Bi-Amping Von Schweikert speakers

StereoNut · « **Reply #40 on:** 12 May 2014, 08:33 pm »

Hello all!

I own a pair of VR-4 Gen.III speakers with the 2012 mods done by VSA. The "old" (original) cross-over specs for my speakers (before they had the 2012 mods done) were 150 Hz and 2.6 kHz. Can anyone tell me whether the crossover specs have changed now with the 2012 mods done and if so, what are they!?!

FWIW - I'm looking into trying to Bi-Amp them. (My current amp is an completely updated N.Y.A.L. Moscode 600 Hybrid modded by George Kaye.)

Thanks!
Bill

Albert Von Schweikert · « **Reply #41 on:** 20 May 2014, 04:39 pm »

StereoNut,
How are the experiments with biamping your VR-4's going?
Albert

walterslw · « **Reply #42 on:** 4 Jan 2015, 03:53 pm »

Hello fellow VSA fans.

Hoping someone can help me.

I have a pair of VSA VR 5 Anniversaries Mark IIs (the last ones build by VSA). As you may have seen I was thinking of selling my Brystons and moving to something else (may still do so), but leaving all options open, and reading through this thread - with Albert making the suggestion of bi-amping I figured what the heck. My Bryston 7 B SSTs put out 600 W into 8 ohms and 900 W into 4 ohms, are very good at controlling the bass, so I figured they would be a great amp for the 4 ohm woofers of my VR 5s. Now here is where I need some advise from the experts - hoping Albert can chime in here...

What do you all recommend for a tube amp for the top? Here are some that I was thinking would be a good match:
BAT VK 75 SE
Assemblage ST 40 - Completely rebuilt to modern specs with SE + Mods (40 W / channel of EL 34 power)
Rogue Stereo 90 / Stereo 100

I do not have a ton of $$$ to invest, and may be selling a 1 year old set of 8 FT MIT Magnum M 1.3 Speaker Cables to finance the purchase of a tube amp. I am trying out Grover Huffman's latest speaker cables to see how they fair. Eventually I would like to go to Master Built Cables, but not in the budget for this year. I have Grover's latest power cords and interconnects (balanced), and they are excellent.

My pre amp has 4 outputs, 2x SE, 2X balanced, and I run everything balanced front to back. Its okay if the tube amp has RCA inputs, I will use the XLR to RCA cardas adapters. I listen to mostly Alternative Rock, Classic Rock, Jazz, and Electronic, so I am not looking for a mushy or romantic tube sound, rather the open, airy and snappy sound that I remember having with my Rogue Stereo 90 6 years ago.

I think that the Brystons can more than handle the bass woofers, and are set to 23 dB of gain for 1 V of input, via XLR inputs.

The reason I like the Assemblage unit is that I live very close to Parts Connexion and they can be serviced and upgraded by PC, without having to ship - they are also not very expensive.

Looking for some input... Am I nuts? Should I just lower the price on the Brystons, sell them, and move onto something else? Or keep the Brystons for the bass and go tubed on the top? Are there any other suggestions for my tweet/mid amp that are not tube -i.e like a digital amp or a different brand of a SS amp? Is Bi-amping even worth it, or is this going to be a giant PITA

Appreciate the information / feedback.

Lou

kernelbob · « **Reply #43 on:** 4 Jan 2015, 05:38 pm »

Hi Lou,

What you suggest for a biamping configuration is what I use with my VR100XS system. I have beefy solid state amps connected to the woofer terminals. This allows me to select amps for the mid/tweeter terminals that may not have the best deep bass extension or woofer damping control, but that have strengths of detail, correct timbre, air, microdynamics, etc.

It's very difficult and expensive to find one amp that excels all areas and since you already have amps that fit the bill for the bass, you have a wide range of options for the mid/tweeter amp(s).

Unless you manage to find a set of amps that have exactly matching gain levels, you'll probably need a means of attenuating the signal to the bass or mid/tweeter amp-- preferably the bass amp to avoid complicating the signal path to the amp on the M/T.

This solution also gives you the capability to fine tune the level of the woofers relative to the mid/tweeter much the same way as do the various VSA Aktive series of speakers.

Best,
Robert

walterslw · « **Reply #44 on:** 4 Jan 2015, 06:03 pm »

Quote from: kernelbob on 4 Jan 2015, 05:38 pm

Hi Lou,

What you suggest for a biamping configuration is what I use with my VR100XS system. I have beefy solid state amps connected to the woofer terminals. This allows me to select amps for the mid/tweeter terminals that may not have the best deep bass extension or woofer damping control, but that have strengths of detail, correct timbre, air, microdynamics, etc.

