[jeffreybehr]

...and that's NOT 'bi-amping'...Quatros, 5s, and 7s is that the imperfections--and they're ALL imperfect!--of the cap in series with the signal is in series with only the lo-frequency amp and not both.

And if you use a direct-coupled amp on the high frequencies, there is NO capacitor in series with the line-level signal but that which MAY be in your preamp.

My experiences with a quad of 20-year-old Marantz MA-24s biamping my 5As are VERY positive.  More details are at my blog...
http://jeffreybehr.myblogsite.com/

[C17FXR]

Jeffery
Let me start by saying you have a very nice setup and Thank you for starting the Vandersteen thread.

I would like to solicit your opinion (and anyone else that cares to contribute) on the difference you hear between vertically biamping and monoblocking. The reason I ask is I'm at that juncture with my current setup. I have a pair of McCormack DNA 0.5's at SMc Audio getting a complete overhaul (everything they know to put in there plus some new stuff they haven't tried yet). I was considering having them made switchable between stereo and monobock which would give me with the opportunity to listen to them biamped with my Vanderrsteen 3A Signature's.

So that you have an idea my system consists of Vandersteen 3A Signature/ 2Wq combo, I'm currently biamping these with a pair of stock  DNA 0.5's which are driven by a McCormack's TLC-1 with SMc Audio's Ultra modifications that made it a buffered preamp.

The reason I'm solicit inputs it's been recommended that I convert these to monoblocks and leave the stereo option off the board, I'm not sure quite what to do, I very much respect the advice of Steve and Kris but would like some suggestion from others.

In advance I would like to Thank anyone who offers any constructive advise or suggestions.

P.S. My future endeavor includes a pair of Vandersteen 5A's or Quatro's.     

[Carl V]

I am not as well versed or technically advanced as Jeffery
but I am still trying to grasp the distinction of Bi-Amping or biamping.
be that as it may.
I have had 2Ci, e, e-sig., e sig-ii, with 2 -2W (later q)subs.
I have run them with tubes cj 52 & ARC classic 60s
in horizontal or Vertical configurations.  Nice system.
still is.

More to your question.  Back then a friend had Hales Trans. 5
and two pair of DNA .5 he upgraded one at a time to the rev. A.
It was an improvement. he was happy.  He later got a DNA 1.0
and upgraded it to the deluxe (rev. A ??).  being geeks we compared &
contrasted often with hales & Vandersteen. 
Statistically, we probably never met the needed confidence level. 
However, with these speakers & systems we liked the
two .5 Rev A slightly better than the single 1.0 .   Usually, this was manifested
with classical music, smaller scale folk, rock, blues or voice.  The sense of scale
and nuance was 'a bit ' better.  Large Scale Symphonic or Rock or Pop...all bets
are off.... just too much going on to make any conclusions---imho.
Playing MONO sources (Lp or CD) & switching Left to Right while attempting to balance
gain took Soundstage/imaging off the table & forced tone & timbre to the forefront.

Again I don't know en'uff about the back emf, the nature of the passive XO
(1st order VS 4th order)
components in line with the amps,
nor the type of Pre-amps.
At the time my system was PV5, MV52 (ARC for a while)
His was McCormack, with Counterpoint off & on or Krell KSA50.

I have since preferred Mono blocs.  Strongly biased Class A
And OCD?anal retentive set-ups.  It's amazing what a tape
measure, spirit level & laser pointer can achieve.

I need to read Jeff's Blog & educate myself.

I believe Jeff once had a heavily Modded PV5.
Mine was sent to Bill Thalman years ago.

[jeffreybehr]

C17FXR, TY--it's taken only about 40 years.   
..and YW.

The one fact of bridging solidstate amps is that each channel is driving only half the rated impedance.  If the amp has a 4-Ohm rating that's double its 8-Ohm rating, the bridged amp most-probably will have a rating of 4 times (into the single-channel rating (into .  If the amp does NOT have a 4-Ohm continuous-power rating that's double the power rating into 8, then the amp won't have a quadruple-one-channel rating into 8 Ohms when bridged.  IOW, if a 100WPC stereo amp that is also rated at 200WPC into 4, then the amp when bridged (probably) will have a rating of 400 watts into 8.  This is all a long way of stating that a bridged amp has to be VERY heavy duty (and, probably, expensive) to be considered a 'high-current' amp when bridged.  For instance, I had a Lazurus H-1 (?; HA-1?) stereo poweramp that was rated at 50WPC into 8, 100WPC into 4, and 200WPC into 2 Ohms.  When bridged, it was rated at 200 Watts into 8 and 400 Watts into 4, but it did NOT have a continuous-power rating into 2 Ohms...WHEN BRIDGED.

Now, understand that NONE of this technobabble means much in respect to your McCormack amps being operated in bridged-mono or stereo.  If it's not costing you anything to leave the bridging option in the amps, I believe that's what I'd do.

I've also heard that biamping speaker systems that are designed to be biwired does not allow the crossovers to work correctly between the sections that are split by the dual terminals.  I don't know what to think about that...BUT...if you like the sounds of your McCs bridged, then I'd use them that way and biwired.

