AudioCircle
Audio/Video Gear and Systems => Owner's Circles => Von Schweikert Audio Owners => Topic started by: Albert Von Schweikert on 16 Sep 2008, 06:13 am
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From Albert Von Schweikert:
Hello Fellow Audiophiles,
Over the past 32 years, I've used bi-amping as a method to achieve more realistic sound quality. A decent, high powered solid state amplifier will give you explosive and tight bass power, while a smaller tube amp will give you the "air" and image float you are seeking from your sound system. Here are a few tips:
1. The bass amp does not have to necessarily be expensive, but make sure it has a large transformer and power supply to ensure "tight" bass. All of our speaker designs employ 4-ohm woofer systems, with a dip down to 3.5 ohms, so make sure the amp is stable into a 4 ohm load. Power requirements depend on your room size and how loud you want to go. I suggest 200-300 watts per channel if you have a large room and want an explosive dynamic range.
2. The tube amplifier can have as little as 20 watts per channel in a small room, but in a large room, you may want to have 50-100 watts per channel to avoid clipping at high volume levels. Due to the distribution of power over the frequency range of 20Hz to 20kHz, you can use a much smaller amplifier on the midrange and tweeter module. Use the 8-ohm taps on the tube amp, but feel free to experiment - it won't hurt anything to try other taps.
3. The "secret" to achieve "killer" sound quality is to ensure that the amplifiers have exactly the same input sensitivity. The amplifier with the lowest numerical rating, i.e. 100mV is much more sensitive than an amplifier with a rating of 500mV - the higher the number, the lower the sensitivity. You'll need to reduce the higher sensitivity by using a series input resistor. This can be installed inside your amplifier, directly at the RCA female jack leading to the input stage. If this sounds a little scary, then build an adaptor to house the resistor outside the amp. If you contact Michael Percy at www.percyaudio.com, he will advise you on what you'll need to get from him. Usually, a female RCA jack, a male RCA plug, a high quality metal film resistor, some plastic sleeving, and a short piece of high quality hookup wire is all that is required. Basically, you're inserting the resistor between the "hot" connection from the female RCA jack to the male RCA plug, and then using hookup wire to connect the ground leads. The entire assembly can be only a few inches long and installed into a plastic or Teflon sleeve to prevent short circuits. This adaptor is inserted into the signal path between your preamp and the most sensitive amplifier. As you can infer from this description, the adaptor is used in between your interconnect and the input jack of the amplifier.
Michael Percy sells these parts for less than $100 for everything you'll need, and he'll also help you select the proper value of resistor to match the sensitivities. Although this simple technique may sound like a "Micky Mouse" setup to "sophisticated" engineers that design chip OP AMPS and sell electronic crossovers to the PA industry, it is a very "pure" form of passive matching that will stomp the crap out of any electronic crossover I have ever tried.
4. Brands and Models: basically, put your money into the tube amp, since even inexpensive solid state amplifiers have stiff power supplies and enough quality to drive woofers with high speed transient response, high volume levels without clipping, and tight bass. Twenty years ago, Adcom built a 200-watt amplifier for around a thousand bucks new, and half that price used. Today, there are many expensive amplifiers that sound great, but you're paying for an expensive chassis, face plate, branding (advertising), and so forth. Instead, look for an amp with a large transformer and high quality power supply.
Tube amplifier choices abound, at all price ranges. Some of the best values are from China if you are on a budget, but large American tube amps from long established companies will be a good investment, with good resale value and the ease of repairs. Don't worry about the availability of tubes, they're going to be around for another 50 years or more due to the ever-expanding market for tube amplifiers.
Happy Listening from Albert Von Schweikert
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Hi Albert,
I'm asking this question on behalf of "you know who" and his VR-11 SEs. He'll have a 7m (W) x 11m (L) x 4m (H) listening room being built from the ground up to be acoustically treated as a recording space as opposed to a control room. He also likes listening fairly loud at times. If he were to use amps with these input sensitivities for the bass modules:
1.076 Volts RMS ± 2% for 220 Watts into 8 Ohms.
Which of the three below would work under the conditions noted above
0.85 Volts RMS ± 2% for 30 Watts into 8 Ohms. (Single Ended Triode)
1.2 Volts RMS ± 2% for 80 Watts into 8 (Push-Pull)
0.775 Volts RMS ± 2% for 18 Watts into 8 Ohms. (Single Ended Triode)
and also
Would there be a need for extensive modification/manipulation of input sensitivities required or would the higher sensitivity to the preamps output actually help balance out the discrepancies in wattage with regards to the SET amps?
Thanks in Advance!
Michael
*for others reading this my name is Michael John. I get my nickname from my second name :)
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Hello Albert! Great to have you join in the discussion here.
I've been bi-amping my MkI VR4jr's for about a year now and the results are truly fantastic. I can heartily recommend the NAD C272 for bass duties. It's a screaming bargain at $750 new, and around $350 used. It's rated at 150W continuous into 8 ohms, but NAD amps are well known for their "dynamic headroom" - NAD specs it at 410W @ 4 ohms and 520W @ 2 ohms. This amp is ideal for bi-amping because it has a gain control on the back with +/- 12dB adjustment, making it a snap to balance it with the M/T amp. This also gives the option of boosting the bass a dB or two if you're a bass head like me, or to compensate for a bright room.
For the top end I'm using an AES (Cary) AE-25 Super Amp Signature DJH. It's a triode wired push-pull amp rated at 35W with KT88 tubes, and a bit less (25W or so) with the EL34's that I'm currently using.
The sound? Nothing short of breathtaking - all the beauty of a triode amp up top with deep, rich bass and explosive dynamics. I couldn't be happier with the sound.
Some of you may also be interested to know that the M/T cabinet of the VR4jr can also be driven with a "flea power" amp. I've used a 3 watt "spud amp" (6cl6/6197 tubes), also matched with the NAD on the bass, and the results surprised me - great sound and plenty of volume (LOUD!!). The M/T cabinet must be a very easy load to drive.
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The M/T cabinet must be a very easy load to drive.
I don't know if this observation means anything in reality, but I try to stare at the midrange driver at loud volume and it doesn't move. You can feel it move with your hand but it doesn't do much. So yeah, it seems like the M/T isn't taking too much power.
Thanks for the flea-power comment - Makes me more interested in getting my amp rewired for triode.
-Mike
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I've been bi-amping my MkI VR4jr's for about a year now and the results are truly fantastic. I can heartily recommend the NAD C272 for bass duties. ....
For the top end I'm using an AES (Cary) AE-25 Super Amp Signature DJH. It's a triode wired push-pull amp rated at 35W with KT88 tubes, and a bit less (25W or so) with the EL34's that I'm currently using.
Hi slinco -- what are you using as a preamp here?
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Hi slinco -- what are you using as a preamp here?
