Synthesis Amplifiers: One of High End's Best Kept Secrets?

I get it for sure, Bill. This "quirky" design flaw could well be a non-starter for many, and I certainly wish they'd make exactly the adjustment to their amps you have suggested.

I will send this advice along directly to Synthesis, for whatever good that might do. All I can say to anyone out there is don't audition it unless you're willing to live with it :)

Agreed.  I would also own the same amp. No issue for me. I am sharing something folks living around the fruited plan should think about.  Also hoping the company or dealers read this so future product has probe locations on top of the amp. 

It is highly unlikely I will do this myself. Then again, the tech for Deja Vu told me that the KT66 tubes in the Synthesis last an average of six years. I'm not exactly fretting over it. I have a tech twenty minutes up the road who could do it, or I might send it to Virginia to have them do it when the time comes for tube replacement.

For context, I just sold an amp that retails for more than twice as much as the A100. If I also end up selling the DAC, interconnects, and digital cable as seems very likely given the quality of the onboard DAC in the unit, I will be pulling about $10K out of the system and still have sound I much (much!) prefer. For me at least, that's worth the nuisance of having someone else setting the bias on the output tubes when the time comes for that. Your mileage, as they say, may vary.

Yes, the Synthesis rep mentioned in his email the need to be careful about the voltage exposure.

Yes, the problem is under that bottom cover you have some 400-500vdc at your fingertips and one better know what the heck they are doing. A wrong move and serious injury or death is possible. So this amp is really not bias capable by most folks.

If the internal bias points are well away from high voltage and “safe” then ignore my comments. Not sure this is the case however.

l strongly suggest the amp maker simply provide bias slots on top of the chassis where one can plug in their multimeter. This is simple to do, not costly, and so needed.

Wonderful amp for sure, but this bias issue is a real one. Not my intent to be negative or hyperbolic here, but simply sharing the realities. Hard to find techs in most places nowadays making it a hassle to bias when needed. I have to think this could be addressed and rather easily.  

Given clear instructions, I don't think it is hard for anyone to bias their amp themselves.  But, the problem is that it is hard to gage how experienced is the person attempting this, how much experience they have with a multimeter, and there is always a concern that someone might poke a probe where it should not go.  I can understand the reluctance to encouraging people to do this on their own.

I was at a pet store once where the owner got a call from a customer who just bought an air pump and could not get it to work.  The customer lived nearby and brought it back to the store a few minutes later.  When she took it out of the plastic bag, water was leaking from the pump.  The dealer asked about how she used it.  She said she plugged it in and just threw it into the tank.  I bet that was not anticipated.

Per my email correspondence with Synthesis :

-  "amps are manual bias except the ROMA96DC and ROMA96DC+ that have autobias"

- T"he biasing procedure is internal and need to open the amp for setting"

- "The bias setting needs to be done when the tubes are spent, or when put the     new. ... need a multi meter for to read the bias value (current) and a little knowledge of electronics."

  - "if you need a bias setting manual, I’ll send you"

I've emailed Synthesis directly about the biasing to see if I can get specifics on the process; will post back when I get a response.

Not yet, but I am sure they will. The tech told me that he actually made a video of the process for one owner, but when he watched it, he decided to bring the amp into the shop after all. Nope, not ideal, but I won't be selling mine, that's for sure.

Thanks for the update. Not ideal. Did the dealer tech provide you with the schematics/process outline for when the time comes to taking it to a local tech?

It turns out that the biasing situation with the A100 is a bit "mysterious" and complicated.

In the specs on the website, it says the amp is "manual" bias for the power tubes, but there is no information otherwise on how or where to adjust the bias. My dealer thought the amp was an autobias design, but that turned out to be incorrect.

The tech at Deja Vu Audio--the distributor for Synthesis in the US--told me that the output tubes would need to be biased manually when I change them. He said that most often, the KT66 tubes last about six years.

Unfortunately, the Synthesis designer did not make it easy to adjust the bias, so the tech recommended taking the amp to a local repair shop when the KT66 tubes have to be replaced. Not convenient and certainly not ideal, but for me at least, well worth it to own this extraordinary amplifier.

If you are especially proficient and knowledgeable, you could probably manage to do this on your own. I'll probably just have my local tech do it when the time comes.

@waltersalas - Can you explain what is involved with biasing the tubes; I see that it is manual biasing? . Also, who is your dealer?

Thank you

Thanks for the recommendation. I will look into the BMC cable. I feel like finding the right USB cable may be the last piece of the puzzle at this point.

Hey if you're trying usb cables. Look into the BMC usb1 (active) cable. 

@waltersalas 

That's a good point and one of the reasons why I'm shopping for a high watt/current amp to try on the speakers I have now before deciding on switching them out.

This kind of demonstration makes you wonder how many audiophiles have given up on speakers without ever hearing their real potential due to an inferior or mismatched amplifier.  While a great amp might make a modest speaker sound amazing, it doesn't really work as well the other way around.

I had a very interesting afternoon at the Synthesis dealer in my area.  He is someone who believes that amps make a huge difference such that systems with “modest” speakers can sound spectacular with the right amplifier.  To prove his point, he had tiny ProAc Tablettes being powered by a Synthesis NYC (part of the Metropolitan series; 4 KT 120’s per channel).  It was quite shocking how good was the sound coming from these tiny speakers—rich, powerful, room filling, and punchy.  While no one would actually go with such a match, it certainly proved that most speakers will deliver far more than one can imagine when given the chance.

@larryi 

The F1-12s are on my radar. A very good deal on a used pair tempted me a few months back, but the timing wasn't good. My wife isn't crazy about their looks either, so there is that to overcome since the system is in our primary living area.

