Revel Performa M20 question…
JayMX
Posts: 446
Thought about putting this in the vintage section, they are around 20 years old…. These came to play the other day, but something was weird on the top end.
There are two selector knobs on the back of each cabinet; one for stand or flush mounting (affects response of woofer somehow) and one that either attenuates or boosts the tweeter level. One speaker’s selectors (#448) have two detents for mounting and five for tweeter level - seems right and matches the silkscreening. The other cabinet (#447) has four detents for mounting and ten for level!!! I’m speculating that the factory didn’t have enough of the proper selector knobs for #447 so they used what they had? Either way, I figured I would measure resistance between pins to see if the values matched…
Measurements for “mounting” selectors do match, despite #447’s extra unused selector steps, which all read as infinite. This makes sense since nothing is hooked up to those pins on the selector:
Measurements for tweeter level selectors were waaaay different, completely missing steps 4 & 5 on #447, all unused steps read infinite:
So, I popped the woofers out and I’m 100% sure someone has been inside of #447 before. Tool marks and the seal wasn’t as good, globby solder on the tweeter xover board. Notice the different resistors on the tweeter xover boards. Obviously I want them to match, but I’m confused… so here’s my question…. This shows my ignorance… why do the larger 5W resistors not have enough bands on them? Missing the black bands, but values match otherwise…. Weird. Thoughts?
#448 - I’m pretty sure this is stock:
#447 - not sure if this one is right…
There are two selector knobs on the back of each cabinet; one for stand or flush mounting (affects response of woofer somehow) and one that either attenuates or boosts the tweeter level. One speaker’s selectors (#448) have two detents for mounting and five for tweeter level - seems right and matches the silkscreening. The other cabinet (#447) has four detents for mounting and ten for level!!! I’m speculating that the factory didn’t have enough of the proper selector knobs for #447 so they used what they had? Either way, I figured I would measure resistance between pins to see if the values matched…
Measurements for “mounting” selectors do match, despite #447’s extra unused selector steps, which all read as infinite. This makes sense since nothing is hooked up to those pins on the selector:
Measurements for tweeter level selectors were waaaay different, completely missing steps 4 & 5 on #447, all unused steps read infinite:
So, I popped the woofers out and I’m 100% sure someone has been inside of #447 before. Tool marks and the seal wasn’t as good, globby solder on the tweeter xover board. Notice the different resistors on the tweeter xover boards. Obviously I want them to match, but I’m confused… so here’s my question…. This shows my ignorance… why do the larger 5W resistors not have enough bands on them? Missing the black bands, but values match otherwise…. Weird. Thoughts?
#448 - I’m pretty sure this is stock:
#447 - not sure if this one is right…
Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
Comments
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If I had to guess both tweeter resistors have had repairs before- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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I wonder if there's an easy way to just bypass all of that knob adjustment stuff.
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Agree with Clip, bypass knobs and upgrade resistor in tweeter circuit to your discretion.Don't take experimental gene therapies from known eugenicists.