I bounce back and forth between a Monarchy Audio NM24 and an NAD C162. The Monarchy is also my DAC (fantastic!!), and has a minimalist tube linestage that's very pure and pristine sounding, and fabulous with great recordings. Definitely puts the spotlight on bad recordings though, and being more of a music lover than an audiophile I find the NAD suits me better more often than not. It's also got something the old fashioned side of me enjoys - defeatable tone controls. It's really a great sounding preamp, a real sleeper.
Oh yeah, the C162 also has two sets of pre outs, one of which is adjustable 0dB to -12dB for bi-amp matching. Very versatile.
When I want to listen to the Monarchy linestage I have to use a Y-connector from it's single pre-out.
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Albert, If you were bi-amping a speaker with tubes on the top that had a 300hz crossover and then added to the mix a ss powered sub woofer below 80hz I guess you would actually be tri-amping. My question for this set up is -- which type of amp would you recommend for the 80 to 300hz range, ss or tube? :scratch: :scratch: :scratch:
Paul
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Anyone else have thoughts on which type of amp would be the better choice?
Paul
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That is the range where Mr. Punch lives so I would say Solid State :)
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That's kind'a what I was thinking too.
Paul
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Is there a formula that I can calculate the resistor value to match one amp's sensitivity to another. Amp 1 has a rating of .72 VRMS for full output and Amp 2 is 1.5 VMRS for full output. I just need to change one resistor and I'd rather not put a potentiometer in due to mounting issues.
So, how do I match two different amplifiers?
Thanks,
Jake
I probably should post this in the Lab circle. :duh:
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Is there a formula that I can calculate the resistor value to match one amp's sensitivity to another. Amp 1 has a rating of .72 VRMS for full output and Amp 2 is 1.5 VMRS for full output. I just need to change one resistor and I'd rather not put a potentiometer in due to mounting issues.
So, how do I match two different amplifiers?
Thanks,
Jake
I probably should post this in the Lab circle. :duh:
Hi Jake, if you get an answer from anyone in the lab section, be sure to point it our way. All I know, from asking Victor K at BAT about biamping was that he told me not to think about input sensitivity but to try instead to match the gain on any two amps used. He was of the view that small gain differences might not even be noticeable but if they were, attenuators could be used. Reading Albert's post above has given me more food for thought, so I'd love to hear from others more knowledgeable than I am.
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This thread is very interesting to me because I have seen so many other opinions that seemed to make it very complicated to bi-amp.
Active crossover, bypass the internal speaker crossover, set the crossover frequency above the speaker crossover frequency, etc, etc.
Now here comes Mr Von Schweikert. Certainly someone we all feel is an authoritative source of knowledge and he promotes the easiest of solutions to implement. Now, I don't need to stress over buying yet another piece of equipment (the crossover), and I don't have to mess with the internals of the speaker and I don't have to figure out if the crossover frequency I've chose is correct.
All I have to do is run the amps to the speakers and if the amps have different sensitivities, pop in a resistor. What could be easier?
Am I missing something?
If someone get the resistor value formula, please post it here.
TIA
Proud VR4.5 owner
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I probably should post this in the Lab circle. :duh:
[/quote]
Hi Jake, if you get an answer from anyone in the lab section, be sure to point it our way. All I know, from asking Victor K at BAT about biamping was that he told me not to think about input sensitivity but to try instead to match the gain on any two amps used. He was of the view that small gain differences might not even be noticeable but if they were, attenuators could be used. Reading Albert's post above has given me more food for thought, so I'd love to hear from others more knowledgeable than I am.
[/quote]
A problem that I find is that not all manufacturers put both input sensitivity and gain in their specs. For example, Mcintosh only puts input sensitivity while BAT only puts gain. So if I were to biamp using amps from these companies for example, I wouldn't know how to match their amps. Is there a formula to derive gain from input sensitivity and vice versa?
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Albert, If you were bi-amping a speaker with tubes on the top that had a 300hz crossover and then added to the mix a ss powered sub woofer below 80hz I guess you would actually be tri-amping. My question for this set up is -- which type of amp would you recommend for the 80 to 300hz range, ss or tube? :scratch: :scratch: :scratch:
Paul
Hi Paul,
I would go solid state for 80Hz to 300Hz - that midbass range needs to be tightly controlled.
AVS
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Hi Albert,
I'm asking this question on behalf of "you know who" and his VR-11 SEs. He'll have a 7m (W) x 11m (L) x 4m (H) listening room being built from the ground up to be acoustically treated as a recording space as opposed to a control room. He also likes listening fairly loud at times. If he were to use amps with these input sensitivities for the bass modules:
1.076 Volts RMS ± 2% for 220 Watts into 8 Ohms.
Which of the three below would work under the conditions noted above
0.85 Volts RMS ± 2% for 30 Watts into 8 Ohms. (Single Ended Triode)
1.2 Volts RMS ± 2% for 80 Watts into 8 (Push-Pull)
0.775 Volts RMS ± 2% for 18 Watts into 8 Ohms. (Single Ended Triode)
and also would there be a need for extensive modification/manipulation of input sensitivities required or would the higher sensitivity to the preamps output actually help balance out the discrepancies in wattage with regards to the SET amps?
Thanks in Advance!
Michael
*for others reading this my name is Michael John. I get my nickname from my second name :)
Hi Michael,
Depending on the actual gain of the amplifier's input and output stages, the most sensitive amplifier (as rated by "input sensitivity" in mV) may be the loudest amplifier in a "passive bi-amp" configuration. However, as we don't know the actual gain configuration of these amplifiers, the closest input sensitivity value would be the "best guess" at this time. It is actually best to use a solid state bass amp with a higher gain and input sensitivity, and use an outboard attenuator to reduce this amplifier's output, see below.
In truth, the best choice for a tube midrange/tweeter amplifier would be the amp that actually has the best sound quality driving the midrange-tweeter enclosure of the speaker, int his case, our VR-11SE. The volume level differences can be handled by using an external attenuator to find the correct resistor value, then installing that value into the input jacks of the amplifier. However, for best results, the amplifier designer should be consulted, as adding a resistor inside the amplifier may void the warranty, while using the outboard attenuator will not.
Channel Islands Audio, one of the Audio Circle Members, offers the VPC-3, which can be inserted in the signal path before the amplifier that is playing the loudest. Use Pink Noise and a RTA (or your ears) to match the levels of bass-to-midrange/treble.
I have found that using the attenuator for the bass amplifier works the best, since the very slight sonic "veiling" is not readily apparent in the bass, but is more audible in the upper midrange/treble area. This is not due solely to the potentiometer in the attenuation box, but also the extra connections and necessary interconnects. In the bass range, the added "veil" is not audible.
