Now, I am asking if it is necessary to swap the resistors to achieve a 'good match'? Is it really important for a stereo pair? I assume there is more to gain with swapping these resistors if we use the Quads stacked?
Here are the cold measured values:
Here are the cold measured values:
An externally hosted image should be here but it was not working when we last tested it.
Honestly, you probably won't notice the difference, those changes are a fraction of a dB. The differences between treble panel stator spacing is probably larger than that.
I change them as part of my rebuilds typically because they are really crappy carbon comp resistors.
Shledon
quadesl.com
I change them as part of my rebuilds typically because they are really crappy carbon comp resistors.
Shledon
quadesl.com
I read somewhere that changing these resistors is a very dangerous procedure as you can short out the coils with the excess heat. As I'll be finished with this speaker I will start to tear down the another, I would check that one's values. If there will be a huge difference, I will swap boths resistors with care. I posted it here before, I had acquired an 'extra' transformer recently off the eBay, and those values measured much below the factory specs for unknown reason.
That's news to me. I've always soldered parts on that tag-board with impunity. I just replaced the crossover components in two pairs of input transformers a couple weeks ago with no issues.
The tag-board is isolated from the transformer by some fairly long wires, as seen in this ancient picture. So the wires and the bee's wax will act like a heat sink to protect the transformer.
Sheldon
quadesl.com
The tag-board is isolated from the transformer by some fairly long wires, as seen in this ancient picture. So the wires and the bee's wax will act like a heat sink to protect the transformer.
Sheldon
quadesl.com
Hi,
well if You fry just long enough that may happen.
But honestly .... in this case it rather sheds a light on the ´expertise´ of the author. 😉
jauu
Calvin
well if You fry just long enough that may happen.
But honestly .... in this case it rather sheds a light on the ´expertise´ of the author. 😉
jauu
Calvin
I assume that the author is rather a journalist than a 'pro' 🙂
I'm not a pro at all, but I think thick solid core copper wire conducts the heat very effectively hence the 'meltdown'.
I'm not a pro at all, but I think thick solid core copper wire conducts the heat very effectively hence the 'meltdown'.
I realised that the very old transformer's audio input wiring is solid core than the later version's tinned and multistranded one's. My pair's audio transformers layout differs, as the older one's has the added tagboard protection with 2*4 resistor layout + solid core audio input yet the other one's a factory 2/5 row layout and a multistranded yellow/green color coded input
I am not sure why, as the serial numbers are very close
I am not sure why, as the serial numbers are very close
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
While copper conducts very well, the bees wax absorbs boatloads of heat as the heat travels down the copper wire. The wax is really great at absorbing heat due to the phase change. I don't think it's possible to damage the transformer if you left a 60 watt iron on a tagboard terminal for hours.
But maybe Art Dudley and Wayne know something I don't.
Sheldon
quadesl.com
There's a couple reasons that they could be different. They could have been worked on before. Or the back grilles could have been moved from one speaker to another.
Or quad just changed the design at that point and ran out of the old and started using the new. It appears that they have no regard for trying to keep matched pairs. I've seen consecutive SN quad 63's with different electronics versions under the plinth. Quad is a lot of things, but anal retentive about keeping everything the same unit to unit isn't one of them.
Sheldon
quadesl.com
Or quad just changed the design at that point and ran out of the old and started using the new. It appears that they have no regard for trying to keep matched pairs. I've seen consecutive SN quad 63's with different electronics versions under the plinth. Quad is a lot of things, but anal retentive about keeping everything the same unit to unit isn't one of them.
Sheldon
quadesl.com
Lol, heh. Ok. These discrepancies aren't a huge concern for me at all if they are OK electrically. I mean matched somehow. From 5 meters away they seem truly identical 🙂
Also don't forget that our ears are not sensitive at all to many things we can measure. It's common for cone and dome speakers to be 1-2 dB different, which is a huge difference in a linear scale and very easily measured.
Sheldon
quadesl.com
Exactly, I was thinking about...
After all, I am more concerned about fixing the new dustcovers, and insulating the edges of the panel to avoid leaks and rattling. The panels now have been standing in plastic bags for 2 months. I hope they won't get damaged sittling 'idle' out of the frame for this long...
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