| ampage Tube Amps / Music Electronics |
For current discussions, please visit Music Electronics Forum. |
ampage archive
Vintage threads from the first ten years
Ceramic strength VS Alnico
:
 1/13/2003 3:07 AM |
|
| SK | Ceramic strength VS Alnico I finally got my hands on some ceramic magnets pretty much identical in size to the A5 bars so I tested them. The charts say they should be weaker, They aren't. They are almost twice as strong and if anything the A5 bars are slightly larger. My meter is "calibrated" and I tested the same polarity on both with everything the same. I even tried both of the ceramics I have and several A5's. I dunno. No wonder this is such an art. |
|---|---|
| 1/13/2003 6:05 AM |
|
Jason Lollar |
I have kept my mouth shut about it but thats what I have found. |
|---|---|
| 1/13/2003 8:11 AM |
|
| Andy |
Well! Well! Thats three of us who at least agree. Andy |
|---|---|
| 1/13/2003 6:01 PM |
|
| Dr. Strangelove |
I have no explanation for this, save that the bulk of alnico comes from China while ferrites are from anywhere. Duramag complained at one time about the quality of Alnico stock they received, so it may be indicative. Since small buyers can't afford to test every magnet batch they buy, they must take the vendor at his word. The vendor, apologetically or not, must take what the manufacturor gives him. FWIW, the Dexter A5 bar stock I have reads 800-1000 gauss and can vary 20% along the same piece. This is in spec. I have no ceramics for testing. -drh -- |
|---|---|
| 1/13/2003 7:17 PM |
|
| Jason Lollar |
I dont know whats going on with the chinese supply thing. The first coil I made with ceramic was in 1979 and I dont think chinese alnico was an issue then and the results were the same. One thing mentioned before is that normally both types of material are polarised in different directions if you dont take that into account it could scew the results |
|---|---|
| 1/13/2003 9:10 PM |
||
| Dr. Strangelove |
SK, Jason, and Andy wrote:
The FEMM magnetic model software predicts it, too. Sorry for all the noise and confusion. -drh -- | |
|---|---|---|
| 1/14/2003 2:23 AM |
|
| SK | What gets me is the charts from the manufacturers...Normally if I give something as a Hard fact, I have a "reliable reference" for it. In this case, I changed my thinking (but not "practices") when I started doing stuff beyond just winding. Charts said it's weaker, it must be. The "results" Im getting must be caused somewhere else(with same indications, but there's many ways to get from pt. A to pt. B)..... Now I gotta go back to my old way of thinking. I'm glad this "chart information" didn't affect what I've been doing, I coulda made some changes and wasted alot of time and wire.... Doc, you're using an uncalibrated meter right? |
|---|---|
| Page 1 of 3 | Next> | Last Page>> |