Wow- tough choice as far as I'm concerned. I have used both the Adcom GFA 535 and the B&K ST140 amps to drive a pair of Magnepan SMGa speakers in the late 80's. I liked what both could do with these relatively inefficient speakers in the small room I had them in (12X15X8). I no longer have the Adcom, but I still have the ST140 and use it in my second system. Excellent products for the price. I have not used either one of the preamps, but I liked my amps! Not sure how big your room is but I believe the 1400 and the 545 put out about the same WPC. In my situation, I felt the Adcom was a little warmer sounding where the B&K was more forward in it's presentation with the SMGa's. YMMV....
I too have owned the ST140 as well as the Adcom 535, 545 and 555. Believe it or not, the Adcom GFA-535 is, by a good margin, the best of the lot and puts out quite a bit more power than the rating would suggest. Perhaps it is due to it having seperate frame transformers for each channel as opposed to the single toroidial in the other amps. The B&K and bigger Adcoms just sound glazed and sluggish compared to it.
Funny thing about opinions, everybody has one. I too have owned all the above amps and completely disagree with the previous posts. The adcoms are all highly mediocre sounding amps with flat 2 dimensional presentations and somewhat dry and brittle high ends. They have very good to excellent low end control and power but can sound overdamped on speakers that already have tight bass. The B&K's have a much warmer and full bodied sound with a lot of the palpable presence one gets with tube amps. They may be slightly less detailed than the Adcoms but present a much more musical overall picture. The bottom end on the B&K's is not as tight as the Adcoms and will sound a little plump on some speakers. The bottom line is I still own and enjoy the B&K's and the Adcom's are long gone and not missed even a little.
I have to agree with Infinitebaffle, I still have B&K M-200's with Cardas output posts and Cardas cables, Shunyata P/C's, and they sound fantastic, just my 2 cents.
Infinite brings up a great point. So much of this stuff is system dependent and listener dependent that recommendations must be taken with a grain of salt. My fast and direct is his brittle and two dimensional, his musical and warm is my sluggish and glazed. One experience that I found with all of the inexpensive amps was that a tube preamp could really minimize some of the shortcomings of these budget perfomers.
What is your price range? There are better amps for sale here on Agon. For example, look at the Kinergetics KBA-75 amps for sale. I am also going to sell mine if interested. You can get two of these class A amps for $1200 or one for $600 from Katli Audio. I own the amp and it was equal to the Rowland M-112 and gave up nothing to the Specton Musician II amp. The amp was rated B by Stereophile but adding a better power cord really made the amp sing. It is much more musical and dynamic than the two amps you are considering and can drive anything.
I agree with Infinitebaffle (Great User Name!). Rx8man the B&K M series are a different animal than the B&K ST series. Many people prefer the older 3 digit B&K ST amps over the newer 4 digit B&K ST amps, and the original 70 watt ST-140 in particular. The Adcom's can handle lower impedance loads easier than the B&K ST series. The M series can handle almost anything thrown at them. I suggest you look in the archives on this matter. Amongst the many valued opinions you'll find some good advise from Sean.
Yes I did Unsound, your right about the older series vs. the newer & Sean's opinions, he's knowledgeable.
Thanks to everyone for all the replies - maybe I need to provide more information. I already have the Adcom 535 and the 500mkII preamp/tuner. I recently biwired my Linaeum model 8 speakers - an obscure discontinued US company that made quality ribbon speakers in the mid-90s ($3K) that are smooth with good bottom end - to the two sets of terminals on the 535 and found a big improvement. Thus I began to think of an amp/preamp upgrade with more power and definition to make my speakers and music really sing in our 25x15 living room. The speakers can likely handle a bit of brightness. On a sparse budget I figured I'd move up to more power in a 545 or 555, or go for the similar setup from B&K, which is presently being offered on Audiogon. I have also considered cheap used integrated amps, such as an Acurus DIA 100, Audiolab 8000, Onix 120 - the list keeps growing and I keep coming back to sticking with what I have. The Creek 5350 is too expensive, the 4330 is too underpowered. I also use the tuner in the GTP500, only really need a CD input, can forego a remote and everything other than a volume control, and have kids, pets, and a wood stove. I don't think I want to venture into tubes, but I do think I want to biwire, as it seems to make a difference. My source, cables, and interconnects are mediocre at best (Marantz, Tara, ?) - an audiophile's nightmare perhaps. I am open and curious to all opinions about whether I should move on from my Adcom gear, and what to - perhaps the B&K is only a sideways move. Thanks.
Hi Hapdog,Looking at your system, it reminded me of a very similar set up I had. It consisted of a Marantz CD player,Hafler 945 Pre amp, Adcom 555 Amp, and Apogee Ribbon/cone speakers it was my first serious rig. At the time I had read many rave reviews about the adcom, so I tracked down a used one. When first heard it I was so disappointed I almost gave up this whole hobby thinking it was just hype or some minor difference in gear that was glorified. With the Adcom driving the speakers the sound was cold and lifeless. Part of the broblem was my speakers are a little bright in the treble added to that was the adcom's tizzy treble and hard midrange. Ribbons are very sensitive to brightness. When I upgraded to a krell amp the difference the detail, depth and involvement was dramatic. Escpecially the soundstaging depth the soundstage extended to the rear another 5 feet or so. Also the seperation of instruments. If you could spend a little more I would go with a used Krell ksa 100, they are so much more refined will match well with your ribbons. They are available for about $1200 and worth it in the long run. Later if your budget allows get a used VTL delux preamp ($400) used) and wow you very a very musical system.Looking back I would have saved so much money buying these component in the first place.Good luck
Thanks for the kind words. I know that i come across as an "opinionated bastard" many times ( and i am ), but i'm glad to see that some folks understand that i'm doing what i can to help others. Hopefully, folks will realize that others may have similar or contrasting points of view / experiences and decide for themselves via their own ears and experience as to what will work best for them. Nobody can tell you what you like better than yourself.
Having said that and if it were my system and i was working on a budget, i would probably pick up another Adcom 535 and look for a more suitable preamp. I suggest this approach for several reasons.
First of all, the 535 is probably one of the two best sounding amps that Adcom has ever made. Not only will you get the benefits of bi-wiring, you'll get the benefits of bi-amping. This approach will double your power capacity, open up the top end, increase midrange liquidity and improve bottom end response and it will do all of this while maintaining the tonal qualities of the system that you are already familiar with. The best part about this is that it will do all of this for an investment of well under $200, which is hard to beat. Since you've already got speaker cables that are capable of bi-wiring, all you would need is another set of interconnects to feed to the second amp.
As far as my suggestion to invest the difference in a more suitable preamp, my experience has been that the Adcom Tuner / Pre's are pretty lacking in sonic performance. These were built as more a matter of convenience and marketing than out-right performance. Going to a better preamp would really let you see what a pair of the little 535's could do in terms of finesse and musicality.
As a side note, you could continue to make use of the tuner in the 500 Mk II or sell that and put those funds towards a good yet inexpensive tuner and possibly some improved cabling. Sean
My post was based on my own personal tastes and experience. My ST140 is one of the first few "iron core" transformer amps that put out 70 WPC hence the moniker ST140. Shortly after, B&K went to a toroid and upped the WPC to 105. The original 535 was rated at 60 WPC but well exceeded that rating. The two amps were very similar in output, but each one did some things dfferently. The little 535 was an amazing product in it's finesse. It made my Magnepan SMGa's really bloom in a small room. With a new retail of 395.00 in early 1988 when I bought it, it was a best buy IMO. My only beef with it were the cheesy speaker connectors. The B&K at 495.00 was also a hell of a deal, very well built but a little more forward sounding, for me, as I stated. I still have 2 of them: the original 70 WPC in my son's system, and the later generation 105 WPC in my second system. I wish to hell I had kept BOTH the 535 and those sweet little SMGa's.
I have the original ST-202 and had it modified shortly after buying it.The sound is totally different than the stock version whereas the forward biasing cleared out the grain or glazed sound that I could really live without.
I had listento the Adcom GFA-555's,I believe they were,and the thing that they exceled at was bass impact,but the mids and high's were to dry for my liking.
I also have an AV-2500II that I am using for 3 channels ,but am not as impressed with it's performance.That being said I will also have it modified and might try a vertical amp setup using modified B&K's.
Here is a better way to go, pick up a Classe CA-100 amp for around $650 and Classe CP-35 for $400At about a $1000 this would be more musical than any Adcom or B&K could ever be! and for a few hundred more you could get a Classe CA200! check it outGood Luck
Do not know how it goes against a modified B&K.Adcom I would only buy if I needed a cheap amp for Bass driver's.
Was considering Classe,but I would rather get a Monarchy ClassA amp that is close in performance to Pass Labs amps.
I have Apogee Centaur Major and for many years used them with Adcom GFA-565 monoblock in bi-wire configuration and 565 preamp. These combo worked very well and I was happy. Then I changed amps for Classe DR 10. The sound completely different - warmer bass extanded and sound much loader I had to decrease my volume for at list half of what I used before. I don't have yet good preamp at the moment but think that I will get Classe and it would improve the sound even better.