It's very difficult and expensive to find one amp that excels all areas and since you already have amps that fit the bill for the bass, you have a wide range of options for the mid/tweeter amp(s).

Unless you manage to find a set of amps that have exactly matching gain levels, you'll probably need a means of attenuating the signal to the bass or mid/tweeter amp-- preferably the bass amp to avoid complicating the signal path to the amp on the M/T.

This solution also gives you the capability to fine tune the level of the woofers relative to the mid/tweeter much the same way as do the various VSA Aktive series of speakers.

Best,
Robert

Thanks KB

If I could find a great pair of balanced passive attenuators that I could plug directly into the most sensitive amp - that would be ideal. I have reached out to parts connexion to see if they can match the assemblage tube amps to that of the Brystons. if they can I may be in luck. I do like the idea of being able to fine tune the bass and may end up building a passive attenuator myself. There are a few passive attenuators available based on 1% descrete metal film resistors. My Brystons do have selectable gain so I could switch them from either 23 dB of gain to 29 dB of gain to get close to whatever amp I end up getting.

JackD201 · « **Reply #45 on:** 4 Jan 2015, 07:02 pm »

I believe Dusty at CIAudio can make attenuators for you Walter. No idea about the price. You can try shooing him a PM.

walterslw · « **Reply #46 on:** 4 Jan 2015, 08:31 pm »

I think this would be my best bet:

http://www.goldpt.com/sa1x.html

Unfortunately, almost always tube amps seem to be more sensitive than big solid state amps. At least any of the brands I have looked at. So would likely need to attenuate the tube amp on the top.

Albert Von Schweikert · « **Reply #47 on:** 6 Jan 2015, 07:34 am »

Do not forget that it is not the most powerful amplifier that must be attenuated, it is the amplifier with the highest input sensitivity. Check our the input sensitivity rating on the Bryston and your proposed tube amps. If they are the same, then only the amplifier's gain structure will dominate, and the higher power amplifier may indeed be the one that will need the attenuation. However, in many cases, the tube amplifier is more sensitive at the input, and even if the tube amp has 50 watts while the Bryston amp has 200 watts, you would need to attenuate the tube amp as it will get loud very quickly, while the Bryston might be just getting enough juice to play, but not quite as loud as the tube amp.

So, what you need to find are 1) Input sensitivity in mV, and 2) gain of amplifier in dB. If the Bryston amp requires the attenuation, you should call Dusty at CIAudio and get one of his attenuators that use an Alps pot. They're low in cost but work very well. If you order a unit from him with a set of switchable resistors instead of pots, the cost will be much higher but would be worth the money if you need to attenuate the tube amp, since a switched resistor sounds much better than a potentiometer (all else being equal).

Have fun!

JohnR · « **Reply #48 on:** 6 Jan 2015, 08:22 am »

Albert, could you please respond to my PM (or the email from audiocircle.com). Thank you...

walterslw · « **Reply #49 on:** 6 Jan 2015, 09:33 pm »

Quote from: Albert Von Schweikert on 6 Jan 2015, 07:34 am

Do not forget that it is not the most powerful amplifier that must be attenuated, it is the amplifier with the highest input sensitivity. Check our the input sensitivity rating on the Bryston and your proposed tube amps. If they are the same, then only the amplifier's gain structure will dominate, and the higher power amplifier may indeed be the one that will need the attenuation. However, in many cases, the tube amplifier is more sensitive at the input, and even if the tube amp has 50 watts while the Bryston amp has 200 watts, you would need to attenuate the tube amp as it will get loud very quickly, while the Bryston might be just getting enough juice to play, but not quite as loud as the tube amp.

So, what you need to find are 1) Input sensitivity in mV, and 2) gain of amplifier in dB. If the Bryston amp requires the attenuation, you should call Dusty at CIAudio and get one of his attenuators that use an Alps pot. They're low in cost but work very well. If you order a unit from him with a set of switchable resistors instead of pots, the cost will be much higher but would be worth the money if you need to attenuate the tube amp, since a switched resistor sounds much better than a potentiometer (all else being equal).

Have fun!

Thanks Albert -

It turns out I am having Parts Connexion do a full upgrade and modification to a NOS Assemblage ST 40 (EL 34) based amp. I spoke with Chris J, and he will match the input sensitivity of the Assemblage to that of the Bryston. I am likely going to get a GoldPoint balanced stepped attenuator - they are a little more money, but they are supposed to be completely transparent, and if I have to use them on the tube amp, it will have the least amount of impact.

So Albert if I understand what you are saying - it is important to match the sensitivity as close as possible, at which point I need to look at the gain, and the amp with the highest gain (will play loudest) and require attenuation.

