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I have read this before and its been said that biamping tube amplifiers is not recommended. What is the reason for this? Does the tube amp really need a full load in order to work properly? I was planning on running a tube amp with some mids and tweeters, while the bass woofer is off a second SS amp. Does anyone see any issues with powering the speakers this way?
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At least with the components that I was using. My electronic crossover was an old Crown VFX2, that was based around 4558 opamps.I built high quality passive crossovers using Solen caps and heavy air-core inductors. The system now sounds much better.
The only problem is in having to use L-Pads to turn the horns down to match the woofer's level. It was easier using the input level control on the power amps when biamping.
I used to use Solen caps in my crossovers until I tried some other brands and realized how raspy the Solens made my system sound. Right now I'm using Sonicaps and I'm very pleased with their sound, and they're reasonably priced to boot.http://www.10audio.com/sonicap_oimp_multicap.htm
The only reason bi-amping would cause a problem with ANY type of amplifier is if the amp in question is not stable without a load. When bi-amping with passive crossovers the amp will be essentially unloaded in the reject band (low frequencies if driving a tweeter). Some amps will oscillate without a load.I used to have an bi-amped system using active crossovers, two modified Dyna Stereo 70 amps and Altec Voice of The Theater horn speakers. It worked very well.
PeteThat's because of global feedback.
Without GFB amps are stable into no load.
Of course I don't use GFB in mine.
If you bi-amp there is no need for the
increased dampening factor for the bass
it isn't doing so I say remove it.
If you NEED GFB for your amp to be linear,
then sell it and buy a good one IMO.
DanL,It is not feedback per se, but the incorrect use of feedback, that causes problems. As for damping requirements, the speaker needs dictate the damping requirements. In the case of the Altecs I mentioned, they were over damped to begin with so a low damping factor was desirable. Modern small box speakers tend to need (and are designed assuming) high damping from the amplifier.
Ok. I'll fill in the details. The tube amp is a McIntosh MC275 V and will be running the mids and tweeters using the speakers internal crossovers. The crossover for the mids is 350HZ. The speakers are B&W 804S units. The MC275 has a input level control. For bass I was planning to use the SS Rotel RB 1070 amp I already have. Preamp may be a McIntosh C220.
I have read those who believe all channels should be identical, but that's sure not my experience. My last 2 system were actively biamped with a big SS amp on the bass and a medium or small tubed amp on the MR and treble.I'm now actively triamping my high-sensitivity system with 2.5 Watts of tubed SET power on each of the treble and MR channels and that same huge SS amp on the bass.
My system sounds better and better as I improve it. Here's the latest improvement, that 2.5WPC tubed SET.
PS. One doesn't biamps amps, one biamps speakers WITH amps. :-)
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I also Bi & Tri amp, SS bottom end, with tube amps on widerangers & tweeters. Woulsn't have it any other way.. Many say mixing differant tube amps btween widerargers or mid drivers & tweeters is not a good idea..I bought that till I tried it & works just fine..in my application..SS bottom end -PP on widerangers-SE on my ribbons...I run mostly bi-amp though. just HP the tube amp in PLLXO mode if you can get away with it or just go active you you are getting crazy.. keep the SS amp @ 4th order active 150hz & down... it will start to show it self in the wrong way if you get to high up..relieving the load on the tube amp works much better IMO..If yo are using widerangers of fairly high EFF.. then just PLLXO the tube amp at the input of it .. if you can handle op-amps, then active is a good bet.
Should not be a problem, if done right. I know a couple of very experienced audiophiles that bi-amp their all-tube systems.
I bi(tri, quad)amp all my setups: SS on subs, PP on midbass, and SET on tweets; call me crazy but I like it on every try, irregardless of application. If you like it, do it!
I *like* the loudness button!
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