Best regards,
AVS
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Hi all,
I got some good advice from the Lab here: http://www.audiocircle.com/index.php?topic=59057.0 (http://www.audiocircle.com/index.php?topic=59057.0)
I was making the mistake of thinking linearly when that's not the case. See Mr. Jeffreybehr's helpful comment at the bottom of the page.
-Mike
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Hello Albert,
This reminds me of a conversation we had some time back and the possibility of you designing a stand alone amp that uses the primary amp as the input stage of the solid state bass driver. This would guarantee a match with practically any amp of less current or voltage. You have done this for the DB-100 and DB-99 SEs. I think it would make for a great option for all double stacked models. Even the triple stacked VR-11s. I remember when Keith and I hooked his 99s up to 220wpc Lamm Hybrids and the sound remained as ballanced as with 3 watt 2a3s. The difference was that they were playing so cleanly even at extreme levels, Security finally showed up. :lol:
If you want to build up a prototype. I volunteer to do some beta testing. Do make 'em pretty from the get go though because in all probability I'll buy them! The thought of using VR-9s with the 30 watt Lamm ML3 GM70 SETs bi-amped this ways has got me in agony while the thought of using them with SRs and say a QUAD II is just as enticing. :twisted:
Jack
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I am just about to pull the trigger on buying a VR-4 SR MK II but have questions...1) if I biwire (or I think you can even biamp with the MAC 252 amp) running separate cables to the mid/high freq top unit and the bottom bass unit, where does the crossover or filtering occur? Long ago I owned Snell Type A speakers which also had separate mid/tweeter and bass cabinets. I biwired them but had to use an external crossover. What am I missing here?...2) I am looking at McIntosh electronics but am wondering if there is a better way to go...Classe? McCormack? I am not particularly fond of tube amps...sorry to those tubers here...2) I have listened to Wilson watt puppies/sophias, B&W 802D and Martin Logan summits most recently and would be interested in hearing, if anyone has heard any of those, how the VR-4 SR MK II sound compares. I have never heard the AVS speakers as we have no dealers here. If someone would care reply rather quickly it would be greatly appreciate as I my trigger finger is itching badly. Thanks in advance for your replies.
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I am just about to pull the trigger on buying a VR-4 SR MK II but have questions...1) if I biwire (or I think you can even biamp with the MAC 252 amp) running separate cables to the mid/high freq top unit and the bottom bass unit, where does the crossover or filtering occur? Long ago I owned Snell Type A speakers which also had separate mid/tweeter and bass cabinets. I biwired them but had to use an external crossover. What am I missing here?...2) I am looking at McIntosh electronics but am wondering if there is a better way to go...Classe? McCormack? I am not particularly fond of tube amps...sorry to those tubers here...2) I have listened to Wilson watt puppies/sophias, B&W 802D and Martin Logan summits most recently and would be interested in hearing, if anyone has heard any of those, how the VR-4 SR MK II sound compares. I have never heard the AVS speakers as we have no dealers here. If someone would care reply rather quickly it would be greatly appreciate as I my trigger finger is itching badly. Thanks in advance for your replies.
Hi ES,
You won't need an external crossover. The High Pass circuits are are on the MT modules and the Low Pass Circuits are on the bass modules. :) I really don't want to ruffle any feathers by comparing the SR IIs to the speakers you've mentioned. I mean I'm bound to since clearly I'm biased! :lol: Just let me say that before I became a dealer, I auditioned loudspeakers from all three companies you mentioned (and many more) and was left unsatisfied. I heard a pair of VR-4 Generation 2s at a friends house and never looked back.
So what did the VRs do that the others didn't? Well to me they sounded more coherent, had realistic weight, didn't have any phase-y artifacts, had a more substantial soundstage (tactile as opposed to pseudo-visual) but, as the ultimate compliment , had me just enjoying the music instead of acting like a high school student dissecting an amphibian. As always, your mileage may vary!
Best of Luck and Happy Hunting!
Jack
Oh by the way, VRs go very well with both Mc'Is and Mc'Cs if you like palpable midranges with nice oomph ;) Never heard them with Classe amps though. If clarity and top-end sweetness is your cup of tea then Plinius is a good option too.
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Thanks for the quick reply Jack (btw nice M3...sold my 98 sedan last year :duh:) I'll quit worrying about the crossover. If these speakers actually whip the watt puppies as some say they do, that's good enough for me considering the $20K price difference. I auditioned the wilsons and liked them so sounds like I will like the SR mkII ever more. Do you see any problem driving them with the McIntosh MC252 SS power amp and the MC46 pre? If the speakers are as neutral as Mr. Von Schweikert says they are, a solid state amp as good as the MAC shouldn't sound overly bright or sizzly. Anyway, that's my story and I'm sticking to it.
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The MC252 should drive the SR IIs as easily as Schumacher can drive a go-kart. The SR Mk1s definitely preferred tubes and all the Mk1s in the Philippines are powered by tube power amps. The Mk1s had a slight upper midrange rise that exposed any shrillness or grain an amp might have. This was addressed with the Mk2 and as a result most SR Mk2s here are powered by solid state amps. If you've been reading between the lines you might have inferred that the SS owning Mk1 owners switched to tubes while the SS owning Mk2 owners stuck to what they already had. That is indeed what transpired.
Expect a walk-in stage with the SRs vis a vis a Puppy 6,7 or 8 neatly laid out stage. A major attribute of SRs is that they image well from almost anywhere in the room (very important to me since I entertain a lot). Image outlines are more rounded than the WP's. Think a fountain pen compared to a tech pen. The SRs are warmer and fuller while the Wilson WP's emphasis is on lightning quick transient response. These are more matters of taste however and while they do differ greatly both are excellent.
Yes my M3 is beauty. I get ribbed a lot when people say the VR9s cost more than my car. My answer is that I don't have potholes or traffic jams in the listening room :thumb:
"Grain of Salt" time as this is just my personal opinion
The SRs will definitely give the Puppies a run. $20,000 makes for lots of LPs and CDs!
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How do you properly attenuate a balanced (XLR) connection?
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This thread is very interesting to me because I have seen so many other opinions that seemed to make it very complicated to bi-amp.
Active crossover, bypass the internal speaker crossover, set the crossover frequency above the speaker crossover frequency, etc, etc.
Now here comes Mr Von Schweikert. Certainly someone we all feel is an authoritative source of knowledge and he promotes the easiest of solutions to implement. Now, I don't need to stress over buying yet another piece of equipment (the crossover), and I don't have to mess with the internals of the speaker and I don't have to figure out if the crossover frequency I've chose is correct.
All I have to do is run the amps to the speakers and if the amps have different sensitivities, pop in a resistor. What could be easier?
Am I missing something?
If someone get the resistor value formula, please post it here.