I will follow up with Parts Connexion as I have all of the information required for the Brystons.

walterslw · « **Reply #50 on:** 25 Jan 2015, 08:53 pm »

Just wanted to post an update, bi-amping the VR 4 Annies Mk 2 is definitely the way to do. Instead of selling my Bryston 7B SST Monoblocks, I decided to keep them, where they would be used for the bass. I really did not want to get into any type of attenuation for either the top amp (tubes) or the bass amps... I lucked out in that I found a NOS Assemblage ST 40 tube amp, based on the EL34 tube. I couldn't settle on stock, so I contacted Parts Connexion where they re-built the amp with many significant upgrades, which included (but not limited to) bypas caps, Silver internal point to point Wiring, upgraded sockets, fuses, even many of the resistors and fuses were upgraded. In addition, because PC was upgrading an already good amp, I contacted the engineers at Bryston, in order to provide all of the important specs regarding input voltage sensitivity and gain to Parts Connexion so that they were able to internally match the Assemblage ST 40 to that of my Bryston 7BSST Monoblocks.

So the Brystons output ~900 W into 4 ohms, and the ST 40 - 40 watts into 8 ohm, and let me tell you the match is perfect. The new ST40 only has approx 10 hours on it, and I am sure the coupling caps (as well as the EL34s) will require some time to break in. But last nights listening session was glorious, this amp has all of the air, texture, and tube goodness that I was looking for - without the euphoric, mushy, or romantic tube sound (which was not what I was looking for). I had a long email exchange with Chris @ Parts Connexion prior to pulling the trigger, and sonically, this amp is a great match for driving the mid / tweet of the VR 5 Anniversary MK II. Yes I could have spent more on something more powerful, or a fully differential tube circuit, but sometimes simple is better, in this case it works perfectly, and even at very loud volumes, I could not hear any signs of tube compression. If the tube amp continues to improve (as I suspect it will) during and post break-in, I am going to be in for a real treat. So far, I am very impressed, and now I know why Albert recommends bi-amping - it is how these speakers are meant to be heard.

kernelbob · « **Reply #51 on:** 25 Jan 2015, 11:32 pm »

Hi Lou,

Great to hear of the excellent results you've achieved with biamping. Going that extra mile to match the levels of the M/T and bass amps is an elegant solution. It's impressive that the amps are so different in power and topology, yet integrate so well. Your implementation provides the power and control for the woofers and the delicacy, detail, and nuance on top to allow the M/T to perform at their best. The load on your tube amp will also be eased since the high impedance below the crossover point in the M/T section will provide an easier load to the tube amp. Getting that net performance from one amp (if you can find an amp that does everything well) would be in a whole other price class.

Best,
Robert

Chrisandalex1 · « **Reply #52 on:** 26 Jan 2015, 01:48 am »

Albert,

I would like your recommendation for a great tube amp to match the Kismet extreme amps Klaus is building for me. I hadn't really planned on Bi-Amping the Vr4jr's, but now that I have spent a few weeks reading and trying to understand, I am thinking what the hell, why not.

I think that the Odyssey Kismets and the 2 V-10 Shockwaves are going to handle super fast, explosive bass. Now I want to have equally impressive results with the Mids and Treble.

What are your thoughts? I know it is important that they match well.

walterslw · « **Reply #53 on:** 26 Jan 2015, 05:16 pm »

Quote from: Chrisandalex1 on 26 Jan 2015, 01:48 am

Albert,

I would like your recommendation for a great tube amp to match the Kismet extreme amps Klaus is building for me. I hadn't really planned on Bi-Amping the Vr4jr's, but now that I have spent a few weeks reading and trying to understand, I am thinking what the hell, why not.

I think that the Odyssey Kismets and the 2 V-10 Shockwaves are going to handle super fast, explosive bass. Now I want to have equally impressive results with the Mids and Treble.

What are your thoughts? I know it is important that they match well.

Hi Chrisandalex1,
Whatever tube amp you pick, since you are having Klaus build you a set of Kismets, you could have Klaus match the levels (input sensitivity and gain) to that of your yet to be purchased tube amp. It will be good to know what the sensitivity is of the M/T section of the 4 Jr prior to deciding on what type of tube amp you choose. Not sure what the sensitivity is with the VR4Jrs are, with the 5 Anni Mk II, the M/T module is efficient with a sensitivity in the mid 90s and an 8 Ohm load, so relatively benign for an amp - so not too much power is required. What type of tube amp may have allot to do with the type of music you listen to. In my case, I didn't want a euphoric tube sound - in addition, I listen to a lot of rock music - so I based my decision on that.

