Sow’s ear, silk purse.
Tube vs Solid State
Folks,
For past few months, I have been trying to achieve best possible sound in my rig. The focus now is clearly on a improving 2 channel sound in what started as a home theater room.
In past couple of years, I have added N10, Modwright DAC and very recently a LS36.5 linestage . The amps are Modwright KWA150SE. I am running pair of KWA150SE's in bridge mode (450Wx1) for the mighty B&W 800D2's. While I like the sound as is, still feel something is missing.
I have been toying with the idea of bi-amping. One thought is to add mono tube amps to run mid's and high's and let the KWA150SE's handle the LF's. I am pursuing that seductive, slightly warm mid-range and top end that usually comes from tube amplification.
I don't think there is any tube amp out there by itself capable of powering up bass hungry 800's. I prefer not to use a subwoofer in 2 channel setup. I listen to mostly jazz and classical music and quite sure that 800's are capable of producing adequate bass with proper amplification.
Any feedback would be appreciated.
Cheers!
For past few months, I have been trying to achieve best possible sound in my rig. The focus now is clearly on a improving 2 channel sound in what started as a home theater room.
In past couple of years, I have added N10, Modwright DAC and very recently a LS36.5 linestage . The amps are Modwright KWA150SE. I am running pair of KWA150SE's in bridge mode (450Wx1) for the mighty B&W 800D2's. While I like the sound as is, still feel something is missing.
I have been toying with the idea of bi-amping. One thought is to add mono tube amps to run mid's and high's and let the KWA150SE's handle the LF's. I am pursuing that seductive, slightly warm mid-range and top end that usually comes from tube amplification.
I don't think there is any tube amp out there by itself capable of powering up bass hungry 800's. I prefer not to use a subwoofer in 2 channel setup. I listen to mostly jazz and classical music and quite sure that 800's are capable of producing adequate bass with proper amplification.
Any feedback would be appreciated.
Cheers!
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- 61 posts total
Modwright KWA150SEThe 800D/2/3 are a bit of a vicious load not just in the bass which can get down to an "EPDR" ( equivalent peak dissipation resistance) of around 1ohm, but also in the 8khz which can get to an EPDR of around 3ohms. http://www.stereophile.com/images/511B800fig1.jpg Your KWA150SE is a very good amp to drive nasty loads with as it is bi-polar output, and having 6 pairs of them per channel, so it should do great current drive into those loads, better than tubes or mosfets Have you tried to use it in high bias class-A mode?, (switch on the back) as this should sweeten things up and not sacrifice any solid state detail and dynamics. Cheers George |
Lalitk I had a look at the amp specs online. so just my opinion walk up a hill at an easy pace. then run up that hill 4 times as fast. Walking up that hill is like your amp in stereo Running 4 times as fast up that hill is like bridge/mono mode. imo - Your stressing the amps. All B&W 800 series have always been far too revealing of upstream components. So agree with Georgelofi to just run them in stereo mode. But I assume you have done that already? You should also be running in high bias mode for those speakers. Again I assume you are doing this. I noted that the amps are also not able to double down. 8 ohms going to 4 ohms and no figure shown for 2 ohms at all. Power Ratings: • 150W @ 8 ohms (Stereo) @ .06% THD. • 450W @ 8 ohms (Bridged Mono) @ .06% THD. • 200W @ 4 ohms (Stereo) @ .06% THD. • 650W @ 8 ohms (Bridged Mono) @ .06% THD. And from the amp manual It is not recommended to run the amplifier in bridged mono into 2ohm loads. This amp would not have made my final checklist for the 800d2 speakers. http://www.modwright.com/products/kwa-150-signature-edition.php ******************** 68pete Hi Pete my systems are shown here just click on the runner. In my Room A - Matrix 800 + Krell Bass Alignment Filter Cheers. |
Not only are your speakers vicious (and tube-unfriendly) loads, as George points out above, but in the bridged mode you are using your amps will "see" speaker impedances equal to half of the already very low values he cited. Which can't be good for the sonics of the amps, even though I note that you indicated in this 2015 thread that Dan Wright had "optimized these amps for bridged mode," whatever that may mean.
Also, as others have alluded to there are a great many ways in which using solid state and tube amps in a biamp configuration can do more sonic harm than good. And even more so when the speaker is inherently not tube friendly in terms of either its impedance characteristics or its power requirements. My suggestion is that you consider trying your existing amps in a passive vertical biamp configuration, with each amp operating in stereo mode rather than bridged mode. Your speakers have low impedances in much of the bass region, and the 250 watt/4 ohm rating of your amp in stereo mode could very conceivably be adequate, especially given that each channel of the amp would only be supplying current and power in part of the frequency range when used in that configuration. The one caveat that occurs to me related to that configuration is that I'm not sure about impedance compatibility with your line stage. In that configuration the line stage's output for each channel would be driving the inputs of two amplifier channels, and would therefore see a load impedance equal to half of the input impedance of each amp channel. The input impedance of the amp is spec'd at "15K at 50Hz; 23K at 1Khz." The LS36.5 has a specified output impedance of 110 ohms, which would seem compatible with a load impedance of 15/2 = 7.5K, but as with many tube preamps the 110 ohm figure might be considerably higher at deep bass frequencies. That would be a question for Dan. Also, assuming you are using balanced interconnections between the line stage and the amps you would need an XLR splitter, such as these. In your older thread that I referenced earlier, BTW, I had advocated against a vertical biamp solution, but that was under completely different circumstances prior to your purchase of the Modwright amps. Good luck. Regards, -- Al |
- 61 posts total