Carl, 'bi', along with 'non', 'un', 'anti', 'pre' (and more) prefixes are NOT words that get attached to words they modify with hyphens.  WORDS that modify other words, such as 'four' as it modifies 'door', get attached with hyphens, to make 'four-door sedan', for instance.  And yes indeed I had a highly improved PV-5 years ago, and I hope I never have to work on a circuitboard for the rest of my life.   

While I'm at it, C17, it's not 'advise' you might be getting from us, it's 'advice'.  'Advise' is a verb that describes what someone might do, so I might advise you, and you'd be getting advice from me...good or bad.   

[C17FXR]

Gentlemen, Sorry it has taken so long to reply it's been a very busy week.

Carl, Thank you that was exactly the type of information I was looking for. I have a DNA-1 Deluxe with the Rev A mod and still preferred the presentation I got from the stock pair of DNA 0.5's vertically driving my 3A Sig’s.

Jeffery, you must have did some home work and read up on the DNA 0.5's because you described them exactly except they do not have the option for bridging in their stock form, that's something that gets done by SMc Audio if you so choose. Part of the upgrade will be to add larger and better capacitors and a large transformer from plitron.  Mr McCormack said the mono’s will drive a 2 ohm load but didn’t give an exact wattage or for how long. I didn't press the issue because I don't think I will ever have a need to drive 2 ohms for a long time.

Speaking of which after talking with Kris and Steve they recommended that I stick with the monoblocks, their reason was that having both the stereo and mono option together would be a compromise between the two and that I wouldn't maximum the benefits as going one way or the other. So I chose to go with the monoblock's, that way I can see (or hear) for myself,  if I don't like the way they sound I can always send them back to be converted back to stereo. Either way it would cost me about the same in shipping or labor. So we’ll see and I’ll keep you posted as to the results if your interested.

Robert

P.S.
Mr Behr my deepest apologies for not proof reading my posting better, I will try to do better in the future and I hope that I have not offended your sense of exactness with the English language, something I was never that great with anyway.

[kernelbob]

I went the biamp route shortly after getting a pair of Double Kronzilla amplifiers.  These use the large T1610 tubes.  I had been using a pair of Spectron Musician III MkII monoblock amps.  Comparing the two showed that the Kronzilla was definitely superior on the mid/tweeter module, but didn't have the iron-fisted control of the Spectrons on the bass module.  These two physically separate modules on my VSA VR5-Anniversary speakers have separate inputs designed for biwiring or biamping.  I'm running the Krons on the top and the Spectrons on the bottom with excellent results.  I've found no problems (to my surprise) with these totally different types of amps blending.  I haven't put anything in the signal path in the way of high-pass or low-pass filtering since the internal crossovers in the speakers are still engaged.

[jeffreybehr]

Gentlemen, Sorry it has taken so long to reply it's been a very busy week.
...
P.S.
Mr Behr my deepest apologies for not proof reading my posting better, I will try to do better in the future and I hope that I have not offended your sense of exactness with the English language, something I was never that great with anyway.

Didn't offend me a bit; just thought you'd like to know.   

[jeffreybehr]

I went the biamp route shortly after getting a pair of Double Kronzilla amplifiers.  These use the large T1610 tubes.  I had been using a pair of Spectron Musician III MkII monoblock amps.  Comparing the two showed that the Kronzilla was definitely superior on the mid/tweeter module, but didn't have the iron-fisted control of the Spectrons on the bass module.  These two physically separate modules on my VSA VR5-Anniversary speakers have separate inputs designed for biwiring or biamping.  I'm running the Krons on the top and the Spectrons on the bottom with excellent results.  I've found no problems (to my surprise) with these totally different types of amps blending.  I haven't put anything in the signal path in the way of high-pass or low-pass filtering since the internal crossovers in the speakers are still engaged.

kernel, I'm surprised there isn't a gain-matching problem between the 2 different amps.  What are their input sensitivities?

[kernelbob]

Hi Jeffrey,
Yes the Spectrons have higher gain than the Krons, enough so that I use an attenuator inline with the input to the Spectrons.  I have a two sets of outputs on my ARC REF3, so I can run one set to the Kronzillas without mucking up the SET top end with additional attenuators.  Attenuators on the bass don't seem to have significant impact on the quality of the bass and with a damping factor of around 500 on the Spectrons, the amps really keep a grip on the magnesium woofers while the SET top end does its amazing dance.

[jeffreybehr]

Hi Jeffrey,
Yes the Spectrons have higher gain than the Krons, enough so that I use an attenuator inline with the input to the Spectrons.  I have a two sets of outputs on my ARC REF3, so I can run one set to the Kronzillas without mucking up the SET top end with additional attenuators.

Sounds good to me, and you're fortunate to have found an existing inline attentuator with the correct amount of attenuation.  I experimented with different series resistors to lower the gains of my amps.  I also added pots to the HF amps to be able to make over-bright recordings more listenable.