TIA
Proud VR4.5 owner
from AVS:
I am gratified to see so many audiophiles interested in trying a "biamp" configuration, even though it is not easy to achieve. In my original post, I alluded that amplifier matching could be accomplished by using resistors to attenuate the louder of two amplifiers that do not have matching SPL levels with the same input volume. I wish to expand on this topic, with the following additional information, below.
First, depending on the actual gain of the amplifier's input and output stages, the most sensitive amplifier (as rated by "input sensitivity" in mV) may be the loudest amplifier in a "passive bi-amp" configuration. However, as we don't know the actual gain configuration of these amplifiers, the closest input sensitivity value would be the "best guess" at this time. It is actually best to use a solid state bass amp with a higher gain and input sensitivity, and use an outboard attenuator to reduce this amplifier's output, see more about this idea below.
Calculating the additional resistance to be added to the amplifier with the loudest SPL is straight forward, but requires that we know the "gain" of the amplifier design. If you have been following this topic at the LAB section, it has been noted that the gain can be measured by using a SPL meter and pink noise, then using the formulas to calculate the additional resistor required. My thanks to JoshK and jeffreybehr for their input, see their latest posts at THE LAB.
In my experience, it is easy to accomplish the level matching by using an external attenuator to find the correct resistor value, then installing that value into the input jacks of the amplifier. However, for best results, the amplifier designer should be consulted, as adding a resistor inside the amplifier may void the warranty, while using the outboard attenuator will not.
Channel Islands Audio, one of the Audio Circle Members, offers the VPC-3, which can be inserted in the signal path before the amplifier that is playing the loudest. Use Pink Noise and a RTA (or your ears) to match the levels of bass-to-midrange/treble. Using music to balance the two amplifiers is difficult, since you will need to play a wide variety of tunes to get a feel for the balance, while using Pink Noise is far easier.
I have found that using the attenuator for the bass amplifier works the best, since the very slight sonic "veiling" is not readily apparent in the bass, but is more audible in the upper midrange/treble area. This is not due solely to the potentiometer in the attenuation box, but also the extra connections and necessary interconnects. In the bass range, the added "veil" is not audible.
If you have balanced inputs and outputs, you can make an adapter to convert RCA to XLR when using the Channel Islands attenuator; contact Michael Percy at www.percyaudio.com for further info.
Albert Von Schweikert
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In the very first post in this thread, it is suggested that for biamping (I am interested in VR5), one should use 200-300 watts for the bass module which is 4 Ohm. Many amps are 150 watts in 8 ohms and 300 in 4 ohms. Are you referring to 200-300 W in 8 ohms (and 4-600 in 4 ohms) or 150 in 8 ohms (and thus 300 in 4 ohms). Thanks.
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Good morning Duguy, Albert was referring to a 6 ohm load which is the speakers average impedance load. The actual power output is not important as the actual sound of the amplifier. Nearly all amplifiers can be partnered for bi-amp, what we are looking for mainly is a tight bass amp with enough power to drive the woofers ( 100 watts - 500 watts per channel ) and a smooth sounding amplifier for the mid range and tweeter. Since most amps do not have equal sound quality from bass to treble, you now have the opportunity to choose the best amp for the bass sound, and the best amp for the mid range tweeter sound. In general, large solid state amps have the best bass and small tube amps have the smoothest and sweetest mid range and treble tones. The power ratings are not as important as the actual tone quality of the amplifiers. By the way, do you have a local dealer that has demoed the VR-5 for you? What amplifiers does he carry? If you are interested in the VR-5, Albert would accept a direct phone call at the factory (951-696-3662) to talk to you about amplifiers.
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How do I biamp my vr4jrs if my preamp only has one pair or outputs? Is it OK to use a y-splitter for this purpose?
Thanks,
Randy :)
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How do I biamp my vr4jrs if my preamp only has one pair or outputs? Is it OK to use a y-splitter for this purpose?
Thanks,
Randy :)
Doc,
Have Harana install a second pair of outputs :wink:
Jack
BTW
Just grab the ICs from Hyper. I'm all out bro.
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Question for VSA Joe or others. If one's SS power amp has potentiometers (R&L), does that circumvent the need for resistors in the input jacks? In other words, will the ss power amp potentiometers proportionally reduce the output so that one may easily match the ss amp to the tube amp output? Thanks.
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Question for VSA Joe or others. If one's SS power amp has potentiometers (R&L), does that circumvent the need for resistors in the input jacks? In other words, will the ss power amp potentiometers proportionally reduce the output so that one may easily match the ss amp to the tube amp output? Thanks.
pretty much :)
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How do I biamp my vr4jrs if my preamp only has one pair or outputs? Is it OK to use a y-splitter for this purpose?
Thanks,
Randy :)
Doc,
Have Harana install a second pair of outputs :wink:
Jack
BTW
Just grab the ICs from Hyper. I'm all out bro.
Thanks Jack. Will text hyper :)
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Hi
I planned on running a pair of tubed Rogue Audio 88's (40-60/channel) with my VR-4's but was told that these were not the best of match with VSA's due to the cathode bias they use and said I'd be better to upgrade to the ST-90's at $1100.00 each plus tax and shipping (from Canada which won't be cheap and the way the Canadian dollar is, ouch!!).
http://www.rogueaudio.com/manuals/88_Manual.pdf
I already own the pair (one needs a repair as it keeps blowing tubes) so I wasn't expecting the negative reply I received when I told them (Rogue Audio) the speakers I was using.
Any suggestions as to whether this would be a good match?
Thanks
Mike
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Rogue blamed the blowing tubes on the speaker? :o Any respectable tube amp should be able to handle anything from the 4ohm taps except perhaps speakers with extreme impedance dips which no VR has. :scratch: Rogue has a reputation for making good sounding, robust amps. I can't see why a CJ MV55 or MV60 or even the little Manley Stingray can drive a 4 HSE without blowing up and the 88 can't. Would you mind PMing me Rogue's reply and I'll ask our tech what a cathode rectifier should have to do with speaker matching. Thanks!
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Hi
I sent a PM to you....Thanks
The one 88 amp was already in need of fixing when I contacted Rogue about repairing it, so no, the 4's were not the Rogue's problem. The reply I received back, after sending a email regarding a repair, stated that the 88's were not a good match to VSA speakers due to that cathode bias, and suggested to go to the ST-90 amp instead.
Thanks
Mike
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Whew! I'm glad I proved myself a bonehead by getting your post all wrong. The guys at Rogue are good guys and the local Rogue dealer is a great guy as well. I know for a fact he's had no problems whatsoever with the Rogue products he's sold here over the years. I researched Rogue thoroughly in the past and considered bringing their line in at one point and research showed them to be reliable and reputable. I passed on Rogue not for lack of quality but rather Rogue did not have the "Cache" here in the Philippines at that time.
