AudioCircle
Industry Circles => GR Research => Topic started by: david45 on 12 Dec 2017, 03:31 pm
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Quick question for you, Danny.
I'm shopping around for a new tube amp and for some reason I had always thought that my NX-Otica speakers were 93.5 db/1W/1M but I keep reading 92db on the forum. :scratch:
Which one is it? How efficient are they?
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I measured them at an average of 93.5db.
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Thanks for the reply, Danny.
I would consider ordering parts from you in the future to get my crossovers modded just so I can bi-amp the Otica's (Jay mentionned that option when I got the flat packs from him). In the mean time, I would want to bypass the M165s entirely and drive the MTM section with some low power SE amplifier (2a3, 421, PSE45, AD1).
Except for the fact that the mid bass woofers wouldn't be playing and that the OB subwoofers would need to cover all the way up to about 200hz, wouldn't it be equivalent to biamping in terms of the load that the SE amplifier would be seeing when driving the mtm section and how many watts it would need to be able to provide? The signal path would certainly be different though...
Do you think I could get away with just a couple watts for the mtm section considering I was able to use a 300b amplifier with the Otica's (run full range) and that I pretty much never went above 1W of continuous power on the front meter? No idea in terms of peak power though but I stay away from classical music...
What I would do is use an in-line crossover in between the pre and amp using a cap and resistor(?) of appropriate value. Speaking of which, I understand it is more complicated to do so when using an integrated amplifier (need to open it up and everything) but what about when using a power amp straight from the DAC? Is it possible to use an in-line crossover too?
Oh and the subwoofers would obviously be kept as close as possible to the speakers so that they can blend seamlessly even at 200hz (not too sure what the formula is to calculate the maximum distance allowed). Is 200hz more or less the crossover point between the m165 drivers and the mtm section?
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Thanks for the reply, Danny.
I would consider ordering parts from you in the future to get my crossovers modded just so I can bi-amp the Otica's (Jay mentionned that option when I got the flat packs from him). In the mean time, I would want to bypass the M165s entirely and drive the MTM section with some low power SE amplifier (2a3, 421, PSE45, AD1).
You can wire them for bi-amping real easily.
Except for the fact that the mid bass woofers wouldn't be playing and that the OB subwoofers would need to cover all the way up to about 200hz, wouldn't it be equivalent to biamping in terms the load that the SE amplifier would be seeing when driving the mtm section and how many watts it would need to be able to provide? The signal path would certainly be different though...
You could drive the lower woofers with a separate amp.
We also have just an MTM version only: http://www.audiocircle.com/index.php?topic=144907.0
Several customers have built them already.
Do you think I could get away with just a couple watts for the mtm section considering I was able to use a 300b amplifier with the Otica's (run full range) and that I pretty much never went above 1W of continuous power on the front meter? No idea in terms of peak power though but I stay away from classical music...
You might be able to get away with it if the room is not huge and you don't need high SPL levels.
What I would do is use an in-line crossover in between the pre and amp using a cap and resistor of appropriate value. Speaking of which, I understand it is more complicated to do so when using an integrated amplifier (need to open it up and everything) but what about when using a power amp straight from the DAC? Is it possible to use an in-line crossover too?
We typically use something like this. But it can be inserted into the signal path to your amp in several ways.
(http://gr-research.com/pics/yconnector.jpg)
Oh and the subwoofers would obviously be kept as close as possible to the speakers so that they can blend seamlessly even at 200hz (not too sure what the formula is to calculate the maximum distance allowed). Is 200hz more or less the crossover point between the m165 drivers and the mtm section?
At that crossover point you'd need to set the MTM section right on top of the servo subs.
Here is a good one. http://www.audiocircle.com/index.php?topic=146187.0
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The Wedgies crossover around 200Hz. The NX-Otica MTM section is around 100Hz.
I have easily driven my Otica MTMs with a 5wpc EL84 based ultralinear amp. I'm not sure how that would compare output wise with a 300B SET amp.
Mike
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I have easily driven my Otica MTMs with a 5wpc EL84 based ultralinear amp.
Hey Mike! Was that with an inline crossover or full range?
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We typically use something like this. But it can be inserted into the signal path to your amp in several ways.
(http://gr-research.com/pics/yconnector.jpg)
So it can be used even without a preamp (in-between dac and power amp)?
At that crossover point you'd need to set the MTM section right on top of the servo subs.