For myself, one thing I may look into - in a few months from now after the new amp is broken in - is to get some NOS small signal tubes (IMO) they can alter the sound of a pre amp / power amp quite significantly.

Good luck with your journey - let us know what you end up with for your tube amp.

StereoNut · « **Reply #54 on:** 26 Jan 2015, 05:53 pm »

Quote from: Albert Von Schweikert on 20 May 2014, 04:39 pm

StereoNut,
How are the experiments with biamping your VR-4's going?
Albert

Sorry, Albert. I just saw this now!

The bi-amping didn't work out very well for me. I'm not saying it can't, but for what I tried, my system sounded better just "plain old stereo" amped. See the "cut & pasted" comments from one of the other audio forums below in blue:

"I have finally (two and a half months after the May Audio Syndrome meeting at my house) gotten around to spending some time with my system to evaluate it better.

First a quick re-cap. My system had been configured as a normal stereo (one amp) set-up.

The purpose of the May meeting was to compare bi-amping to my original set-up. The Bi-Amping was set up with my Moscode 600 Hybrid (tubes front end/Moscodes on the back end) powering (300 WPC into 8 ohms) my (top) mid/tweet cabinets with old MIT "Music Hose" cable and two Dayton monoblock subwoofer amps (900 WPC into 4 ohms) powering my (bottom) woofer cabinets with "nothing special" Monster cable home-brew speaker wires.

Pre-amp was my battery powered 12B4A tubed Dodd.I haven't listened to this Bi-Amped set up enough to really have a good grasp on what it sounds like. Initially, I liked the clarity, dynamics and ease that the Daytons brought, but I felt like the system (with my CDP & DAC) sounds a bit too clean (if that's possible?) and lean, Accurate, but almost "Hi-Fi clinical" to me. Maybe my QED speaker cables (without Bi-Amping) were giving me a better synergy than the set up now with the MIT "Music Hose" that Tom lent me...??? I don't know, but I felt that something was missing!?!

Fast forward >>> I re-evaluated my system this past week with a fellow Syndrome members help.

*** Note: I removed one variable by nudging my right speaker over a little closer to my amp and putting my QED Silver Spiral speaker cable back in place. No longer using the Music Hose cables. ***

1) Bi-amped: Same as before. I liked the clarity, dynamics and ease that the Daytons brought, but I felt like the system (with my CDP & DAC) sounds a bit too clean (if that's possible?) and lean, Accurate, but almost "Hi-Fi clinical" to me. Bass was a bit "thumpy", but if you dialed the Daytons down, the system got even leaner! My buddy agreed.

2) One Amp Stereo: Less Hi-Fi 'isn than Bi-Amp. Bass wasn't quite as articulate, but we lost the "thumpiness" (is that a word!?!

) Sound was MUCH more cohesive. No longer a gap between the bass and the mid-bass. Bi-amped set-up sounded like there was a poorly dialed in subwoofer in a sub/sat system vs. the one (Moscode) amp set up. Again, my buddy agreed.

3) One Amp Stereo (again with Moscode 600) but with a Pre-amp change. We replaced the Dodd 12B4A battery powered pre with a Primaluna Prologue Premium pre-amp. (http://www.primaluna-usa.com/product-main/prologue-premium/pro-prem-pre) Wow! This is what I've been chasing ever since I heard Rob's (rpf) Rogue Cronus (?) Magnum Integrated in my system a year ago! Everything became more musical. More body and richness. A more relaxed presentation, yet without losing any detail. Is it as linear and un-colored as the Dodd...??? Absolutely not, but I like it better! Once again, my buddy agreed."

I hope this helps to answer your question.
SN

P.S. to Albert: Regardless of the higher sensitivity on my 2012 modded VR-4 Gen.III as compared to before, they just LOVE the power the Moscode 600 gives them!

walterslw · « **Reply #55 on:** 26 Jan 2015, 09:09 pm »

Thanks for sharing SN.

