Is Bi - amping worth the trouble?

If you can run Solid state on the bottom with LEVEL controls, which many do not unless running a pro audio amp than you will have difficulty matching up gain with a tube amp on top.. YES there are still benefits of running 2 of the same amps in a verticle bi-amp config, this is because you will still have dedicated Current running to just the bass drivers not sharing it with the upper end. However it can be as explained here to some more accurate degree very little advance, unless it is just the right amp speaker combo it could be substantial even in a passive crossover system. The VK 500 you have in question is a Dual mono with dedicated power supplys to each channel I believe, so Having 4 Dedicated transformers, with Hi current and Higher Capacitance per channel can be better even with the same 2 amps... Also, I totally agree that DO NOT bridge and expect better results, the Verticle bi-amping with 4 channels should prove to sound better anyway, but you could experiment both ways if you have the amps that can bridge in the first place.

Sweet jumpin' jellyfish! ...and all I thought I was going to need was another amp and a couple wires! Oh. My. God... or Gosh! for the more reserved among us.

I mean, really. that's a bunch. Can't just come out of the preamp to the X over and then to the amps and use the X over in the speakers, huh? Super. Just super. More than two amps just ain't happening sportsfans. Nope! Sorry. I'd not trust myself these days to do any fine electronical work. that's over with... I have the know how. I have the technology. but I can't rebuild the six million dollar man, eh, speaker.

If removing X overs in the speakers, is a 'MUST DO' with either method, passive, or active, I'd need farm that out.... and if THAT entailed more amps... well, see previous paragraph.

..and we're back to the "Is it worth the trouble?", thingy, once more. Sure sounds like a lot of trouble to me. Unless I can add another pair of ICs... another amp... maybe make a move in changing out my speaker cables... then I'll have to cry "Uncle!"... it's just beyond me... I'd even go so far as to add another device like an outboard X over... the consequential wires it would dictate, but then you all said that would mean gutting the present X overs in the speakers... and doing each driver in and of itself... Whoa Nelly! Sorry kids. That dog won't hunt. Unless!? well, there's that redneck retirement we got down here each week.... maybe then.

What an 'eye opener'. For real. Guess times and technology have changed greatly. I remember this aspiration as being far simpler. To wit, my aforementioned, and succintly now debunked plan. Well if two amps do wind up somehow driving my speakers, then super! If not, getting a tube abp will happen. Till then, I'm disappointed. yet in all glad to know the truth of things up front. The purist approach is out almost entirely. Gone. We'll see just how slam bang a tube amp I can come up with first... then refer to these notes one more time.

Now, you're beginning to get it.

So back to your origional question: Is it worth it?

I had a pair of power pigs and an old 100 wpc amp. It was a very strong 100 watts though but I auditioned another pair of monoblocks that were much more refined and had great imaging. Unfortunately the monoblocks didn't have nearly the bass depth and slam. No problem, just use all the amps, right?

The good part was that the bass crossover was at 90 Hz. If it was any higher, it would be more difficult because the hearing is more sensitive in the midbass.

Still, not that simple. First, the old amp was inverting. Easy fix; reverse speaker wires to bass. Then the gains didn't match so I went down to the doohicky shop and bought a 5 KOhm carbon potentiometer, a box and some female RCA's. Wired that up and twiddled for weeks. It was better but not quite right. Every time I changed the volume, I had to adjust the gain. Every CD had to dialed in. Even then, it always seemed bloated around the crossover point. Went back for a different doohicky. This time, it was a wire-wound pot. No better. Another thing that happens with multiple amps is ground loops and hum. Just another part of the learning experience.

Started looking at active crossovers and what would be involved. They ain't cheap. While I knew the crossover point, I could not find the slope of the passives in the speaker. Considering that each order (1st, 2nd...) adds 90 degrees of phase and and the speakers were designed to be coherent at one of those, I thought I should know. Turns out that wasn't relevant because active X-overs have a choice between 24dB/octave and 48(8th order). I also started to learn something about notch filters that I could not account for. In the speaker, the x-over was soldered on a circuit board. This seemed like brain surgery at the time and I could have ended up with a pile of parts. Now, with a bit more knowledge, these aren't simple problems but nothing insurmountable.

There was one other alternative, or so I thought. I bought a dual, 23 position rotary switch (attenuator) and a bag of resistors. This ain't cheap either and it certainly wasn't easy but Mr. Doohicky was happy.. Soldering 46 tiny resitors on a tiny switch is not fun. The ones that can be bought preassembled had a higher range than I needed. I chose all the resistors between 1K and 3K and added a DPDT switch that added another 3K (paralleled 6K), 6K or nada. Much better. No more fiddling with it, at least not after the first month, and no bloating. It also gave a great way to adjust the bass to my tastes. The DPDT switch turned out to be unnecessary.

Granted, an active would have killed that passive parasite and made the speaker much more efficient, I still have to wonder. I was planning on building a set of speakers from the ground up with an active x-over, because I'm convinced that's the best, but a sweet deal popped up.