Ok so unless I choose to biamp with a seperate amp, I'm better off with a 80hz or 100hz inline crossover. My subs are right against the NX-Otica's and just a few inches back. I can measure the distance between the center of the lower woofer and the center of the upper mid driver using a piece of rope (?).
You don't happen to know the formula by heart by any chance?
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The Wedgies crossover around 200Hz. The NX-Otica MTM section is around 100Hz.
I have easily driven my Otica MTMs with a 5wpc EL84 based ultralinear amp. I'm not sure how that would compare output wise with a 300B SET amp.
Mike
Mike,
Assuming 10% THD specs for 8 watts (SET 300B) and 5 watts (EL84 Ultralinear), the difference in power is just 2dB.
A difference of 3dB and you can start hearing a “difference” in output power, but a difference of 10X (like 50 watts) is easily heard by the human ear especially when you push the speaker to play at higher SPL levels.
Best,
Anand.
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So it can be used even without a preamp (in-between dac and power amp)?
You can if you have a volume control on your DAC.
Ok so unless I choose to biamp with a seperate amp, I'm better off with a 80hz or 100hz inline crossover. My subs are right against the NX-Otica's and just a few inches back. I can measure the distance between the center of the lower woofer and the center of the upper mid driver using a piece of rope (?).
Yeah, that's about right on the filter. You'll need to know the input impedance of the amp and then this will help you figure out the cap value. http://www.pronine.ca/capimp.htm
For the distances this will help. http://www.soundoctor.com/freq.htm
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Hey Mike! Was that with an inline crossover or full range?
David,
Yes, that's with an inline filter.
Mike
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Mike,
Assuming 10% THD specs for 8 watts (SET 300B) and 5 watts (EL84 Ultralinear), the difference in power is just 2dB.
A difference of 3dB and you can start hearing a “difference” in output power, but a difference of 10X (like 50 watts) is easily heard by the human ear especially when you push the speaker to play at higher SPL levels.
Best,
Anand.
This is something I don't fully understand. If you are only using 1 or 2 watts, why would there be a difference in the sound between a 5 watt, 8 watt, or 15 watt amp (assuming the only difference between the amps is power)?
Mike
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This is something I don't fully understand. If you are only using 1 or 2 watts, why would there be a difference in the sound between a 5 watt, 8 watt, or 15 watt amp (assuming the only difference between the amps is power)?
Mike
I’m talking about the differences in amplifier power alone, if you put them both on the test bench.
But if you are using only 1-2 watts, correct, it doesn’t matter. You have to be sure about that though! It assumes your peak SPL levels is ALWAYS the same, etc...
Best,
Anand.
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David, just a few things to consider
As Danny mentioned, setting up your NX-Otica networks for bi-amping would be simple. Buy a set of tube connectors, make a block to add to your existing c/o board. snip the pos lead going to the low pass inductor and neg wire to the neg tube conector, attach them to the new tube connectors..
There is a pretty big difference between the NX-Oticas with the extra woofers compared to the NX-Otica MTM's. I've spent significant time with both...... when originally setting up the MTM's I thought they were pretty equal. Spent a few months with them while Don borrowed the Oticas during the finishing of the NX-Tremes. When I got the Otica's back, I was really surprised at how much mid bass detail there was Those 4 extra woofers in the 80 to 200 range make a big difference.... you've got them... I'd keep them in the loop.
If you choose to go for the MTm section only you should know the MTM's use a different network setup, the mids are not high passed as they are in the full Otica's so you'd want to pull out that bundle.....you wouldn't want to be passing your filtered signal through the high pass bundle of caps for the NQ's. IIRC, there is also a different resistor value on the notch filter on the high pass filter for the tweeter (comparing the full Otica to the MTm's).
If you followed through with the ICE Power AS/2, hold off doing anything until you give this a try.... you may be surprised. I'm hoping to have one in the room here in the next week or so for some trials... will keep you posted
jay
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There is a pretty big difference between the NX-Oticas with the extra woofers compared to the NX-Otica MTM's. I've spent significant time with both...... when originally setting up the MTM's I thought they were pretty equal. Spent a few months with them while Don borrowed the Oticas during the finishing of the NX-Tremes. When I got the Otica's back, I was really surprised at how much mid bass detail there was Those 4 extra woofers in the 80 to 200 range make a big difference.... you've got them... I'd keep them in the loop.
