About 9 years ago I bought a Classe CAP-101 integrated amp for my 2 ch. living room audio system. At the same time I bought a pair of B&W CDM 7NTs to go with it. The sound was great and all was well. The CAP-101 is rated at 100w/ch into 8 ohms, and the speakers are rated at 50 - 150w.

When I decided three years ago to build an HT system with an Outlaw 1070 I moved the speakers upstairs to go with it. A neighbor was selling a pair of B&W 703s at a reasonable price, so I put them in the living room. The 703s are rated at 50 - 200w. The problem is that I have always thought the 703s were a little less clear sounding than the smaller CDM 7s. It's not that they're unpleasant, but music is not as tight. Drums and other low frequency sounds tend to be a little fuzzy.

The question: is it the speakers themselves, or is it that the amp has to work harder to drive the larger speakers? If it's the speakers then I either live with them or replace them. If it's the amp, I could use it as a preamp and fix the problem with a bigger power amp?

whats the specs of the speakers(ie efficiency)? im not that well versed on their line, but i have a friend here that raves about his 703's, but he is pushing them with a large Pass labs amp though.

It is possible that the amp is a little underpowered but the 703s have a 90db efficiency which should allow 100 watts of power to drive them just fine.

To answer an earlier questio, the sensitivity of the 703s is listed as 90db, but the CDM 7NTs have the same rating. The difference is the 3d driver in the 703s and a power rating of 50 - 200 watts into 8 ohms, as opposed to 50 - 150 watts into 8 ohms for the CDM 7s.

I have been searching the net and found some posts saying the 703s are relatively easy to drive and others saying they suck lots of power. But that is the way of the internet. Everything has fans, anti-fans and lots of people somewhere between; and it's hard to tell which among them actually know what they're talking about.

For me, the immediate question is, do I spring for a pair of M2200s while they're on sale, in hopes they will improve the sound? If that will work great, but if not I send the amps back.

An old axiom comes to mind when comparing speakers. The louder speaker almost always sounds better. If the M2200s will drive your speakers harder, then they will likely appear to sound better. Do you have all four speakers connected to the same amp such as channel A/B. If you are trying to drive all at the same time, it is likely that the most the amp can output is less than the max and possibly less than the recommended power of 50 watts. If this is the case then I wouls expect the M2200s to make a big difference.

This is just a 2 speaker system. I was using the CDM 7s for comparison, not as part of the system. So the CAP-101 is driving only one pair of speakers, now the 703s, and they are receiving all the amp can put out.

XenonMan is wise. do it while the price is right, might not be this cheap again until Xmas.


....and be sure to follow up afterward with your opinion!

At 100 watts or slightly more for each channel, I would expect the Classe to easily drive the 703s to painful levels without breaking a sweat. Have you tried moving them around the room some to see if the room is a little too absorbent? Also verify the polarity of your speakers to make sure they aren't canceling each other out. I would expect both sets of speakers to behave similarly based on there similar efficiencies. They may sound different but they should both play very loudly without distorting. Are all the screws tight on the 703s and no damage to the speakers themselves. I don't know how the speakers are constructed but sometimes the flex ring around the edge deteriorates and the speakers sound terrible.

Volume is not the issue. I can crank them way beyond where you could sit in the room and listen, although I have to turn the volume up several notches above where it was with the CDM 7s. With the 703s I'm still in the lowest 1/3 of the amp's range.

The issue is more clarity at the low end.

I will try moving the speakers around a bit and I'll put the bungs in the air ducts to see if I can fix the problem. The speakers are in very good condition, no damage to the cases or the cones, and the cables are tightly connected.

Thanks

If you can drive them very loud the addition of the M2200s is probably not the solution to the issue. At most, it would provide 3 db more SPL at max output. I do not think your Classe is the issue. Moving the 703s around is likely the solution along with playing with the plugs. I did notice in a review that the 703 uses a diffent type of seal ring around its midrange which you might want to inspect closely. I doubt if that is a problem but since it is different I would look at it.