I felt we didn't have the time to build up the brand as we were concentrating on VSA. We did that by literally bringing the loudspeakers around the audiophile circuit. The audiophile version of a tupperware party but we knew the only way we could get the word out was from positive home based experiences filling the word of mouth. There was also the novelty of a Congressman and an Investment Banker lugging speakers around door to door :lol: :lol: :lol: It took a lot of energy. The brand got it's name and reputation back, we honed our set up skills but were just too spent to go marketing another brand from scratch. A problem we didn't have when we decided on Lamm and their countless reviews. We just got the word out and people just started trouping to the showroom. The powers of the audiophile mainstream press can not be denied.
I'll still ask my tech in what way a cathode rectifier matters in a push pull amp when it comes to speaker matching. I have no reason not to believe Mark and the guys at Rogue. They know their amps better than anyone else. I'm just genuinely curious. :)
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Thanks Jack
Since I already own these I would like to run them. With the cost of the CDN dollar compared to the US, I can't see myself getting the upgrades on these till it's closer to par. So I will send the amp to get repaired and try running bi-amped. As of now, the DR-8's work great but that's not really what I wanted to run with them.
My dealer also wanted to know if I would be interested in the upgrade to the VR-5 specs, and at a great price, compared to the VR-5's he has on the floor!! But, the condition these are in and the chance of not liking the final result, makes me hesitate a bit!!
Thanks
Mike
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Still trying to figure this out but I'm getting close.
I'm hoping a VSA person knows this.
What is the nominal impedance of the woofer cabinet for the VR4.5 and what is the nominal impedance for the mid/tweeter cabinet?
The specs just say 6 ohms nominal for the entire speaker but I'm guessing the two cabinets differ.
TIA
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IIRC 8ohms for the MT module and 4 ohms for the bass modules.
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Does it matter when you bi-wire if you plug the banana connectors from the amp to the sub binding posts or the tweeter-midrange posts on the bottom? They are both connected on the bottom of the speakers I would imagine.
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Hi boe,
For biwiring (as opposed to biamping), you want to connect the single pair of connectors ( +,-) to the amplifier; one of the biwire pair (+,-) to the top terminals (mid/tweeter); and the other biwire pair (+,-) to the bass module terminals on the bottom. If your speakers have an additional pair of terminals on the bass module to allow a single run from the amp to the bass module, jumpered to that other pair or terminals, you don't want to use those-- connect the mid/tweeter module to the amp directly to the amp, not jumpered from/to the bass module. By the way, if there are jumper plates between the bottom terminals, you should remove those.
The point is that the mid/tweeter crossover (which is independent of the bass crossover) has high impedance in the bass frequencies so bass current doesn't flow significantly through the mid/tweeter speaker cable. That avoids the relatively high current of the bass frequencies from interacting with the mid/tweeter frequencies on their way from the amp to the mid/tweeter terminals.
If you just jumper the mid/tweeter and bass connections at the speaker, you lose this benefit and essentially aren't biwiring.
Biamping, of course, gives you that benefit also since you would be running completely separate connections from amp A to the mid/tweeter and amp B to the woofer. Biamping can give you the opportunity to use an amp that excels in the mid/tweeter range on top and a beefier amp with, say, high damping factor to drive the bass module. On the other hand, biamping can have its own issues with seamlessly integrating the qualities of the two amps without audible anomalies.
Hope this is helpful.
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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
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StereoNut,
How are the experiments with biamping your VR-4's going?
Albert
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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
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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
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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.
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I believe Dusty at CIAudio can make attenuators for you Walter. No idea about the price. You can try shooing him a PM.
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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.
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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!
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Albert, could you please respond to my PM (or the email from audiocircle.com). Thank you... :)
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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.
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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.
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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
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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.
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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.
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StereoNut,
How are the experiments with biamping your VR-4's going?
Albert
Sorry, Albert. I just saw this now! :duh: 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!?! :o) 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!
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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 :lol: [size=78%] .[/size]
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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
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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!
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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.
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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! :D
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Hello all. I am new to this forum, but Albert has been helping me for years thru private email.
I have a pair of VR4jr's that I have recently bi amped.
The most difficult part has been trying to adjust the sensitivity of the 2 amps.
Can anyone please help with the mathematics? My tube amp is rated for 1.1V, my solid state for 1.31V.
I have been trying different attenuator pads on the tube side. I currently have a 12dB pad in the system, it may be just a tad too much.
I would like to know how to calculate the exact dB required, although I may just keep the inexpensive and already in place pads.
Thanks -
Eric
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Eric,
I can't tell you how to do the calculations but thought I would share my experience bi-amping my IV jr's, since others may be in the same boat.
I had never bi-amped a system but wanted to try it, based on the comments I read. I tried to figure out amp sensitivity and so forth but got pretty frustrated (my technical knowledge of electronics is limited . . . ). I ended up buying an NAD C275BEE amp (solid-state). I was running a pair of tube amps as monoblocks (Golden Tube SE-40's). I reset one of the monoblocks to stereo and use it on the treble/mid section, and the NAD on the bass modules.
The NAD has a little dial on the back to set the output level. After setting up the bi-amped system, I played very familiar music and set that dial so that what I heard sounded about the same as it had previously in terms of treble/bass balance; this gave me a good starting point. Then I made some small adjustments in the output level as I continued to listen.
I might get better results if I could do the calculations, but I have been very happy with this combination; the ears seem to do a pretty good job! I cannot hear any discontinuity or lack of integration between the two halves of the speakers. Maybe I just got lucky, but this could be another way to approach bi-amping for those of us who are technically challenged.
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Can anyone please help with the mathematics?
Instead, maybe consider investing in a $12 multimeter. You can simply measure the output voltage at the speaker terminals of both amplifiers while adjusting the l-pad. Use a sine wave as an input signal. You should get it dialed in perfectly in less than 5 minutes. Once you've done this you can use the same multimeter to measure both legs of the l-pad - so you can replace them with quality fixed value resistors.
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Thanks to all that responded.
I never worked out the math - but it would be very difficult in my opinion. Luckily, both my amp choices are rated for the same impedance value. Had they not been, I think that would represent quite a challenge.
I never followed up with the group, but I had several sets of attenuators, 3dB, 6dB, and 12dB to experiment with.
Thru trial and error, I ended up having Percy Audio make me a pair of 8dB attenuators for the tube amps.
That has seemed to do the trick, although my digital side can get a little bass heavy at times, mostly at louder volumes.
I have ordered a DSpeaker Core to try and help smooth out the low frequency bass.
While searching, I did find a product made by CI Audio, their VPC3, that would have solved the issue as well for about the same amount of $$ and less headache than the attenuator route - the 8dB ran me about $75 and the other 3 sets were $30 each.
If anyone does purchase the CI Audio device, I would like to know how it performs since it is a dial and not stepped.