Darn it Jay, why did you have to say this? :wink:
I have been living with my MTMs listening blissfully secure in the knowledge that the trade off of footprint to sound was minimal. If I try to put any more speaker (MTM to full Otica plus H Frame) in the living room I will be living alone in short order :lol:.
Time to build a new listening room :thumb:.
Best,
Ed
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David, just a few things to consider
As Danny mentioned, setting up your NX-Otica networks for bi-amping would be simple. Buy a set of tube connectors, make a block to add to your existing c/o board. snip the pos lead going to the low pass inductor and neg wire to the neg tube conector, attach them to the new tube connectors..
There is a pretty big difference between the NX-Oticas with the extra woofers compared to the NX-Otica MTM's. I've spent significant time with both...... when originally setting up the MTM's I thought they were pretty equal. Spent a few months with them while Don borrowed the Oticas during the finishing of the NX-Tremes. When I got the Otica's back, I was really surprised at how much mid bass detail there was Those 4 extra woofers in the 80 to 200 range make a big difference.... you've got them... I'd keep them in the loop.
If you choose to go for the MTm section only you should know the MTM's use a different network setup, the mids are not high passed as they are in the full Otica's so you'd want to pull out that bundle.....you wouldn't want to be passing your filtered signal through the high pass bundle of caps for the NQ's. IIRC, there is also a different resistor value on the notch filter on the high pass filter for the tweeter (comparing the full Otica to the MTm's).
If you followed through with the ICE Power AS/2, hold off doing anything until you give this a try.... you may be surprised. I'm hoping to have one in the room here in the next week or so for some trials... will keep you posted
jay
Jay,
I did follow through with the ICE Power AS/2 but I was only planning on using it as my summer amp. It would replace my Virtue Audio Sensation with tube buffer. I should be getting it relatively soon.
As for the Otica's, the plan is not to get rid of them but simply to have the option of using a low power set amplifier with them. The 300b amp integrated I had in my system for 2 days only was a revelation and obviously there was no in-line crossover being used. Honestly in my system I did not feel like I needed more power than what the 210ia was able to produce. I would definitely keep the full Otica's in the loop and not acquire the mtm section only, but I was thinking that using a high pass before the tube amplifier would allow me to use an even less power (3-3.5 wpc). Call me crazy but I would actually get both a 300b amp (full range or with 80hz hi-pass) as well as a PSE45 amp (100hz hi-pass or biamp configuration) that I would rotate in my system. I feel like I need tubes in my life lol and the kt88/120 push pull integrated I have at the moment isn't up to the task.
2017 was a big year for me in terms of speakers and subs, 2018 is going to be about amplifiers and possibly a new server/streamer/dac from your buddy at mivera audio as well when it is ready (or 2019). My audio rack is quite a bit smaller than it used to be but I can easily store amplifiers in the same room and rotate them in the system depending on my mood (or temperature haha). The biamp configuration would make things more complicated for me however even though that would probably be the best option sonically speaking.
By the way I appreciate all the help I've been getting :thumb:
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David,
You don't have to use the inline filter to roll of everything up to the crossover point of the Oticas. Just filtering out the first octave (20-40Hz) will go a long way toward reducing the power required by the amp.
Mike
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Darn it Jay, why did you have to say this? :wink:
I have been living with my MTMs listening blissfully secure in the knowledge that the trade off of footprint to sound was minimal. If I try to put any more speaker (MTM to full Otica plus H Frame) in the living room I will be living alone in short order :lol:.
Time to build a new listening room :thumb:.
Best,
Ed
Well Ed, I did say I really liked the MTM's too :beer: Unless you go back and forth withthem, you won't know the diff so no worries. And like you said, the space saving is really nice... that was a huge plus in my room when I was running the MTM's.
jay
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Jay,
I did follow through with the ICE Power AS/2 but I was only planning as using it as my summer amp. It would replace my Virtue Audio Sensation with tube buffer. I should be getting it relatively soon.
As for the Otica's, the plan is not to get rid of them but simply to have the option of using a low power set amplifier with them. The 300b amp integrated I had in my system for 2 days only was a revelation and obviously there was no in-line crossover being used. Honestly in my system I did not feel like I needed more power than what the 210ia was able to produce. I would definitely keep the full Otica's in the loop and not acquire the mtm section only, but I was thinking that using a high pass before the tube amplifier would allow me to use an even less power (3-3.5 wpc). Call me crazy but I would actually get both a 300b amp (full range or with 80hz hi-pass) as well as a PSE45 amp (100hz hi-pass or biamp configuration) that I would rotate in my system. I feel like I need tubes in my life lol and the kt88/120 push pull integrated I have at the moment isn't up to the task.
