AMT3000 being modulated by it's simple onboard processing, and would like to hear how it sounds when fed properly processed audio.
I've had my head fully engaged with this project since I started it a few weeks ago, and am glad that I can slow down a bit and take a step back now that I know it is working, and I didn't completely mess it up with some wrong moves from a hot soldering iron in the middle of a frenzied late night soldering session!
I'm feeling pretty good about this little project. More to follow........