Inside and Out: Audionics of Oregon CC-2

[M Jarve]

It's been years since I've done one of my classic Inside and Out pictorial/commentaries. A quick search shows the last one was all the way back in 2011. So, I suppose it's about time for one, since I have a unit I think is interesting to share.

The unlikely and (perhaps) controversial history of the CC-2 by Audionics of Oregon (or Audionics, or Audio of Oregon) is recounted elsewhere on the internet, so I will not do so here. But I will mention that it was one of the first US made power amplifiers designed using the precepts of Dr. Matti Otala. In the 1970's, Dr. Otala had proposed that high that a "new" form of distortion, transient inter-modulation distortion (TIM) was more harmful to a musical signal than the much more well known total harmonic distortion (THD). At the time, one of the main methods of reducing THD was incompatible with reducing TIM; he seemed to suggest that sacrificing by accepting a bit lower THD rating, an amp designer could reduce IMD, and the amp would output a signal more faithful to the musical signal, and the amplifier would be more stable over all. Manufacturers in Europe and Japan (notably Electrocompaniet in Norway and harman/kardon (under the ownership of Shirasuna) in Japan) already released amps/receivers, etc using Dr. Otala's philosophy.

The CC-2 is a medium power amp, capable of 70-watts per channel into 8-ohms. The amp can nearly "double-down" outputting 120WPC @ 4-ohms and 170WPC @2-ohms. Bridged to mono, it can output >200-watts @ 8-ohms. It is a very dynamic amplifier that provides a sense of immediacy that few others can. Although not a DC design (there is an input coupling cap), it suffers no restriction of the low-end, nor is there any softness to the high-end.

Physically, the amp is quite compact. While maintaining a pro-standard 19-inch width (complete with rack-mount holes and handles), it's only 2-rack units tall, and less than 8-inches deep. It's dimensions belie its mass, though, as a good amount of the internal volume is taken up by a very large split-core power transformer (~600-650VA by quick calculation). Power is rectified by a large, quasi-heat sinked full-wave bridge rectifier, and smoothed by a pair of 15,000uFd caps. There are no large heat sinks, as the whole chassis and covers act as the heat sink; being moderately powered, and not biased highly into class A, it doesn't need large heat sinks.

To either side of the power supply are the amplifier boards themselves. Output devices are (now) unobtainable Motorola 2N5630 and 2N6030 (one pair each per channel). Bias test points, as well as bias and DC offset adjustments are conveniently located near the output transistors.

One nod to the audiophile community of the time is the then uncommon gold-plated input jacks. And like many many purest amps, there is no turn-on delay or output relay; protection is provided by a 3-amp fuse and nothing else.

 

[rickl]

I have the BT-2 pre. I don't know the drama surrounding the company but the pre is very nice.

 

[EvanF]

I have the BT-2 pre. I don't know the drama surrounding the company but the pre is very nice.

There is a bit of drama on the preamp alone. Apparently Audionics thought it was best for the customer to have the unobtanium boards half submerged in black epoxy. I did a full recap on the unit and they used (good testing) Elna caps for the DC ripple filter, but really old looking caps waxy caps on the phono preamp board. One transistor was bent so its metal tab wouldn't hit the metal shielding of that board, with very little clearance. The power cable needed to be replaced as well and the balance control wasn't detented, so I marked the halfway point with a pencil as a courtesy to the customer. Everything else was well put together. Oh yeah, no tone controls or headphone output. It's an audiophile preamp.

 

[Bob]

the CC2 was unusual in that the case was used as a heatsink for the output transistors. the inside of the
top cover was properly silicone greased.

 

[bimasta]

Great write-up, M Jarve. I have four CC-2s. I love 'em. But I don't use them because they all need recapping now, which may not be easy; the main PS caps are a very odd shape; new ones may have to be mounted externally, not a good thing.

Run as normal stereo amps, I found them average. But magic happens when you bridge them. It's not just the extra 225 Watts — there's more vitality, more radiance. Sheer joy. They run really hot, biased very high into Class A, and that Class A warmth and smoothness is very evident in the midrange and crystalline highs. With the entire chassis as heat-sink they can handle the heat, without adding huge heatsinks. All in all, a very elegant design.

Bridged, they were the best amps I ever found to drive my Quad 63 'statics — and I was comparing them to bigger and far more costly Krell, Audio Research, VAC, and the dedicated but lame Quad 405. They astonished me — and they fit beautifully under the Quad's stands, like they were designed for it.

The modular design is really useful. I bought 4 "parts-only" units because all had one dead channel (so very cheap). But it only took 30 minutes to combine 2 good channels in one chassis, so I ended up with 2 beautiful 225W monoblocks. And the compact size can be even more compact. The body is only about 15" wide, but the rack-able faceplate makes it 19". If you don't need to rack-mount them, you can cut them down — I'll replace my faceplates with some really nice wood, like a rosewood, once the recap is done. I know, wood is a matter of taste, but I like it.

Never heard the matching preamp. But I was driving my CC2's with tube preamps and it was bliss.

Thanks OP for reminding me. They've been in the closet 5 years, and out-of-sight is out-of-mind. Thanks to you, that recap is now on a front burner.

 

[michigannick]

thank you guys for all the information its been a great help i have a pair of these that needed a little love. The caps in them are not very good ones, they do not age well but the design of the amp is quite simple to take apart and recap. the only adjustment made was to switch the 4uf axials for radials mostly cause of price on the axials. My filter caps tested better than spec so i left them in I will deal with them another day

As fror the main filter caps there are several options on how to replace them there are some avaiable that will fit right in, or you can do like is being done on the Phase Lineary 400s that is make a small bridge between smaller caps and stack them up.

 

[Retsel]

I had an Audionics CC2 and purchased a second to bridge them, although I have not yet done that. I replaced the power supply capacitors in them with DNM 4 pole capacitors and that really makes a difference. I also changed out the tantalum input capacitors, but since I was only using these amps from 50 to 500 hz, I was able to use much higher quality film capacitors instead. They are now sitting around because I need to replace the other electrolytic capacitors after one of the amps blew and took out a woofer.

Retsel