It's interesting how different everyone's experience is (plus personal tastes). So when I posted my initial feedback of how the bi-amping sounded it was with "MacGyvered" speaker cables for the bass, and my bi-wire set of big MIT cables connected to my tube amp and both ends (high pass and low pass) connected to the M/T module. Not ideal for many reasons:

1) I have found that the big MIT Magnum 1.3 is not the best match for the VR 5 Anniversary Mk 2.5s (mine were the last ones to leave the factory and have a special special mid-range)
2) Using standard 12 Gauge solid core house wiring, is not ideal for the bass speaker cable (it will work, but not ideal)

I cannot afford to purchase an entire loom of Master Built cabling - but I have had excellent results with Grover Hoffman power cords, and interconnects. In fact, his latest balanced IC just so ever beats out a 2500 set of Matrix HD 23 ProLine MIT cabling.... Well today my order of GH speaker cables arrived. His prices are VERY reasonable and the sale of my BIG MIT is funding the tube amp purchase and the new cables. One set of speaker cables (thick hose like) for the bass, and another set (about half the thickness) for the M/T. When I wired up the new speaker cables, it was a revelation. The bass is now so powerful, but without over-powering the M/T. The M/T is organic, snappy, and textured. My VR 5s have come alive - there is clarity, but not the hi-fi type as you mention SN. The dynamics have greatly improved. With my Brystons running full range, there was a bit of upper-midrange glare, and I was missing some micro-dynamics. With the tube amp and new cables in place, that glare is gone, and I am hearing many more micro details as well as resolution and texture. The one fall back - for me - is that the image is not quite as wide or deep - the tube amp doesn't present as big an image as the Brystons do - but this isn't a big deal because the gains far outweigh the slight shrinkage

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kernelbob · « **Reply #56 on:** 26 Jan 2015, 11:24 pm »

This is a duplicate of a post on another biamping thread, but it applies here also...

I apologize if I'm stating the obvious, but the first thing one should do when setting up a bi-amping configuration is to put one of the bass amps on, say, the left speaker and one of the M/T amps on the right speaker. Drive each speaker full range and adjust the left/right level to get a reasonably close balance. Check if the relative L/R polarity is in phase or out of phase-- a strong center image or a diffuse extremely far left, far right sound.

If you get a solid center image, then you're good to go for bi-amping. Otherwise, you'll need to connect the bass amp and M/T amp in opposite polarity when you bi-amp, since the test showed one of the amps inverts polarity relative to the other.

If you don't test the relative polarity of the amps and connect them so the bass amp is out of phase with the M/T amp, you may not get a horribly out of phase sounding result, but the two amps will null the frequencies where they overlap, causing a terrible mid-bass hole in the frequency response.

Again, I'm sure everyone checks this before bi-amping, so sorry for stating the obvious.

Robert

Albert Von Schweikert · « **Reply #57 on:** 5 Feb 2015, 09:56 pm »

Hello Fellow Audiophiles,

Thanks for sharing your experiences with bi-amping our speakers. I will admit the concept sounds simple to implement, but your mileage may vary.
In our experiments over the years, we have heard a variation of sound from bad to excellent, depending on how well the impedance and sensitivity of the two amplifiers can be matched. Sometimes the two chosen amplifiers will not seem to work well together, but when you get the right match, you can hear angels sing!
In Stereonut's case, we could pontificate on why he did not get the desired sonic blend. However, I would not venture to guess why his setup did not work. It could be a number of things. If we had a chance to measure the electronics in our lab, we could find the problem and hence a solution. However, if one single high quality amplifier drives the speaker to perfection, then you have achieved Nirvana in the easiest method possible.

As Always,
Happy Listening!

walterslw · « **Reply #58 on:** 7 Feb 2015, 07:47 pm »

Albert is right,

Sometimes two very unlikely amplifiers can sound glorious. My heavily upgraded Assemblage ST40 has no right to sound as good as it does, but with top-shelf parts, pure silver point to point wiring, and the right power cables, and speaker cables - along with the fact that I had parts connexxion match the input sensitivity and gain to that of my Brystons. Mid-range and top end of my system is glorious, the texture is phenomenal. Since all of the caps (electrolyitcs, and bypass caps were replaced with top shelf components), there is going to be some break in needed. Now with 200+ hours, the image size has opened up, and I have NEVER heard my VR5 Annies sound this great. I am hearing my recordings for the first time. The brystons seem to be thriving by only driving the woofers, as base is tight, fast, but articulate right down to the lowest notes. Note to anyone who is considering doing this, the Assemblage ST 40 is NOT an expensive amp. They can be found for about $500 - 600 on the used market. Mine cost a bit more as it was a complete re-build with upgraded parts and wiring, but it was still very reasonable, and the sound that this little EL 34 based amp can produce is a match for the VR5s M/T. I'm glad I was reading this forum and took the advice of Albert.

gbeard · « **Reply #59 on:** 19 Feb 2015, 12:58 pm »

Hello all,

I wanted to let all VSA owner's who bi-amp or are thinking about bi-amping, about a terrific and inexpensive way to control the volume of the higher gain amp. I have a pair of Dave Slagle's Basic Slagleformers wired up in a little box that I have been using. It works extremely well to match the two amps.

That's it!

Cheers!