2017 tas a big year for me in terms of speakers and subs, 2018 is going to be about amplifiers and possibly a new server/streamer/dac from your buddy at mivera audio as well when it is ready (or 2019). My audio rack is quite a bit smaller than it used to be but I can easily store amplifiers in the same room and rotate them in the system depending on my mood (or temperature haha). The biamp configuration would make things more complicated for me however even though that would probably be the best option sonically speaking.
By the way I appreciate all the help I've been getting :thumb:
Davd, understood and nothing wrong with having lots of amp choices available :thumb:
One thing to remember, if you are going to bi-amp, you'll need a volume/gain control on the amp driving the bass section of the Otica's to be able to be able to balance with the low powered SET amp driving the MTM section. Once dialed in, you'l lbe able to simply adjust the volume as normal with pre / volume control etc (can't reacll your setup).
As you probably saw in Mike's ICE thread, we've been comparing the As/2 with Don's 6C33C parallel SET mono's and everyone who's heard them all back to back, is surprised.. Pretty anxious to get that amp over here and have a listen with the Otica's
David,
You don't have to use the inline filter to roll of everything up to the crossover point of the Oticas. Just filtering out the first octave (20-40Hz) will go a long way toward reducing the power required by the amp.
Mike
I was kind of thinking the same thing at first then realized after reading it again he was wanting to take the load off the SET amp :thumb:
jay
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I’m talking about the differences in amplifier power alone, if you put them both on the test bench.
But if you are using only 1-2 watts, correct, it doesn’t matter. You have to be sure about that though! It assumes your peak SPL levels is ALWAYS the same, etc...
Best,
Anand.
Anand,
Thanks. For me 95% of the time I'm probably not getting much past that first watt: 93dB efficient speakers, LP 8' away, average SPL high 60's to low 70's, peaks in the low to mid 90's.
Mike
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Anand,
Thanks. For me 95% of the time I'm probably not getting much past that first watt: 93dB efficient speakers, LP 8' away, average SPL high 60's to low 70's, peaks in the low to mid 90's.
Mike
Totally agree :thumb:
For me, 95% of the time, I'm probably past 5 watts and under 10 watts: 96dB efficient speakers, LP 11-12' away, average SPL 80dB with peaks as high as 95dB. 5% of the time though, I do hit 100-105dB spl though :icon_twisted:
Best,
Anand.
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David,
You don't have to use the inline filter to roll of everything up to the crossover point of the Oticas. Just filtering out the first octave (20-40Hz) will go a long way toward reducing the power required by the amp.
Mike
Excellent news!! :hyper:
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Davd, understood and nothing wrong with having lots of amp choices available :thumb:
One thing to remember, if you are going to bi-amp, you'll need a volume/gain control on the amp driving the bass section of the Otica's to be able to be able to balance with the low powered SET amp driving the MTM section.
Cool. I still have a Millenia MG3 from TBI somewhere I could play around with. I'm very limited in terms of how much room I have on my rack however...
As you probably saw in Mike's ICE thread, we've been comparing the As/2 with Don's 6C33C parallel SET mono's and everyone who's heard them all back to back, is surprised.. Pretty anxious to get that amp over here and have a listen with the Otica's
Same here!! :green:
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Dave and I have been exchanging a few ideas offline and share some similar taste in equipment. I think biampable NXOtica’s are a great foundation. At 93dB they can be driven with low power tubes but not necessarily flea power tubes.
My recommendation is to use the tube integrated or pre/power amp of your choice (300B in this case) to power the MTM section, and use the speaker-level signal to drive the input of a Firstwatt F4 (or F4 clone or a Burning Amp Clone with output section only). The F4 is a zero-gain design, so it will match the tube amp’s output perfectly and pick up its sonic character while being better suited to drive the our woofers. There are a number of builders who would put together an F4 (parts are <$1k) and custom-build a SET amp as well.
The F4 manual includes connection diagrams for driving the amp with the output of a flea power tube amp: http://www.firstwatt.com/pdf/prod_f4_man.pdf