Bartockfan, FWIW, while you are doing your research factor in a couple of more issues, or at least possibilities....
1) Its not some much whether it's 4 or 8 ohms for a well made PP tube amp, its about the impedence curve and the minimum impedence. Some tube amps do quite well down into the 2ohm area and even come with 2 ohm taps. Its much more about the design of the actual tube amp than anything else generically speaking. Its also important to understand the actual output impedence curve of the amp and its synergy on the impedence (curve of the amp).
2) Be sure that the bass below 35 hz is unimportant to you by what you actually hear in your room, not just by looking at the supposed frequency response of instruments. If for example your room has a null in the 35 - 40 hz area your going to have nothing below 35hz to reinforce the bass which even starts to resemble the deep bass you would hear in a hall. Now if you room is flatish down to 35hz and you have a node at 30 hz the Towers may be more than enuf.
Perhaps its just because I don't listen to the Sig Systems at ear bleeding levels but I have no problems with tube amps with 40 to 80 watts in my medium sized room. In my room the Super Towers would not work due to room acoustics.
FWIW. |
Trelja,
Sure glad you can read thru my lack of editing skills. For others, last words in 1) "(curve of the amp)" should read (curve of the speakers).
Glad I don't get paid for this! :-) |
"Duke builds panels"
I didn't know that. Bartockfan, you are a wealth of obscure information. :-) |
Tvad, ROTFLMAO. Don't hang around any crosses. You are far too nice.
Bartockfan, may I suggest that before you burden the forum readers further with your 'experience' using tubes that you take some time to read about tube technology and get some understanding of whats actually going on. You might just learn what the benefits of properly biasing tubes are and what the risks of not properly biasing your tubes are. Its got nothing to do with getting "a tad more highs" as you seem to think. |
Divad, You might consider posting a new thread - I think a lot of folks not already signed into this one will open it and see it, and some of the more knowlegable folks that have posted probably may not be following it any longerby now.
I think it is possible (actually quite probable) that a tube amp with a wattage limitation of 65 in Ultralinear can drive a 90db speaker depending on the actual impedence curve of both the amp and the speakers and how they interact. Your nominal impedence and minimum impedence are not ideal for just any old tube amp, unfortunately.
Usually ultralinear is going to be a bit more forward/focused and triode will be a little more recessed and relaxed. Usually, but this is very amp dependant, and either mode can better fit with certain speakers that the other. I have a 'triode amp' which sounds neither laidback nor unfocused, and responds much as another amp I have when its in ultraliner.
Your speakers are fairly well know (to others) but you prospective amp is not. I would suggest that you post here and on Audioasylum and try to find folks who have actually used a tube amp with your B&W so you can find out what they need to drive them.
If you can find out, it is helpful to know exactly where your speakers minimum impedence droop appears (at some frequencies it won't be near as important as others) and if you can find out the maximum output impedence of the amp and at what frequency it appears. With that info there are some very knowlegable folks about who can give you some advise.
I hope this helps a bit, I know it really doesn't do much to specifically answer your question. But, if you are a gambler, you can afford a buy and sell loss should you be unhappy, and you are not a bass nut (thats usually where you will run into problems) you can always get a tube amp and drive it off its 4ohm tap and hope for the best. :-) |
Tvad
The Tyler Signature Systems (1 Piece) have a nominal 4 ohm impedence and a minimal impedence of 3.5 ohms. I have driven mine with 160 wt amps w/6550s off an 8 ohm tap, 80 watt with KT88's off an 8 ohm tap, the PrimaLuna Five a 40wt amp with KT88's off the 4ohm tap (and 6550's as well), and my present Cayin a 70 watt amp w/KT88's off the 4ohm tap. The KT88's I was using are SED's. Power wise they all worked fine, the differences were in tone. I also used a 100wt high(ish) current ss amp and it in no way improved on the tube amps.
But, I also used another brand of KT88 in each of those amps and the sound of this KT88 was rolled off/enimic on both extremes and flat in the midrange. Very boring. I would have much preferred some of my 6550's, maybe even some of my old EI KT90's, if that was the only KT88 available to me. If I had speakers with no bass and a bright highs that particular tube might just be the tube needed.
I doubt that BF's experience has anything to do with Tylers Linbrook speakers impedence curve.
FWIW. |
Tvad, This info came from the horse's mouth. I've never seen it in print, its what Ty told me.
Re impedences, there was an excellent thread in which Duke participated, within the last 6 months, where in not only were speaker impedence loads discussed but amp output impedences were also discussed. Amp putput impedences are seldome discussed and their impact is not generally understood. Most folks assume they are constant but they are not, they rise and fall with frequencies and have considerable impact of the sound which is produced by a speaker. You might be able to ferret it out by looking up some of the threads in which he participated. And, I think you are right the Ralph could help explain, but I can't recall if he participated in that particular thread. Maybe you could start a thread and get a discussion of this going and invite Duke and Raplph to participate. This may help you. Good luck...... |
Divad, You didn't ask, but what the hell.....
If you want powerful bass stay with an amp that is designed around the 6550/KT88/KT90. EL34's are potentially great mid-range tubes but lack the bass of one of these power tubes. In my systems the KT88 has more 'color' (as does the EL34) than the 6550 or the KT90. It reminds me, somewhat of an EL34 with balls.
In your place I would start with an amp designed around the KT88. There are a lot of different brands with different tone available for substituting in KT88's, most new production are quite good.
Re Chinese tube amps (I've got three) be mindful of a couple of things which can be important. Support is #1! If you're not a techie type and can't maintain and fix things yourself, get something which can be serviced without a return to China.
Also, one of the things that some Chinese amps are starting to appear with are on-deck bias meters and bias pots for each tube. Highly recommended feature! Allows you to easily maintain proper bias, follow tube wear, and replace or substitue tubes. Auto bias curcuits are also good for new tube amp users, but IMHO, in the long run manual bias with post for each tube are far more beneficial to the user.
Also, some Chinese amps are now coming with fuses that protect the bias curcuit in case of a tube short. Very important unless you can solder in new resistors. The sonic compromise by having a fuse is, IMHO, minimal if any for most folks.
Hope that helps you a bit. |
Tvad - FWIW, dealing with like kinds, ie SED's, I found the 6l6GC slightly mellow thru the upper mids/highs compared to the EL34 in both of my Primaluna amps which were primarily designed around the EL34 or the KT88 and to my ears both sound best with that the tube around which it was designed. I've been sort of interested in hearing an amp designed around 6L6's but I haven't found one yet. I tried them in my Baron but they were to hot - I'd have to get it modded (it takes 5881's).
JJ is the only maker of KT77's right now that I'm aware of. On AA several posters have been high on the sound they make, but there is some strong comments on quality control and pin size. FWIW - you probably already knew that. |
Eagleman,
A simplified response -
If bass control seems to be a problem for you when you use the 8 ohm taps use the 4 ohm taps. If you use the 4ohm taps and the highs are not smooth use the 8 ohm taps.
Simply said, use the taps which sound best to you. My guess is that if you are listening at moderate levels the 8 ohm taps might sound best. |
