Cary Audio CAD-805 Amplifier

Details: Written by: Grzegorz Makarewicz; Published: 04 July 2025; Hits: 26

Prepared by Grzegorz "gsmok" Makarewicz, This email address is being protected from spambots. You need JavaScript enabled to view it.
(updated 12/10/2017)

Interesting tube monoblocks combining a rational approach from the technical side with audiophile "gadgets". They were manufactured by the American company Cary Audio Design. The set that fell into my hands probably comes from the early stage of production. I do not know when the first copies appeared - probably around 1994, because then the Stereophile magazine (01/1994) published a detailed review and measurement results.

The monoblocks whose photographs I would like to show are audio amplifiers with a rich history behind them. They changed owners, were repaired (including repairs of a "serious" nature). This affected their external and internal appearance. They are similar to a long-standing car of a good brand, which the owners took care of, but did not protect from minor scratches or even collisions. But to the point. Before I go into details, I would like to show what a single monoblock looks like in all its glory - here it is:

It's beautiful - of course in my subjective opinion. What I like, apart from the electron tubes used, are the transformer boxes rounded at the edges. I know it's a small thing, but it really "turns me on" and makes my head spin (and there's nothing I can do about it).

The amplifier that I had the opportunity to see in real conditions differs from those presented in various tests in one strange feature. So it's time for a riddle. Here is a photo of a typical copy (slightly different because it has two tubes in the voltage stage, but I don't have an exact photo of the single-tube version):

Here is an analogous photo of the monoblock described later:

And the question for ten points. What is missing in the presented copy? The question is difficult and the answer unexpected. Here it is:

A beautiful switch (I've marked it with an orange rectangle) that has no wires running to it. And there should be, if only because the switch shaft has a wonderful audiophile knob mounted on it and its functions are described on the front panel.

At first I thought it was a defect of one monoblock, but it turned out that these dummies are installed in both. So what do we have inside? The diagram of the power amplifier and power supply explains it.

According to the power amplifier schematic from the original user manual, the feedback loop switch is indeed unused. So why is it not just a dummy in the "factory" photos?

The amplifier that I had the opportunity to see underwent typical modifications that did not contribute anything from a technical point of view. What does such a modification mean? Of course, capacitors were replaced wherever possible. It is good when good capacitors (and such are installed in high-end amplifiers) are replaced with better ones. It is worse when the same or worse ones are installed. Unfortunately, replacement means interference in the design of the device and it is not always done with due care. I show a few examples below. Here are photos of the original design. Please note the capacitors connected in parallel to the large electrolytic capacitors in the power supply.

And now a set of photographs documenting, quite simply, audiophile customer deception:

The installed polyester capacitors are certainly remembered with nostalgia by older radio enthusiasts. But in the end, a capacitor is a capacitor. However, there is still the question of the style in which the factory capacitors were removed and the "audiophile" ones were installed. Here is a detailed photo, which is better than the commentary:

As you can see, the old capacitors were cut off or removed together with the soldering tips, and the new ones were attached to the "adapted" soldering eyes. A beautiful sight, isn't it? Oh, and I almost forgot one more interesting fact. Capacitors - this is a very important matter for every audiophile - in particular, the coupling capacitors were attached with straps by Mariusz Pudzianowski himself (a Polish MMA fighter). Thanks to this, the attachment straps caused their visible geometrical distortions - they simply "cut" into the bodies of these delicate elements. See for yourself:

Now it's time for a sad, even very sad, part of the description. As I mentioned, the presented amplifier is a device with a history. It came to me because, among other things, it had problems with setting the quiescent current of the 300B tube in one of the channels. Supposedly (I'm deliberately using the assumption mode, because I didn't witness these problems, but they seem highly probable due to the "fault" found) the 300B tube burned out in one of the channels and along with it the speaker transformer burned out, which had to be replaced with a new one (made by a well-known transformer manufacturer in the community).

After the repair, there was still a problem with setting the current of the 300B tube, which even ended up damaging the valuable tube. After looking at the monoblocks, the first characteristic feature I noticed were incorrect fuses, including one "repaired" with a piece of wire. It's true that the fuses are not typical (they are not 5x20 but 6x30), but they can still be purchased and installed according to the amplifier manufacturer's recommendations. Further observation revealed a combined transformer and quiescent current regulation problem. Please see the diagram below.

Due to too high current flowing through the 300B electron tube and probably the fuse not firing, a section of the wire connecting the R12/13 resistors with the large Jack socket intended for connecting a milliammeter to measure the quiescent current burned out. This is symbolically shown by a red cross. So there was no connection between the 300B tube cathode and ground. Do you know how the "repair" was done? Someone simply connected the common point of R12/13 directly to the amplifier ground, which can be seen in the photo below - this is the green-yellow wire.

If anyone couldn't believe it, I'm showing a detailed photo:

This "repair" caused the quiescent current regulation system to continue to work, but the milliammeter connected to the measuring socket always indicated 0mA. The user of the amplifier, following the instructions for setting the 300B tube current, turned the potentiometer trying to obtain the recommended value of 60mA and exceeded the permissible value of the 300B tube current, burning it and seeing 0mA on the milliammeter constantly and invariably. Good for you, isn't it?

And one more interesting fact. This burnt part of the connection marked with a red cross in the diagram physically consists of a wire connected from resistors R12/13 to the loudspeaker transformer and a second wire coming out of this transformer connected to a test socket for measuring the quiescent current of the 300B electron tube. I don't know why it was done this way. Perhaps in the flooded transformer box (housing) these are the leads of some kind of screen. If anyone knows the details, please contact me. Either way, this burnt wire has no effect on the transformer's operation and there was no need to replace it. Whether it was really replaced is another matter. In my opinion, probably not. The only interference is traces of poking around in the filling material at the transformer leads, which is shown in the photo below. But maybe I'm too inquisitive ;-).

Since you, dear Reader, have made it this far, I invite you to take a look at the detailed photos of the exterior and interior. The amplifier is still in my hands. I will try to add additional information. Enjoy watching.

The amplifier, after some "repair", was deprived of some of the screws that fastened the bottom panel to the chassis. The repairman probably thought that it wouldn't be visible anyway. It's true that monoblocks are heavy, but you never know who and when will turn them over and, what's worse, take photos. I don't know if the visible deficiencies are related to the repairs performed - just in case, I removed the stickers with the service technician's data from the photos (these are the white areas on some photos). If this is true, however, instead of warranty seals, it would have been better to screw both monoblocks together properly.