Does anyone know where I can get a schematic or have any experience repairing these?

Billy

I don’t know. Good question. I have two fabulous A5Xs and an Adam subwoofer. Four years of great sound with no problems. Love that ribbon tweeter.

There was a fuse question on Gearspace.

Do you have A7 or A7x? Might matter.

HI Matt,

I have looked in all the typical places, DIY Audio, and such. No luck so far. Perhaps Trev can comment, or I can send him a video of the device, and he may be able to point me in the correct direction.

I think a good many of us here own these monitors so it would be good to find repair solutions. The on-off switches have failed twice on mine but I was able to buy a replacement on reverb.

I would be glad to repair these monitors for people on the forum for free, time permitting if I had the schematics and can get the parts.

Billy

That’s very generous. I would probably have to pay $200 to the guy who does repairs for me (big ones; I ran an electronics store and am good at the small stuff like a switch).

And I see your problem. Google just doesn’t turn up any leads for service manuals. I suppose I would write to Adam directly but people commented on their slow response time.

ps I’ve actually never turned mine off. They are on a Furman power strip, and I use them all day on and off anyway. But now I’ll be especially careful not to touch the switch.

Hi Matt,

I was able to fix mine. After a very critical look at the components, I found a leaking electrolytic capacitor. That is a little unusual to get that lucky.

After taking a good look at the device, I would absolutely not be able to repair it without a schematic.

There is also one board with tiny surface-mount components that would be difficult to work with for me. I have a digital microscope to do this sort of work but pretty limited experience/skillsets soldering small surface mount stuff.

I will post a photo later. Perhaps Trev will comment, and maybe he has so place to find the schematic.

Billy

Would really love to help, Billy, but I have no experience with this system at all.

I did some searching, and found two other ADAM systems (earlier/different versions). The download links are on this page

Maybe there is some similarity in the schematics?

Hope this possibly helps (a little).
Trev

Thanks, Trev

I found on that site in post 12 what I think is a schematic of the A7.

As I located the issue without the schematic, I did not try to inject a signal and trace it so I did not really need the schematic this time. Thanks for pointing it out as the next time it fails I may not be so lucky.

Everything is very compact, and without a point-to-point service manual, one would need to be a pretty skilled repair person to diagnose and fix the issue.

This is the problem with solid-state/transistor devices. They are not designed to be repaired, and very often the repair parts are not available. This is true with even very expensive stereo equipment.

Billy

I’m glad it’s resolved for now.

I never did find a service manual. I suppose I could write to Berlin.

The bad capacitor makes sense. With those, you have a fighting chance of spotting one in a board. Your A7s are older than the current model and maybe they were manufactured during that ‘era of bad caps’ we went through. Let’s hope.

Here are a few photos of mine. As you can see, everything is pretty compact.
There are several separate PCBs. There are several pages of schematics. It would take me a good bit of time to try to figure out just what is what.




As you can see in this photo, there is a surface-mount PCB with some pretty small components, which would be a challenge to desolder and replace.




The manufacturer of the speakers says they can not or will not repair them, plus they are in Europe. Highly skilled electronics people here in the United States could most likely repair these units because I don't see anything that would be hard to get in parts. Perhaps some of the operational amps would need to be replaced with newer components, but the specifications would most likely work.

Let's hope none of us have any failures. There is a limit to what is logical to repair in any event. The A7 schematics I saw on the DIY website were dated 2006. I have had these for about that long.

Billy

Some of the threads mentioned a problem with the Chinese manufactured toroidal core transformers, although that appears to not be your issue, however, looking at the photos, all of the electrolytics (and probably more) seems to come from China or similar. I would definitely be replacing all of those large value caps. They are all the same age as the crook one that you already identified. I'll bet if you measure them (out of circuit) they'll be out of tolerance.
My 2 cents, anyway...

You are very likely correct about the caps being out of specification. Capacitors are a very critical component in tube guitar amps. They are one of the main reasons it is very difficult to duplicate the sound of vintage guitar amps because those types of caps are no longer manufactured to the exact specifications of the originals. The electrolytic are what I am speaking of.

I am not sure how far a cap in a transistor circuit could drift from standard before there was a noticeable change in the sound quality on studio monitors.

The Adam studio speakers are pretty expensive, well, at least to me. My intent is to keep mine running as long as I can. For one thing, I like them, and second I don't want to spend the money to replace them unless forced to.

I also read the toroidal core transformers issue referred to in the DIY post. My experience with toroidal-type transformers has been pretty good. Toroidal transformers generally offer better sound quality for audio equipment.

Gallian Kruger uses them in their bass guitar amps, along with switched power supplies. The power supplies are not so simple to work on. They had asked me at one time to do warranty work for them in south Florida. The power supplies cost enough that they wanted them to have troubleshooting at the component level; there were too many other irons in the fire for me to take them up on the offer.

Billy

EDIT: On another electronic note, I now have enough room in the house in Sebring that I may build a set of Electrostatic loudspeakers. I have the woodworking tools I need to build the cabinets. I have always wanted a set just to see what they would sound like. I have also wondered if I could use them in a guitar amp.

Billy, the main reason for toroidal core transformers in audio equipment is to minimize external interference (in the case of audio equipment we are referring to 60/50 Hz 'hum'). Well designed and manufactured transformers should never give an issue. But I guess you already know that

Regarding:
In carefully designed and calibrated tuned circuits this is definitely an issue (low pass, high pass filters etc), however, my concern is that the caps are old and likely to fail, especially those in the P/S parts of the circuit. Old electrolytics are notorious for this.

Hey Trev

I have replaced a fair amount of standard high voltage transformers in tube amps I have repaired. I think I have only replaced one toroidal core transformer in a Gallian Kruger solid-state bass amp.

As failures go, transformers in the guitar amps I have experience with have been pretty reliable. I don't know what they cost in those days, but new "iron" is pretty pricy.
I have worked on a good many 1950s/1960s guitar amps that had the original transformers. Power supply caps are the first thing to fail.

As I get older and less physically able to take a butt-wiping on the boat, electronics and other less physical hobbies are becoming more attractive. Also, the cost of offshore fishing is getting to the point it is less fun. Covid has put a bit of a damper on international travel along with the increased cost. I do really miss playing guitar in Europe with my friends. The house here in Sebring lends itself to live acoustic drums and higher volume levels of live music than I had in Miami. Of course, at the ranch, I can turn it up on 14...lol

I may actually try one more time to get a little better skilled at solid-state technology.

Eye surgery in a couple of weeks may make things less problematic for the small surface mount components. Well...at least I hope things go well.

Billy

The second post was a mistake.

Interesting stuff. I bought a pair of Adam T7Vs earlier this year. The rear mounted power switches are a problem for me given my set up so the speakers are "always on" though hooked to a powerboard with individual switches. I flick those when I need them. I did spend a few months with them actually always one & slaved to the power of my computer as I too & from a bit from the room but am much happier to have them hooked up as they are now.