Cary CAD-211 AE monoblocks

I own a pair of these amplifiers. For some time I had issues with the amplifier - one of the tubes kept blowing. Eventually my tech diagnose the problem. This is the email I sent to Cary:

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Dear tech support,

I am writing to let you know of a problem with the 845 socket on the CAD-211 Anniversary Edition. I have owned my CAD-211AE's for 5 years, bought new from my distributor in Melbourne.

The problems started when I tried installing another valve in my amplifier. The valve was quite tight and difficult to remove. As you can see from the included picture, the terminal was inadvertently bent upwards when I tried to remove the tube - although I did not know this at the time.

Over the next few months, I suffered a series of expensive tube failures. It was always the same socket that was killing the tube, and it has been returned for repair a number of times. Some of these failures have been spectacular - on one occasion it took out the bias pot and a resistor. On a couple of occasions, the fuse literally exploded with fragments of glass in the fuse socket!

What really threw me was the intermittent nature of these failures - the tubes would fail with no rhyme nor reason, even when I didn't touch the amp. At first I thought I had bought faulty tubes, but after the 3rd tube died I started to smell a rat.

I have included a picture of the suspected problem. The terminal comes very close to touching the metal sleeve of the 845 (arrowed). I have also drawn a diagram to illustrate the problem.

My technician suggested changing the sockets on the amp, which I did. He showed me the design of the new socket - the area at risk of touching the tube has a rebate on it that reduces the risk of a short.

I am providing this information FYI only to help you improve your product. I otherwise remain a satisfied customer and am very happy with all my Cary products.

Kind regards,

Keith

... and the reply from Cary:

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Hello Keith.

This is incredible. We've never seen anything like this but would like
to know more about this socket your tech installed. Could you let me
know what this socket is?

Is it possible on your 845 tube that the metal guide pin broke off and
the tube twisted further then it should? I'm sorry that you've had this
experience and we are always looking for ways to improve our designs and
so if there is a socket that would protect the tubes better we would
love to know.

I'm glad things are working well again. These are wonderful amplifier
and we want you to have many more years of enjoyment from them!

Have a great day!


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My reply:

Hello Dan, unfortunately I do not know any more about the socket beyond what my tech said - "this is another Chinese socket like the one installed, but it is a different make of Chinese socket". I have CC'ed this email to him so he can reply.

Kind regards,

Keith

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Cary again:

Thank you, we will look closer at our sockets.

A friend of mine has a pair of these amps and he too has had problems with the 845 socket.

I suspect I am one of the few guys who can show you an interior shot of this amp So here it is:





Note the quality of the parts used. You can also see the underside of the transformers - these are potted in wax to kill off any vibration. The transformers are massive and extremely heavy. The messy cabling is a little unfortunate, but presented no problem to my tech who was able to trace the circuit and repair the amp. If you look closely at the second picture, you might spot a burnt out resistor. It is at the 9 o'clock position in the bottom 845 socket (the big white socket).

My tech also measured the voltages across all the valves. His conclusion was that the 845's were being driven at a "normal" voltage expected of this valve type, but the 300B's were being driven very gently. His opinion was that it would be possible to substitute the 300B that comes with the amp with a more "fragile" 300B - one of the mesh plates comes to mind. No need to install 300B-XLS tubes in this amp.

This is one of the most powerful triode amps on the market, and probably the only one which sells for realistic money. It sounds like what it is described as - a really powerful triode amp. It is very difficult for me to describe the presentation of sound from this amp - musical notes seem to have a natural sounding timbre and decay, as opposed to my solid state amp which presents notes more in a stark, matter-of-fact manner. Despite the power of this amp, it does not hold a candle to my SS amp when it comes to bass control. The SS amp simply sounds tighter and less woolly. I recognize that some people might like triode bass - it sounds softer and less aggressive - but that's up to you.

Before I bought my CAD-211AE I had a CAD-805AE. I sold the 805 because it did not have enough power. It would consistently clip with my speaker. But the 805 has even more of that lush triode quality and amazing top end than the 211, which is a more neutral amplifier in that regard.

If you have no need for power and think 50W is enough, I suggest the 805AE. It simply sounds more pleasant. The 211AE is more muscular but has less magic.

Cary SET amps sound slow and syrupy to these ears. They also have woolly bass in my experience.

There are better SETs out there at similar costs.

KeithR said:

There are better SETs out there at similar costs.

Click to expand...

Could you name a few?

Tubes aren't going to make an amp sound slow, syrupy, and have woolly bass. You need to point your finger at the amp design if that is what you truly hear.

Hello to everybody,
A friend have the Cary CAD 211 AE monoblocks. He got recently 845 Psvane replacement tube sets. In order to rebias the new 845, asked me why they are so hard pushed to 100 mA as per manual. Does anyone knows the working voltages for the 845 output tubes ???
Thank you in advance
George

Hi George, if I recall correctly they are 900V. I am using 845 Psvanes on my CAD-211AE's and I had no trouble when I rebiased them to 100mA.

Keith_W said:

Hi George, if I recall correctly they are 900V. I am using 845 Psvanes on my CAD-211AE's and I had no trouble when I rebiased them to 100mA.

Click to expand...

Thanks a lot for the answer Keith. If 845 Va=900 Volts then bias them to 100 mA pushes them to 90 watts of dissipation, (90% of 845's ) seems a little hard for me as tube life could be an issue. By the way .... Chris, my friend, have them all replaced with Psvane and he 's very happy with the result.
Regards,
George

Yes George, I remember my tech telling me that the 845's are run pretty hard. OTOH the 300B's are quite gentle at 300V. This opens the door to more "fragile" 300B designs, such as the Emission Labs mesh plate 300B which I am keen to try as soon as funds permit.

BTW I have tried a few 845's in my Cary - the Psvane 845T's are currently mounted, but I also have a set of Shuguang 845B's and KR Audio 845. The best by far are the KR's. Unfortunately, I only have 3 of them. The fourth one blew up.

It's been almost 2 years since i sold my diy 845 PSE ( 2 * 845 parallel SE) monoblocks. I was a lucky bastard to have 4 nos RCA 845.
The schematic i implemented was the famous Ancoru except the input tube. I used the 5842, rc coupled to 300B, IT coupled to 845. All irons including chokes were 2C core and finally the OPT were Bartolucci, enormous irons.
Give me a email to send some photos and meauserents.
Regards,
George

Do you still have the RCA 845's, George? I would love to get my hands on a pair

..Sorry Keith, amp sold complete with tubes. It took me almost a year to collect all parts and six months to finish it. They cost me around 5500 euros and sold it to a friend the same price ....

my 845 PSE

Freq. resp. : 13HZ - 45KHZ, (1khz, -3db) at 72 Watts
Va 845 : 1110 Volts, Ia = 75 - 78 mA
THD : 0.5% --> 25 Watts
0.8% --> 40 Watts
2.5% --> 50 Watts
3.7% --> 64 Watts
5.8% --> 72 Watts

Keith_W said:

Could you name a few?

Click to expand...

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