Author Topic: Tube Friendly Speakers for Guys who Drive Volvos  (Read 5188 times)

BrentoRudra

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Tube Friendly Speakers for Guys who Drive Volvos
« on: July 18, 2011, 05:56:14 PM »
I get most of my stuff second hand; stuff which had been close to the top of the line ten years ago or reasonable priced high end gear that got slapped with an A or B rating in Stereophile in kinder days. I now drive very fine sounding Vandersteen 2ces with a Conrad-Johnson PV-10 preamp and a Rotel RB-991 solid state muscle amp running at 200 watts. For some time now I've been happy with this combo but once again dissatisfaction has set in. First of all, I love all tube systems. But the Vandersteens don't. My current setup is a compromise which gives me satisfactory sound for mostly large orchestra classical listening, meaning the Big Romantic stuff from modern instrument Beethoven to Wagner, Burckner, Mahler, Sabelius, Shostakovitch, etc.

Now, I've gone after my disatisfaction in the Amp and Preamp Fourm and gotten much helpful advice from some very nice chaps. My objective here is to approach it from the speaker end.

Having had a wonderful experience with a friend's open baffle speakers, which I would have simply bought (at the unbelievable price of $270!) had my wife not vetoed the idea, declaring them simply too ugly to live with. Well, I can't go against that: she lives here, too. So. There it is.

My goal now? Well, how about this? A high efficiency, full range speaker that loves tubes yet will tolerate solid state if it has to. More, that it doesn't oblige me to knock over a Chase branch or take out a second mortgage. What interests me is synergy. I find I've gotten marvelous results with my Conrad-Johnson tubed preamp going into a modified ST-70 or a restored Anthem Integrated 1, using the power stage. Two very different amps. One is EL-34 based, the other EL-84 based. I use them both, depending on my mood. I don't intend to stop with them but no doubt go on later to more refined amps, as my budget permits, but right now I am completely happy with them.

So. Any advise about speakers for such a person? Must he settle? Must he perish? Or is there a life beyond?

Thanks in advance,

Brento

Offline Triode Pete

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Re: Tube Friendly Speakers for Guys who Drive Volvos
« Reply #1 on: July 18, 2011, 06:12:14 PM »
I get most of my stuff second hand; stuff which had been close to the top of the line ten years ago or reasonable priced high end gear that got slapped with an A or B rating in Stereophile in kinder days. Now, I've gone after my disatisfaction in the Amp and Preamp Fourm and gotten much helpful advice from some very nice chaps. My objective here is to approach it from the speaker end.

My goal now? Well, how about this? A high efficiency, full range speaker that loves tubes yet will tolerate solid state if it has to. More, that it doesn't oblige me to knock over a Chase branch or take out a second mortgage. What interests me is synergy. I find I've gotten marvelous results with my Conrad-Johnson tubed preamp going into a modified ST-70 or a restored Anthem Integrated 1, using the power stage. Two very different amps. One is EL-34 based, the other EL-84 based. I use them both, depending on my mood. I don't intend to stop with them but no doubt go on later to more refined amps, as my budget permits, but right now I am completely happy with them.

So. Any advise about speakers for such a person? Must he settle? Must he perish? Or is there a life beyond?


This is a good deal, free shipping, no tax... ]http://www.overstock.com/Electronics/Klipsch-RF-82-II-Floorstanding-Speaker-Pack-of-2/5254370/product.html?rcmndsrc=2]

This is a good deal, free shipping, no tax... http://www.overstock.com/Electronics/Klipsch-RF-82-II-Floorstanding-Speaker-Pack-of-2/5254370/product.html?rcmndsrc=2
No settling, real good sound... reasonable price...

BTW, Top of the Line 10 years ago doesn't mean it isn't top of the line today... actually some "top of the line" stuff from the late 1930's, 40's & 50's may be "state of the art" today (at least by some sonic standards)...

Enjoy!
Pete
« Last Edit: July 18, 2011, 06:14:19 PM by Triode Pete »
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Offline richidoo

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Re: Tube Friendly Speakers for Guys who Drive Volvos
« Reply #2 on: July 18, 2011, 06:58:39 PM »
A speaker needs to have three attributes to make a tube amp happy.

1. Efficiency. For the 20-40W amps you're talking about, 93dB+ @2.83V/1W/1m would be welcome to play symphonic music convincingly. Efficiency with full range response means large drivers in large cabinets. You can't fool mother nature. Large cabinets are expensive, as are large drivers with low distortion. She may wish she went for the ugly open baffles. ;)

2. Impedance. 8 ohms nominal, with dips no lower than 4 ohms. Smooth impedance curve free of sharp spikes and ripples. The higher impedance load requires less current from tubes, which do voltage better than current. A SS amp fears high impedance spikes because it can't deliver high voltage, while a tube amp fears low impedance spikes because it can't deliver high current.   But a speaker with flat 4 ohms would work great with a tube amp. Flat impedance across the bandwidth is more important than high impedance. But very low impedance is a nono because it will cause the amp to clip - when it can't make the current the voltage must clip, same as when the voltage is limited by supply rails. You can't fool mother nature, Ohm's law.

