B&K Sonata Series M200

audiocr381ve

Thinking about picking up a pair of these locally. They have supposedly been gone through a few years ago by B&K and checked out fine.

Can anyone comment on these monoblocks? Did a little research and what I read looked good, but I'd love to have a Polkie's take

I'll be pushing LSi9's (for now) and the amps are 200w @ 8ohms and double @ 4ohms for 400w.

zingo

There are a pair of those selling local to me as well, and I chatted with the owner a little. They seem like great amps that could power about anything. May I ask what they are selling for? The only thing you may not like is the warm LSi speakers coupled with warm B&K amps, but that would be a personal choice.

Dawgfish

The M200s were essentially monoblock versions of the ST-202+. I used to own a ST-202+ and it is to this day one of my all time favorite solid state amps. It had the famous B&K warmth and bass, and excellent soundstage, especially for a SS amp. If I had a pair near me that were in good shape and priced reasonably, I wouldn't hesitate to jump on them.

audiocr381ve

Zingo, to answer your question I got a pair of them for $400.

I picked the amps up today from the seller at his storage unit. The amps haven't been powered on in years and I didn't have any way of testing at the storage unit. He assured me that they were serviced only a few years ago by B&K and that they should check out fine.

I take them home and get em' set up in the system. I triple check the wiring and then fire them up, and the instant I turn them on I hear ... BUZZZZ SNAPPPP POPPPPPPPPPPP!!!!!! I instantly powered down.

It was LOUD. I'm not entirely sure that the drivers are okay, but I brought my old amp in and everything tested fine which means that it's definitely the B&K's.

Anybody have any idea what's going on?

nooshinjohn

audiocr381ve wrote: »

I triple check the wiring and then fire them up, and the instant I turn them on I hear ... BUZZZZ SNAPPPP POPPPPPPPPPPP!!!!!! I instantly powered down.



Anybody have any idea what's going on?

Other than it would appear you got scammed. I haven't got a clue. I hate it when people knowingly screw people over like that, and I am sorry this has happened to you bro. Any chance of finding the guy and getting your hard earned money back?

heiney9

audiocr381ve wrote: »

Zingo, to answer your question I got a pair of them for $400.

I picked the amps up today from the seller at his storage unit. The amps haven't been powered on in years and I didn't have any way of testing at the storage unit. He assured me that they were serviced only a few years ago by B&K and that they should check out fine.

I take them home and get em' set up in the system. I triple check the wiring and then fire them up, and the instant I turn them on I hear ... BUZZZZ SNAPPPP POPPPPPPPPPPP!!!!!! I instantly powered down.

It was LOUD. I'm not entirely sure that the drivers are okay, but I brought my old amp in and everything tested fine which means that it's definitely the B&K's.

Anybody have any idea what's going on?

Should have used a variac to slowly bring them up. Any older piece of electronics sitting unused for a longer period of time could have issues. Sounds like dried out caps, etc.

audiocr381ve

Well the seller is meeting me at a local repair shop tomorrow and will front the bill for repairs. I don't think I'm going to find a pair of monoblocks that double at 4 ohms for under $400, so I'm gonna have these fixed instead of getting a full refund. I'm fortunate that the seller is a great guy and wants to make it right.

Brock, the tubes came in just fine and I spent less than 5 minutes hearing them last night. I liked what I heard! They're a hell of a lot fuller sounding than the stock tubes. Can't wait to spend more time with them.

zingo

Glad to hear the seller is helping you out, and for reference, the local pair of those amps is going for $900. You got a good price if it's a simple fix, or if the seller will front the repair bill.

audiocr381ve

So I meet the seller at the repair shop today, and both amps checked out FINE. The repair shop owner both amps to the back and tested them on his machines. Said they were fine but refused to actually hook them up to speakers. I take the amps home, apologize to the seller, only to have the problem happen AGAIN.

This time I figured out what it was. It is the RCA connections on both amplifiers. Wiggle them the wrong way and kiss your speakers goodbye. It is just crazy how both amps have the same issue. Should I check what's under the hood and see if I can get to the RCA connections to inspect? Or is this an even more simple job? Would love some direction at this point and thanks in advanced.

