JJT Posted March 17, 2003 Share Posted March 17, 2003 I'm getting ready to swap out the coupling caps on my EICO HF-81. I picked up some Auricaps and Hovland Musicaps and noticed the leads are color coded: black-red (Auricap) and green-red (Hovland Musicap). From what I understand the black lead is the "in" and the red lead is the "out". To give an example the driver stage is coupled to the output stage, so the red lead is connected to the driver stage "out" and the black lead would be connected to the output stage "in" is this correct? Does it really matter? If it does matter, I would really be interested in knowing why. Thanks in advance. Joe T Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted March 17, 2003 Share Posted March 17, 2003 AFAIK, the Auricaps are actually not polarized and it doesn't matter. But, I set mine up just like you mentioned. don't have info on the Hovlands, but Al Klappenberger here on the forum probably does. Look around over in the Updating Older Speakers section, you can find a post and email him from the profile. Tom Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 17, 2003 Share Posted March 17, 2003 The IN means the signal enters the cap the OUT means the signal is leaving the cap. So the caps that hook to the 6BQ5 you would attach the red to the 6BQ5. But like Tom says this is not crucial in a coupling cap but if its a bypass cap the black goes to ground. Be prepared to listen as these caps come to life they really become more and more transparent with use from what I have heard. I believe if you email Chris Robinson he has some photos of the HF-81 I put Auricaps in and you use it as a guide. Enjoy Craig Quote Link to comment Share on other sites More sharing options...
Deang Posted March 18, 2003 Share Posted March 18, 2003 Break-in with the Auricaps is brutal -- took mine almost three weeks. Mine were in the speaker crossovers. Quote Link to comment Share on other sites More sharing options...
JJT Posted March 18, 2003 Author Share Posted March 18, 2003 Thanks for the replies! Tom, did you get around to changing the power transformer on your HF-81? I have a similar problem, the power x'former vibrates, there's some wax residue on the bottom plate and a noticeable hum through speakers. I found the power supply resistor R63 measuring 479 ohms, it should be 360 ohms, plus or minus 10%, hope it solves the problem. I'll probally pick up a x'former from Heyboer Transformers, just to have around. Craig, thanks for the lead on the photos, I actually found them using the forum search function and bookmarked. It was your post: "HF-81 Kiwame resistors and Auricaps". I won't have to bother Chris now. Dean, I've heard about the long break in period. It will be a good test for me to hear if I can tell a difference before and after break in. If I can, maybe down the road, I'll pick up some decent speaker wire. Joe T Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 18, 2003 Share Posted March 18, 2003 My little Eico HF-12 power supply transformers both have vibrations. The vibration has no effect through the speakers, they are quiet. I could fix some of it using rubber washers in certain places, to kill chassis vibrations. They are 40 year old power supply transformers, small, and run hot. And still holdin' out for now.... Quote Link to comment Share on other sites More sharing options...
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