Welcome! Need support, you got it. Or share your ideas and experiences.
Return to Planar Speaker Asylum
50.46.197.214
In Reply to: RE: A warning from Magnepan posted by josh358 on April 15, 2017 at 08:06:07
I did not mention overheating and I did mention that the volume was not high. I saw a blue flash. There was a hole in the Mylar. There was no melted aluminum. The fuse was intact.
On a 1.7 the tweeter can have a break so narrow it takes a magnifying glass to see. It can then arc over the break.
There are various repairs for these breaks reported on forums which are less irritating than shipping to MN for repair and I had one last for 3 years.
Given more amp power (but not more volume) the soprano can now pierce ear drums over and over and the tweeter is unaffected.
In the humor department...back in the 80's when I bought my Apogees I took one of these offending soprano CDs in for a demo. The dealer had them hooked up to some Tandberg amp. When the soprano hit a high note blue flames danced over the aluminum without doing any damage...at least at that moment. The salesman was certain it was the CD. So I drove to the only other Apogee dealer this side of the Cascades and played the same CD on the same model speakers with a PS Audio 200c...no problems with that amp for 30 years. That dealer also had a pair of I recall Krells which he demoed at cilia destroying levels with no ill affects on the Apogees....at least at that moment.
Follow Ups:
I happen to have a PS Audio 200C. I'll be trying it with the M/T panels of the T-IV's in the near future, with another oldie---the Electron Kinetics Eagle 2b, on the bass panels, bi-amped.
Blue flames? That's truly bizarre!
I always try to point out that bypassing the fuses requires that you can trust your amp not to clip at the levels you play. Biamping does this well, reducing the chances that you get high current demand from the bass playback that brings the amp to clipping.
my mid/treble tube amp simply can't put out enough power to kill the tweeters when it is clipping..Particularly as they are crossed over so high into the top octave. So I trust it. The DR-9 that did tweeter duties before is a high current design and is rated to 2 ohms even when bridged. So I trusted that amp. The little Nuforce switching amps ran hot on the mids and on the tweeters but I trusted them not to make any clipping noise in my use. The Bryston 4B NRB ran hot on the tweeter, and sometimes had the leds glow orange in warning. Didn't trust it. It was sold off quickly. The Fosgate amps in SE mode did fine but ran hot. They were supposed to get cooling fans for a 2 ohm load. In differential mode they simply went into overheating and blew their transistors. So I didn't do that again. Now that amp only gets used with a resistor in series to bring up the load to 4 ohms.
LOL, and ouch re blowing your transistors.
Paradoxically, I think I'd worry less about blowing the ribbon tweeters than the quasi ribbons, since they can easily be replaced. But I think that even with an amp that's clipping, the tweeters are unlikely to blow if you use the right fuse. My Hafler used to hard clip sometimes into the 1-D's, and I used to blow fuses periodically without harm (to the speakers, anyway, not sure about my neighbors or ears).
Still not sure what I'll use to drive the tweeters -- I'm assuming now A-21 on the bass, Benchmark on the mids . . .
Yeah that Fosgate was a real toaster. I have another and a friend with a RM30 ribbon box speaker used one for a while for the upper portion for its' Chocolaty midrange: smooth rich and dark, as he described it. Burned his too. I still recommend the amps from this series, but no longer for low efficiency speakers and low impedances. The 4200 is amazing so long as it does not have to do deep bass.
Should be similar to the haffler amp design IIRC. Lovely amps. Particularly when converted into NYALs with a SE tube front end. Also a long standing recommendation for amps, particularly the XL600 and the 9000 series. I can easily see the amps clip into a T1D.
I thought about modding my Hafler for a bit, but it looks like I'll be Ebaying it at some point. Though maybe I should reconsider -- it might be a good match for the tweeters. It's been packed up in the basement since like forever.
If you do use it for the tweeters it will benefit from some updated PS caps, diodes and direct contact to the output wire since the OEM binding posts are not all they should be. Lots of mod projects for the Haffler progeny online.
It would be fun to rebuild it, but God knows when I'll have the time! Latest is it seems the contractor didn't prime the sheetrock on my listening room ceiling before he skim coated it, and as a consequence, when I pulled off what looked like some peeling paint from the ceiling, the plaster started coming off in big chunks. So I primed and started patching, and for the next few days the room will be unusable:
Then I'll have the new amp to try, after which I have to rebuild the speakers, try the Mini DSP, and hang the projection screen, which has been lying on the floor for a month now. So I have to be realistic about what I can hope to accomplish.
Most Maggie owners mark the floor once they finalize the best speaker positions. It looks like you are planning to mount them on the walls and/or ceiling. Or perhaps the tape marks off multiple crime scenes!
Seriously though you have a room filled with old world detail and character!
Shhh, you'll give away my trade secrets!
Seriously, this room was built in 1695 and someday I must complain to the guy who built it because the ceiling is too low for Acoustats. The beam above the speakers is part of the original frame and was hewn from a gigantic chestnut log -- wonder what they'd think about MDF?
"Room built in 1695" and some other posts in this thread:
Hey, the ghosts say they *like* the music, though a distinct minority argue that I'm guilt of witchcraft and should be burned at the stake.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: