April 17, 2014 - 08:28 am|
|Hello, I just wanted to send a short note to let you know how much I enjoyed your article about the Eico Cortina 3070. What a thrill of nostalgia! Awwwww.... was my first reaction on seeing the photo. I had an Eico Cortina 3070, a gift from my Dad who was an engineer and built his own Heathkits and always had the latest and best in stereo for himself, from about 1970(?) until 1992, when I sold it to move to France. (I was afraid it wouldn't survive the journey, or the converted electrical current, etc. upon arrival here).|
Nobody ever snubbed my little Eico Cortina; in fact men loved it and treated it with great respect. ("Look, she has an Eico Cortina !"...) (...Women didn't care.) It gave great sound, on four speakers throughout my apartment, from Daniel Barenboim to Ted Nugent, and no trouble ever for all that time.
By the time I had my own apartment here in Paris and bought a "new" stereo system, I made the mistake of buying a used Akai. Boy did I hate that amp. It didn't hold a candle to the little Eico! It finally died, thank goodness, and I'm replacing it, so I've been reading a lot on the web about amps and tuners.
Your article made me realize that it's possible to "love" and to "hate" inanimate objects like hi-fi amplifiers. How I miss my little Eico! Enjoy yours and keep up the blog!
October 02, 2013 - 05:33 pm|
When you replace the output coupling caps, I highly recommend using 4700uF instead of the original 2000uF. See "Low Frequency Stability Problem" above. Good luck with your project!
October 02, 2013 - 04:07 pm|
|i just found one in a dumpster. all 3 fuse caps are missing and upon opening it up i can see why every electrolytic cap is either blown, about to blow, or got so hot the plastic covering has melted!!! they look like those nasty Seimens things i find in old german radios. !! they ALWAYS are ng. i'm first going to re cap it then see if i've got any ng transistors as a result of bad caps!!! AH, but this won't be as much fun as totally re working my Kenwood 1100u!!!!! N1ACK Russ |
April 17, 2013 - 07:55 pm|
|Hi Max, That's a good point about replacing the electrolytics. In my reply, I presumed that he would replace all of them or test all circuits, to assure that they were good. I found that most of the small electrolytics were bad. (Larger ones tend to be more reliable.) You are quite right, that a bad electrolytic could, for example, throw bias off enough to greatly increase distortion. Like you, I enjoy the sound of the 3070. It might not have the power of some big modern amps but hey, like I said above, at low frequencies where you need lots of power, it can kick the ass of any of those EL84 amps you see going for big-bucks on eBay :) |
April 17, 2013 - 06:33 pm|
|Haven't looked here for a while - If Marco B. didn't replace all of the electrolytic capacitors, this would explain why he wasn't happy with the sound, they will all be well past their best before date by now. I've been using my Cortina 3070 more or less daily for the last year now, and still not bored with it in the least. Could use a little more power occasionally, but generally speaking it's more than adequate for whatever I throw at it. |
September 03, 2012 - 07:39 am|
|Hi Marco, Thank you for your kind words. [By the way, I'm the author of this article. Dave edits the "Dave's Lab" section of Tronola.] I understand your wanting to preserve the original amp. It's often hard to decide between preservation and improvement. Sorry that you weren't impressed with the stock sound of the amp. It's a pity that Eico only needed to change a few details, to make it a beauty. |
You already mentioned the line stage noise, which is easily fixed by replacing one transistor per channel. The other possibility that comes to mind, which could audibly degrade the amp, is the tone control issue addressed in the section, "Tweaking the Tone Controls" on page-2. I should also mention that the low frequency peaking, addressed in the section, "Low Frequency Stability Problem" could cause audible problems, depending on conditions. After finishing the work which I did on the amp, I must say that it sounded magnificent. But I totally respect your decision to keep the amp stock. Thank you for your comments.