Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Quickie => Topic started by: oguinn on January 26, 2019, 05:33:11 AM
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My current setup is JDS Labs DAC>Quickie>The Fix>SEX>Orcas and a powered sub. I’m looking at replacing the powered sub with a Blumenstein Benthic. Since it’s passive, I know I need a plate amp that can also provide power and a crossover.
Could I build or buy a crossover and use a Quickie to power a passive sub? If the stock Quickie wouldn’t provide enough power, would a Quickie/Quicksand combo?
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Jameson,
I don't know how sensitive the Benthic sub is, but at home I run a 250w plate amp on each of the two subs mated to my Stereomour II and at work I run a 100w plate amp to a single 8" sub with a SEX amp.
Both integrate well, but are by no means bass heavy.
I run the desk speakers full range, but I built a high-pass x-over to releave the main speakers of bass duty at home. (About 105 Hz into 4 Ohms) I just jump off each channel of the input of the x-over to the speaker-level inputs of the plate amps.
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The stock Quickie isn't a power amp and won't provide much of anything you need to drive a sub. You would need a proper amp or plate amp for that purpose. Now I can't answer if the Quicksand would effectively power a sub. Depends a lot on the driver used in the sub, your room, and your personal preferences. But even the Quicksand is pretty low power so I wouldn't expect miracles.
I don't have much experience with subs and plate amps but most subs I've heard are pretty boomy/rumbly and I'd be inclined to drive the Benthic with a "real" amp to get the best out of it. But it may do just fine with a plate amp. I'd be inclined to cross over after Quickie and drive separate amps for the mains and sub.
I'm curious what others will say.
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Jameson,
You might want to consider getting a simple electronic xover, something like an NHT X2. Crossing over actively will provide some advantages over speaker level connections. The X2 has a 12db/oct slope which will integrate well with a lot of speakers. I think Cpaul is correct about amp choices, but try an X2 with your plate amp sub first and see what you think. The X2 is no longer available new but I see them on ebay alot for reasonable prices. Crossing actively to powered subs can make a big difference.
Jamie
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Thanks, all. I have a search saved on eBay for the NHT X2, but I might just wait and buy a proper subwoofer amp once I'm ready to upgrade. I was hoping to make do with what I have laying around, but doesn't sound like I currently have the right tools for the job.
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Can you pull the plate amp out of your current subwoofer?
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Eesh, maybe. I’m not sure how that would work. It’s an older Yamaha in a particle board cabinet.
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Jameson,
If you get the X2 you can use it with your Yamaha sub as is. The main advantage of actively crossing is that your SEX will not be burdened with the task of producing the lowest frequecies.This will allow the amp greater "headroom" and the whole system will play louder but more importantly you will have less distortion at your normal listening level. You can do this with the sub you have as long as it has line level inputs. Remember that the lowest frequencies require the greatest effort from your amp. There are many advocates of active systems. This sort of active system gives the most bang for the buck. The X2 has outputs for 2 subs which will really bring a system to life. If you get an X2 get Y sub cable(s) so that you input into both channels on the subs amp.
Jamie
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Yeah, sounds good, Jamie, thanks. I have my wye our for one. I’d eventually like to replace the Yamaha anyway, but it sounds like a good investment.
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You don't need to replace the Yamaha, just add the Benthic and have stereo subs. Get a an equally powerful amp for it and run the two subs in stereo. They don't have to be identical especially if your room is not symmetrical. I run a velodyne mini- vee and a Goldenear Ff4 in the same room. I put the minivee in the corner and the FF4 on a straight wall and the base response is pretty even between the channels. Just play with the positions and you will eventually get the response you want.
Jamie
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Jamie,
Maybe I’m missing how, but I only see one set of outputs for a sub. Unless you’re saying I’d split the right and left channels with a Y cable and put one channel to each sub? https://www.audiogon.com/listings/lis9bcbj-nht-x-2-electronic-crossover-subwoofers
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Exactly, you can get sub cables that are "y" s. You connect the y end at the sub's plate amp, one into the right channel, the other in the left. The side of the cable with the single RCA goes to the X2 and into one of the Sub Out RCA females, right for the right side sub or left for left. There is a switch on the back of the X2 to select for mono or stereo subs. You could also use a short Y and a single ended sub cable if you like, I have done it this way also and it works just as well. You can use the X2 with a single (summed) subwoofer signal but when you have actively crossed stereo subs the result is very satisfying. After adjusting the sub positions and the X2 levels you will have really good integration without the boominess that cpaul referred to in his post. A well adjusted sub system should not be obnoxiously loud and boomy. It should, sort of, disappear except for the improved low end extension. Even in a small room, using actively crossed stereo subs is still appropriate because of the greater control that you will have.
Jamie
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Jamie,
I just got an X2 off eBay. Am I correct in assuming that the chain should look like this:
Source > Quickie > X2 > a) Subwoofer b) SEX
Jameson
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You could also use a short Y and a single ended sub cable if you like, I have done it this way also and it works just as well. You can use the X2 with a single (summed) subwoofer signal
Just be careful not to plug a Y-cable into the left and right outputs of your linestage preamp.