Thanks -
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Eric,
I can't tell you how to do the calculations but thought I would share my experience bi-amping my IV jr's, since others may be in the same boat.
I had never bi-amped a system but wanted to try it, based on the comments I read. I tried to figure out amp sensitivity and so forth but got pretty frustrated (my technical knowledge of electronics is limited . . . ). I ended up buying an NAD C275BEE amp (solid-state). I was running a pair of tube amps as monoblocks (Golden Tube SE-40's). I reset one of the monoblocks to stereo and use it on the treble/mid section, and the NAD on the bass modules.
The NAD has a little dial on the back to set the output level. After setting up the bi-amped system, I played very familiar music and set that dial so that what I heard sounded about the same as it had previously in terms of treble/bass balance; this gave me a good starting point. Then I made some small adjustments in the output level as I continued to listen.
I might get better results if I could do the calculations, but I have been very happy with this combination; the ears seem to do a pretty good job! I cannot hear any discontinuity or lack of integration between the two halves of the speakers. Maybe I just got lucky, but this could be another way to approach bi-amping for those of us who are technically challenged.
I looked at the NAD product. My tube amp is more sensitive than my solid state, so I actually have to pad the tube signal to equal the input sensitivity of the solid state.
So, not sure it would work in my situation.
Please correct me if I am wrong w/ this statement, but I thought that it is OK to add passive resistors in a system to reduce the sensitivity, but you would not want to go the the other way of introducing additional gain?
Thanks for your help -
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Dear Albert,
thank you for starting this post on bi-amping :o. I have a pair of VR-4 Gen III that I was single amping with the KR Kronzilla (2X22W stereo), fine sound, but lacking bass foundation. Then I started bi-amping with a Krell FPB600, one of the best amplifiers for a solid bass. This worked out disastrously, horrible sound, no coherence. It turned out that there was no way the Krell and the KR could work together; I know very little about electronics :duh:, but some people who claim they do mentioned that a simple resistor would not solve the problems with these two amplifiers. Then I bought a KR VT 20 (2x50W stereo) solid state amplifier and this sounded much better, but it still lacked power. So I got a second KR VT 20 and had both converted to monoblocks by Creato Audio (Utrecht Netherlands). Now it really sounds great, I use a volume control for the mono blocks (balanced) and am using a Audio Research LS 25 II (Creato converted) pre-amp. As you stated the tube amplifier for mid/high works excellent and for a solid bass the solid state amplifiers do their job :lol:!!
Frank :D
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For anyone who might be interested in trying to bi-amp without spending too much on a volume control solution for the higher gain amp, I can highly recommend Dave Slagle's Autoformers. For a little over $3 large and a bit of work, you can have a volume control that very simple, yet one of the best. The best part is, if you decide not to bi-amp, you have a terrific AVC as a second linestage for those passive moments in your life. :wink:
Should have said $3 C-notes. Not that expensive! :duh:
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The Tortuga Audio LDR passive controllers sound great whether driving an amp full range or level matching one amp in a biamp'ed system. The light dependent resistor system is self calibrating, so impedance drift is a non-issue. They also have user adjustable input impedance from 1 to 99 kohms (you can change it on the fly from the remote). That's a useful feature to optimize the impedance presented by different types of amps on the bass versus mid/tweeter amp as well as selecting an input impedance where your source component sounds best. You can get a balanced version for around $1700 and a single ended version for around $1100. I've replaced my active pre-amp with the LDR1-V2B balanced model. Not only less expensive, but with better sound.
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Hello KB,
I forgot about your LDR. Still haven't tried one. Good to meet you at the show, it was a fun weekend. (Sorry about the hijack...back to the regular biamp thread)
Gary
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I have had my VR5 anniversary MKII for about 6 months and have had much better luck using mono amps biwired. I think Alberts main reason for recommending a tube amp on the uppers is he made them so dang revealing they are relentless on a bad sounding front end. I am thinking the tubes are to mellow out the uppers. I hope Albert or Damon reads and replies. I want to thank Von Schweikert for producing such revealing speakers. Truly amazing.
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Hi Nc42aac
Congrats on the VR5 Annies MK II. I too have the same speaker, I purchased the last set - prior to some additional pairs being made available. Ive owned the Vr5s for 1.5 years now, and couldn't be happier! You may have seen some of my previous posts. I have tried a few tube amps, and solid state bi-amping, and I have to say that tube on the top, solid state on the bottom is the way to go (in my experience). I recently (6 months or so) acquired a used Sonic Frontiers Power 1, completely re-built and upgraded by Parts Conexxion. The changes made to the stock power 1 were extensive upgrades, but main change is increasing the plate voltage so that the amp can accommodate the new KT 120 tubes. The new Power 1 delivers about 70 watts into 8 ohms for the top, and my Bryston 7B SST^2 deliver around 600 watts into 8 ohm - so there is no shortage of power.
I had Chris match the input sensitivity and gain of the Power 1 tube amp to that of the Bryston monoblocks. So no passive attenuators are required anywhere in my signal path. With the sonic Frontiers Power 1 (Platinum SE upgrade) there is no rolling off of the top end, or smoothing. Almost the opposite, it almost sounds like a solid state amp - WITH the magic of tube midrange. The soundstage is wide and deep, but the midrange is better than any solid state amp that I have heard. Anyway - sorry to ramble :-) I agree, these speakers will reveal any weak link upstream. Vacuum tubes in pre-amp, power cords, cables, isolation, everything!. It took me 6-8 months of tuning my system, but the major win for me was when I changed to the above bi-amping set up. I feel the VR5 Annies really come alive with a properly set up bi-amped configuration.
Let us know how you make out!
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I'm driving my VR5 Annies with McIntosh amplification...C500P preamp and MC601 monoblocks. I also am running a pr of Velodyne Optimum 12 subs crossed over at 60hz. Me like!
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I'm driving my VR5 Annies with McIntosh amplification...C500P preamp and MC601 monoblocks. I also am running a pr of Velodyne Optimum 12 subs crossed over at 60hz. Me like!
NICE! es347 - what are the dimensions of your room? Do you situate the subs right beside - or behind - the vr5? Adding a pair of subs is something I would like to explore in the future. Any base humps or weird anomalies?
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16W x 30D x 10H...no weird bass humps or dips
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Hello -- new to this forum, but have followed this thread with much interest, as it inspired me to biamp my VS 4.5s about five years ago. I have a Dared tube amp with a volume control on the top, and an Emotiva solid state amp (without a volume control) on the bottom. The tube amp's input sensitivity is 250 mv... and the solid state amp's is 1.1 v.
I love the sound I'm getting from the current setup, but am thinking it could be even better, so... recently I had the tube amp modded with a switch to optionally bypass the volume control, and (you can probably guess where this is heading). I would like to swap out the Emotiva for a solid state amp with a volume control, but have not been able to find one with a viable input sensitivity.