3. Phase. The electrical phase should be mostly above 0 degrees, which is capacitive reactance. Inductive reactance is when the phase is lower than 0 degrees and this is uncomfortable for a tube amp.
http://en.wikipedia.org/wiki/Electrical_reactance

There is no speaker with high efficiency, high flat impedance with no dips, and low all capacitive phase shift. There will be warts on any speaker when you evaluate it for tube power. Higher budgets can solve many of these warts with an all out tube optimized design.

I just finished building speakers that are full range, high efficiency, easy load for low power tube amps. Love 'em! And I drive a honda! But my labor made the price very low. Parts alone were $2k.

Legacy, Coincident, AudioKinesis, make tube savvy speakers. Your Vandersteens are excellent tube speakers, if you have solid 100W to make enough current for the loud passages. Lots of vintage speakers like Klipsch horns were designed for low power tube amps. There are many others being made today also by smaller companies. Like Volti Audio.
« Last Edit: July 18, 2011, 07:08:34 PM by richidoo »

Offline JLM

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Re: Tube Friendly Speakers for Guys who Drive Volvos
« Reply #3 on: July 19, 2011, 04:46:35 AM »
I agree with Rich on the basics, but offer a couple of alternatives:

Subwoofers are the friends of tube amps, especially the wee little ones.  Takes the heavy lifting off the amp and opens up the midrange driver.  Also allows for smaller main speakers (even small standmounts with good efficiency).  For very high WAF consider TBI (very small, very placement flexible).  If you own and have the right architecture, also consider infinite baffles (a woofer built into walls/floor/ceiling) that would show just a grill.

The original Decware amps love low impedance, but are only rated 2 wpc.

BrentoRudra

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Re: Tube Friendly Speakers for Guys who Drive Volvos
« Reply #4 on: July 19, 2011, 06:50:45 AM »
All of this is helpful. Klipsch is an option. I've heard older models (also an option) but would tend to go for newer simply because they are not so bulkly and once they are here I don't have to have my DIYers go over them and then invest more to have them recapped, etc., or learn to do it myself with their guidance.

As usual, Rich (?), a throrough report, most helpful (and educational!), giving me an idea of what I'm up against here. I'll file it with your other papers for future reference.

One thing I should mention here that concerns me: I'm begininng to get dips with the Vandersteens now, even with the Rotel amp. I'm wondering if the speakers are needing recapping. If that is the case, I don't know as I'd bother. I think there are kits for this but only if they let you know how you unwrap the bloody things would they be of any use. My feeling is, they get consigned to the garage if I can locate something I like that I can afford. I'd even have to save up for the Klipsches at this point.

I do have a pair of BSRs which came with a load of stuff from a friend. There are ways of fixing these up so that they are fit for human ears, mainly with stuffing the speakers in such a way that the huge 15" woofer is fooled into thinking it is housed in a larger cabinette. Somebody sent me some advice on this. The main job is putting in new surrounds and refoaming the drivers. My DIY pals tell me it probably wouldn't be worth it, even though I have tried them and they do well with the tube amps, being of some unnumbered higher efficiency but of course there is the shrillness you'd expect from foam rot surrounds.

Right now I'm a bit stalemated. Need to save up. I had not planned on buying new speakers!

Thanks for the help thus far.

Offline richidoo

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Re: Tube Friendly Speakers for Guys who Drive Volvos
« Reply #5 on: July 19, 2011, 07:28:44 AM »
Not sure what you mean by dips in the Vandys, but they probably use film capacitors which should last forever.

It is easy to refoam your speakers. I did a pair of Cerwin Vegas D5s for a friend last year. They sounded great and sold to a local passionate midfi music lover. I found this to be the best place to buy refoaming supplies, they have complete kits with good instructions for most popular speakers.

http://www.speakerrepair.com/
BSR page: http://www.speakerrepair.com/mm5/merchant.mvc

The most important things to remember when doing this job is to clean the surfaces very well before you stick the new foam onto frame and cone. The other thing is to make sure there is no rubbing before it dries. It is not hard to center a vintage speaker because the magnetic gaps are not so small as the modern super drivers.  The glue is wet and can be slid around until the rubbing is gone. The instructions spell it all out.

Plain old pink fiberglass insulation is fine for acoustic damping. You still have to tune it by ear, because too much will make the speaker sound dead, not enough makes it ring. If it is a ported speaker keep a clear pathway to the open air volume, not obstructed by FG. Sometimes the original fluff inside old speakers is cheap polyfill which has poor absorption. But by changing anything you are redeigning the sound of the speaker, so you have to listen and tweak each change.

BrentoRudra

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Re: Tube Friendly Speakers for Guys who Drive Volvos
« Reply #6 on: July 19, 2011, 07:47:54 AM »
Well, I may or may not go to the trouble with the BSRs. It would be one way to get past my DIY block. I'll have to locate my BSR file in which someone had advised me on refurbishing these speakers. He had recommended a specific kind of material for lining the speakrs in additon to stuffing them. Interesting thinig about these things is their 15" woofers. Ridiculous for the cabinet size but I'm told they can sound good. They already do, if a bit boxy from enclosing all those drivers in a small space. We shall see. I'll get back.