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Jameson,
Yes, the chain is: source>quickie>X2>a)high pass out (R&L) to your SEX, with standard RCA cables) b) sub out with R to right sub, L to left sub with the Y cables (Y end towards subs) into both R&L inputs on each subwoofer.
Start with gain @ 0db and high pass filter at 80 Hz and be sure to set Trigger to Audio. Then adjust your settings from there.
Jamie
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I think I understand. If I were to synthesize information from Jamie, Paul, and the X2 user manual, I think the attached image is what I'm going for. Anything in red or green are my edits. Am I on the right track?
I would have been pretty set but then PB's warning about Y cables made me nervous so I wanted to confirm.
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One small tweak to that diagram would be a left output cable from the X2 to a left input jack on the amp (since my amp has both inputs).
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You've got it. I think PB was just reinforcing the cable directions/connections. Definitely add the other cable and input both L and R sides on your sub. You will have an improved low end that way. When you add the second sub you will really hear the difference. Don't hesitate to move your sub around and experiment with position in the room. Placement within the room can make a big difference. Don't cross too high, if you start to pickup the low end of the vocals you have gone too high. When you have stereo subs you can cross higher as long as your main speakers are close to the subs.
Jamie
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Awesome, thanks for the recommendations and help!
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Remember, with one sub use the mono setting.
Jamie
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Holy shit, man. Adding the X2 had a massive impact. Before getting it I was preparing myself for turning it around and re-selling it if it didn't work, but this is a game changer. Thanks again for the advice!
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Jameson,
Really happy to hear that the X2 worked out for you. I love mine and it's proably the only piece of gear that is constantly in my setup. Crossing subs actively always seems to produce better results for me than using speaker level connections. When you add the second sub in stereo mode you will be even more impressed.
Jamie
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I can only imagine.
I put a Smash in the chain to replace the Quickie and noticed that if I move the balance pot to the left channel, the bass disappears completely. I assume that's in how the X2 handles mono subs.
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That doesn't sound right to me. Do you have both inputs on your sub connected and the X2 in mono mode?
Jamie
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Yeah. It's strange. I have it hooked up the same way I outlined in the drawing above. I noticed the right side was sounding a bit louder and when I turn the SEX amp all the way down I noticed the bass is only coming out of the right side. If I turn the balance pot on the Smash all the way to the left, there's no sound.
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Disconnect one of the sub cables, keep it in mono and see if that corrects the problem. If it does,you will need to get the Y cable and run your X2 in mono mode with only one sub out connected but the Y inputting both channels on your sub.
Jamie
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Something is weird. Switched sources to my iPad and it's fine again. One of the following is happening:
- The record I was listening to had the bass on one channel. It was a Sam Cooke album, so it might have been converted from mono and put all the bass on one channel.
- When the Smash warms up it's exposing a shitty solder joint someplace.
- Other weird problem tbd.
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Jameson, I would try connecting your sub, in mono mode, to each of the sub out connections in your X2, one at a time. This will tell you if you have a bad channel in the X2.
Jamie
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Yeah, I unplugged one out connection at a time and there was bass. I believe this may be a balance pot problem on the Smash compounded by a recording that had the bass track moved to one channel during conversion from mono.
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Channels are out of phase.
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Ok, I did a couple of tests.
- I took the X2 out of the chain and went straight from the Smash to the SEX and noticed the left channel was far quieter than the right channel when I had the pot turned from one direction to the other.
- I took the Smash and the X2 out of the chain and ran it again. Although there's no balance control in that setup it appeared that the speakers were getting roughly the same dB level (I unplugged the speaker I wasn't testing).
So I think this might actually be a Smash balance pot issue. I'll reheat those joints and open a thread in the Smash forum if it persists.
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Or you could, you know, turn the balance control...
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I did do that. If I understand the balance pot, the way it works is that when it’s all the way to the left the left channel should be as loud as the right channel is if it’s turned all the way to the right. That’s not the case here. The left channel doesn’t get anywhere near as loud.
I can use the balance pot to adjust, but I thought the point was to use it to adjust for speaker distance and all that, not fix significant imbalances inherent in the build.
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I’m new to an amp with a balance pot, so if I’m missing the point of the balance pot let me know.
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The output of the Smash should be well balanced without using the balance pot at all. What you're describing sounds like a build issue that you're now discovering.
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Jameson,
Put your Q back in, use the X2 and enjoy some music while you sort out your Smash. I'm sure you'll find the problem in short order. Besides, the Q is a pretty good pre, I wish Doc hadn't retired it, but maybe he's got something else coming down the road that's even better for the low,low price of a hundred bucks.
Jamie
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I actually think it’s one of The 4P1L tubes! It follows whenever I swap them.
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Jameson,
Do you have some other 4P1Ls to swap in?
Jamie
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I have some on order from, like, Romania... we'll see if they arrive. I've also emailed the replacementparts address to see if they have stock. And finally I've ordered some polish to try and clean the pins just to see if that's the issue.
In the meantime I've swapped the Quickie back in and it sounds great!