At some point down the line, I might consider Synthesis separates, but I expect I'll be enamored with the A100 for quite some time, and I love the simplicity of it. I may take the proceeds from selling my DAC and cables and have some fun exploring some different cartridges. It really never ends.

It is great to hear about someone satisfied by a purchase, particularly one that I personally like as well.  I know someone who traded in some quite new $70k+ electronics for the new Synthesis separate power amp and linestage which are a step up from the A100, but, not that big a step up.  This gear is that good.  

Of course it doesn't end here.  There is always the Fyne F1 series of speakers.  I quite like the F1-12S that I heard.  It has the kind of lively sound that I look for with less of the sibilant peak in the upper midrange that I hear with their closest competitor (Tannoy).  

The Muon USB cable will be very good. Looking forward to hearing which one you keep. I own the Network Acoustics Muon Pro streaming cables and streaming filter.They are outstanding. I have also owned their USB cable.

Don’t forget to try an SR Purple fuse in your amplifier. The uptick in sound quality will please you Chris.

Thanks very much, Bill. It really has been somewhat of an odyssey, but I had some fun along the way and got to sample a wide swath of great-sounding amps, while at the same time coming to terms with exactly the kind of sound I was looking for. I forgot to mention a dalliance with the Linear Tube Audio Ultralinear+, another very fine amp indeed but, once again, not exactly right for me.

I would love to get together sometime and hear the Synthesis and Circle Labs in the same system. That would be great fun I'm sure.

I have an audition this weekend of an Infigo USB cable and also have a Network Acoustics Muon USB cable on the way to compare. If that goes as well as I hope it will and think it may, my DAC will soon be for sale.

The Synthesis has changed my paradigm on how good an onboard DAC can be. It has been quite a ride rebuilding my system around the Fynes, but I think at last I am almost there.

Chris, you have found a wonderful match to your Fyne 704 speakers and that is everything! The transformers in your amp are a big reason why it sounds so good. They are very special. I admire your dedication to finding the perfect amp for your system and tastes. It often takes effort and you gave it your all!

Very happy for you. I am sure you will enjoy this amp for a good long time. Please bring it by so we can listen on my 704’s and compare to my Circle Labs A200 🙂.

@waltersalas I often find myself impressed by great solid state and class D amps, but invariably I migrate back to tubes.

I just believe that at the end of day if executed properly, tube amplification and circuits are more natural sounding and thus more engaging and realistic. Not every tube product successfully pulls this off.

Charles

Thanks for all who have chimed in, those who have also had thrilling experiences with the Synthesis gear and those with very kind and supportive comments. I have always appreciated this about our community, our shared enthusiasm for good sound and fun discoveries.

I forgot to mention that the stock TAD KT66 tubes are sounding just terrific to me, though I did swap out the smaller Electro Harmonix tubes and for some NOS tubes I had lying around and experienced a nice litte jump in performance.

I often find myself impressed by great solid state and class D amps, but invariably I migrate back to tubes. I guess they must be worth the trouble, for me at least. And, yes, I sure do like looking at them, especially at night in the dark, when my system becomes a little cathedral of sound and beauty.

You all sound like happy customers. They must be pretty great amos to impress your experienced ears so much. Congrats! They're nice to look at too.

Very cool Chris. You have a terrific set of ears and I for appreciate your candor and well written thoughts. Enjoy!

The new amp and linestage are terrific sounding components.  Like the A100s, a local dealer has had quite a few "shocking" trade-ins of very expensive gear for these items based on the sound.  Off hand, I cannot think of commercial, non-custom made amps that I prefer over the separates or the A100.  Synthesis has some very upscale, extremely large amps in the "Metropolis" line that I've heard which are very good amps.  Yes, these are even better, particularly if one needs a lot of power, but, I like the more compact form of the new separates, the A100 and the A40.  They have a cheaper integrated with built in DAC and phono stage that is no slouch too, but, I like the above-mentioned gear because they are built into large enough chassis that make long-term damage from heat less of an issue.

I had the A40 in my system for a long time and absolutely loved it, the A100 was out of my price range at the time. The DAC model is the same in both and is amazing. I just upgraded to  Synthesis Roma 98 DC mono blocks and the Roma 117DC pre-amp and my system has gone to another level. Luigi builds some fantastic equipment. 

@waltersalas 

You have owned some highly regarded non tubed amplifiers, Vitus/Boulder/Lyngdorf.  Yet in a sense I'm not surprised by your return to a tube amplifier.  It's quite apparent that you are very pleased with the Synthesis -Fyne pairing.  I am happy for you. Congratulations!!!

Charles

Agreed I've also heard this amp a number of times and the A40 as well really great sounding amps and under the radar. As I type this I'm listening to an older Synthesis Encore amp a little stereo 25 watter using 4 5881 tubes. It's on loan from my dealer and sounds lovely. Congratulations Walter!

I am sure I would have been fine with the A40, as the Fynes are quiet efficient, but it is great to have the power to spare. The amp is not necessarily inexpensive, but let's just say I was able to pull thousands of dollars out of my system by selling my last amp and buying the Titan. I'll recoup thousands more if I decide to sell my DAC and interconnects. That makes the Synthesis an unbelievable bargain in my book.

I like that integrated amp a lot.  It has enough power for just about any application.  It sounds full, authoritative, dynamic, and warm, without sounding murky.  As you noted, the built in DAC is not just something thrown in to sweeten the pot; it is worthy of this great amp.  If one has efficient speakers, the A40 might be powerful enough, but having the A100 means freedom to get any speaker on the market.