The next set of speakers had an active x-over/bass amp from the factory. Well, semi-active, but let's not go there. It has controls for gain, low-pass, hi-pass and phase. Hooked it up with those little monoblocks because I didn't exxpect the midbass and up to take much power. Lots of trial and error with the settings and location. Changed from RCA to XLR. Different preamps, even built one myself. Learned that phase is more than quarter turns (90 degrees) and could hear within 10 to 15 degrees on either side and went for the middle.

No matter what I did, there was a dip at the crossover until a friend brought over his behemoth SS amp and the dip went away. I also tried with tube amps but not my taste. You could say the little monoblocks was a mismatch of character. The 1600 watt bass amp had a lot more. I was expecting to buy a new amp for the speakers but not quite so soon. Now, I've got three behemoths and it all worked out beautifully. By the way, bridging does work for some amps.

If you want to know see how complex it can be to make a versatile x-over, check out Wisdom's "Brain".

Did you expect a short story?

I am sorry Blindjim to scare you like this, but this is what it means when somebody talks about using an active Xover to change slopes or Xover points, and bipassing the speakers XOver.

Like I said on my first post:
Just use the Xover in your speakers, they were designed with them and you should keep them, just add a tubed amp in the mids and highs, and an SS on the bottom, use a passive preamp like the EVS attenuators or the Luminous Audio preamp on the bass amp and let the tubed amp run free. The speaker xover will allow your speakers to do their job properly.

I recommended a passive attenuator to match the gain on both amps, it is always best to "loose" some definition on the bass than on the mids, that is why the volume should be adjusted on the SS amp. To add an active stage (active XO) just for this would take away from the signal, because of this Marchand Electronics made a Bass Correction EQ :
http://www.marchandelec.com/wm8.html
Which is like an Active Xover for bass only, adding some other niceties... and leaving the mid and high source as pure as possible.

"I can add another pair of ICs... another amp... maybe make a move in changing out my speaker cables"

That is all it takes!

"I'd even go so far as to add another device like an outboard X over"

This would be good also, I would use the bass correction thingy for "bass" and a passive line level XO for the only other amp: the tube amp.

If you love this too much, in a couple of years you will be gutting your speakers to tear away the original Xover and hard wire....and maybe not, I wouldnt do it....I would get horns for that!!!

All the Best!

Ngjockey

“Did you expect a short story?”

uh, well, yeah, I did. At the onset. Not now, however.
Man! That’s a lot of doing… we can nix the soldering business right off.. I’m a plug and play sort these days… though not by choice. Thanks much.

Jsadurni
“I am sorry Blindjim to scare you like this, but this is what it means when somebody talks about using an active Xover to change slopes or Xover points, and bipassing the speakers XOver.”

…it will take a mite more than this info to scare me off… far more, for I’ve faced far worse.

“use a passive preamp like the EVS attenuators or the Luminous Audio preamp on the bass amp and let the tubed amp run free. The speaker xover will allow your speakers to do their job properly.”

…. So simply attenuate the bottom amp with one of these items? So come out of the preamp to “IT” AND then to the amp? OK… a gizmo and two more sets of ics…. Yikes! Though that’s the cheapest path thus far … I think.

“If you love this too much, in a couple of years you will be gutting your speakers to tear away the original Xover and hard wire....and maybe not, I wouldnt do it....I would get horns for that!!!”

…not bloody likely. Were I to survive this endeavor, you can stick a fork in me. . .. I’m done. Well save the tube rolling, isoing, and PCing…. And extra riders on the home owners.

I just got off the phone w/BAT. Had a short little chat with VK. He uses a lot of words like perhaps, maybe, it’s possible, and so forth…. Yet he is inclined to think my now ‘semi’ debunked (there’s been a spurious post mortem resurrection, albeit short lived or no), plan should either be a safe & secure one that remains bright and shiny still, or ‘perhaps’ not. Still in all, he did say just what you did apart from the passive X over makers name…. he seemed to think or indicated that an ‘inline’ (one for each outgoing IC to the SS amp), was available. Plug & play! But no idea of who made them… but thereby just pluggin into the preamp, and moving the dial… IF things weren’t homogenous. He also cast his vote for the VK 75/75SE, along the way. Naturally. I am inclined to go with BAT up top… or a VAC, or…, we’ll see., but at least 60wpc or above.

He also indicated some degree of flexibility with the use of the various speaker taps on the amp as some accommodation… but did say it would affect more than the ‘matching’ aspect, and affect the sonics to some degree.

Any hesitation I uttered was only due to expense. Not involvement. Given things always work out just the way they are supposed to…. One way or the other… I still remain 100% undaunted (almost). You might even say “I am entrenched with my upcoming effort to bi-amp”. I wouldn’t but you might.

Is there such a thing as an inline attenuator like what VK said? If so, are they worth having?

I remain deeply grateful for any and all input/experiences provided me and others herein…. Really.
Many thanks.