Can I jump in here with a question about low-powered amplification? I recently upgraded my makeshift center-channel speaker from a Totem Acoustic Mite to a Von Schweikert VR-1, now I'm thinking of switching monoblocks to drive it. I'm currently using a Marantz MA-500 amp, which kicks 125 watts. Suddenly I've been thinking about a tube mono or something, but that means maybe 45 watts. Will that be enough to push the VR-1? I've read that it is a pretty "efficient" speaker, but maybe I should just stick with higher wattage? I've also thought about going bigger with an Outlaw M2200, though the sale just ended. I do everything on the cheap, so I have to strike when I can catch a deal.

The VR-1s are 89 db efficient. 45 watts ought to drive them pretty hard. I would expect at least 104 db SPL out of the tube amp. For the solid state amps I would stick with what you have. 200 watts is not a lot more than 125 watts as far as SPL. It is less than 3 db increase and will be hard to hear.

Thanx, XenonMan. Great info. Next step, finding a tube monoblock that's audiophile quality, compact and affordable. Here we go again…

Anyone have any experience with Dynaco tube amps? I've come across a couple in my price range, but I'm a bit skeptical, not because they're vintage, but more for things like bass control, which seems to be their weak spot.

I have rebuilt a few ST70's and have been very pleased with them. I've used them with a variety of speakers from Klipsch LaScalas, Polk LSI's, many different NHT's, KEF's, AV123 Encore's, Advents and many more. I love the Dynaco's and bass control has never been a problem, even when using the stock driver circuitry. Try one out, you won't lose money they hold their value.

they can turn a average set of book shelf speakers into a mind-blower!

Thanx, cats. Really helpful to hear about the ST-70 in particular, Keta, because the monoblocks I've been assessing, Mark IVs, are actually the mono versions of that stereo amp. They also fit my space requirements; one Mk IV will easily slip into the space currently occupied by the Marantz MA500. I'll report back if I end up acquiring something. Thanx again.

Just checkin' in to say that I've been living with a Quicksilver Mini-Mono tube monoblock for about three days now, and the 25wpc power seems to be enough. I'll check in again when I've done some critical listening and tube rolling.

Tube update: Think I'm done tube-rolling with this Quicksilver monoblock, because the current configuration sounds positively stunning. I think I said that the Telefunken 12AX7 tube was an instant improvement in the input slot, but it even got a boost when I rolled a matched pair of bottle-looking JJ/Tesla KT88s into the outputs.

JJ/Teslas in particular seem to make this amp sing…before I settled on the KT88s, the other pair that impressed me were JJ/Tesla 6L6GCs. In between, I rolled in some vintage Russian military tubes shipped from Moldova (6P3S-Es; dull-sounding) as well as a pair of extremely hard-to-find EI KT90 v.IIIs from Serbia, which were s'posed to blow everything else away, but sounded a bit shrill to me even though they had hefty bass. (I'll probably sell them soon.) With the KT88s, I suddenly got the same feeling I got when I blundered into mid-fi by bi-wiring my former Totem Mite loudspeaker. Sometimes you're just experimenting, and voila! it feels perfect.

I have a ST70 that needs a little love. Care to recommend any good parts and kit sources?

very nice tru blu! I am red with envy, I want a tube amp to play with so much. Congrats on the audio nirvana!


charlie, Ive seen a lot of upgrade kits for those Dynaco amps on ebay. I know there is one guy even doing them on a mail in basis.

confession: I lurk ebay tube amps.

Try www.curcioaudio.com

Jimna, you don't get to have a tube amp 'cause you already have a Grace Lunatec v.3. How's about saving some fun for the rest of us?

Rolled in those EI KT90 tubes again, and realized I misrepresented them. It's not that they're shrill; their sound is actually pinpoint accurate. The JJ/Tesla KT88s, however, provide a real balance between clarity and what I think is perceived as "tubey" sound. There's a fullness in the presentation that's liquid without being mushy. It turns out to be the optimal (optimum?) blend with my RR2150-driven NHT Classic Threes.