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jfjacques

New to me Heresy 1 - yellow powder on tweeter?

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Hello - 


I acquired some 1973 Heresy 1 - Walnut Oil with risers and cane grills - cosmetically they are a 9/10. I opened them up and they have type "C" crossovers that appear to have been modified to type "E" with a Bob Crites kit. 

 

They sound amazing - I am getting a vibration or resonance out of one cabinet at high volumes I think it may be the back cover so I'll seal and tighten - but when I opened this one up I noticed some yellow powder substance all over the back of the tweeter - anyone know what this is - the other one does not have this? 

 

Other than the crossover modification - everything seems bone stock. THanks for any tips! 

 

 

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Did the prior owner fancy Donovan?

 

Since that's probably not the explanation, I'm stumped.  Does it look like the tweeter magnet was, at one time, painted yellow?  Could it be adhesive residue or crumbling insulation?  Neither of which explains this.  I'd clean it up and check again later for a recurrence. 

 

Please keep us apprised.

 

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Looks to me like crumbling old foam, but is likely some type of corrosion given it's localized appearance.    I'd remove the tweeter, clean it up and reinstall.  You might want to check the other speaker as well.  Cabinets are very nice.

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thanks for the tips - I'll report back - the cabinets were shockingly good when I saw them I cannot believe they are 44 years old! 

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5 hours ago, jfjacques said:

I opened them up and they have type "C" crossovers that appear to have been modified to type "E" with a Bob Crites kit. 

Just for clarity, the crossover may have been modified with parts from me, but what I see in that picture, is NOT my work.

Bob Crites

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On the yellow powder subject, I see that on most of the K-77s that age or older.  I guess it is some sort of oxidation of whatever coating is on the tweeter.

Bob Crites

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Looks like Zinc Chromate?

 

Common on EV magnet structures (woofers too).

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5 minutes ago, djk said:

Looks like Zinc Chromate?

 

Common on EV magnet structures (woofers too).

According to report from a customer of mine it is quite irritating to the eyes.  He opened up the back of his old Heresy, saw the yellow powder, took a deep breath, got as close as he could to the back of the tweeter then blew as hard as he could.  Said he got a pretty even coating of the yellow powder on his face including the eyes.  Spent quite awhile with eyes under a faucet trying to wash that out.

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I can confirm that both tweeters had that coating I was able to carefully brush off most - I would also agree with Mr Crites that is NOT an example of his shop's work having purchased their services before. 

 

I did discover that whoever did the xovers not only had poor soldering skills, but the woofers were hooked up out of phase - that has been corrected! 

 

Thanks again to everyone for the great advice. James 

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Your H700s should NOT have Type E crossovers.  I urge you to restore them to the original Type C configuration, using modern capacitors.  If you wish, you could try reversing thee squawker phase, like Klipsch did in the Type E, but I would not do it initially. 

 

I have one lonely H700, from 1967, needing a mate, or a new home.  It is as pretty as yours.  I prefer a mate, but I can be had.  It has a more balanced sound compared to my other 3 Type E Heresies, from 1979. 

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I am hoping for some help with the crossover on these they are clearly marked TYPE C and the prior owner had done a cap upgrade with a kit from Crites but did a lousy job with the wiring. Something just doesn’t sound right at louder volumes bass gets muddy and almost muffled. Both speakers. I am wondering if they did not wire the new caps in correctly? While I have redone a set of type E in the past I am far from an electrical engineer! Here is a pic of the mess thinking I should just snip snip and start with fresh solder and clean wire routing hoping for a picture of a redone type C I can copy?

 

thanks JAMES 

 

 

 

 

 

 

 

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On ‎8‎/‎26‎/‎2017 at 11:22 AM, jfjacques said:

but when I opened this one up I noticed some yellow powder substance all over the back of the tweeter

 

Uranium.

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The Russians put it there. Definitely.

Sent from my SM-G920R4 using Tapatalk

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I had this powder on my '74 Heresy tweeters as well. I didn't clean it at the time. I used the speakers for about a year and then open them up to clean the tweeters and 'lo, they were clean. The speakers were previously stored in a hit bonus room in TN for about 26 years.

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I use brasso on the back to clean. I use that and an old toothbrush.

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On 8/26/2017 at 8:22 AM, jfjacques said:

I noticed some yellow powder substance all over the back of the tweeter - anyone know what this is 

It's the cadmium plating reacting with the elements, aka, oxidizing

 

On a steel chassis it will commonly show as silver or grey, but yellow is common too - all depends on the base metal that was plated with it

 

I think the proximity of large magnets can give you the "cadmium yellow" effect as well 

 

The dust/powder is extremely toxic and you should avoid handling it and if and when you do wash your hands well afterwards

 

DEFINITELY AVOID BREATHING THE STUFF

 

Shows up on a lot of vintage electronics' chassis as well

 

I wear rubber gloves (now), soak a 99 cent store micro fiber cloth with WD-40 and clean it up as such, wash it with one and wipe down with another

 

I hate using them, but rubber gloves are a very smart move when cleaning any vintage electronics - and I used to avoid rubber gloves for working like the the plague

 

Rubber glove hate?  When I started working as a mechanic it was bare handed and not just me (EVERYTHING, brakes, the parts washer, solvents, B-12, gasoline for hand cleaner, the whole schmear "old school") and when they came into use in the trade in a major way during the '80s I scoffed at them - been too many years and wasn't going to change - plus I couldn't "feel" my work and didn't won't to make the effort to make the transition (the acclimation)

 

Got my first cancer diagnosis in 2011 

 

Whenever you see cadmium dust take every precaution to take care of yourself and avoid that shit - smart to wear a disposable particle mask as well when opening up ANY pair of old speakers or if you use compressed air to blow out old electronics

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