Members bengerm77 Posted March 3, 2011 Members Share Posted March 3, 2011 So I just changed my power tubes a few months ago, and now my amp has less sizzle and high end. Like, I should turn up the presence on my amp (but my amp doesn't have a presence knob). There are a couple of reasons I suspect this may be... Reason the first: My speakers just broke in? Like they hit puberty or something? Even though I've had them for years now and they've probably been broken in for a while. I did spill a beer on them a couple of gigs ago, but I don't think that's it. Reason the second: One of my power tubes turned out to suck. I didn't bias my amp, because it's a Peavey and the amp is apparently biased so cold I didn't think it made a difference. Maybe one of my power tubes is terrible and it sucks high end or something like that. Reason Final: I recently switched from using my 4 ohm tap to my 16 ohm tap because the 4 ohm tap was failing. I find this to be the most likely cause; I have no actual reason for saying that. I have the idea in my head that using the 16 ohm tap would sound different than the 4 ohm tap, cause of the transformer being haunted or some such tone nonsense that I don't understand. The amp in question is an old Peavey ultra 120, and I just want to know why the sound may have changed. Maybe even get the caps changed or have the whole amp retubed and rebiased. Maybe my preamp tubes have become turds, who knows? I just want to know why this may have happened, any thoughts? Link to comment Share on other sites More sharing options...
Members Nerine Posted March 3, 2011 Members Share Posted March 3, 2011 Use 16 Ohm output for HAUNTING MIDS! Cool. Link to comment Share on other sites More sharing options...
Members BSS Posted March 3, 2011 Members Share Posted March 3, 2011 Reason Final: I recently switched from using my 4 ohm tap to my 16 ohm tap because the 4 ohm tap was failing. I find this to be the most likely cause; I have no actual reason for saying that. I have the idea in my head that using the 16 ohm tap would sound different than the 4 ohm tap, cause of the transformer being haunted or some such tone nonsense that I don't understand. What is the cab ohms rating? If you are mismatching ohms, I would suspect that it could cause some tonal "differences". Link to comment Share on other sites More sharing options...
Members TruSlice Posted March 3, 2011 Members Share Posted March 3, 2011 There are a lot of unsaid variables at work here...:poke: That being said, an obvious one would be from switching from 16ohm to 4ohm. That's gonna make a pretty big difference in the highs and presence for one. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted March 3, 2011 Members Share Posted March 3, 2011 How many ohms is the speaker configuration rated at? Link to comment Share on other sites More sharing options...
Members Noak Posted March 3, 2011 Members Share Posted March 3, 2011 I remember trying out 16 and 4 Ohm settings when I used a Marshall 4x12 with the ability to change between the two. I couldn't really tell one from the other. With my Rivera knucklehead that is. Link to comment Share on other sites More sharing options...
Members tedmich Posted March 5, 2011 Members Share Posted March 5, 2011 poorly matched (or BAD) new power tubes AND/OR spent preamp tubes could suckify an ULTRA 120 4ohm tap failing? what does that mean? You can't bias an ULTRA 120, mine anyway. Using a lower imp speaker in a higher tap means the upstream imp to the power amp (from the OT) is similarly decreased:4ohm speaker in 8ohm tap gives 1/2 the imp to the power amp and "pushes the tubes harder" 4ohms into 16ohm tap likely bad for amp long term, like running w/out any speaker, which can make you need a new OT, or leaving amp in standby long term which poisons power tubes Link to comment Share on other sites More sharing options...
Members grunge782 Posted March 5, 2011 Members Share Posted March 5, 2011 You needz teh gold pins to fix yur phazzing Link to comment Share on other sites More sharing options...
Members bengerm77 Posted March 7, 2011 Author Members Share Posted March 7, 2011 poorly matched (or BAD) new power tubes AND/OR spent preamp tubes could suckify an ULTRA 1204ohm tap failing? what does that mean? You can't bias an ULTRA 120, mine anyway. Using a lower imp speaker in a higher tap means the upstream imp to the power amp (from the OT) is similarly decreased:4ohm speaker in 8ohm tap gives 1/2 the imp to the power amp and "pushes the tubes harder" 4ohms into 16ohm tap likely bad for amp long term, like running w/out any speaker, which can make you need a new OT, or leaving amp in standby long term which poisons power tubes Well I have a stereo cab (like a marshall 1960) that has a 16 and 4 ohm input. My amp has multiple outs, each rated at different ohms. Whenever I plug into the 4 ohm input, my sound will cut out from time to time or just stop (I suspect the connection is bad). In that case I will just switch from running 4 ohms into the 4 ohm input on my cab to 16 ohms into the 16 input. This post is making me lean toward the "new tubes" solution, which I don't care for because I don't want to spend any money. Link to comment Share on other sites More sharing options...
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