stratocaster Posted February 17, 2023 Share Posted February 17, 2023 (edited) So in my quest to experiment with tubes, I ended up building an all tube rig with Manley phono stage, preamp and monoblocks. A few weeks ago, I threw in the 2WQ in the mix as well and I am noticing that each time I switch off the amps, there's a loud boom from the 2CE's. It's loud enough to cause concern and I have disconnected the subwoofer. I am using the X2 crossover (200K) and the input impedance of the Manley's is 475K. Previously, I was using a Mccormack with the Manley preamp and I never got the boom when I turned the amp off. Is this something related to the tube gear or is it more localized to the crossover value? Edited February 17, 2023 by stratocaster Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted February 17, 2023 Share Posted February 17, 2023 1 hour ago, stratocaster said: So in my quest to experiment with tubes, I ended up building an all tube rig with Manley phono stage, preamp and monoblocks. A few weeks ago, I threw in the 2WQ in the mix as well and I am noticing that each time I switch off the amps, there's a loud boom from the 2CE's. It's loud enough to cause concern and I have disconnected the subwoofer. I am using the X2 crossover (200K) and the input impedance of the Manley's is 475K. Previously, I was using a Mccormack with the Manley preamp and I never got the boom when I turned the amp off. Is this something related to the tube gear or is it more localized to the crossover value? The loud boom must be coming from both the 2Ce's and the 2Wq. For some reason the X-2 in the circuit is causing a DC pulse when the amp is turned off. The X-2 is not transparent enough for your system and compromising your sound noticeably, but its value is close enough and has nothing to do with this problem. Are you turning off the Pre-amp and power amp at the same time? Could try the power amp first in your sequence. Borow a M5-HP someday as it is dramatically more transparent. RV Link to comment Share on other sites More sharing options...
TomicTime Posted February 17, 2023 Share Posted February 17, 2023 (edited) swing by and borrow my M5 filters - have to warn you they have the upgraded Teflon caps 😉 Jim Edited February 17, 2023 by TomicTime 1 Link to comment Share on other sites More sharing options...
ctsooner Posted February 17, 2023 Share Posted February 17, 2023 Those Teflon caps are very very special Link to comment Share on other sites More sharing options...
stratocaster Posted February 17, 2023 Author Share Posted February 17, 2023 1 hour ago, Richard Vandersteen said: The loud boom must be coming from both the 2Ce's and the 2Wq. For some reason the X-2 in the circuit is causing a DC pulse when the amp is turned off. The X-2 is not transparent enough for your system and compromising your sound noticeably, but its value is close enough and has nothing to do with this problem. Are you turning off the Pre-amp and power amp at the same time? Could try the power amp first in your sequence. Borow a M5-HP someday as it is dramatically more transparent. RV I am turning the amplifier off first and then the preamp. Should I be trying the other way round? Link to comment Share on other sites More sharing options...
stratocaster Posted February 17, 2023 Author Share Posted February 17, 2023 1 hour ago, TomicTime said: swing by and borrow my M5 filters - have to warn you they have the upgraded Teflon caps 😉 Jim Thanks Jim.. will call you this weekend.. 1 Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted February 18, 2023 Share Posted February 18, 2023 2 hours ago, stratocaster said: I am turning the amplifier off first and then the preamp. Should I be trying the other way round? No, you are doing it correctly. Check your DC offset on the output of your amplifier especially when you turn it off. If the pulse is less than 2 volts don't worry about it as it won't hurt the sub or your speakers. RV 1 Link to comment Share on other sites More sharing options...
stratocaster Posted February 25, 2023 Author Share Posted February 25, 2023 On 2/17/2023 at 11:17 AM, Richard Vandersteen said: The loud boom must be coming from both the 2Ce's and the 2Wq. For some reason the X-2 in the circuit is causing a DC pulse when the amp is turned off. The X-2 is not transparent enough for your system and compromising your sound noticeably, but its value is close enough and has nothing to do with this problem. Are you turning off the Pre-amp and power amp at the same time? Could try the power amp first in your sequence. Borow a M5-HP someday as it is dramatically more transparent. RV So I got my hands on a set of M5-HP and there’s certainly a significant improvement in sound from the X2s. The loud boom is now replaced by a soft thud when I turn off the amps. This happened for a couple of different values I selected. Am guessing this is normal… 1 Link to comment Share on other sites More sharing options...
ctsooner Posted February 25, 2023 Share Posted February 25, 2023 Glad to hear that you like the difference. Link to comment Share on other sites More sharing options...
stratocaster Posted February 25, 2023 Author Share Posted February 25, 2023 13 minutes ago, ctsooner said: Glad to hear that you like the difference. Yeah, it's quite uncanny..I didn't think the improvement would be so significant. The litmus test of component upgrade is when high command asks if I have spent money again since things are sounding different and better.... 2 Link to comment Share on other sites More sharing options...
Steve Edwards Posted February 25, 2023 Share Posted February 25, 2023 1 hour ago, stratocaster said: The litmus test of component upgrade is when high command asks if I have spent money again since things are sounding different and better.... That is a solid marital foundation Udit. While my “high command” has been lovingly supportive of my passion, when the subject of an upgrade (of any proportion) comes up, her usual response is “how much better can it sound?” Oh, the curse of being among the enlightened few ………. 🥴 1 Link to comment Share on other sites More sharing options...
ctsooner Posted February 25, 2023 Share Posted February 25, 2023 Funny as I have the same with with my wife. She rarely even hears the system, but when she does, she remembers what it used to sound like. I have no idea how, but she does and she knows when something changes, good or bad. Pretty funny to me. Link to comment Share on other sites More sharing options...
stratocaster Posted April 14 Author Share Posted April 14 @Richard Vandersteen I am getting the same loud boom/thump from my Quatro’s when I turn the Manley monoblocks off. How do you check the DC offset that you suggested? Link to comment Share on other sites More sharing options...
Oregon Posted April 14 Share Posted April 14 14 hours ago, stratocaster said: @Richard Vandersteen I am getting the same loud boom/thump from my Quatro’s when I turn the Manley monoblocks off. How do you check the DC offset that you suggested? Ditto. I am running an all Manley line. Link to comment Share on other sites More sharing options...
Delkat Posted April 14 Share Posted April 14 I got this thud for years when I was running an old PS Audio 200CX with Model 2s. When I switched to a BAT amp the noise went away. It didn’t seem to hurt anything as my daughter is still enjoying the 2s 35 years later. Todd Link to comment Share on other sites More sharing options...
Steve Edwards Posted April 15 Share Posted April 15 On 2/17/2023 at 11:17 AM, Richard Vandersteen said: Are you turning off the Pre-amp and power amp at the same time? Could try the power amp first in your sequence. RV, on powering up, should it be pre-amp first then power amp? Link to comment Share on other sites More sharing options...
Brad O Posted April 15 Share Posted April 15 I am here with Richard and he says yes preamp first and power amp last. 1 1 Link to comment Share on other sites More sharing options...
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