Suggestions anyone? I'm not interested in getting a different tube amp, or padding the tube amp's output -- just in finding a SS amp that will work as per the preceding... preferably a power amp with volume controls, not an integrated amp.
TIA.
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I believe Parasound Halos have input sensitivity trims at the rear :)
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NAD is an option.
I recommend this as a much less expensive option that will allow you to obtain the same results and is completely passive.
http://ciaudio.com/products/VPC3
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Both recommendations are appreciated. Thank you.
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....but unless I'm missing something, neither of the suggestions are quite what I was hoping for.
I want the volume control to be on the front of the SS amp -- the input sensitivity should be 250 mv or better. Currently I'm using the volume control on the tube amp as a primitive tone control, and it works quite well in that I listen to a wide range of material with some being a bit too bright (the most common problem), and some not bright enough. So "treble adjustment' is very important to me (and my pre-amp, an AR SP-16 does not have tone controls).
Now that I have a bypass switch on my tube amp, and can skip the tube amp's volume control entirely, I am getting a sense of the sleight veiling the volume control has been adding all these years. But I don't want to lose the capability of making fine adjustments to the bass vs. MT balance, so rather than attenuating MT via the tube amp, I want to be able to achieve the same result by boosting bass on the SS amp.
So why not just use a better attenuator on the tube amp? That may end up being my last resort, but another issue is that I often listen to (old-school, not modern brickwalled) CDs and 24/96 or 24/192 FLACs at about 75%-80% max volume on my pre-amp. If I can run my tube amp with the bypass switch engaged it, and have the SS amp "make up the difference", the overall effect will be to move that average volume level down to 65%-70% on my pre-amp.
So, an SS power amp (not integrated) with volume controls on front, plenty of watts per channel, and, say 200 mv input sensitivity. Suggestions/recommendations anyone?
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That little CI Audio device allows for variable control on both inputs via a jumper switch.
I went thru lots of research and trial & error to get my 4jr's sounding the right way.
I had 7 dB custom attenuators made for my tube amp.
Ultimately, when my jr's went back in for the latest upgrade they came back @ 4 Ohm impedance and that fixed the problem w/o the requirement of attenuation.
For $375, I recommend trying that CI Audio device and asking about the return policy. You can always try it and hopefully return it w/o having to purchase another amp.
Just my $0.02 - I have a friend that uses it and was blown away once he was able to adjust the levels on his bi amp set up.
Also, I use 2 x powered subs crossed over @ 50 Hz to really even out my bottom end. Not terribly loud, just enough to know they are there.
Good luck -
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I have been wanting to experiment with biamping but without a big expenditure and without worrying to much about sensitivities. After reading this thread, I found an older NAD amp as suggested on the board and it has a dial to adjust output for biamping. I then played some pink noise and using a multimeter adjusted the output so the readings on the upper and lower modules of my vr5 were about equal. it took just a few minutes to do this. For the top, I was using a BAT tube amp.
I am a believer. I knew the top amp was never strong enough to give me good bass. Now, I get good bass and the upper end sounds less congested (actually not congested) with big orchestras. Big difference. I am now ready to experiment with other big amps for the bottom. This has been a huge difference in my system.
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I've been biamping VSA speakers for years, across three different models. Currently, I'm using Tortuga LDR attenuators for both the primary preamp/controller that switches between inputs and another one with only one input to adjust the level of the bass amps. I would recommend using a primary controller and bass amp attenuator that can be adjusted from the listening position. Once you have the capability to fine tune the level of the bass amp relative to the mid/treble amp, you really come to appreciate the control.
I've found that different recording labels have very different approaches to the bass/mid-treble balance. For example, the bass on Naxos recordings is unfortunately not as extended or dynamic as it should be. In a word, it sounds polite. I frequently bump the bass one or two dB's compared to, say, a London/Decca. Similarly, different streaming services each have their own frequency profiles and often need a bass amp adjustment up or down a dB or so.
One other recommendation that I'd make is that the primary preamp/controller should include the capability to toggle the absolute phase of the system... from the remote. Once you use that for a while, you won't want to be without it. FYI, my Tortuga LDRxB has that feature. The difference between the right and wrong setting is clearly audible on a reasonably good system. Unfortunately, there's no consistency between labels (and even recordings within one label), so you'll need to confirm that you have the right setting for each recording.
Best,
Robert
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From Albert Von Schweikert:
3. The "secret" to achieve "killer" sound quality is to ensure that the amplifiers have exactly the same input sensitivity. The amplifier with the lowest numerical rating, i.e. 100mV is much more sensitive than an amplifier with a rating of 500mV - the higher the number, the lower the sensitivity. You'll need to reduce the higher sensitivity by using a series input resistor. This can be installed inside your amplifier, directly at the RCA female jack leading to the input stage. If this sounds a little scary, then build an adaptor to house the resistor outside the amp. If you contact Michael Percy at www.percyaudio.com, he will advise you on what you'll need to get from him. Usually, a female RCA jack, a male RCA plug, a high quality metal film resistor, some plastic sleeving, and a short piece of high quality hookup wire is all that is required. Basically, you're inserting the resistor between the "hot" connection from the female RCA jack to the male RCA plug, and then using hookup wire to connect the ground leads. The entire assembly can be only a few inches long and installed into a plastic or Teflon sleeve to prevent short circuits. This adaptor is inserted into the signal path between your preamp and the most sensitive amplifier. As you can infer from this description, the adaptor is used in between your interconnect and the input jack of the amplifier.
Michael Percy sells these parts for less than $100 for everything you'll need, and he'll also help you select the proper value of resistor to match the sensitivities. Although this simple technique may sound like a "Micky Mouse" setup to "sophisticated" engineers that design chip OP AMPS and sell electronic crossovers to the PA industry, it is a very "pure" form of passive matching that will stomp the crap out of any electronic crossover I have ever tried.
Assuming I know the input sensitivity and gain of each amp - what is the math to calculate the resistor value?
Specifically, I am looking to use my DIY ICEpower 1000asp based monoblocks on the LF cabinet (2.96V input sensitivity) with a pair of VTA m-125 monoblocks on the HF cabinet (1V input sensitivity). From Albert's statement above the m-125 is more sensitive than the 1000asp so I need to add a series resistor to its inputs. Since I am building the m-125 from a kit I want to add the resistor inside the amplifier. What value will I need?
Martin
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It's been a few years since I originally posted in this thread, and I'd like to share what I ended up doing, along w/ some related observations, because I have solved this problem to my complete satisfaction, and perhaps someone else will find this information helpful.
Once you have the capability to fine tune the level of the bass amp relative to the mid/treble amp, you really come to appreciate the control.
