200S - Couple of questions

[+Leo+]

Hi guys, this is my first post, but I'm a regular guest here. Lots of useful information, great board!

I have recently scored 200S for really reasonable price (100€ - around 130$), especially for Europe, without tubes inside. Amp is in excellent condition as you can see on the photos, I was really surprised.

I guess by the look of the grill cloth and that little "r" after the logo that it's a '71-'72 model. Is that correct?
I was told by the guy who sold it to me that it has a tube rectifier, not SS. Is it true? I hope it can be seen from photos.
Does this transformers look original to you? I was told that Amp is intact except for the tubes.
What is the power of this model? Is it 60W or 80W?

I can't wait to put him in action!

[loudthud]

The transformers look original. It has a tube socket for a tube rectifier. There should be a small piece of paper glued to the inside of the box above where the line cord comes out of the chassis that shows what tubes go in what sockets. The fuse holder does not look original. What type of mains plug does the amp have? There may be a date written on the inside of the chassis. The grill cloth and (R) logo mean the amp was made after mid 1969 and the tube rectifier was discontinued some time in 1970 when the 200S was upgraded to 80W. The CSA sticker may mean the amp was originally sold in Canada.

[+Leo+]

Thanks for the help!

You are right, they messed something with the fuse holder and something with power transformer. After closer inspection I noticed that power transformer has been opened. My guess is that they modified it for 220V, but I have to take it to local tube amp guru to check that out.
The small piece of paper, that map for tubes you mentioned, is missing, but I found schematic so that shouldn't be a problem.
I found a date on power transformer and it says NOV 1970. When I opened amp with my friend, we found another date inside of the chassis, and it says 71. This really confuses me, because you told me, and I have read earlier that Sunn discontinued tube rectifier in 1970.

I shot some photos of inside, you can see that messing with the power transformer that I mentioned above. (that weird cable that goes out of transformer and its covered with isolation tape)

[loudthud]

There are two small red components that might be solid state diodes on the soldered to the back of the rectifier tube socket. That's not normal and there should also be two yellow wires going to that socket. The two yellow wires look like they come out of one side of the transformer and go into the other side. The two large "Beaver" capacitors are not normally seen on the 60W amps. So your amp may have been one of the first 80W models or converted to one. Sunn used rivets to hold terminal strips so anything held by a rivet probably came from the factory that way. The black tape is not original though. I see a "Death Cap" normally seen only on 120V 60Hz amps. There appears to be a resistor between the power switch and the ground switch. That doesn't make any sense. Does the amp have a USA type plug on the power cord?

[+Leo+]

Thanks again for helping me!
Yeah, I'm kinda bummed right now... It isn't intact at all, obviously some major modifications have been made.
The amp has european type plug, and that's the reason why I believe it has been modified to work on 220V.
I will take it to technician and ask him to return the amp to original condition if it's possible. I'm just not sure right now in what schematic to use, is it tube rectifier 60W or a solid state rectifier 80W model.

I hope that those changes can be undone, because I would really love to sound as original as possible.

[+Leo+]

I have taken the amp to tech and he told me that it shouldn't be a problem to fix it.
The yellow wire was just cut and taped, and although on the picture here looks like it's going back inside the transformer it just felt that way when we opened chassis. As tech explained me, someone just converted with those red wires transformer to work on 220V, and if transformer works good, that wouldn't be a problem at all. They have also soldered those 2 diodes like you noticed and made rectification  solid state, and I asked tech to make me a switch, cause I already have one hole in the chassis where original fuse holder was, to switch between solid state rectification, tube rectification and both at the same time.
I will also try KT-90 instead of KT-88, because they're domestic EI Nis tubes here in Serbia and I can find them cheap, I've heard that it's a good quality tube.

I will post more pics when I bring this beast to life, and maybe some sound samples too.

[Soundmasterg]

Those EI KT90's are fabulous tubes and are in very high demand worldwide in the hi-fi community. I had heard that EI stopped making them several years ago, but perhaps they are still being made and just not being exported? There was a huge worldwide market for those EI KT90's and the for the EI ECC83/12AX7's, and to a lesser extent the EI EL84's. EI seems to have dried up though on the worldwide scene the last couple years......

Greg

[+Leo+]

Yes, they stopped making tubes in 2006. The factory went through privatization, I think that Philips bought it, and then they just stopped producing tubes, I'm not sure, but I think that they closed the factory. There where even talkings that Marshall was interested in buying factory and start producing some amps there, but that never happened. EI was producing tubes for Marshall for many years so I wasn't surprised that they were interested in buying it.

[Soundmasterg]

Yeah thats what my suspicion was....too bad because EI had old Telefunken equipment and made some great tubes.....well great sounding anyway...their quality was spotty sometimes.....

Greg