Glen B

If the original RCA jacks are attached directly to a PC board, they could have developed a bad connection. In either case, for peace of mind I would replace the existing ones with new, better quality chassis-mount connectors. If the originals are PC-board mounted, the replacements can be jumpered to the board. I've done many such replacements, and its not difficult to do. My favorite chassis-mount RCA jacks are Furutech FP-901 at $92.99/pair, if you want the very best, or Dayton RCAs, part #091-1120 at $6.89/pair from Parts Express, a good quality for the price.

http://www.vhaudio.com/connectors-rcaxlr.html#FURUTECHRCAfemale

http://www.parts-express.com/pe/showdetl.cfm?partnumber=091-1120

Here original short nickel plated RCAs have been replaced with the Dayton gold plated RCAs for a more secure connection:

Systems

You can also solder some short wire from the board to normal solder type rca inputs, and eliminate any vibration problems than can occur from inputs soldered directly to the board.
I know the normal solder types are easier to find, and there is a bigger selection as opposed to pcb board type inputs.
I would consider using some good ones, because it is a nice upgrade from basic rca inputs, and does add some benefits IMHO.

Being some older amps, I have my doubts the inputs are soldered directly to the board, but I have a history of being wrong, so YMMV with my advice.:cheesygrin:

Mine is an older B&K, and it had wire soldered directly to the rca inputs, to a Molex connector, and the female Molex was soldered to the pcb.

I eliminated the Molex all together, and reaped some detail in my amp using some decent wire straight from input to board, and eliminated the stock silver plated copper wire in the process (which I dislike).

John can take care of ya, and I think you will love the mono's (ALOT better than the Ref 200.2 you bought from me)!
The mono's are actually some of my dream amps, that I have always wanted and never bought.
The upgraded rca inputs will just be icing on the cake!

Systems

I also wanted to mention while you are under the hood, you might want to consider a good visual inspection of all electrolytic caps.
Cheap insurance, and free to boot.:cheesygrin:

Polkie2009

+1 on Brock's advice with using a variac to bring old pieces of gear up to power that have been sitting dorment for years and years. I've been lucky over the years just plugging in some old equipment and hoping nothing blows, but yea, I've seen the magic smoke a couple of times,lol. I was a bit surprised the repair shop tech didn't check the rca connections just by giving them a wiggle and actually putting a load (spekers) on the amp. Good luck with these amps,it sounds like you got a good deal on them still. I once thought about using one of these amps to do center channel duty.

Systems

+1 on Brock's advice with using a variac

+2!
I use a dim bulb tester that I made (ALOT cheaper than Variac), not as versatile, but alot more portable for those Craigslist finds!
I also like the visual indication it offers, and the worst case scenario you loose a .40 cent light bulb if it is a major short.

Attachment not found.
Attachment not found.

Polkie2009

Ok, I've got to get one of those dim bulb testers pepster!

Systems

Polkie2009 wrote: »

Ok, I've got to get one of those dim bulb testers pepster!

If you want to make one yourself dirt cheap, pm me.:cheesygrin:

I just use an old computer pc with mine.
The IEC input and toggle switch makes it alittle more difficult to make, but its still not hard to build, especially if you have a continuity tester on hand.

VERY handy thing to have when you don't want to drag all the test peripherals around with you when testing amps ect. (speakers, source, linestage, wires, ect.).

If it tests good with the DBT, chances are it works, without hooking it up to all the other peripherals.

You are basically testing the trannys, and any filter caps.
If there is a major short anywhere else also, it will tell you without feeding said short.
It takes all of 2 seconds to show ya if there is a problem.:cheesygrin:

Systems

If you want to make one yourself dirt cheap, pm me.

I should mention, anyone wanting to build one of these, it is wired different than a normal receptacle.
In "series" (tabs removed) as opposed to "parallel" for a normal receptacle.

I am not going to give 120v wiring advice to anyone, but can provide links to other sights that do so.:cheesygrin:

audiocr381ve

Mine aren't connected to a PC board. I was going to attempt a repair but John offered to take a look at them which I'm much more comfortable with

Can't wait to get these up and running, very excited to hear them!