Completely agree. This has been a guiding principle for me. I did not want any unnecessary component, not even passive attenuators, in the mid/treble signal path. Any adjustment should, ideally, take place on the solid state / bass end... but I was unable to pull this off, until, about two years ago, I found an add-on device to balance things out (see below).
Gear: I'm now on my second pair of VSAs, in this case VR4 SR MkIIs which I am in love with. Also, my tube and solid state amps have changed since I last posted... I now have a Cary tube amp on the top end and a Wyred4Sound solid state amp on the bottom.
A note re: the tube amp -- before I obtained the Cary, I had a Dared amp, and to achieve the correct balance between it and my solid state amp, I used passive RCA attenuators... I tried two different brands and a variety of db levels... since they were more expensive I expected Rothwells to sound cleaner, but to my surprise, the less expensive ones from Harrison Labs were a better fit for my system -- they simply were invisible, which is to say, if they added any sonic "veiling" (Albert's term) I could not hear it. However, once I switched to the Cary tube amp, I no longer needed any passive attenuators at all.
A note re: the solid state amp -- the Emotiva was a bit mushy, so I ended up going w/ a Wyred4Sound amp instead. I also have a really nice Parasound power amp which I've been quite happy w/ at my office running full range (i.e., not part of a bi-amp setup). I briefly tried it at home in place of the Wyred4Sound, and didn't care for it at all. In fact, I tried it on two separate occasions, because "on paper" it seemed to me that the Parasound was the better unit. Point being, do not assume all solid state amps are created equal (despite having similar or identical power ratings).
One other piece of gear worth mentioning is my pre-amp, an AR SP-16, which has a dual pair of outputs, i.e., perfect for bi-amping VS-es. And I'm guessing that for anyone who cares enough to bi-amp their VS-es, I don't need to point out that it's worth experimenting to find the right interconnects, especially the mid/treble pair.
Okay, having shared every bit of background info I can think of, here's what I ended up doing. As stated at the outset, my goal was to do all the "heavy lifting" on the bottom end, to allow the mid/treble signal path to be as simple as possible. So, I ended up purchasing an Eastern Electric BBA ("booster buffer amp")... the company is no longer in business, but you can find used BBAs typically in the $400-$600 range. For more information, see Doug Schroder's review here (https://www.dagogo.com/eastern-electric-minimax-bba-preamplifier-review/), though of course he was not contemplating using it as a bass adjustment component in a bi-amp scenario.
What I like about the BBA... 1. it's an amplifier, so it can boost the signal, as opposed to merely being a passive attenuator, and 2. it has both a "gain" and a "volume" control... I don't know what's going on technically, but in my system, "gain" equates to "punchiness" and "volume" equates to "boominess", and I tend to keep both controls in the 12-1 o'clock position, though depending on the recording I will sometimes go up to 2 or 3 o'clock w/ one or the other control. If I found that I was routinely wanting to push either gain or volume into the 4 o'clock range or higher (5 o'clock is the max), that would be an indication to me that it was time to insert a pair of passive RCA attenuators into the signal path between my pre-amp and the tube amp. (Which I had to do w/ the Dared tube amp, but not w/ the Cary.)
Between the gain and volume controls I can "sculpt" the bass to my liking on a track by track basis. Typically the adjustments are subtle (ranging between 12 and 1 o'clock), but the result is NOT subtle... I find that oftentimes the difference between "okay" and "incredible" is a small adjustment via the BBA.
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P.S. in case it wasn't clear in my previous posting, the audio chain on the top end is...
pre-amp > tube amp > mid/treble
...and on the bottom...
pre-amp > BBA > solid state amp > woofers
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A note re: the solid state amp -- the Emotiva was a bit mushy, so I ended up going w/ a Wyred4Sound amp instead. I also have a really nice Parasound power amp which I've been quite happy w/ at my office running full range (i.e., not part of a bi-amp setup). I briefly tried it at home in place of the Wyred4Sound, and didn't care for it at all. In fact, I tried it on two separate occasions, because "on paper" it seemed to me that the Parasound was the better unit. Point being, do not assume all solid state amps are created equal (despite having similar or identical power ratings).
Status update: The Parasound alluded to above was an HCA-1500A. On my home system, to power the VS woofers, I recently replaced the Wyred4Sound with a Parasound Halo A21, and while I wasn't complaining before, now the bass is even better (specifically, tighter and more solid).
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Hi, guys!
I'm considering bi-amp my VR35 with Crown XLS 2052 class D amp for bass dutty. This amp have several features like adjustable imput sensitivity, gain and so.
For mids and highs I have a very very good SET amp monoblock with 30W of finesse and beauty. The bass is very good indeed, but I whant to try some huge bass setup.
Im in the right way?
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..sounds like you’re onto something..go for it!
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Man oh Man!
The Crown came, play for 4 weeks and just gone. Thats not my taste, no detail etc.
I've change the SET amp generic power cables to Furutech Alpha3 with Oyeide P079 plugs and all the bass that I whant just starts to flow beautifully.
Huge deeper taller an wider soundstage, better channel separation, more body and the right amouth of weight.
Another amp is no more needed.
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If you do you may consider using a passive preamp or volume control for bass amp.
charles
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If you do you may consider using a passive preamp or volume control for bass amp.
charles
Hi, Guys!
I'm back here!!
This endless idle times makes me look for something to do. So I will bring back the CROWN but now with 2 XLS 1052 in mono just for the bass.
This time I will burning them fully and make the right efort to blend so many amps lol.
About that quoted post, do I need volume control considering that the CROWNs have gain knobs and I will use a active preamp ?
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Perfect match
Vr35 with 30w class A to handle the uper drivers and the beast XLS2502 to subdue this amazing 10inch back fire master bass woofer.
Don't judge me, just try this amp in your set and come here to tell us how it work.
I got a new speaker that is more clear, have more finesse at mids and more tight, lean, right bass.
With so much power its not necessary to use room gain. Less room gain here means more smooth bass. No boom or booming bass.
Very easy to match the gain. For that I use REW.
Im using the speakon conector, that is very important. Perfect grip.
Im split my speaker cable, so both amps has the same wire with same length.
Bach Cellos suits never ever sound so so good.
I was never so inn the room of the Nirvana MTV Unpluged.
Reagge songs are rendered beatifully, with pace, flow and rithym in spades.
Drums have a great ease here, very natural.
The staging and imaging improve a lot.
More smooth sound in the room corners, less low pressure spots.
An even power response that arouse of nowhere
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Glad to hear that everything worked out! I have my 4jr’s bi amped and it was like I had purchased a new pair of speakers.
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So,
This is whats going on...
I just double de spekaers cables gauge and that prove to make a huge diference...
So the SET with double cabling is much much better than sSET+XLS Crown amp..
This set surpas the XLS+ SET by far...
Much better with only 1 good amp properly wired to the gloryous VR35.